L

O

B

A

L

A

N

A

L

Y

T

I

C

A

L

S

O

L

U

T

I

O

N

S

News from GERSTEL GmbH & Co. KG · Eberhard-Gerstel-Platz 1 · 45473 Mülheim an der Ruhr · Germany · Phone + 49 (0) 2 08 - 7 65 03-0 · gerstel@gerstel.com
No. 15

Automatedsample preparation

Don’t WorkDay and Night!
The MPS handles
the night shift p. 16

Material Characterization
Medical Implants –A Product Quality Check p. 4

Metabolomics (part 1)
Automated Extraction andFiltration on the MPS Dual
Head WorkStation p. 22

Forensic Toxicology
Automated Determination of Opioids, Cocaine and Metabolites inBlood and other Matrices p. 13

Water Analysis
Clean and Sensitive: On-line
SPE-LC/MS Determination of
Pesticides p. 19

ISSN 1619 - 0076

www.gerstel.com

GDear Reader,

GERSTEL Solutions worldwide 15
Contents

Further information on applications, news, workshops and events can be found on our website underwww.gerstel.com where you can also sign up for the
GERSTEL Newsletter. More content is listed on the righthand side of this page and a preview of articles in thenext GERSTEL Solutions Worldwide Magazine (No. 16)
is offered on the back cover. We hope that the selected
topics are of interest to you and that you will enjoy reading the magazine.
Yours sincerely,
GERSTEL management.

Sequential dynamic headspace sampling of brewed coffee
and other beverages provides more information in a single
GC/MS run. ............................................................................................. 3
Extractables & Leachables

Medical Implants – A Closer Look

In order to assess the quality and compatibility of a polymer
based implant, simulated in-vivo studies are performed todetermine leachable compounds from the device. ................. 4
Stir Bar Sorptive Extraction (SBSE)A Fully Established Technique
Stir Bar Sorptive Extraction (SBSE) based on the patented
GERSTEL Twister is a fully established solvent-free
extraction and concentration technique. ................................................ 7
Beverage Flavor Analysis

Focusing on Taste and Flavor
Using SBSE, the analysis of flavors and off flavors can be combined.
If a high-end GC/MS system is used, the amount of information
gained is significantly increased. ..............................................................9
Forensic Toxicology

Efficiently Automated Drug Analysis
Comprehensive automation of SPE-GC/MS based analysisof serum and other matrices for opioids, cocaine andmetabolites. ...........................................................................................13
L

O

B

A

L

Inside the Laboratories of
Schülke & Mayr GmbH

The MPS does
the Night ShiftNews from
No. 15GERSTELGmbH &

Co. KG ·A

NA

Eberhard-GerstelPlatz 1 ·

L

Y

T

45473 Mülheim

I

C

A

an der Ruhr

L

· Germany

S

O

L

U

T

I

O

N

S

- 0076G· Phone +49 (0) 2 08

Automated
Sample Prep
aration- 7 65 03-0

· gerstel@gerstel.com

ISSN 1619

Ralf Bremer

Although it seems like yesterday, the GERSTELTwister was introduced in 2000 and we are celebrating our 15th anniversary with stir bar sorptive extraction(SBSE). In recognition of this important milestone, thisissue will feature a number of articles on the technique.
The inventor, Professor Pat Sandra from the Research Institute for Chromatography (RIC) in Belgium has provided
a guest editorial with insights to the recent SBSE Technical
Meeting in Paris, which hosted experts from all over theworld. Other Twister articles include the determination of
Leachables from whole medical implants and using themulti-SBSE technique to achieve good recovery of a widepolarity range of flavor volatiles in beverages.

Tracking the Whole Range of Flavor Compounds

l.com

Holger Gerstel

The degree of automation in the laboratory was increased based on the GERSTEL MultiPurpose Sampler(MPS), of which to date, over 5000 have been installedin laboratories worldwide. Whoever invests in automating
GC/MS or LC/MS analysis based on the MPS gets sample
preparation work done reliably and efficiently – any time,
day or night. Individual requirements are easily incorporated into the workflow, often significantly reducing solvent
usage, and no one has to watch over the instrument. This iswhat we would refer to as an intelligent productivity boost.
And why did Schülke & Mayr decide to go for the MPS?
Hint: Our automated weighing option played a key role.
You can find more information in the article on page 16.

Flavor Analysis

www.gerste

Eberhard G. Gerstel

Did you ever consider adding a second or third shift inyour laboratory to keep up with the workload? In manyorganizations around the world, the laboratory workload isincreasing and at the same time results must be delivered
ever faster to keep up with production and on-time shipping requirements. The analytical laboratories of the pharmaceutical company Schülke & Mayr near Hamburg, Germany were faced with these same increasing demands
and management considered all possibilities to solve theproblem, including adding a night shift. In the end, a more
attractive solution for laboratory staff was found:Don’t work
day and nig
ht!

The MPS han
dles
the night shift p. 14Analytical Quality Control(QC) of pharmaceuticalproducts follows a strict
set of guidelines. .................................................................................16.................................................................................
Material charac

Medical Implants terization
Quality Check – A Productp. 4

Water Analysis

Metabolomics PartAutomated
Extraction andFiltration on
Head WorkStathe MPS Dualtion p. 18

Forensic Toxicol

Automated determina ogy
tion of
Cocaine andmeta-bolites in opioids,
other matrices
blood andp. 20

Water Analys
isClean andSensitive: On-line
SPE-LC/MS
determination
Pesticides p.
of28

Clean and Sensitive Determination of Pesticides
Online SPE sample clean-up based on replaceable cartridges
provides higher sensitivity and lower limits of detection –without the risk of carry-over. ..........................................................19
Metabolomics

Automated Sample Preparation Using the
GERSTEL MPS Dual Head WorkStation
Part 1: Automated Ultrasonic Assisted Liquid Extraction
and Filtration. ........................................................................................ 22

Preview......................................................................................24
Imprint .......................................................................................24

A peek into the future of manufacturing?
3D printed MultiPurpose Sampler (MPS)model in celebration of 5000 units sold.

Flavor Analysis

Tracking the Whole Range of Flavor Compounds
Sequential dynamic headspace sampling of brewed coffee and other beverages provides more
information in a single GC/MS run.

Aroma profiles oftem using a highly flexbrewed coffee andible MultiPurpose Sampler
other beverages are(MPS). The flexibility ofcomposed of a wide
the system allows different
range of compounds,
adsorbent traps to be used.
representing a mulThis enables the extractitude of compoundtion and trapping of moreclasses. These span notvolatile compounds in a
only a wide volatility
traditional DHS step priorrange, but also a wide
to the FEDHS extracsolubility range in aquetion step. A novel multious solution. Until now,
volatile method (MVM)
it has been extremely
was developed based on
difficult to combine
sequential DHS samplingand determine all these(and desorption) using acompounds in a single
variety of trapping condiGC/MS run with adtions for the determination
equate recoveries andof a wide range of aroma
useful results for allcompounds in aqueouscompound classes. In
samples. The MVM meththe following, an overod consists of three differview is given of theent DHS sampling steps
Multi-Volatile Method
including a final FEDHS(MVM), developed by Flavor analytes are extracted from the sample in three separate DHS steps and the analytes concentrated on threestep. The DHS parameters
separate TDU liners packed with different adsorbents. The three TDU liners are desorbed separately and the analytes
GERSTEL application are concentrated in the CIS inlet. When the CIS is heated, the analytes are transferred simultaneously to the GC/MS
were examined with theexperts, which relies on and determined in one run.
model aroma compounds
a new analyte concenspiked in 100 µL of water.
tration technique andFeasibility and benefits ofautomated sample preparation to overcomeof aroma compounds from several sample
using the MVM method is demonstrated
the problems of determining all compounds
types [1]. FEDHS of 10-100 µL of sample
through the determination of key odor comfrom beverages in a single GC/MS run.
at 80 ºC using a valve-less short-path DHS
pounds in brewed coffee [2].
Headspace gas chromatography (HSsystem, enables near complete vaporizationGC) is frequently used for flavor analysis
and uniform recovery of aroma compounds,
due to the volatility of flavor compounds.
while largely eliminating non-volatile maFor more information
Several established HS techniques are availtrix. However, the FEDHS method often[1] Flavor and Fragrance Analysis of Consumer
able, for example, static headspace (SHS),
requires a large purge volume in order to
Products – Dynamic Headspace Compared to
dynamic headspace (DHS),
remove water from the adsorbent trap. This
Some Traditional Analysis Approaches, GERand headspace using solid
can lead to loss of volatile compounds due
STEL AppNote 06/2012: www.gerstel.com/
phase microextraction (HSto breakthrough in the adsorbent trap durpdf/p-gc-an-2012-06.pdf
SPME). However, in terms
ing the purge step. The loss of volatile com[2] Multi-volatile method (MVM) for aroma analyof analyte recovery, thesepounds can be overcome by using replaceable
sis using sequential dynamic headspace sampling with an application to brewed coffee,
techniques tend to discrimiadsorbent traps for analyte concentration,
Jun Tsunokawa, Nobuo Ochiai, Kikuo Sasanate in favor of more volatile and/or hydroenabling sequential sampling from the same
moto, Andreas Hoffmann. Journal of Chrophobic compounds. Recently, a full evapoHS vial under different trapping conditions.
matography A, 1371 (2014) 65–73. Free
ration DHS (FEDHS) method, based on aThis method is made practical through the
Download: www.sciencedirect.com/science/classical full evaporation technique (FET)
use of a completely automated GERSTEL
article/pii/S0021967314016859
was demonstrated for uniform enrichment
DHS system mounted on a GC/MS sys-

GERSTEL Solutions worldwide – No. 153Extractables & Leachables

Medical Implants – A closer look
In order to assess the quality and compatibility of a polymer based implant, it is vital to perform simulated
in-vivo studies to provide qualitive and quantitive information concerning the compounds that are leached
out of the device. These compounds are referred to as Leachables. Since they are present at very low
concentrations, analysts often turn to Stir Bar Sorptive Extraction (SBSE) followed by Thermal Desorption
GC-MS/MS for an accurate answer. In the following, we report on a joint effort to test polymer based
tibial knee inserts for Leachables.

A look inside: Implants at work

4

GERSTEL Solutions worldwide – No. 15

PDMS or EG-Silicone Coating
Magnetic Core
Glass

P

harmaceutical products in general
should serve to maintain the health ofthe patient. Under no circumstances should
they endanger or adversely impact the patient’s health. Manufacturers are required toperform extensive testing on pharmaceutical products, including the packaging used,over an extended period during the development phase and regularly once it has been
approved and is in production. If unallowed
Leachables from the packaging are found, orif they are found in too high concentrationsin the product, it will not be approved, forexample, by the US FDA, which means it
cannot be sold in the US.
In simulated “worst case” scenarios, Extractables studies are performed on complete, undamaged packaging and the extracted chemical compounds determined.
The packaging is exposed to solvents of different polarities at elevated temperature to
extract a wide range of compounds. Thosecompounds identified as potentially hazardous that could leach into the product arethen studied further in formalized Leachables studies based on the actual product using validated methods [1].

Author: Guido Deussing

Image/s: GERSTEL, Istockphoto

Implants must be safe as wellImplants are generally made of both metaland polymer materials and they must be
analyzed for the presence of contaminants.
Further, it should be studied whether additional contaminants could be formed while
the product is inside the patient (in vivo),
endangering the health of the patient. Up
until now, manufacturers of medical implants have not had an easy way to perform
such analyses on medical device implants.
However, since implants remain inside thebody for an extended period of time in direct contact with body fluids, these analyses
are even more important. Leached contaminants from implants can gain direct access tothe patient’s blood, unlike most pharmaceuticals, which are ingested orally and have togo through the digestive tract.
Unlike the situation for pharmaceuticalproducts, until now there are no legally binding regulations for implants and prosthetics,
or indeed any standardized methods for performing Extractables or Leachables studies
according to Gyorgy Vas. For this reason,

GERSTEL Solutions worldwide – No. 15®

The patented GERSTEL Twister serves as extraction medium based on the Stirthe researcher who works
Bar Sorptive Extraction (SBSE) technique. The Twister is coated with a relatively
for the US based company
large volume of sorbent, either polydimethylsiloxane (PDMS), mainly for non-polar
compounds, or Ethyleneglycol silicone (EG Silicone Twister), which provides
Intertek, followed regulaenhanced extraction of various polar compounds in addition to non-polar comtions for performing E&L
pounds. Analyte extraction is performed while the Twister stirs the sample or, in
studies on pharmaceuticalthe case of the Twicester, with one Twister immersed in the sample, but held inplace on the vial wall, while another Twister stirs the sample.
packaging when describing
the leaching properties of
implants. They further adDuring this process, the mechanical properhered to guidelines of the „Product Quality
ties of the polymer are improved, but freeResearch Institute” (PQRI), a US non-profit
radicals are formed, which can attack theorganization, which recommends a Maximaterial and negatively impact its chemimum dose for genotoxic or carcinogenic
cal and mechanical long term stability. To
leachables of 150 ng/day [2].
prevent oxidation processes in the material
and improve product stability, an antioxiNot identical but comparable
dant is added, such as pentaerythritol tetraIn its guidelines, the PQRI refers to results
obtained from testing of inhaler products.
As Gyorgy Vas and his colleagues reportin their article in Journal of Pharmaceuticaland Biomedical Analysis [3], they based theirstudies on the PQRI guidelines, which represent a more “conservative” approach inthe sense of erring on the side of caution inorder to ensure the greatest possible safety
for the patient. The researchers report how
they determined leachable compounds inmedical implants, in this case tibial knee inserts, based on Stir Bar Sorptive Extraction(SBSE) followed by GC/MS analysis. The
goal of their study was to develop
a systematic procedure, by whichantioxidant-related leachables
can be determined accurately. These are formed
in knee implants duringsterilization with gamma
radiation.

Of Additives andGuidelines
The tibial knee inserts that were
investigated by Vas et al. are produced
from ultra-high molecular weight polyethylene (UHMWPE). After the molding
process, these are cross-linked and sterilizedusing a very high dose of gamma radiation.

Twisters are desorbed in the Thermal Desorption Unit
(TDU) shown in this picture or in the Thermal Desorption System (TDS). The process is automated.

Stir Bar Sorptive Extraction using the GERSTELTwister is followed by thermal desorption in the
Thermal Desorption Unit (TDU), cryofocusing,and GC/MS analysis – fully automated using the
GERSTEL MultiPurpose Sampler (MPS) under
MAESTRO control.

kis (3-[3,5-di-tert-butyl-4-hydroxyphenyl]
propionate). The purpose of adding thiscompound known as PBHP is to remove
free radicals, prevent oxidation processes
and improve the long-term stability of the
product. However, PBHP can degrade andthe degradation products formed leach fromthe implant into the surrounding tissue. A
total of 16 such PBHP degradation and byproducts have been identified in simulated
in-vivo experiments with knee implants thatwere between ten and thirty years old. Because of these findings, the researchers stressthat implants need to be tested for leachables. Studying the leaching behavior oflarger implants, however, requires large volumes of aqueous simulants. This results inthe extracted analytes being present at very
low levels. As reported by Vas et al., a concentration step is required prior to GC/MSor LC/MS determination in order to enable
quantification as per the PQRI guidelines.
Typically, such a concentration step would
be time consuming and would require highly pure organic solvent. These factors makethe whole process expensive, challenging,and environmentally unfriendly.

Turning to Stir Bar Sorptive
Extraction (SBSE)
Evaporative concentration of organic solvent extracts inevitably leads to loss of volatile analytes. Additionally, a solvent peaktypically masks peaks of interest in thechromatogram and a solvent could easily
introduce interfering compounds leading
to errors and uncertainty. Stir Bar Sorptive Extraction (SBSE), on the other hand,relies on the GERSTEL Twister to extractorganic compounds from an aqueous solution with high recovery without any use ofsolvent.
Following an extensive evaluation ofvarious widely used methods, Dr. Vas andhis team decided to use SBSE and the
PDMS Twister as extraction medium combined with GC/MS analysis. The Twister
extracts and concentrates analytes in a single step, no further sample preparation is6

required before GC/MS analysis. Thanks to
the large PDMS sorbent volume and the efficient stirring of the sample by the Twisterstir bar, analyte recovery is far higher thanwhat is achieved with Solid Phase MicroExtraction (SPME). In the words of Vas etal.: ”Case-by-case, we have found SBSE tobe significantly more sensitive than SPME
for the determination of organic compounds
in aqueous matrices”.

Technical details
This is how the scientists approached the
project: Whole implants were immersed in
500 mL of an aqueous extraction solution(90:10 water/acetone). Extraction times of
24 hours and 30 days were used. The resulting extract was stirred with a Twister for
two hours at 1,000 rpm, during which time
the organic compounds in the extract solution were absorbed into the PDMS coatingof the Twister. The Twisters were collectedfrom the aqueous extract, briefly rinsed with
deionized (DI) water, dried using a lint-free
paper cloth, placed in a TDU liner, and transferred to a TDU liner tray. The next step wasthermal desorption in the Thermal Desorption Unit (TDU), fully automated with the
GERSTEL MultiPurpose Sampler (MPS).
The desorbed analytes were cryogenicallytrapped in the GERSTEL Cooled Injection
System (CIS), a PTV-type inlet, mounted
in an Agilent 7890 GC (Agilent Technologies). Analytes were determined using an
Agilent Triple Quad MS/MS detector. As
an aside, three different sources of DI water
were tested. All had detectable backgroundconcentrations of antioxidants. Monitoring
and controlling the blank level, and choosing the right DI water source, is clearly very
important in order to obtain accurate results
at these low concentration levels.

End of a successful study
The SBSE-GC-MS/MS method developed
and validated by Vas et al. enabled them todetermine Leachables in medical implants
at trace level concentrations equivalent toleaching rates below 150 ng/day. The scientists reported that no genotoxic or carcinogenic compounds were determined to leachfrom the tested implants at rates higher
than 150 ng/day in the 24 hour extraction
tests. For the PHBP degradation products,
the linearity of the developed method wastested over the 1–150 ng range (equivalent
to 40–6000 pg/mL) for all relevant components. Calibration curves with internal
standard were prepared using the extraction
media as the matrix. The linear range foreach component was 1.0–150 ng with good
RSDs and the method was subsequently
used to analyze eleven tibial knee implants.
Unlike other methods, which can only analyze fragments, the developed method cananalyze the entire implant, which is the approach preferred by regulatory authorities toeliminate sampling errors, according to Dr.
Vas. Most of the sample preparation was
automated; only minor manual steps wereneeded. The method had the added benefitof eliminating the use of expensive, toxic
solvents that are also expensive to dispose of
and which can negatively impact the laboratory air quality.

References[1] GERSTEL Solutions No. 10 (2010) 20-22[2] Summary of the PQRI Leachables andExtractables Reconnedations (www.pqri.org/
workshops/leach_ext/imagespdfs/posters/
PQRI_Recommendations_Poster.pdf)[3] J. Pharm. Biomed. Anal. 74 (2013) 62-70

Extractables and Leachables
In the case of pharmaceutical packaging,
Leachables and Extractables studies are requiredin order to determine if packaging will leach contaminants into the product under normal storage
conditions or if contaminants can be extracted by
the product under well-defined more aggressive
conditions.

GERSTEL Solutions worldwide – No. 15

Stir Bar Sorptive Extraction (SBSE)

Established, Useful and Quite Often
Simply the Extraction Technique of Choice
Stir Bar Sorptive Extraction (SBSE), based on the patented GERSTEL Twister, is a fully established techniquein the world of chromatography. Quite often, SBSE is simply the method of choice. Professor Pat Sandra,
SBSE inventor and founder of the Research Institute for Chromatography in Kortrijk, Belgium, casts somelight on the beginnings of SBSE, the current status and what the future may hold.
By Professor Pat Sandra,
founder of the Research Institute for Chromatography (RIC), Kortrijk, Belgium

tir bar sorptive extraction
was simply to have a good scien(SBSE) was developed as atific outcome of this work. With
reaction to a negative comment
approximately 1000 citations inon one of our publications related
the literature that hope has certo the partitioning mechanism
tainly been realized. However,occurring between polydimethylGERSTEL showed strong intersiloxane (PDMS) and water [1].
est in the technique and commerTheoretically, absorption (sorpcialized SBSE under the nametion) and not adsorption is tak“Twister®”. Thanks to this move,ing place but this was obscured
the great potential of the techby adsorption of polychlorinatednique has been shown over andbiphenyls (PCBs) on a PTFE
over again.
stir bar. Coating the stir bar withProfessor Pat Sandra The Inventor of SBSE, Professor
PDMS resulted in 100 % abEmeritus Pat J. Sandra received his Master‘s degree in Organic Chemistry in
The benefits of thesorption of the PCBs proving
1969 followed by a Ph.D. degree in Analytical Chemistry in 1975 from theTwister technology
Ghent University, Belgium. He joined the Faculty of Sciences of the Ghent
the partitioning mechanism andUniversity in 1976 as Assistant Professor and was promoted to Full ProfesThe main features and advanthe relation with the octanol/
sor of Separation Sciences in 1988. In 1986 he founded the Researchtages of the SBSE technique arewater distribution coefficient.
Institute for Chromatography in Belgium, a center of excellence for researchthat it is a green sample preparaSBSE was introduced in 1999
and education in chromatography, mass spectrometry and capillary election technique; analyte recovery
as a solvent-less sample preparatrophoresis. He was Co-founder of the Pfizer Analytical Research Centeris predictable and can be calcution technique combined with
(PARC) that he directed during the period 2003-2011. During this time
he has authored or co-authored over 500 scientific publications. Amonglated from the log P value; very
thermal desorption coupled onnumerous awards are the ACS Chromatography Award (2005) and Doctor
low detection limits (ppq’s haveline to capillary GC. It immediHonoris Causa degrees in Pharmaceutical Sciences, in Food Safety and in
been mentioned e.g. for organoately became clear that this new
Chemical Engineering. In 2013, he was appointed member of the Researchtin compounds) can be reachedmethod offered unprecedented
Council of President Barroso of the EU commission.
as well as excellent reproducibilsensitivity for compounds with
ity; different in-situ derivatizationa log P value larger than 3. For
methods are available, broadening
compounds with log P < 3, several
in-situ derivatization methods were developed to cope with more the technique to compounds with low log P values and at the samepolar compounds in different matrices e.g. food, beverages, biological time, improving chromatographic performance; a wide variety of mafluids, etc. SBSE combined with liquid desorption was the next step trices can be handled; and further clean-up steps are not needed (asin its development opening the combination of SBSE with liquid opposed to other recently introduced sample preparation techniques).
chromatography and the electrically-driven separation methods. Ini- Moreover, the method is cost efficient since the Twisters can be retially SBSE was mostly used for the extraction of compounds from used many times. More recently, GERSTEL has developed an adaqueous matrices. The technique has also been applied in headspace ditional coating: Ethylene glycol – silicone (EG-Silicone) Twisters
mode for liquid and solid samples and in passive air sampling mode. have become available, leading to high recovery extraction of speInitially it was not our intention to commercialize SBSE – our hope cific solutes in a wide variety of matrices (beverages, biological flu-S

GERSTEL Solutions worldwide – No. 15

7Impressions from the
SBSE technical meeting:Stimulating discussions
about applications,trends, and possibilities
of SBSE.

ids, etc.). Any new analytical method needs
high visibility to become successful. GERSTEL considered the Twister an importantdevelopment and marketed the productaccordingly. Soon after its commercialization, David Benanou from Veolia Water inParis demonstrated the enormous potentialof the Twister for detection of off-odors indrinking water and became one of the first
proponents of the technique. Moreover,through his organization, he introduced thetechnique in several laboratories worldwide.
He organized the first SBSE symposiumin Paris in 2011 and decided to make thisa biennial event. This year we had the third
SBSE Technical Meeting with a strong
international presence including speakers
from laboratories in France, Belgium, theUS, Japan, the Slovak Republic, the Czech
Republic and Italy. This symposium series
has definitely contributid to the spread of
the Twister technology. In the past, one of
the comments often heard about the Twister
was: “It is too sensitive; we do not like to
see all those compounds at ultra-trace levels.” However, in recent years environmental concerns have increased tremendously,
reducing the maximum allowable levels of
several contaminants to extremely low values (ppq’s for organotin compounds in water
samples, zero tolerance of pesticides in baby
food, etc.). The application of techniques
like SBSE with its extreme power of concentration, will become mandatory to ensure
the required accuracy and precision at theselevels. Also, new analytical challenges are
emerging for which Twister technology canbe extremely useful. To mention a few examples: domestic passive sampling to elucidate
endocrine disrupting chemicals, detection ofallergens in cosmetic products, detection of
toxic substances in shipping containers, release of chemical products from packaging
materials, etc. Also, new Twister coatings
can be developed for untargeted or targeted
analysis. A polymer based on ionic liquids
can be the next candidate for coating that
small stir bar. The Twister technology isdefinitely on the move!
Literature[1] E. Baltussen et al., Study into the Equilibrium Mechanism between Water andPoly(dimethylsiloxane) for Very Apolar Solutes:
Adsorption or Sorption? Analytical Chemistry
10 (1999) 71(22). DOI: 10.1021/ac990313g

8

SBSE Technical
Meeting organizer
David Benanou
poses a question.

SBSE methodology wasactively discussed insmaller groups during
session breaks.

It is always worth
listening to experienced
users. GERSTEL Marketing
Manager Kaj Petersen inconversation with Naïke
Noyon, Research Engineer
from CIRSEE, SUEZ
environnement’s main
Research and Expertise
Centre near Paris. Mr.
Noyon presented his workon interaction of disinfectants with polymer pipes at
the SBSE conference.

GERSTEL Solutions worldwide – No. 15

Figure 1: Multi-SBSE (mSBSE) procedure.

Beverage Analysis

The Twister Sisters pick up
the Flavors
By utilizing Multi-SBSE and SBSE with in-situ derivatization, you can determine non-target analytes acrossa wide polarity range as well as target off-flavors and key flavor compounds. If a high-end GC/MS system
is used, the amount of information gained is significantly increased
By Nobuo Ochiai, GERSTEL K.K., Tokyo, JapanS

tir bar sorptive extraction (SBSE) has
been successfully applied to food analysis including aroma analysis. For aroma
analysis, SBSE has been applied to various
sample matrices, such as water, beverages,
fruits, herbs, plant material, essential oils,
and vinegar [1–3]. These applications havebeen mostly performed using polydimethylsiloxane (PDMS) coated stir bars, because
this was the only available phase for commercial stir bars (Twister®) before 2011.
SBSE recovery can be estimated if theoctanol–water distribution coefficient(Kow) of the analyte is known. Hydrophobic solutes with a high Kow can beextracted with high recovery, while hydrophilic solutes with a low Kow show
lower recovery [1]. Therefore,
SBSE using PDMS phase isgenerally more selective forhydrophobic solutes, often
resulting in a partial chromato-

GERSTEL Solutions worldwide – No. 15

gram biased towards less hydrophilic solutes.
In 2011, a new Twister phase coated with
polyethyleneglycol-modified silicone (EGSilicone) on a metal mesh support was introduced and applied to various sample types
including whisky, wine, essential oils, andbrewed coffee [4, 5]. This new polar coating

showed good performance for the extractionof polar/hydrophilic solutes. A novel SBSE
procedure termed multi-SBSE (mSBSE) was
developed in 2013 [6]. mSBSE consists of the
PDMS Twister stirring at the bottom of thevial and the EG Silicone Twister attached tothe inner side wall of the vial (a magnetic clip
is used for the set-up). Compared to conventional SBSE, mSBSE provides more uniform
enrichment of a wide range of aroma compounds in aqueous medium since the two
Twister phases complement each other.
For the extraction (and analysis) of
specific hydrophilic/polar solutes, SBSEin combination with in-situ derivatization (e.g. acylation, esterification, andoximation) can also be used (derivat-SBSE). For polar/hydrophilicsolutes with low Kow values, thecorresponding derivatives generally have higher Kow values, resulting in higher recovery and

9Figure 2: Comparison of recovery for test
aroma compounds between single SBSE
and mSBSE.

sensitivity [1]. Also, the higher molecularweights of derivatives provides higher selectivity in GC-MS analysis.
In this paper two SBSE approaches,m
SBSE and derivat-SBSE will be describedfor aroma/off-flavor analysis of beverages.
m
SBSE shows more uniform enrichment ofaroma compounds covering a wide polarity
range in roasted green tea. Also, derivatSBSE will be used to demonstrate trace
analysis of key aroma compounds and offflavors in beer.

Multi-SBSE (mSBSE) for
non-targeted analysis ofaroma compounds
Comparison of recovery between
single SBSE and mSBSE
Fig. 1 describes the multi-SBSE (mSBSE)
procedure. The extraction was performed byusing a 24 µL PDMS Twister and a 32 µL
EG Silicone Twister on a 5 mL sample after addition of 30 % NaCl. After extraction,
the Twisters were thermally desorbed in split
mode with a split ratio of 1:1 using the low
split option controlled by the pneumatic boxof the TDU system, and analyzed on a 30 m
length × 0.25 mm i.d. × 0.25 µm df DB-Wax
column using MS detection in scan mode.
Recoveries obtained by mSBSE for test
aroma compounds in water, including various types of chemical classes (e.g. alcohol,
ester, hetero-cyclic, ketone, and phenol),
were compared with those obtained by conventional single SBSE. The log Kow valuesof the test compounds were in the range of
1.34 (guaiacol) to 4.21 (β-damascenone).
The concentration of the test compounds
was 10 ng/mL each. Fig. 2 demonstrates arecovery comparison between 4 different
SBSE conditions; (a) single SBSE using the
PDMS Twister (1×), (b) single SBSE using
the EG Silicone Twister (1×), (c) mSBSE
using the PDMS Twister (1×) and the EG

10

Silicone Twister (1×), (d) mSBSE using two
PDMS Twisters (2×) and two EG Silicone
Twisters (2×) (one PDMS Twister is stirring,
while another PDMS Twister and two EG
Silicone Twisters are attached on the innerside wall of the vial). For the condition (a)single SBSE using the PDMS Twister (1×),
the solutes with log Kow > 2.5 showed morethan 80 % recoveries, while the solutes withlog Kow < 2.5 showed low recoveries, especially for guaiacol (log Kow: 1.34, recovery:
8.3 %) and phenethyl alcohol (log Kow: 1.61,
recovery: 10 %). For the condition (b) single
SBSE using the EG Silicone Twister (×1),
the solutes with log Kow > 2 showed higher

than 70 % recovery, while thesolutes with log Kow < 2 also
showed low recovery. However,compared to the condition(a), the recoveries for guaiacol (log Kow 1.34) and indole(log Kow 2.05) increased from
8.3 % to 21 %, and 29 % to71 %, respectively, while therecovery for β-damascenone(log Kow 4.21) decreased from
96 % to 74 %. Meanwhile, thecondition (c) mSBSE using the
PDMS Twister (1×) and the EG Silicone
Twister (1×) showed higher recoveries for all
test solutes except for indole (log Kow 2.05,
recovery 60 %) compared to single SBSE
approaches. Moreover, the condition (d)m
SBSE using two PDMS Twisters (2×) andtwo EG Silicone Twisters (2×), which has
the highest phase ratio, showed the highest recoveries for the solutes with log Kowof less than 2.5. Consequently, the mSBSE
approach not only combines the extraction
power of the PDMS Twister with the EG
Silicone Twister, but also results in higher
recovery due to increased phase volume(smaller phase ratio).

Figure 3: Total ion chromatogram of roasted green tea obtained from mSBSE-TD-GC-MS.
1. Furfuryl alcohol (log Kow 0.45), 2. Benzyl alcohol (log Kow 1.08), 3. Phenethyl alcohol (log Kow 1.57), 4. cis-3-Hexenol (log Kow1.61), 5. 1-Hexanol (log Kow 1.82), 6. 2,6-Dimethyl-1,3,7-octatrien-6-ol (log Kow 3.24), 7. Linalool (log Kow 3.38), 8. Geraniol (log
Kow 3.47), 9. Citronellol (log Kow 3.56), 10. Furfural (log Kow 0.83), 11. 6-Methyl-5-hepten-2-one (log Kow 2.06), 12. cis-Jasmone(log Kow 3.55), 13. Guaiacol (log Kow 1.34), 14. p-Cresol (log Kow 2.06), 15. Vinyl Guaiacol (log Kow 2.24), 16. p-Vinyl phenol (log
Kow 2.41), 17. p-Ethyl phenol (log Kow 2.55), 18. 2-Methyl pyrazine (log Kow 0.49), 19. 2,5-Dimethyl pyrazine (log Kow 1.03), 20.
2-Ethyl-5-methyl pyrazine (log Kow 1.53), 21. 5,6,7,8-Tetrahydroquinoxaline (log Kow 1.90), 22. 2-Ethyl-3,5-dimethyl pyrazine (log
Kow 2.07), 23. 2-Acetyl pyrrole (log Kow 0.56), 24. 2-Formyl pyrrole (log Kow 0.60), 25. 1-Ethyl-2-formyl pyrrole (log Kow 1.14), 26.
1-Ethyl pyrrole (log Kow 1.92), 27. Indole (log Kow 2.05), 28. 2-Methyl indole (log Kow 2.60), 29. 2-Acetyl thiazole (log Kow 0.67),
30. Coumarin (log Kow 1.51), 31. 2-Formyl thiophene (log Kow 1.53), 32. 2,4,5-Trimethyl oxazole (log Kow 1.86).

GERSTEL Solutions worldwide – No. 15

Figure 4: Comparison of thenormalized areas of some aroma
compounds between single SBSE
and mSBSE.

Analysis of roasted green tea
Aroma compounds in green tea are present
at trace level (from pg/mL to ng/mL), andtherefore analytical methods should include
powerful extraction and enrichment steps
before GC analysis. Several sample preparation techniques, e.g. liquid phase extraction,gas phase extraction/distillation, and solid
phase extraction, have been proposed for isolation and extraction of aroma compounds
in green tea. The major drawbacks are,however, large sample volumes, e.g. 3-30 L[7], and the fact that the enrichment factor(original sample amount versus final extract
volume) obtained with these techniques arerather limited and require additional evaporative concentration to a very small volume(<1 mL).
Roasted green tea (Houji-cha) was
analyzed as an example of trace analysis ofa wide variety of aroma compounds. The
Maillard reaction roasting process of Houjicha replaces the fine green and vegetative
tones of standard green tea with more complex aroma (e.g. toasty, nutty, and caramellike) [8], but those additional aroma compounds are still only present at trace level.
Fig. 3 demonstrated a total ion chromatogram (TIC) of roasted green tea obtained
from mSBSE using the PDMS Twister (1×)
and the EG Silicone Twister (1×). A variety of solutes which contribute to the aromaof roasted green tea were detected in thechromatogram from only 5 mL of sample,
including coumarin (log Kow 1.05), guaiacol (log Kow 1.34), p-cresol (log Kow 2.06),
indole (log Kow 2.05), 2-ethyl-3,5-dimethyl
pyrazine (log Kow 2.07), linalool (log Kow3.38), geraniol (log Kow 3.47), and cis-jasmone (log Kow 3.55). Most of these solutes
were determined in the range of 7.0 to 43
ng/mL with the standard addition calibration method [6].
Fig. 4 shows a comparison of the normalized areas of some aroma compounds
between single SBSE using the PDMS
Twister, single SBSE using the EG Silicone
Twister, and mSBSE using both the PDMS
Twister and the EG Silicone Twister. These
data suggest that solutes which form a hydrogen bond were mainly recovered by EG
Silicone Twister, while some heterocyclic

GERSTEL Solutions worldwide – No. 15

Figure 5: Selected ion monitoring (SIM) chromatograms of spiked beer at 500 pg/mL obtained from derivat-SBSE-TD-GC-MS.
1,1’: E-2-Octenal, 2,2’: E-2-Nonenal, 3,3’: E,E-2,4-Decadienal

solutes (2,5-dimethyl pyrazine, 2-ethyl5-methyl pyrazine, and 2,4,5-trimethyl
oxazole) were mainly recovered by PDMS
Twister.

SBSE with in-situ derivatization (derivat-SBSE) for targeted
analysis of off-flavors and key
aroma compounds
Analysis of stale flavor aldehydes in beer
Oxidatively produced unsaturated aldehydes play a major role in the development of stale-flavor in beer. E-2-Nonenalhas been considered as the major sourceof the papery/cardboard stale-flavor inbeer because of its very low odor threshold level at 0.1 ng/mL [9]. Analysis of
E-2-nonenal and similar congeners inbeer is generally rather challenging taking into account the relatively high levels of matrices (e.g. fusel alcohols, fatty
acids, and esters). A simple and effective method to decrease the interference caused by beer matrices during
both sample preparation and GC analysis is to use derivatization. E-2-nonenaland similar congeners can be enrichedand selectively detected by GC-MS
using SBSE with in-situ derivatisation(derivat-SBSE). For in-situ derivatiza-

tion,pentafluorobenzylhydroxylamine(PFBHA) was used to derivatize the targeted aldehydes (log Kow 2.57-3.33) into thecorresponding oximes (log Kow 5.36-6.13),
resulting in a highly selective and sensitive
method (LOD 21-32 pg/mL) [10]. This is
illustrated in Fig. 5 showing the analysis ofa beer sample spiked at 500 pg/mL with amixture of 3 aldehydes (E-2-octenal, E2-nonenal, and E, E-2,4-decadienal). The
extraction was performed by derivat-SBSE
using a 47 µL PDMS Twister on a 30 mL
sample (10-fold diluted with water) after
addition of 0.45 mL of PFBHA solution (10mg/mL). After extraction, the oximes were
thermally desorbed in splitless mode andanalyzed on a 30 m length × 0.25 mm i.d.
× 0.25 µm df HP-5MS column using MS
detection in selected ion monitoring (SIM)mode. The excellent sensitivity is clearly illustrated.
Analysis of tropical aroma thiols in beer
Polyfunctional thiols in food and beverages have received special attention due totheir extremely low odor threshold levels
and high sensory impact. Several thiols,e.g.
4-mercapto-4-methylpentan-2-one(4MMP), 3-mercaptohexan-1-ol (3MH),and 3-mercaptohexyl acetate (3MHA), arewell known for their contributions to the11fruity/citrus/tropical aroma. For strongly
hopped beer, the odor threshold levels are in
the low ng/L range [11], and consequently
very sensitive and selective methods areneeded. A derivat-SBSE method was developed for these thiols by Ochiai et al. [12] using a 24 µL PDMS Twister and the simple
ester of propiolic acid as derivatization reagent. After extraction, thermal desorption(TD)-GC-QQQ-MS in selected reaction
monitoring mode (SRM) was performed. In
Fig. 6, SRM chromatograms of a beer sample spiked in the range from 1-10 ng/L aresuperimposed on the SRM chromatogram
obtained for the non-spiked beer sample.
At 17.18 min, thioacrylates of 3MHA (cisderivative) appears in the SRM chromatogram of the beer samples. This compound
was detected below its odor threshold levelof 5.0 ng/L.

Figure 6: Selected reaction monitoring (SRM) chromatograms of spiked (1-10 ng/L) and non-spiked beer obtained from derivatSBSE-TD-GC-MS/MS.

Conclusion
Multi-SBSE (mBSE) and SBSE with in-situ derivatization (derivat-SBSE) can be successfully applied to the
non-targeted analysis of a wide range of aroma compounds,
and target analysis of off-flavors and key aroma compounds, respectively. These two SBSE modes can be considered as very complementary for aroma/off-flavor analysis of beverages, and can offer even more information content and/or improved sensitivity/selectivity when combinedwith high-end GC-MS (e.g. mSBSE with GC-high-resolution TOF-MS, and derivat-SBSE with GC-QQQ-MS).

Acknowledgements
All co-authors of the references [6, 10, 12] and Dr. Kevin
MacNamara (Dublin, Ireland) are thanked for their contributions.

References
[1]
[2]
[3]
[4]
[5]

F. David, P. Sandra, J. Chromatogr. A 1152 (2007) 54.
F.M. Lancas, M.E.C. Queiroz, P. Grossi, I.R.B. Olivares, J. Sep. Sci. 32 (2009) 813.
C. Bicchi, E. Liberto, C. Cordero, B. Sgorbini, P. Rubiolo, LCGC NA (2009) 376.
Y. Nie, E. Kleine-Benne, GERSTEL AppNote 3/2011, 2011.
B. Sgorbini, C. Cagliero, C. Cordero, E. Liberto, P. Rubiolo, M. Rosanna, C. Bicchi,
J. Chromatogr. A 1265 (2012) 39.
[6] N. Ochiai, K. Sasamoto, T. Ieda, F. David, P. Sandra, J. Chromatogr. A 1315
(2013) 70.
[7] K. Kumazawa, H. Masuda, J. Agric. Food Chem. 47 (1999) 5169.
[8] M. Kawakami, A. Kobayashi, K. Kator, J. Agric. Food Chem. 41 (1993) 633.
[9] M. Meilgaard, A. Elizondo, E. Moya, MBAA Tech. Q. 7 (1970) 143.
[10] N. Ochiai, K. Sasamoto, S. Daishima, A.C. Heiden, A. Hoffmann, J. Chromatogr.
A 986 (2003) 101.
[11] T. Kishimoto, A. Wanikawa, K. Kono, K. Shibata, J. Agric. Food. Chem. 54 (2006)8855.
[12] N. Ochiai, K. Sasamoto, T. Kishimoto, in preparation.

Dynamic Headspace (DHS) and DHS Large

Improved Limits of Detection
The GERSTEL DHS is an accessory
module for the MultiPurpose Sampler(MPS) in combination with the Thermal Desorption Unit (TDU). DHS
offers significantly improved limits ofdetection combined with the ruggedness and ease of use of static headspace
analysis. The headspace above a solid, viscous or liquid sample is purged with inert
gas and analytes are transferred to, and concentrated on, a replaceable adsorbent trap. The process isfully automated, including trap desorption in the TDU
and GC/MS analysis.
The GERSTEL DHS Large (DHS L) is an extension of the DHS option for sample containers with avolume of up to 1 L. A single sample DHS L extension
or an autosampler for up to 11 samples can be chosen.

12

DHS Large can be used for material
emissions screening and for volatiles
inconsumerproducts mongother application areas.

GERSTEL Solutions worldwide – No. 15

Forensic Toxicology

Efficiently
Automated
Drug Analysis
Comprehensive automation of SPE-GC/MS
based analysis of serum and other matrices for
opioids, cocaine and metabolites.

By Oliver Lerch, GERSTEL GmbH & Co. KG, EberhardGerstel-Platz, 45473 Mülheim an der Ruhr, Germany, andOliver Temme, Thomas Daldrup, University Hospital Düsseldorf, Institute of Legal Medicine, Department of Forensic
Toxicology, Moorenstrasse 5, 40225 Düsseldorf, Germany

A

Source[1] O. Lerch, O. Temme, T. Daldrup: „Comprehensive automation of the solid phase extraction gaschromatographic mass spectrometricanalysis (SPE-GC/MS) of opioids, cocaine,and metabolites from serum and other matrices“, Anal. Bioanal. Chem. 406 (2014) 4443;
Free download of the article under: http://
link.springer.com/article/10.1007/s00216014-7815-7[2] O. Lerch, O. Temme, T. Daldrup: „Comprehensive Automation of the SPE-GC/MS
Analysis of Opioids, Cocaine and Metabolites
from Serum and Other Matrices“, GERSTELAppNote 07/2013 (www.gerstel.com/pdf/
p-gc-an-2013-07.pdf)

GERSTEL Solutions worldwide – No. 15

nalyzing blood serum for opioids, cocaine and metabolites isa routine task in forensic laboratories. The most commonlyused methods involve several manual or partly-automated sample preparation steps such as protein precipitation, solid phaseextraction, evaporation and derivatization followed by GC/MSor LC/MS determination. In the work reported here, a comprehensively automated method is compared with a validated,partly-automated routine method. Following manual protein
precipitation, the automated method relies on a GERSTELMultiPurpose Sampler (MPS) to perform all remaining sample
preparation steps. These include solid phase extraction (SPE),evaporation of the eluate, derivatization and introduction to the
GC/MS. Quantitative analysis of close
to 170 serum samples, as well as morethan 50 samples ofother matrices likeurine, different tissues and heart
blood, was performed using bothmethods.
Cocaine, benzoylecgonine,methadone, morphine,
codeine, 6-monoacetylmorphine, dihydrocodeine and 7-aminoflunitrazepam
were determined quantitatively andthe methods were found to produce
equivalent analytical results even near
the limits of quantification.

Instrumentation
GC/MS System used for the determination of opioids,
cocaine, and metabolites in serum, as well as for THC andmetabolites in serum [3]. The system performs automatedSPE, evaporative concentration, derivatization as well as
introduction to the GC/MS.

A GERSTEL MultiPurpose Sampler (MPS) was used, configured witha 2.5 mL syringe with gas supply forthe sample preparation steps and a 1013

5000048000
46000

Benzoylecgonine
172 ng/mL

44000
42000
40000
38000
36000
34000

Methadone
442 ng/mL

32000
30000

Morphine
70 ng/mL

28000

Standard solid phase extraction cartridge (bottom) adapted for automated SPE.

26000
24000
22000

Figure 2: Top: Standard solid phase extraction cartridge adapted for automated SPE.
Bottom: Standard solid phase extraction cartridge.

µL syringe used for sample injection into a
GERSTEL Cooled Injection System(CIS 4) coupled to a 7890 GC/5975
MSD (Agilent Technologies). The MPS
was equipped with modules for solid
phase extraction (GERSTEL SPE), forevaporation of solvents under controlled
vacuum and temperature (GERSTELmVAP), for shaking under controlledtemperature conditions (Agitator) andfor supplying large volumes of solvents(GERSTEL SFS).

10000

8000
6000
4000
2000

6.50

LOQ -OtherLOQ
ULOC-OtherULOC- ULOCLOQ - ULOC
LOD -LOQ
LOD
LOQ
- LOQ
LOD - LOQ LOD - LOQ
1

1

10

10

100

100

1000

10

1

10

1

100

Serum Serum
Other Other
Serum

10

1

1

Serum

LOQ Other- LOQ
ULOCOther- ULOC
LOQ - ULOC LOQ - ULOC
LOD LOD
- LOD
LOQ
- LOQ
- LOQ
LOD - LOQ
1

10

10

100

100

1000

1000

10000

Concentration (MPS), ng/ml

100

1000

GERSTEL MPS automation [ng/mL]

GERSTELMPS automation[ng/mL]
Concentration(MPS), ng/ml

GERSTELMPS automation[ng/mL]
Concentration(MPS), ng/ml

1000

1000

Benzoylecgonine
Benzoylecgonine
Benzoylecgonine
Benzoylecgonine

10000

10

1

0,1
0,1

10000

10

1

100

1

1

Serum Serum
Other Other
Serum

10

Serum

LOQ Other- LOQ
ULOCOther- ULOC
LOQ - ULOC LOQ - ULOC
LOD LOD
- LOD
LOQ
- LOQ
LOD - LOQ
- LOQ
1

10

10

100

100

1000

1000

10000

10000

ValidatedInstitutereference
Validatedreference
institutemethodof legal
institute
medicineofRapidTrace
legal
Düsseldorf
medicine[ng/mL]
Düsseldorf
InstituteofLegalmethodofMedizin
Legal
MedizinDüsseldorf,
Düsseldorf,
RapidTrace(ng/mL)[ng/mL](ng/mL)

Concentration (MPS), ng/ml

100

1000

8.50

9.00

9.50

10.00

10.50

11.00

Morphine

10

10

100

Serum

Serum

Other

Other

LOQ - ULOC

LOQ - ULOC

LOD - LOQ

LOD - LOQ

100

1000

1000

CodeineCodeineCodeineCodeineAnalysis Conditions
MPS
Syringe:
Injection Volume:

100

10

Serum Serum
Other Other
Serum

1

Serum

Other
LOQ - LOQULOC- OtherULOC
LOQ - ULOC LOQ - ULOC
LOD - LOD
LOQ - LOD
LOQ
LOD - LOQ
- LOQ

1

1

10

10

100

100

1000

1000

InstituteofLegalmethodofMedizin
Legal
MedizinDüsseldorf,
Düsseldorf,
RapidTrace(ng/mL)[ng/mL](ng/mL)
ValidatedInstitutereference
Validatedreference
institutemethodof legal
institute
medicineofRapidTrace
legal
Düsseldorf
medicine[ng/mL]
Düsseldorf

GERSTEL MPS automation [ng/mL]

GERSTELMPS automation[ng/mL]
Concentration(MPS), ng/ml

GERSTELMPS automation[ng/mL]
Concentration(MPS), ng/ml

1000

1

0,1
0,1

1000

Methadone
Methadone
Methadone
Methadone

10000

8.00

10

1000

100

ValidatedInstitutereference
Validatedreference
institutemethodof legal
institute
medicineofRapidTrace
legal
Düsseldorf
medicine[ng/mL]
Düsseldorf
InstituteofLegalmethodofMedizin
Legal
MedizinDüsseldorf,
Düsseldorf,
RapidTrace(ng/mL)[ng/mL](ng/mL)
10000

7.50

InstituteofLegalmethodofMedizin
Legal
MedizinDüsseldorf,
Düsseldorf,
RapidTrace(ng/mL)[ng/mL](ng/mL)
ValidatedInstitutereference
Validatedreference
institutemethodof legal
institute
medicineofRapidTrace
legal
Düsseldorf
medicine[ng/mL]
Düsseldorf

1000

ValidatedInstitutereference
Validatedreference
institutemethodof legal
institute
medicineofRapidTrace
legal
Düsseldorf
medicine[ng/mL]
Düsseldorf
InstituteofLegalmethodofMedizin
Legal
MedizinDüsseldorf,
Düsseldorf,
RapidTrace(ng/mL)[ng/mL](ng/mL)
10000

Morphine

7.00

100

1

1

Concentration (MPS), ng/ml

0,1
0,1

Serum

GERSTELMPS automation[ng/mL]
Concentration(MPS), ng/ml

Serum

1

GERSTEL MPS automation [ng/mL]

0,1
0,1

Serum Serum
Other Other

100

1000

Concentration (MPS), ng/ml

1

10

1000

GERSTEL MPS automation [ng/mL]

10

100

GERSTELMPS automation[ng/mL]
Concentration(MPS), ng/ml

Concentration (MPS), ng/ml

GERSTEL MPS automation [ng/mL]

Concentration (MPS), ng/ml

GERSTEL MPS automation [ng/mL]

100

1000

CocaineCocaine Cocaine
Cocaine7-Aminoflunitrazepam

16000
12000

All analytes and deuterated analogues
were certified standards purchased from
Lipomed AG or LGC Promochem
GmbH. All solvents and salts were ofanalytical grade and purchased from
VWR. N-Methyl-N-trimethylsilyltrifluoroacetamide (MSTFA) for silylation
was purchased from Macherey-Nagelor Sigma-Aldrich. Bond Elut Certify
130 mg, 3 mL format SPE cartridges from
Agilent Technologies were used. For au-

1000

Codeine

18000
14000

Materials

1000

20000

23 ng/mL
tomated SPE these9,4 ng/mL
cartridges were cutat the top, equippedwith a transport
adapter and a disposable syringe neeFigure 5: Chromatogram resulting from a real serum sample. Quantified
ion chromatogram resulting from a real serum sample.
compounds are named.
dle (canula). Blood, Extracted
Quantified compounds are named.
urine and tissue
samples were taken
tylmorphine) respectively and were calfrom authentic forensic cases at the Insticulated for 0.6 mL serum sample (ninetute of Legal Medicine in Düsseldorf.
levels). A 20 µL aliquot of the internal standard solution was added to each individual
Preparation of standards
sample, calibration sample and quality conand solutions
trol sample.
For calibration, multi-compound calibraIn agreement with the guidelines oftion solutions and one multi-compoundthe Society of Toxicological and Forensic
internal standard solution containing deuChemistry (GTFCh, Germany) a blank interated analogues of every analyte were
jection of pure derivatization solution was
prepared in methanol. The calibrations
performed after every sample, quality conranged from 25 to 1500 ng/mL (methatrol or calibration sample.
done), from 50 to 1500 ng/mL (benzoylecgonine), from 5 to 150 ng/mL (codeine),
Results and Discussion
from 5 to 300 ng/mL (cocaine, dihydrocoThe validated, partly-automated routine
deine, morphine), and from 2.5 to 150 ng/
analysis method was successfully automatedmL (7-aminoflunitrazepam, 6-monoaceusing the MPS – from dilution of the sample
after protein precipitation to injection into
the GC/MS. Some modifications were necMorphine
Morphineessary:Dilution of the supernatant after protein precipitation was partly performed inSerum Serumthe autosampler syringe. A 0.75 mL aliquot
Other Otherof the supernatant was diluted with 0.75 mL
LOQ - LOQULOC- ULOC
phosphate buffer and 0.75 mL of this mixLOD - LOD
LOQ - LOQ
ture was aspirated. After that, another 1.75

100

10

1

0,1
0,1

6-Monoacetylmorphine
6-Monoacetylmorphine
6-Monoacetylmorphine
6-Monoacetylmorphine

CIS inlet
Temperature:

50 °C -12 °C/s 280 °C (5 min)Splitless 3 min
Quartz wool
deactivatedPneumatics:
Liner:GC
Oven Temperature:

100

10

Serum Serum
Other Other
Serum

1

0,1
0,1

10 µL
2 µL

Serum

Other
LOQ - LOQULOC- OtherULOC
LOQ - ULOC LOQ - ULOC
LOD - LOD
LOQ - LOD
LOQ
LOD - LOQ
- LOQ

1

1

10

10

100

100

1000

1000

InstituteofLegalmethodofMedizin
Legal
MedizinDüsseldorf,
Düsseldorf,
RapidTrace(ng/mL)[ng/mL](ng/mL)
ValidatedInstitutereference
Validatedreference
institutemethodof legal
institute
medicineofRapidTrace
legal
Düsseldorf
medicine[ng/mL]
Düsseldorf

140 °C (1 min) 120 °C/min 225 °C (5.29 min) 		
- 120 °C/min - 		275 °C (5.2 min)Post Run:
300 °C (2.5 min)Column:Rxi-5Sil MS (Restek) 		
30 m, di = 0.25 mm, 		df = 0.25 µm
Helium, constant 		
Pneumatics:
flow, 1 mL/min
MSD		
Detection mode:
SIM mode

FigureFigure6: Correlation
6: Correlationof determinedof determined
analyteanalyteconcentrations
concentrations
in double
in double
logarithmic
logarithmic
Correlation of determined analyte concentrations in double logarithmic scale. Line with a slope of one – representing
complete equivalence of results – is shown.
ng/mL: Nanogram per milliliter or nanogram per gram for tissue respectively; Other: Other matrices than serum - urine,
blood, lyophilized kidney tissue, heart blood, lyophilized and native brain tissue; LOD: Limit of detection; LOQ: Limit ofquantification; ULOC: Upper limit of calibration.

14

GERSTEL Solutions worldwide – No. 15

60%

f

20%
0%
Serum
-20%
Other
Mean

-40%

± 1.96 SD

20%
60%
0%
40%
Serum

Other
-20%
20%
Mean

± 1.96 SD
-40%
0%
60%

Cocaine± 30%

Morphine

40%
Limit of detection(LOD), limit of quantification (LOQ) andupper limit of calibration (ULOC) for each compound using
20% partly-automated reference method.
the validated,

40%
20%

Analyte
0%

0%
Serum

LOD

[ng/mL]

LOQ[ng/mL]

ULOC[ng/mL]

CocaineSerum
1.1
3.5
300
-20%
Benzoylecgonine
9
47
1500
Other
Mean
Mean
Methadone
4.2
16.7
1500
± 1.96 SD
-40%
-40%
60%
Cocaine± 1.96 SD
Morphine± 30%
Morphine
300
1.2
4.9
60%
Morphine± 30 %
Codeine
0.4
2.6
150
-60%
50
100
150
200
250
300
-60%
40%
0
50
250
6-Monoacetylmorphine
0.31000.8150 150 200
0 method and
50 MPS automation
100
150
200
250
300
Average of reference[ng/mL]40%
reference method
Dihydrocodeine Average of0.8
4.2 and MPS
300automation [ng/mL]
Average of reference method and MPS automation [ng/mL]
20%
Benzoylecgonine
7-Aminflunitranzepam
0.6
2.5
150
20%
f

f

Benzoylecgonine

Relative deviation (MPS/Reference)
Relative deviationRelative(MPS/Reference)
deviation (MPS/Reference)
Relative deviation
Relative(MPS/Reference)
deviation (MPS/Reference)
Relative deviation (MPS/Reference)
Relative deviation (MPS/Reference)

60%
± 30%
-60%
0
50
100
150
200
250
300
40%
Average of reference method and MPS automation [ng/mL]

60%Morphine
Relative deviation (MPS/Reference)

40%

Other

-20%

60%
0%

Codeine

40%
-20%

Serum
Other

20%
-40%

Mean

Relativedeviation (MPS/Reference)
Relativedeviation (MPS/Reference)
Relative deviation(MPS/Reference)
Relative deviation (MPS/Reference)
Relative deviation(MPS/Reference)
Relative deviation (MPS/Reference)
Relative deviation (MPS/Reference)

CocaineCocaine60%
Relativedeviation (MPS/Reference)
Relative deviation (MPS/Reference) Relative deviation (MPS/Reference)
Relativedeviation (MPS/Reference)
Relativedeviation(MPS/Reference)
Relative deviation (MPS/Reference)
Relative deviation(MPS/Reference)
Relative deviation(MPS/Reference)f

Relative deviation (MPS/Reference)

Cocaine

60%

Se

Ot

Me

±1

±3

Codeine0%
Quantifier40%
and qualifier ions for analytes and internal
standards. Serum
Other
-20%

20%
Mean
CompoundCocaine± 1.96 SD± 1.96 SD
-40%
60%
60%
Morphine0%± 30 %
Cocaine 0%
± 30%
Serum
-60%
Cocaine-d3
250-60%
300
50
100 0
15050
200100250150Other 300200
40%
40%
Serum
-20%
-20%
0
Benzoylecgonine
Mean
reference method
MPS automation [ng/mL]
Average of reference method Averageand MPSof
automation[ng/mL] and
Other

Se

Quantifier Qualifier
[m/z]

Ot

[m/z]

Me

182
±3
185
306, 201
Se
50
100
150
200
250
361
256,
346
Mean
O
-40%
20%
± 1.96 SD
Averagemethod364of reference 259,
349and MPS automation [ng/mL] M
Benzoylecgonine-d± 1.96 SD
Benzoylecgonine
3
Mean
20%
20%
-40%
-40%
60%
± 30 %± 30 %
Methadone± 1.96 SD
223
294, 236
60% Benzoylecgonine±
Codeine
-60%
0%
60%
±
226a, 303b
303aCodeine, 318b, 242
Methadone-d± 30 %
0 1500
250
500
750
1000
1250
1500
250
500
750
1000
1250
0%
0% 3
-60%
-60%
40%
40% method and MPS automation [ng/mL]
Morphine
220, 40175
Average of reference
Average of reference method and MPS automation [ng/mL] Serum0
25 429
50
100
125
0
25
50
75 Serum
100
125
150
-20%
40%
Serum
432of reference223,
404 and MPS automation [ng/mL] S
Morphine-d
Averagemethod3
Other
Average of reference method andOther
MPS automation [ng/mL]
-20%
-20%
20%
20%
Other
O
Codeine371
234, 343
Mean
Mean
60%
60%
60%
6-Monoacetylmorphine
6-Monoacetylmorphine
Methadone-40%
Methadone
20%
Mean
M
± 1.96 SD± 1.96 SD
374
237, 346
Codeine-d
-40%
-40%
3
0%
±
1.96
SD
±
0%
± 30%
± 30%
6-Monoacetylmorphine399
340, 400
40%
40%
40%
-60%
Serum
0%
± 30 %±
402
343, 403
6-Monoacetylmorphine-d
-60%
-60%
50
100
150
200
250-20%
50
100
150
200
250 Serum
300
3
Other0 300
Serum
-20%0
50 MPS automation
100
150Other200
250 20% 0 300
50 373
100 315, 358150
200
250
Dihydrocodeine
20%
Average of reference method and MPS automation [ng/mL]20%
Average of reference
method and[ng/mL]
Mean
Se
Other
-20%
Average of reference method and
MPS automation [ng/mL]
AveragemethodMean± 1.96 SD
379 of reference318,
364 and MPS automation [ng/mL] O
Dihydrocodeine-d
8
Mean
-40%
60%
-40%
Benzoylecgonine
Benzoylecgonine± 1.96 SD± 30 %0%M
0%0%326a, 356a, 327b, 354b
7-Aminflunitranzepam
326b, 355a
± 1.96 SD
-40%
60%
60%
± 30 %
Relative deviations of measured concentrations displayed in Bland-Altman-plots.
CodeineCodeine±± 30 %
7-Aminflunitranzepam-d
362
333, 363
250
500
750
1000
1250-60%
7
40% 1500-60% Other: Other matrices than serum - urine,±S
ng/mL: Nanogram per milliliter or nanogram per gram
Serum
-20%Serum
0 for tissue
250respectively;
500
750
1000
1250 Serum 1500
-20%
Average of reference method and MPS automation [ng/mL]-20%
0
25
50
75
100
125
150
-60%
a
40% LOD: Limit of detection; LOQ: LimitOther
40%
O
Other
blood, lyophilized kidney tissue, heart blood, lyophilized
and native
tissue;of
Other
Qualifier ion
usedin partly-automatedanalysis
method.
Averagebrainof reference
method and MPS automation [ng/mL]
0
25
50
75
100
125
Averageofreference
methodandMPSautomation[ng/mL]
b
20%
M
Mean
quantification; ULOC: Upper limit of calibration; -40%
SD:Standard deviation of-40%
relative deviations.
Qualifier-40%
ionMeanused in fully automated analysis method.
Mean
50

100

150

200

Serum
250-20%
-60%
40%
0
Other

300

Methadoneff

Average of reference method and MPS automation [ng/mL]± 1.96 SD60%
0%± 30 %
-60%
0
150
300
450
600
750
900
40%
Serum
-20%
Average of reference method and MPS automation [ng/mL] OthermL phosphate buffer was aspirated resulting
in the final dilution (same as in the reference
MeanSPE
method). This solution was added to 20%
the-40%± 1.96 SD
cartridge and the process was repeatedonce± 30 %
0%-60%
totransfer
theentiresample.
The
elution
250
500
750
1000
1250 Serum
0 1500volumewasmethod
reducedfrom
2 mL
to-20%
1.9
mL.
Other
Averageof reference
and MPS
automation[ng/mL]
Mean last
The first 0.6 mL was discarded and the± 1.96 SD-40%
1.3 mL was collected
60%
Methadone based on an established± 30 %
elution profile. The derivatization time was

60%
20%

6-Monoacetylmorphine± 1.96 SD± 1.96 SD
20%60%± 30 %
-60%
-60%
40%
0% 0
75 0%0
90
150
300
45015
600 30750 45
900 6040%
Serum
Averagereference[ng/mL]
method and MPS automation [ng/mL]
Average of reference method and
MPS ofautomation
Other
20%
Serum
-20%
-20%
Mean
20%
Other

Methadone± 30 %

303, Morphine
198±1

Average of reference method and MPS automation [ng/mL]
6-Monoacetylmorphine

±

±

15
30 and 7-amino45
60
75
positive for dihydrocodeine
shortened from 30 min to 5 min with shakAverage of reference method and MPS automation [ng/mL]
flunitrazepam theseresults are not plotted.
ing at 90 °C by employing a mixture of isoocSamples and quality control samples were alsotane/pyridine/MSTFA 14/5/1 (v/v/v) instead± 1.96 SD
Mean0%
in good-40%
concordance
for these compounds.
of the -40%
isooctane/MSTFA
19/1 (v/v) mixture± 30 %± 1.96 SD
0%Nocarryover
for any of the compounds
originallyused.
±Serum
30 %
250
500
750
1000
1250
1500
-20%
-60%
-60%
be
detected
when
extracting
blank
se-100S
Close
to 170 25serum
samplesandmore100 could
Average ofreference
MPS automation[ng/mL]0 method and
50
75 Serum
125-20%Other
0 150
25
50
75
125
O
Other
rum
afterMeanreal samples.
Byoverlapping
than 50
samples ofothermatrices
like-40%
Averageof reference
methodand urine,
MPS automation[ng/mL]
Average ofreference
method and samMPS automation [ng/mL]
M
Mean± 1.96 SD-40%
60% tissues
60%
ple
preparation
steps
with
the
GC/MS
run
different
and
heart
blood
were
ana6-Monoacetylmorphine
6-Monoacetylmorphine
Methadone±± 1.96 SD± 30 %-60%±
a throughput
of around 29 samples per day
lyzed by bothmethods.
Results
are45 equiva± 30 %15
3060
75-60%
90
40% 0
40%
could
with60can be seenin thedoublelogarithmic
015which is30comparable
4575150lent as 300
450Average
750
of600
reference
methodand MPS900
automation[ng/mL]be achieved,
Averageof referencemethod.
method and MPS automation [ng/mL]
Averageof reference
method and MPS automation [ng/mL]
the partly
automatedreferencelineandBland-Altman-plots.
This is true20%
20%
The analyses were performed in different
for serum samples and also for alternative
0%0% by different personnel at different
laboratories
matrix samples.
Although results between thetimes proving
the ruggedness of the instrulimit of quantification and the limit of detecSerum
Serum
-20%
-20%
mentationand methods and the suitability fortion may not be reported routinely, they
are
Other
Other
Mean
Mean
routine-40%
forensic
analysis tasks.
includedcon-40%in the line plots. Even in this± 1.96 SD± 1.96 SD
centration range the method equivalenceis± 30 %± 30 %-60%-60%
obvious.
Since only a couple of samples wereConclusions
15
75
0
90
15
30
45
60
75
150
3000
450
60030
75045
90060

450

600

750-60%
40%
0

900

20%
0%

Serum
-20%
Other
Mean

-40%

± 1.96 SD± 30 %

-60%

150

300

450

600

750

Average of reference method and MPS automation [ng/mL]

Evaporate the eluate to dryness at
70 °C, 8 kPa and 300 rpm in them
VAP station

0900

Relative deviation (MPS/Reference)

300

Average of reference method and MPS automation [ng/mL]

Relative deviation (MPS/Reference)

150

Relative deviation (MPS/Reference)

Figure of
7: measured
Relative deviationsof measured
concentratio
gure 7: Relative deviations
concentrations
displayedin BlandAltman-plots.
tman-plots.
per permilliliter
per gram f/mL: Nanogram per ng/mL:
milliliterNanogramor nanogram
gramorfornanogramtissue respectively;
Other- matrices
thanlyophilized
serum - urine,
blood,
lyophiher: Other matrices Other:than serum
urine, blood,
kidneytissue,he
Automated sample preparation
blood,
lyophilized
nativebrain
tissue;
LOD:
of
ood,
lyophilized
andnativebrain
tissue;and
LOD:
Limit
detection;
LOQ:
Limit
gure Condition
7: Relativeofconcentrations
displayedin Limit
BlandSPE cartridge with 2deviations
mL methanol
andFigure7: measured
Relativedeviations
ofofmeasuredconcentratio
2 mL phosphate buffer (pH 7.9)
quantification;
ULOC: Upperof calibration;Sta
antification;
ULOC: Upper
limit of calibration;
SD:limit
Standard
deviationSD:
of relatman-plots.
Altman-plots.
Dilute the supernatant of the protein precipitationin the SPE syringe and add the diluted sample toviations.
/mL:
Nanogram
per deviations.
milliliterNanogramor nanogram
gramorfornanogramtissue respectively;
the SPE cartridge
ng/mL:
per permilliliter
per gram f
Wash the cartridge with 2 mL water,
her: Other
matrices Other:than serum
urine, blood,
kidneytissue,he
2 mL acetic acid, and 2 mL methanol.
Other- matrices
thanlyophilized
serum - urine,
blood,
lyophi
The following achievements were made:samplepretreatment
Dry cartridge briefly using
a flow native Manual
ood,
and
brain
tissue;LOD:
Limit
ofmeasured
detection;
LOQ:
Limit
•brainComprehensive
automation of a validated,partlygure lyophilized
7: Relative
FigureAlllyophilizedof7:
measured
Relativedeviations
concentrationsofdisplayedconcentratio
in
Blandblood,andnativetissue;
LOD:
Limit
of
of nitrogen deviations
automated analysis method for opioids, cocaine
liquids (urine, blood, serum) were treatedandmetabolites from blooddeviation
serum and otheridentically:
antification;
Upper
limit of calibration;
SD:limit
Standardof relaElute with 1.9 mL ofULOC:
dichloromethane/isopropatman-plots.
Altman-plots.
quantification;
ULOC:
Upper
matrices. of calibration; SD: Sta
1. Protein precipitation
by drop-wise additionofnol/ammonia. The first 0.6 mL are discarded and• Analysis results of the methods were found to bea mixture of 0.6 mL sample, 0.1 mL water andthe following 1.3 mL are collected in a vial
viations.
equivalent
on GTFCh recommendations.
µL internal
standard solution
to a mixture/mL:
Nanogram
per deviations.
ng/mL:
milliliter20Nanogram
or
nanogramperpermilliliter
gramorforbasednanogramtissuerespectively;
per gram freference method
Average of reference methodAverageand MPSofautomation[ng/mL]and MPS automation [ng/mL]of 1 mL acetonitrile and 0.1 mL isopropanol.
2. Mixing and centrifugation.
3. Transfer of an aliquot (0.75 mL) of the supernatant to individual vials for both analysis
methods.
Tissues (brain and kidney, native and lyophilized)
were homogenized. An aliquot of approximately
0.6 g was weighed and handled like the liquids
above though the acetonitrile/isopropanol solution was added to the sample/standard mixture.
The protein precipitation steps could be automated using a centrifuge option with the MPS,
but this was not within the scope of this study.

Average of reference method and MPS automation [ng/mL]• The automated method proved to be rugged andsuitable for routine analysis in forensic
laboratories.
• The automated method saves manual work andreduces the risk of human error. It generates
a throughput of 29 samples per day, which
is similar to the reference method and is wellsychronized with the GC/MS analysis time.
• The analysis system is highly flexible and canreproduce manual sample preparation workflows.
Therefore it can be used to automate othervalidated GC or LC analysis methods or for standalone automation of sample preparation.

her: Other matrices than
Other:
serum
Other- urine,
matrices
blood,
thanlyophilized
serum - urine,
kidneyblood,
tissue,lyoph
heReconstitute in 200 µLand
isooctane/native
ood, lyophilized
blood, brainlyophilized
tissue;andLOD:
nativeLimitbrainof detection;
tissue; LOD:
LOQ:
Limit
Limit
o
pyridine/MSTFA 14/5/1 (v/v/v)
antification;
ULOC:
Upper
quantification;
limit of calibration;
ULOC: Upper
SD:limit
Standardof calibration;
deviationSD:
of relaSt
Shake for 5 min at
90 °C for derivatization
viations. Inject 2 µL into the GC/MS deviations.
Calibration solutions were treatedanalogous to the eluates.

GERSTEL Solutions worldwide – No. 15

15

Inside the laboratories of Schülke & Mayr GmbH

The MPS handles the Night Shift
Analytical Quality Control (QC) of pharmaceutical products follows a strict set of guidelines. The quantity ofingredients, standards and solvents used must be accurately determined; stability tests must be performed;
analytical methods must be validated, the performance of analytical instrumentation must be verified andcertified; and replacement of consumable parts and preventive maintenance must be scheduled at regularintervals. A key element in the analytical Quality Assurance program at the Pharmaceutical producer Schülke& Mayr GmbH in Germany is the GERSTEL MultiPurpose Sampler (MPS) with integrated Weighing Option.

chülke & Mayr GmbH was foundedin 1889 in Norderstedt near Hamburg,
Germany and is today a wholly owned subsidiary of Air Liquide. The company is aleading international provider of products
for industrial hygiene, infection prevention, Microbiological Quality Management(MQM), as well as chemical preservatives or
stabilizers for technical products such as fuels and oil drilling liquids. The company has
around 800 employees worldwide, of which
550 are located in Germany. Around ten
percent of staff work in R&D at company
Headquarters in Norderstedt.
Schülke & Mayr produces and sells disinfectants, antiseptic agents, preservation
agents, biocides, medical skin care products,
active agents for deodorants, and systemcleaning liquids. Among their customers
are hospitals and other medical facilities, aswell as pharmaceutical companies, cosmetics producers, and food companies. Fuelproducers add preservatives from Schülke& Mayr to their diesel fuels, and emulsions
from the company are used for oil drillingand production.

16

Since the bulk of the products from
Schülke & Mayr are used for medical, clinical or pharmaceutical purposes, the company is officially classified as a pharmaceuti-

cal company. A requirement for getting andmaintaining this classification is that guidelines for product monitoring and quality
control must be strictly adhered to:• Good Manufacturing Practice (GMP)• German Medicinal Products Act (AMG)• German Pharmaceutical and Active Ingredient Production Guidelines (AMWHV)• European Union GMP Guidelines• EU Regulation 1223/2009(Cosmetics Regulation)• EU Regulation 528/2012(Biocides Regulation).

Schülke & Mayr Headquarters in Norderstedt near Hamburg,
Germany.

These regulations require strict control
of incoming raw materials, continuous monitoring of product intermediates and control
of active ingredient concentrations in the
final products. Finished products regularly
undergo stability testing to ensure that there
is no significant change in product safety
and performance as a result of aging processes. The regulations also require regularscheduled inspection and validation of measuring and testing equipment.

GERSTEL Solutions worldwide – No. 15

Text and images: Guido DeussingSA view of the Schülke & Mayr laboratories.

No Quality Control without
instrumental analysis
Schülke & Mayr perform all chemical
analysis in-house. The analytical techniques
used for most of this work are Gas Chromatography (GC) and High Performance
Liquid Chromatography (HPLC). Analytical methods are developed in the company’s Quality Control (QC) laboratory andvalidated according to regulatory guidelines.
Long-time employee Andreas Teevs fromthe Quality Control and Process Control
Department is the key person charged withoverseeing analytical method development,
method validation, instrument qualification,
as well as method implementation and routine analysis. Schülke & Mayr has around
40,000 samples to analyze each year, 90 % ofwhich are performed using GC and HPLC.
The GERSTEL MultiPurpose Sampler(MPS) performs automated sample preparation of ten thousand mainly liquid samples every year. “The number of samples hasgrown dramatically over the past years,” reports Mr. Teevs, “and this has been a sizeable
challenge for the company and the QC laboratory team. Just in the past five years, thelaboratory staff has doubled in size.” However, in spite of the growth in the numberof samples that must be analyzed, the number of employees in the laboratory will notchange in the foreseeable future. In order
to increase lab productivity without adding
staff, while continuing to meet the required
high standards, introducing a night shift wasseriously considered. “An extra shift wouldof course have improved the utilization of
the laboratory instrumentation and laboratory productivity, but having to work nights
was considered by most to be an unattractive
option and an extra burden. Every one of us
would have had to make big adjustments,”
said Andreas Teevs. After considering thealternatives, a more attractive solution was

GERSTEL Solutions worldwide – No. 15

As part of their daily tasks, Andreas Teevs (left) and hiscolleagues Michael Bosnak and Beate Teevs-Aschinger are
responsible for developing and implementing analyticalmethods and qualifying the analysis instruments.

found: It was decided to increase the levelof automation in the laboratory. Today, the
GERSTEL MPS handles the night shift.

No reliable analysis without
precise weighing“Analyzing a large number of samples overnight without the need for a staff presence
to prepare samples, generate standards, andto monitor the process is not just a great idea
in theory, it actually works!” says Andreas
Teevs. But there was one condition that had
to be met in order to ensure the success of
implementing such a significant amount of
automation: The automated sample andstandard preparation system had to include
an integrated balance. This is required, notonly to weigh samples, but also to generate
standard and reagent solutions as well as

extensive dilution series for calibration andquality assurance purposes. Today, in manycases, Schülke & Mayr have replaced using
standard pipettes with precise liquid dispensing based on the GERSTEL MPS and
its automated Weighing Option. “It is easy
to see why,” says Mr. Teevs: “The accuracyof a 1000 µL syringe is greater than 99.5 %with a relative standard deviation of lessthan 0.2 %. This means that the MPS provides more accurate results with higher precision than a person using a manual pipette.”
When they prepared a laboratory restructuring plan that focused specificallyon improving laboratory automation, Mr.
Teevs and his team started searching for an
autosampler with an integrated weighing
option. “We found what we were looking
for in the GERSTEL MPS, specifically the
Dual Head version, which enables the use of
two different syringe sizes that can dispensea wide range of volumes accurately and efficiently without time-consuming syringechanges.” The MPS weighing option offers
the possibility to monitor, control and document the volumes dispensed. But the MPS
also performs all standard sample preparation steps for GC and HPLC and injects
the sample into the chromatography system.

A well balanced selection oflaboratory equipment
Andreas Teevs and his colleagues currently
work with several MPS systems: A standalone MPS WorkStation is used to add
internal standards and generate dilution series. An XL version of the MPS, called “thebridge”, handles sample preparation for two
GCs. This is combined with sample introduction to the GC on the left and delivering a vial with a prepared sample into thestandard GC autosampler on the right handside. A third MPS is mounted on anotherGC system. Each MPS is equipped with17

the Weighing Option, i.e. with a laboratory
balance, in this case a Sartorius ME 235S
OCS. Thermostatically controlled trays areused to store standard and reagent solutions
at a constant temperature of 20 °C. Finally,each sampler has two towers (Dual Headversion), enabling the simultaneous useof two different syringe sizes. The weighing step is freely selectable in the PrepSequence method settings in the GERSTEL
MAESTRO Software (please see workflow
diagram). “The resulting weighing protocol
can be exported as a Microsoft Excel file oras semicolon separated (CSV ) text file forfurther processing, for example, in a LIMS
or Chromatography Data Handling System,” says Andreas Teevs.
“Does the complete automation save
time? Probably not a lot in the sense thatanalyses are finished faster”, says the laboratory manager. “But the MPS with weighing option has enabled us to work bothmore efficiently and more productively”.
The MPS performs analyses overnight
without staff watching over it. When thestaff comes to work in the morning, analysis results are quickly processed and evaluated and the production batches released.
This has led to reduced waiting periods inproduction, which is of course important.
“All in all,” says Mr. Teevs, “the MPS handles the complete analysis, which is something we could only dream of before.” Thestaff is still trained and able to perform all
sample preparation steps manually in caseany problems should arise with the laboratory automation system.

find potential sources of errors and inaccuracies before they develop into something
bigger,” says Andreas Teevs. This is anotherimportant aspect in which the MPS with
automated weighing option plays a key
role. Analysis instruments can significantly
influence the accuracy of the analysis results, as Mr. Teevs has seen in his 35 years
at Schülke & Mayr.
Since the GERSTEL MPS was introduced to the Schülke & Mayr laboratories, it has enabled a more comprehensive
control of variations in analytical data resulting from system deviations and instrument wear. As an example, a gas bubble
could form inside a syringe when sample
is drawn leading to a deviation in sample
volume. “This could happen,” says Andreas Teevs, “If the syringe barrel has beenworn from extensive use and as a result, air
is being drawn in between the barrel andthe plunger.” If the sampler is equippedwith a balance, the resulting variations insample volume can be seen directly, trends
can be followed and countermeasures such

Stability Test
Pharmaceuticals are subjected to stability tests on a regular basis: During productdevelopment, during the approval phase,and after the product has been approvedfor sale into the market (ongoing stability
tests). It is established, whether contamination is formed or introduced into the productand, if so, which compounds are found andin which concentrations. Even after years
on the market, product stability can potentially change leading to changes in estimatedshelf-life or even product recalls. Samples ofdifferent batches of a product are stored under various storage and temperature conditions. During this process, samples are regularly taken and extensive analysis performed.

as replacement of consumable parts can bescheduled. This helps to ensure that thelaboratory always delivers reliable and accurate data. “Without a weighing option,”says the expert, “A regular or ongoing system monitoring and control would never bethis easy – or even possible.”

Monitoring instrument performance – required and necessary
Where pharmaceuticals or products for
medical use are manufactured, a high levelof precision and accuracy is required. “Allanalysis instruments must undergo regulardetailed checks and controls in order toEvery GERSTEL MPS in the Schülke & Mayr laboratories is equipped not only with a Weighing Option, but also with two towers(Dual Head version) in order to accurately dispense a wide range of volumes without having to go through the process of changing syringes. “The Bridge”, an XL version of the MPS spans two GC systems. Prepared samples can be introduced to the GC on
the left and vials with prepared samples can be placed into the autosampler of the GC on the right hand side.

Steps that are performed automatically in the MPS weighing option
Vial is placed in the vial weighing position in
the laboratory balance
Weighing is performed, the value is exported
and entered into the weighing protocol
The vial is returned to the MPS tray andsample is dispensed into the vial
The vial is returned to the weighing position
Weighing is performed, the value is exported
and entered into the weighing protocol
The MPS returns the vial to its position in thesample tray

18

When they prepared their laboratory restructuring, Schülke & Mayr focused on automated sample preparation. Mr. Teevs and his
team specifically wanted an autosampler with integrated weighing option that can dispense a wide range of volumes accurately
and efficiently without time-consuming syringe changes while offering the possibility to monitor, control and document thedispensed volumes. They found all this and more in the GERSTEL MultiPurpose Sampler (MPS).

GERSTEL Solutions worldwide – No. 15

Water analysis

Clean and Sensitive
Determination of Pesticides
Online SPE sample clean-up based on replaceable cartridges provides higher sensitivity and lower limitsof detection – without the risk of carry-over.
By Norbert Helle and Franziska Chmelka, TeLA GmbH, Geestland, Germany,
norbert.helle@tela-bremerhaven.deAnalyzing food, water and soil for pesticide residues constitutes a significant
part of the workload in laboratories thatspecialize in food safety and environmental analysis. Given the vast and increasing
number of samples, efficiency is key and thestrategy has to be automation – sensible andefficient automation.
The weed killers (herbicides) most frequently used for crop protection in fruit production are based on phenyl urea or triazine

compounds. Both these compound classes
enter the plant through the roots and aretransported to the chloroplast where theyinterfere with the process of photosynthesis, ultimately leading to the death of theplant. It is in the nature of weed eradication through chemical agents that residues
applied to the upper soil layers will reachdeeper layers where the crop roots are located and will be transported into both thewider environment and the food chain. Pes-

ticides and herbicides accumulate in groundand surface waters which are also our drinking water reservoirs. To avoid any danger tohuman health, governments have limited the
maximum allowable concentrations for such
residues in water to 0.1 µg/L with a required
limit of determination ten times lower at
0.01 µg/L. Reaching this limit of determination normally requires direct introduction toa highly sensitive HPLC-MS/MS system,
but not all compounds can be determined

Pesticides are found in surface and ground water.

GERSTEL Solutions worldwide – No. 15

19Sample preparation and LC-MS/MS analysis are performed simultaneously in parallel.

Standard mixture of the target analytes (100 ng/L) following extraction and cleanup in the SPExos unit.

this way, especially not early eluting compounds. To circumvent these obstacles, larger volumes (up to 100 µL) are injected directly into the LC-MS/MS system – or thecompounds in question are concentrated on
fixed on-line SPE cartridges, a widely used
procedure. However, both these alternatives
are associated with certain drawbacks: The
introduction of a large sample volume frequently leads to peak broadening. In addition, highly sensitive and expensive analysis
instrumentation would typically be needed
to reach the required limits of determination. Analyzing a series of samples using
only a single fixed cartridge to concentrate
analytes, on the other hand, will regularly
lead to sample-to-sample carry-over andincorrect results with the need to re-analyze
especially high concentration samples alongwith several of the following samples. Since
the cartridge is typically loaded with sample
from one side and eluted from the otherside, the clean-up effect is also limited because the analytes don’t have to traverse theentire column.

Online Solid Phase Extraction
with clean-up
The goal of this project was to reach therequired limits of determination based on
injecting only 1 mL of water sample. In
order to combine the advantages of online SPE concentration with the required
Automated sample prep workflow[LOAD]
Load the SPEXOS cartridge

LC-MS/MS peak overlays resulting from SPExos clean-up and analysis of 1 mL (SPExos) and direct injection of 50 µL(d) of a pesticide standard-mix (100 ng/L). Compared to direct injection of 50 µL, a factor of 50 increase in sensitivity
was achieved without peak broadening. Please note, the SPExos process leads to retention time delays of up to 30 s.

LOQs < 10 ng/L
for all target compounds[SPE PREP]
Condition with 4 mL of methanol[SPE PREP]
Condition with 4 mL of water[ADD]
Load 1 mL of sample into the MPS injection
valve loop.
[SPE PREP]
Transfer the sample from the loop to the
SPEXOS cartridge using 1.5 mL of water[SPE PREP]
Valve switch: The flow from the binary pumpis switched to the SPEXOS cartridge

Standard mixture of the target analytes (10 ng/L) following extraction and cleanup in the SPExos unit. A Limit of
Quantitation (LOQ) below 10 ng/L was achieved for each analyte.

20[INJECT]
Start signal for the Agilent MassHunter
Software and the LC-MS/MS system.

GERSTEL Solutions worldwide – No. 15

The SPExos-HPLC-QqQ-MS systemused for the determination ofphenylurea and triazine herbicides.

ceivable since we could freely select sorbent
materials. Finally, focusing the analytes on
the analytical column after they had beentransferred quantitatively from the SPE
column would lead to sharp peaks and improved separation and sensitivity – thus thetheory and the high expectations.

Screenshot of the sample prep work flow as seen in MAESTRO software. Method and sequence set-up is easy anduncomplicated based simply on selecting the necessary steps from a pull-down menu or using copy-paste from existing
methods and sequences.

clean-up, we configured our LC-MS/MS
system with a separate online SPE Module(GERSTEL SPEXOS), which is based on replaceable cartridges. Some technical detail:
SPEXOS cartridges contain only 50 mg ofsorbent compared with 100 to 1000 mg ofsorbent used in regular SPE cartridges. Thismeans that the SPE process can be completely integrated into the HPLC processsince significantly less solvent is required
for analyte elution. SPEXOS is integrated
into the system between the autosampler(GERSTEL MultiPurpose Sampler, MPS)
and the LC-MS/MS system (Agilent 1260
HPLC/6460 Triple Quad MS). Sample
introduction to the HPLC follows online,
i.e. the SPE eluate, and thus 100 % of theanalytes, is transferred directly and quantitatively into the HPLC mobile phase. In practice, the analysis requires only a very small
amount of sample, in the order of 1-5 mL,
and the complete process is fast enablinghigh throughput. System control for thecomplete process from sample preparation
through introduction to the LC-MS/MS isconveniently controlled by mouse-click using the GERSTEL MAESTRO software.
Sample preparation and analysis can be
performed in parallel using the PrepAhead
function to ensure that the next sample isalways prepared and ready for introduction
when the LC-MS/MS system is ready forthe next run.

GERSTEL Solutions worldwide – No. 15

We had anticipated that the addition of
the SPEXOS module would provide several
interesting and useful benefits. For example,
since the cartridges are exchangeable we expected carry-over to be eliminated. Further,
we expected the clean-up effect to be superior since analytes had to travel the entire
length of the sorbent bed. Further, different– even specific – clean-up steps were conLC/MS method parameters
Mobile phase:
Flow: 0.35 mL/min; A - Formic acid 5 mmol/L;
B - Acetonitrile; 0 min: 5 % B – 10 min: 50 %B – 22 min: 100 % B – 22.1 min: 5 % B - End:28 min.
Column Oven Temperature:

60 °C

Column material:

C18

MSD Source:

Agilent
Jetstream,
ESI positive

Gas Temperature:

300 °C

Gas Flow:

9 L/min

Nebulizer:

45 psiSheath Gas Temperature:

270 °C

Sheath Gas Flow:

12 L/minCapillary:

5500 V

Nozzle:300 V

A glimpse at the technicaldetails of the analysis
The practical analysis was performed as follows: The one and only manual sample preparation step was to load water samples into
vials and place them in the proper positions
on the MPS autosampler. All further steps
were performed automatically, as specified in
the instrument method.

Results and discussion
A method is only useful if it can prove itself in practiceal use. The idea of using online SPE for analyte concentration and asa clean-up step proved highly useful and
SPEXOS reliably replaced SPE cartridges
between samples. In samples of only 1 mL
volume, the following analytes were determined: metolachlor, metazachlor, diurone,
terbuthylazine, metoxurone, methabenz-thiazurone, chloridazone, atrazine, metribuzine,
chlorotolurone, isoproturone, metamitron,
desethylatrazine and desisopropylatrazine.
Compared to a direct injection of 50 µL,
we achieved a factor 50 increase in sensitivity– without peak broadening. Only the retention time was shifted with a delay of 30 seconds. Carry over effects were not observed
when comparing injections of a standard [c =100 ng/L] through the SPEXOS system withsubsequent blank injections. Apart from theincrease in sensitivity, the additional cleanup step resulted in a significantly cleaner
solution, which should have a positive longterm effect on system stability. Not least,
a limit of determination of < 10 ng/L wasreached for all compounds. The calibration
resulted in good linearity throughout.

21

Metabolomics

Automated Sample
Preparation Using the
GERSTEL MPS Dual HeadWorkStation
In metabolomics studies, relatively large sets of samples are processed to allow differentiation between
sample types and the analytical variability must be lower than the biological variability. In order to achievethis, automating the sample preparation is a good first step, which can contribute significantly towards
improving the repeatability of the total analytical procedure. Part 1of a series of 3 takes a closer look at
Automated Ultrasonic Assisted Liquid Extraction and Filtration

By Koen Sandra, Frank David, Christophe Devos, Bart Tienpont, and Pat Sandra,
Research Institute for Chromatography, President Kennedypark 26, 8500 Kortrijk, BelgiumM

etabolomics studies focus on the analyplaced inside the vial. Next, automated extracMultiPurpose Sampler (MPS), extraction,
sis of small molecules (MW<2000) intion and filtration is performed using an MPS
filtration and further processing of samples
biological matrices from micro-organisms,
Dual Head WorkStation (Figure 1). Extraccan be automated.
plants, animals, and of human origin. Relation solvent (5.8 mL of 75/25 methanol/waThis is illustrated by an automated samtively large sets of samples are processed to alter) is added using a 2.5 mL syringe, followed
ple preparation protocol developed for the
low differentiation between sample types andby 0.2 mL internal standard solution using aultrasonic extraction of glycosides and pheit is of course critically important to ensure
1.0 mL syringe. The vial is then transported
nolic compounds from plant material for athat the analytical variability is lower than theby the MPS to the ultrasonic bath (Figure 2)
metabolomics study. The implementation of
biological variability. In order to achieve this,and sonicated for 30 min. An aliquot (400screen filters to prevent blockage of the MPS
automating the sample preparation is a goodµL) of the extract is transferred from thesyringe along with 0.45 µm replaceable filter
first step, which can contribute significantly
sample vial (from inside the stainless steel
cartridges to filter the extract have enabled
towards improving the repeatability of thescreen filter) and filtered by the MPS using
direct injection of the sonicated and filteredtotal analytical procedure.
a disposable 0.45 µm filter cartridge (Figure
samples into an LC/MS system without the
A typical metabolomics workflow in3). Figure 4 shows the sample vials before
risk of system contamination with sample
cludes extraction, fractionation or clean-up,
and after sample preparation. The MPS
matrix.
derivatization, and a concentration step, folconfiguration is detailed in Table 1, and thelowed by GC or LC separation and MS deMAESTRO Prep Sequence is described inExperimental
tection. In a series of articles, we describe a
Table 2.
Automated Extraction
number of automated methods that are curA 60 mg sample of ground plant material isLC/MSrently applied in our laboratories. In this firstweighed into a 10 mL headspace vial. Before
An Agilent Technologies 1290 Series UPLC
article, we focus on extraction and filtration.
capping the vial, a 17 µm stainless steel screen
System coupled to a 6540 Q-TOF LC/
In a second article, an automatic fractionation
filter (GERSTEL p/n 020006-050-00) is
MS was used for the analysis of the extracts
procedure based on solid phase extraction will
(Agilent Technologies, Waldbronn,be described and in a final article, weGermany). A reversed-phase sepawill describe the use of an automatration was performed on a C18
ed derivatization procedure prior tocolumn using water, acetonitrile
GC analysis.
and formic acid as the mobile phase
For the extraction of plant maconstituents.
terial, ultrasonic assisted liquid extraction is a well-established method. However, ultrasonic extraction
Results and Discussion
is mostly performed manually. ThisFor a metabolomics study of glyis in part due to the fact that solid
cosides and phenolic compounds
particulates can create a suspension
in plant material, 86 samples werein the extraction solvent, which can
prepared using the automated Prep
easily block syringes, making autoSequence described above. Of themated collection of the extract and86 samples, 18 were quality consubsequent injection into the GC
trol (QC) samples that were used
or LC unreliable. Applying recently Figure 1: MPS Dual Head WorkStation configured for automated ultrasonic extraction
to assess the reproducibility of theintroduced tools for the GERSTEL and filtration.

22

GERSTEL Solutions worldwide – No. 15

Table 1: MPS Dual Head WorkStation Configuration.
MPS Module

Description

Left Arm
Right Arm
Tray and Holder
Tray and Holder
Solvent Filling Station
Tray and Holder
Tray and Holder
Waste

2.5 mL syringe with magnet for 10 mL vials
1.0 mL syringe with gripper
Ultrasonic bath with holder for 10 mL vials (6 positions)
10 mL headspace vials (VT-32)
Extraction solvent (75/25 Methanol/Water) + Wash (Methanol)
Filtration Tray (0.45 µm filters)
1.5 mL high recovery vials (VT-98) with filtration cover
Waste unit for used filters

Table 2: MAESTRO Prep Sequence used for Automated Sample Preparation.
ActionArm

Description

Add
Add
Move
Ultrasonic
Move
Move
Get
Filtrate
Put

Left MPS
Right MPS
Left MPS

5,800 µL 75/25 Methanol/Water (Pre-rinse)
200 µL IS (Pre-rinse Methanol)
Tray 10 mL → Ultrasonic
30 minUltrasonic → Dry*
Dry* → Tray 10 mL
Get filter (Gerstel # 017450-103-00)
400 µL + 600 µL air, Filter from above
Transfer filter to the waste receptacle

Left MPS
Left MPS
Right MPS
Right MPS
Right MPS

*Dry is the name of the position in the ultrasonic tray, in which excess water is removed fromthe outside of the vials.

Table 3: Targeted analysis of the 18 QC samples.
CompoundAccurate MasstR (min)%RSD Area

610.1450
354.0950
142.0570
286.0480

4.444
3.319
3.349
7.197

5.32
5.95
13.67
13.60

Rutin
Chlorogenic acid
Salicylic acid D5 (IS)*
Kaempherol**Low intensity.

samplepreparationand LC-MS protocol.
The combinationof the consecutive filtration steps allowed
unattended error-freesamplepreparationand injection sequences of 86 samples to
Figure 2: Ultrasonic bath option for the MPS WorkStation
be executed. The reused for automated extraction of the plant material.
usable stainless steel
screen filter inside eachsample vial prevents clogging of the MPS syringe needle bysample particulates dispersed in the extract. The liquid extract (methanol/water solution) was turbid after the ultrasonicagitation (see Figure 4) and additional filtration was needed.
This was efficiently performed using the 0.45 µm disposable
cartridge filters. Finally a clear extract was obtained that could
be injected into the LC-QTOF system. All 86 samples wereanalyzed without any pressure increase on the 1290 UHPLC
system.
Both targeted and untargeted data analysis was performed
on QC samples. For targeted analysis, the internal standard
and a number of known compounds were selected and the area
repeatability calculated; the results were excellent (Table 3). It
should be noted that for metabolomics studies, the cutoff forarea RSD values is typically 30 %. As can be seen from Table
3, the targeted analysis results obtained from the QC samples
gave an area RSD of less than 14 % for the low intensity peaks,
well within the limit for metabolomics data, and less than 6 %for Rutin and Chlorogenic acid.
For untargeted analysis, 590 features were considered.
Plotting the area RSD values against RSD limits (Figure 5),
it is clear that the results from the untargeted analysis werealso excellent. As can be seen, 98 % of all features had area
RSD values lower than 30 %, making them useful for further
statistical evaluation.

Conclusions
Figure 3: Picture of the MPS picking up a 0.45 µm filter from the filtration tray.

Sample Vials at Start

Sample Vials at End

17-µm-Stainless Steel Screen Filter

Plant Material

After Sonication

After
Filtration (0.45 µm)

Figure 4: Sample vials at the start (left) and end (right) of the automated sample preparation protocol.

The GERSTEL MPS Dual Head WorkStation is particularly useful for the automation of sample preparation in metabolomics studies. The combination of automated ultrasonicassisted liquid extraction and a dual filtration process resultsin extracts that can be analyzed directly by LC/MS. For the
extraction of glycosides from plant material, in-vial stainlesssteel screen filters were successfully utilized to prevent blockage of the MPS syringe. Extracts were aspirated from inside
the screen filter inserts, and taken through a further automatedfiltration step based on 4 mm 0.45 µm syringe filters before
being injected into an LC/MS system. Following analysis of
the quality control samples used in a metabolomics study, it
was determined that the results obtained werehighly repeatable.
In a following article, the automation of a
SPE fractionation protocol applied in lipidomics will be described.
Glycosides

Figure 5: Bar plot showing the percentage of features with an area RSD value lower than the RSD
limit (untargeted analysis).

GERSTEL Solutions worldwide – No. 15

Glycosides are a class of compounds that contain a sugar and a
non-carbohydrate moiety. The non-carbohydrate moiety is typicallya small organic molecule. When the non-carbohydrate moiety is aphenol, the glycoside is for instance a flavonoid. In general, glycosides are secondary plant metabolites that are not involved in plant
growth, development, or reproduction, but rather, in the interactionof a plant with the environment, such as UV protectants, pigment
sources, and interactions with insects. In many plants, glycosides
are important precursors of flavor-related compounds.

23

Preview - coming up in the next issue

www.gerstel.com

Determining Microplastics
in the Environment
Recent research has documented that the presenceof microplastics is a growing problem for aquatic
life and anyone relying on aquatic life forms for nutrition. Polymer products have been – and continue
to be – released into our oceans on a huge scalein various ways. They are then slowly ground up
into small particles. Until now, it has been difficult
to gauge the consequences for the environment letalone for animals and humans. Increasingly proof issurfacing that plastic micro-particles find their way
into organisms and into the food chain. The political class, industry and environmental organizations
increasingly see the need for action to stop andreverse this development. When it comes to finding and characterizing microplastics, Pyrolysis-GC/
MS can help provide answers.

GERSTEL online: Information on products,
applications, events and downloads, aswell as e-Newsletter subscription andgeneral information about GERSTEL andour customer focused solutions:www.gerstel.com and www.gerstelus.com

Determining
THC Residues in Hair
Imprint

In cooperation with renowned forensic toxicologists, GERSTEL has produced a series of Applications and solutions over the past five years. A
further project is underway and will be reported
in the next GERSTEL Solutions Worldwide Magazine. The topic is the determination of THC,
CBN and CBD in hair samples. This type of drug
screening and analysis is used, for example, todetermine whether or not a person has been
consuming drugs regularly over a period of time.

Published by
GERSTEL GmbH & Co. KG
Eberhard-Gerstel-Platz 145473 Mülheim an der Ruhr, Germany
Editorial director
Guido Deussing
Uhlandstrasse 16
41464 Neuss, Germany
guido.deussing@pressetextkom.deComposing
Flavors Efficiently
GERSTEL Solutions has again been on the
prowl, looking for novel and interesting applications of our technologies in the wider laboratory world. In the next issue, we report from
Symrise AG in Holzminden, Germany, a leadingworldwide producer of flavors and Fragrances
for food and cosmetics, where the MPS is used
to compose flavors. Something to look forward
to….

Scientific advisory board
Dr. Eike Kleine-Benne
eike_kleine-benne@gerstel.de
Dr. Oliver Lerch
oliver_lerch@gerstel.de
Dr. Malte Reimold
malte_reimold@gerstel.de
Translation and editing
Kaj Petersen
kaj_petersen@gerstel.com
DesignPaura Design, Hagen, Germany
www.paura.de

www.gerstel.com
www.gerstel.com

GERSTEL,GERSTEL,
Inc.,Inc.,
USAUSA+1 410+1 410- 247- 247
58855885
sales@gerstelus.com
sales@gerstelus.com

GERSTELGERSTEL
GmbH
GmbH
& Co.
& KG,
Co. KG,
Germany
Germany+49 +49
208 208- 7 65- 703-0
65 03-0
gerstel@gerstel.com
gerstel@gerstel.com

GERSTELGERSTEL
AG, AG,
Switzerland
Switzerland
GERSTELGERSTEL
BRASIL
BRASIL+41 +41
41 - 41
9 21
- 997
2123
97 23
+55 +55
11 5665
11 566589318931
gerstel@ch.gerstel.com
gerstel-brasil@gerstel.com
gerstel-brasil@gerstel.com swiss@ch.gerstel.com

Subject Subject
to change.
GERSTEL®,
GRAPHPACK®,TWISTER® and
TWICESTER®
areareregisteredtrademarksof GERSTELGmbHGmbH& Co. KG.
to change.
GERSTELTWISTER®
register ed
trademarksof GERSTEL& Co. KG.
®, GRAPHPACK®andPrinted Printed
in Germany· 0615 · ©· Copyright
GERSTELbyGmbH& Co. KG
in Germany
0713 · ©byCopyright
GERSTELGmbH & Co. KG

GERSTELGERSTEL
K.K.,K.K.,
Japan
Japan
+81 +81
3 57331
5753
3121
53 21
info@gerstel.co.jp
info@gerstel.co.jp

GERSTELGERSTEL
LLP,LLP,
Singapore
Singapore+65 +6566226622
54865486
sea@gerstel.com
sea@gerstel.com

S00135-615-02

G L
G O
L B
O A
B LA LA N
A A
N LA YL TY IT CI A
C LA LS O
S L
O U
L T
U IT OI N
O SN S