Determination of the δ(

34S/32S) of 

Total Sulfur in Solids: 

RSIL Lab Code 1800 

Chapter 4 of 

Book 10, Methods of the Reston Stable Isotope 

Laboratory 

Section C, Stable Isotope-Ratio Methods 

Techniques and Methods 10-C4 

U.S. Department of the Interior 

U.S. Geological Survey

Determination of the δ(

34S/32S) of 

Total Sulfur in Solids: 

RSIL Lab Code 1800 

By Kinga Révész and Haiping Qi 

Chapter 4 of 

Book 10, Methods of the Reston Stable Isotope 

Laboratory 

Section C, Stable Isotope-Ratio Methods 

Edited by Kinga Révész and Tyler B. Coplen 

Techniques and Methods 10-C4 

U.S. Department of the Interior 

U.S. Geological Survey
U.S. Department of the Interior 

DIRK KEMPTHORNE, Secretary 

U.S. Geological Survey 

Mark D. Myers, Director 

U.S. Geological Survey, Reston, Virginia 2006 

Revised July 2007 

For sale by U.S. Geological Survey, Information Services 

Box 25286, Denver Federal Center

Denver, CO 80225

For more information about the USGS and its products: 

Telephone: 1-888-ASK-USGS

World Wide Web: http://www.usgs.gov/

Any use of trade, product, or firm names in this publication is for descriptive purposes only and does not imply 

endorsement by the U.S. Government. 

Although this report is in the public domain, permission must be secured from the individual copyright owners to

reproduce any copyrighted material contained within this report. 

Suggested citation: 

Révész, Kinga, Qi, Haiping, 2006, Determination of the δ(

34S/32S) of Total Sulfur in Solids: RSIL Lab Code 1800, chap. 

C4 of Révész, Kinga, and Coplen, Tyler B., eds., Methods of the Reston Stable Isotope Laboratory: Reston, Virginia, 

U.S. Geological Survey, Techniques and Methods, book 10, sec. C, chap. 4, 31 p. 
Foreword 

The Reston Stable Isotope Laboratory (RSIL) provides stable isotope analyses on a routine basis 

for a large user community within the U.S. Geological Survey (USGS) and elsewhere. The RSIL 

also serves the USGS National Research Program (NRP) through its project on Stable Isotope 

Fractionation in Hydrologic Processes. The NRP conducts basic and problem-oriented hydrologic 

research in support of the mission of the USGS. The stable isotope project conducts research on

the use of isotope-ratio measurements in studies of water resources and environmental quality. 

One objective of this project is to develop new techniques for isotopic analysis of H, N, O, C, and 

S in environmental samples. New analytical techniques expand the range of tools available for 

studying the movement of those elements in hydrologic and biogeochemical systems. Another 

objective of the project is to test new applications of isotope measurements in specific field 

settings. Field studies of isotope behavior have contributed to understanding of water-supply 

sustainability, ground-water/surface-water interactions, paleoclimate history, biologic cycling of 

nutrients, ground-water contamination, and natural remediation. This project also contributes to 

the improvement of measurement science and the development of isotope databases. 

Book 10 of the Techniques and Methods Series of the USGS contains detailed descriptions of 

methods of the RSIL, including routine analytical methods called standard operating procedures 

(SOPs), along with safety guidelines, maintenance procedures, and other information about the 

operation of the RSIL. Section C of Book 10 contains the SOPs for a variety of methods to 

measure stable isotope ratios, each of which constitutes a chapter. Each chapter is limited to a 

narrow field of subject matter to permit flexibility in revision as the need arises. 

Pierre Glynn 

Chief, Branch of Regional Research, Eastern Region 

 iii

 

Contents 

Forward ..........................................................................................................................................................iii

Conversion Factors, Acronyms, and Abbreviations ..............................................................................vii

Summary of Procedure.................................................................................................................................1

Reporting Units and Operational Range ....................................................................................................1

Reference Materials and Documentatione...............................................................................................2

Reference Material Used, Storage Requirements, and Shelf Life........................................2

Documentation ..............................................................................................................................2

Labware, Instrumentation, and Reagents .................................................................................................3

Sample Collection, Preparation, Analysis, Retention Times, and Disposal.........................................4

Sample Container, Preservation, and Handling Requirements .............................................4

Sample Preparation and Time Requirements...........................................................................5

Performing the Analysis and Time Requirements ...................................................................6

Problematic Samples....................................................................................................................7

Interferences .................................................................................................................................7

Troubleshooting and Bench Notes ............................................................................................7

Maintenance and Maintenance Records .................................................................................8

Sample Retention Time and Disposal ........................................................................................8

Data Acquisition, Processing, Evaluation, Quality Control, and Quality Assurance ..........................9

Laboratory Information Management System for Light Stable Isotope (LIMS-LSI) ..........9

Quality Control (QC) Samples ......................................................................................................9

Acceptance Criteria for All QC Samples ...................................................................................9

Corrective Action Requirements ..............................................................................................10

Responsible Parties for All QC/QA Functions for Procedures Covered in RSIL SOPs.....10

Data Management and Records...............................................................................................10

Health, Safety, and Waste-Disposal Information...................................................................................10

Applicable Health and (or) Safety Issues................................................................................10

Personal Protection....................................................................................................10

Electrical Hazards.......................................................................................................10

Chemical Hazards .......................................................................................................11

Gas Cylinder Handling................................................................................................11

Specific Waste-Disposal Requirements .................................................................................11

Revision History ...........................................................................................................................................12

References Cited .........................................................................................................................................13

Appendixes...................................................................................................................................................14

A. Step-by-Step Procedure to Log-In Samples to LIMS-LSI..............................................14

B. Step-by-Step Procedure to Generate an Excel Sample Workbook or to Print a 

Template and a Samples-to-Be-Analyzed List ................................................................16

C. Step-by-Step Procedure for Weighing and Storing Samples .......................................20

D. Step-by-Step Procedure of Zero Blank Autosampler Operation..................................21

E. Step-by-Step Procedure to Add Sample Information to Sequence Table..................22

F. Step-by-Step Procedure to Retrieve Data from ISODAT 2.0 for LIMS-LSI and for 

Data Back-Up ........................................................................................................................23

G. Step-by-Step Procedure to Transfer Data to LIMS-LSI, to Transfer Data to

Back-Up Computer, and to Reevaluate Old Data ............................................................24

H. Step-by-Step Procedure to Determine and Apply Correction Factors and 

Evaluate Data ........................................................................................................................25

I. Step-by-Step Procedure to Check Elemental Analyzer for Leaks................................26

J. Daily Checklist.......................................................................................................................27

 v 
K. Changing the Insertion Tube...............................................................................................28

L. Changing the Water Trap ....................................................................................................29

M. Changing the Reaction Tube...............................................................................................30

N. Step-by-Step Procedure to Report Data...........................................................................31

Figures 

1. Diagram of the Carlo Erba Instruments NC 2500 (CE NC 2500) Elemental Analyzer ..................... 4 

2. Diagram of a Finnigan ConFlo II Open Split.......................................................................................... 4 

3. Schematic of a continuous flow isotope-ratio mass spectrometer (CF-IRMS)............................. 5 

 vi
Conversion Factors 

Multiply By To Obtain 

Length 

millimeter (mm) 0.03937 inch 

centimeter (cm) 0.3937 inch 

meter (m) 3.281 foot 

Volume 

micro liter (μL) 0.0610210

–3 cubic inch 

milliliter (mL) 0.06102 cubic inch 

cubic centimeter (cm3

) 0.06102 cubic inch

Mass 

nanogram (ng) = 10–3μg 3.527 × 10–11 ounce 

microgram (μg) = 10–3 mg 3.527 × 10–8 ounce 

milligram (mg) = 10–3 g 3.527 × 10–5 ounce 

gram (g) = 10–3 (kg) 3.527 x 10-2 ounce 

kilogram = 103

 g; 106 mg; 109μg; 1012 ng 2.205 pound 

Density 

gram per cubic centimeter (g/cm3) 0.5780 ounce per cubic inch 

Temperature

Celsius (°C) °F = 9/5 (°C) + 32 Fahrenheit (°F) 

Pressure (force/area) 

kilopascal (kPa) 9.869 × 10–3 atmosphere, standard (atm) 

kilopascal (kPa) 1.450 × 10–1 pound-force/square inch (psi) 

kilopascal (kPa) 1.000 × 10–2 bar 

kilopascal (kPa) 2.961 × 10–1 inches of mercury at 60°F 

Acronyms and Abbreviations 

ANSI American National Safety Institute 

ASR analytical services request

CF-IRMS continuous flow isotope-ratio mass spectrometer 

DIW deionized water 

EA elemental analyzer 

GC gas chromatograph 

IAEA International Atomic Energy Agency

 vii 
IRMS isotope-ratio mass spectrometer 

LIMS-LSI Laboratory Information Management System for Light Stable Isotopes 

mg/g milligram per gram

MSDS Material Safety Data Sheets 

NBS National Bureau of Standards 

NFPA National Fire Protection Association 

NWQL National Water-Quality Laboratory (USGS) 

per mill, ‰ 1/1000 

pF picofarad 

QA quality assurance 

QC quality control 

QC/QA quality control/quality assurance 

RSIL Reston Stable Isotope Laboratory

SOP standard operating procedure 

USGS U.S. Geological Survey

VCDT Vienna Cañon Diablo Troilite 

Symbols 

Ω ohm

< less than 

> greater than 

≥ greater than or equal 

≤ less than or equal 

 viii 
Determination of the δ(

34S/32S) of Total Sulfur in 

Solids: RSIL Lab Code 1800 

By Kinga Révész and Haiping Qi 

Summary of Procedure 

The purpose of Reston Stable Isotope Laboratory Lab (RSIL) Code 1800 is to determine the 

δ(

34S/32S), abbreviated as δ34S, of total sulfur in a solid sample. A Carlo Erba NC 2500 elemental analyzer 

(EA) is used to convert total sulfur in a solid sample into SO2 gas. The EA is connected to a continuous 

flow isotope-ratio mass spectrometer (CF-IRMS), which determines the relative difference in stable sulfur 

isotope-amount ratio (34S/32S) of the product SO2 gas. The combustion is quantitative; no isotopic 

fractionation is involved. Samples are placed in tin capsules and loaded into a Costech Zero-Blank 

Autosampler on the EA. Under computer control, samples are dropped into a heated tube reaction tube 

that combines both the oxidation and the reduction reactions. The combustion takes place in a He 

atmosphere that contains an excess of oxygen gas at the oxidation zone at the top of the reaction tube. 

Combustion products are transported by a He carrier through the reduction zone at the bottom of the 

reaction tube to remove excess oxygen and through a separate drying tube to remove any water. The gasphase products, mainly CO2, N2, and SO2, are separated by a gas chromatograph (GC). The gas is then 

introduced into the isotope-ratio mass spectrometer (IRMS) through a Thermo-Finnigan ConFlo II 

interface, which also is used to inject SO2 reference gas and He for sample dilution. The IRMS is a 

Thermo-Finnigan DeltaPlus CF-IRMS. It has a universal triple collector with two wide cups and a narrow 

cup in the middle. It is capable of measuring mass/charge (m/z) 64 and 66 simultaneously. The ion beams 

from SO2 are as follows: m/z 64 = SO2 = 

32S16O16O; and m/z 66 = SO2 = 34S16O16O primarily. 

Reporting Units and Operational Range 

Variations in stable isotope-amount ratios typically are small. Stable isotope-amount ratios 

commonly are measured and expressed as the relative difference in the ratio of the amount of the less 

abundant isotope (usually the heavy isotope) to the amount of the more abundant isotope (usually the 

light isotope) of the sample with respect to a reference. This relative difference is designated δi

E, which is 

a shortened form of δ(

i

E/jE) or δ(

i

E) and is defined according to equation 1:

( ) ( ) ( ) ( ) ( ) ( )

n ( ) n ( )

n n n n δ = δ = δ = i j

i j i j

i i i j

E E

E E E E

E E E E

ref ref

X X − ref ref (1)

where i and j are isotopes of element E and n ( E)/n ( E) and n ( E)/n ( E) are the ratios of the isotope 

amounts in the unknown X and a reference ref

X

i

X

j

ref

i

ref

j

. A positive δiE value indicates that the unknown is more 

enriched in the amount of the heavy isotope ( E) i than the reference. A negative δi

E value indicates that the 

unknown is depleted in the amount of the heavy isotope relative to the reference. Values of δi

E have been 

reported in parts per hundred (% or percent), parts per thousand (‰ or per mill), and parts per ten 

thousand. For stable sulfur isotope-amount ratios, δ S34 is defined as follows: 

Prepared by: Kinga Révész and Haiping Qi RSIL SOP: 1800 

Approved by: T. B. Coplen Page 1 Effective: March 3, 2004
( ) ( ) ( ) ( ) ( ) ( ) ( ) S ( ) S

S S S S S S S S 32

ref

34

ref

32

ref

34

ref

32

X

34

34 34 34 32 X

n n

n n n n δ δ = δ − = = (2)

The primary reference material for measurement of the relative difference in sulfur isotope-amount 

ratio (δ S) is IAEA-S-1, which has a consensus δ S value of –0.3 ‰ relative to 34 34 Vienna Cañon Diablo 

Troilite (VCDT)(Robinson, 1995; Krouse and Coplen, 1997; Coplen and Krouse, 1998). By interspersing 

isotopic reference materials with accepted δ S values with unknown samples, δ S values can be 

determined relative to VCDT. These isotope ratios are made with a CF-IRMS, which measures the ratios 

of the sample SO gas and one or more injections of the “working reference” SO gas.

34 34

2 2 Values of δ S 

typically are reported in parts per thousand (‰).

34

The system was tested by analyzing pure inorganic samples (BaSO4 and Ag2S), an array of biological 

tissues from vertebrates and invertebrates, and geologic samples, such as suspended organic matter in 

sediment. The routine analysis requires a minimum of 40 μg of sample as sulfur in a maximum of 40 mg

of solid sample; however, the system is capable of analyzing samples as small as 19 μg of S in one 

sample aliquot with reduced analytical precision. The δ34S values ranged from approximately –34 to 

+21 ‰, which covers the range of δ34S values of most natural samples. It was found that the precision and 

accuracy of the results were acceptable (± 0.2 ‰), and no memory effects were observed. 

Reference Materials and Documentation 

Reference Material Used, Storage Requirements, and Shelf Life 

The primary reference material for δ34S measurements is IAEA-S-1, which has a consensus δ34S 

value of –0.3 ‰ relative to VCDT (Robinson, 1995; Krouse and Coplen, 1997; Coplen and Krouse, 

1998). Other internationally distributed isotopic reference materials that are used have a wide range of 

δ34S values. In the procedure reported herein, barium sulfates (BaSO4) that are used for isotopic analysis 

of inorganic samples include NBS 127 with δ34S of +21.1 ‰, IAEA-SO-5 with δ34S of +0.5 ‰, and 

IAEA-SO-6 with δ34S of –34.05 ‰. Silver sulfide (Ag2S) reference materials are used for organic sulfur 

or sulfide samples, and they include IAEA-S-1 with δ34S of –0.3 ‰, IAEA-S-2 with δ34S of +21.1 ‰, and 

IAEA-S-3 with δ34S of –32.55 ‰. No locally prepared isotopic reference materials are used in this 

method. 

All of these reference materials are stored in the RSIL at ambient temperature in glass bottles capped 

with Teflon-coated or cone-shaped caps to keep moisture out. Their shelf life is indefinite. 

Documentation 

All calibration results are stored in the Laboratory Information Management System for Light Stable 

Isotopes (LIMS-LSI) (Coplen, 2000) under the following sample identifiers: S-1304 (IAEA-SO-5); S-97 

(NBS 127); S-1302 (IAEA-SO-6); S-95 (IAEA-S-1); S-200 (IAEA-S-2); and S-808 (IAEA-S-3). 

Prepared by: Kinga Révész and Haiping Qi RSIL SOP: 1800 

Approved by: T. B. Coplen Page 2 Effective: March 3, 2004
Labware, Instrumentation, and Reagents 

Preparatory labware and apparatus include tin capsules and a microbalance capable of measuring 

samples with 0.0001-mg precision. The analytical apparatus consists of four different units: (1) EA, 

(2) ConFlo interface, (3) IRMS, and (4) computer software. 

The EA is a Carlo Erba Instruments NC 2500 system (CE NC 2500), and it has a Costech “Zero 

Blank” autosampler that holds 49 samples enclosed in tin capsules (fig. 1). Each tin capsule falls into the 

reaction tube, which is kept at 1020°C and is under constant He flow (90 mL/min). The sample 

immediately reacts with a measured amount of oxygen released from a 5-mL loop purged at 35 mL/min. 

The reaction of oxygen with the tin capsule is exothermic, resulting in localized temperatures of up to

1800°C, thus ensuring complete and instantaneous sample combustion. This is called “dynamic flash 

combustion.” Because the S-bearing solid has a decomposition temperature commonly in excess of 

1500°C, it is critical to synchronize the He flow, the oxygen flow, and the timing of the sample drop to 

achieve quantitative combustion (Révész, 1998; also see in the present report the section titled 

“Troubleshooting and Bench Notes”). To boost the combustion, V2O5 is added to each sample

(Yanagisawa and Sakai, 1983). The ratio of V2O5/S is not critical; usually the mass ratio is approximately

10. The combustion gases are first carried by He through an oxidative catalyst layer (tungsten oxide, 

WO3, on alumina) in the top of the reaction tube, where oxidation is completed, and then through a 

reduction agent (Cu) packed on the bottom of the reaction tube where any excess oxygen gas is 

consumed. At the outlet of the reaction tube, the gas mixture (N2, CO2, SO2, and H2O) enters a trap 

containing Anhydrone that absorbs water. The gas mixture, now N2, CO2, and SO2, flows through a 

Teflon tubing GC column (0.8-m Poraplot W kept at 90°C), which separates the gases and ensures that 

pure sulfur dioxide gas passes separately through the thermal conductivity detector, through the ConFlo II 

open split, and into the IRMS. 

The Thermo-Finnigan ConFlo II provides the means for coupling the EA to the CF-IRMS with an opensplit arrangement (fig. 2). The principle of an open split is that it reduces the 90 mL/min He flow needed 

to operate the EA to a 0.3 mL/min He flow needed to operate the IRMS. This is placing the end of the 

capillary that leads to the IRMS directly in the flow of He coming from the EA. The narrow diameter and 

length of this capillary limit the flow of gas to the IRMS. Furthermore, extra capillaries carrying reference 

gas or He gas can be added to the open split, thereby making it possible to inject reference gas to the 

IRMS or to dilute the sample with extra He if the sample is too large (or to direct gases away by dilution 

if they are too large to ensure total separation). 

The IRMS is a Thermo-Finnigan DeltaPlus CF-IRMS (fig. 3). The fundamental principle of the CFIRMS technique is that a carrier gas transports the analyte through an initial stage of online chemistry for 

conversion to a form acceptable by the IRMS (Brenna and others, 1997). This is an automated system

generating online, high-precision δ values of bulk solid and nonvolatile liquid samples. In the IRMS, gas 

molecules are ionized in a source by electrons emitted from a hot filament. The ions are accelerated into 

an analyzer, separated in a magnetic field, and collected in Faraday cup collectors. The ion beam

intensities are measured with electrometers. This IRMS has a universal triple collector with two wide 

cups and a narrow cup in the middle. The resistor–capacitor combination on the electrometer of the lowmass cup is 3 × 108 Ω and 680 pF. At the high-mass cup, it is 3 × 1010 Ω and 5 pF. The instrument is 

capable of measuring m/z 64 and 66 simultaneously. 

The Finnigan ISODAT 2.0 software is designed (1) to advance the autosampler carousel, (2) to 

control the ConFlo II interface to inject reference gases at the desired time and dilute the sample if 

desired, (3) to operate the IRMS, (4) to acquire data from the IRMS, and (5) to calculate delta values. 

Prepared by: Kinga Révész and Haiping Qi RSIL SOP: 1800 

Approved by: T. B. Coplen Page 3 Effective: March 3, 2004
 

Figure 1. Diagram of the Carlo Erba Instruments NC 2500 (CE NC 2500) Elemental Analyzer (used with permission of 

Thermo Electron Co.). 

 

 

 

Figure 2. Diagram of a Finnigan ConFlo II Open Split (used with permission of Thermo Electron Co.).

Sample Collection, Preparation, Analysis, Retention Times, and 

Disposal 

Sample Container, Preservation, and Handling Requirements 

Each sample is collected in a high-density polyethylene scintillation vial with Polyseal cap (Wheaton 

986706), provided by RSIL free of charge. Sample size should be a maximum of 1 g. The sample should 

be homogenized, oven dried (90°C), and powdered by the submitter to 100 to 200 μm. Containers are 

Prepared by: Kinga Révész and Haiping Qi RSIL SOP: 1800 

Approved by: T. B. Coplen Page 4 Effective: March 3, 2004
labeled with isotopes whose concentrations are to be determined and labeled with the respective 

laboratory code or schedule number. A minimum of 0.15 mg of sulfur per sample is required. The 

minimum sample concentration is 1 mg/g sample for S. Lower concentrations can be analyzed; contact 

the laboratory for further information. No treatment, preservation, or special shipping is required. 

Figure 3. Schematic of a continuous flow isotope-ratio mass spectrometer (CF-IRMS) (modified from Clark and Fritz, 

1997). 

Sample Preparation and Time Requirements 

Sample preparation involves logging in samples to the LIMS-LSI, creating a sample work-order 

sheet, and weighing samples into capsules. 

The logging-in procedure involves logging samples in batches to LIMS-LSI that could contain from

1 to 100 samples per batch (also called a project), printing labels for each sample, and printing a summary

project report. Each sample label contains the Field ID (the identifier by which the sample submitter 

knows each sample) and the unique RSIL Lab ID assigned by the LIMS-LSI. The summary project report 

is inserted into a three-ring binder titled “Samples in Progress.” 

Prepared by: Kinga Révész and Haiping Qi RSIL SOP: 1800 

Approved by: T. B. Coplen Page 5 Effective: March 3, 2004
If samples are submitted through the USGS National Water Quality Laboratory (NWQL), the Field 

ID is a unique number for each sample assigned according to NWQL guidelines; this unique number is 

written on the analytical services request (ASR) form accompanying a sample, and the ASR information 

is entered into the LIMS-LSI system. This information is e-mailed to the submitter of the samples for 

identification of any errors and subsequently e-mailed to NWQL. Copies of the ASR forms are mailed to 

NWQL. Step-by-step procedures are given in Appendix A. 

An Excel sample workbook is generated. The step-by-step procedures are shown in the Appendix B. 

Sample weighing includes balance conditioning, weighing appropriate amount of sample into capsule, 

recording weight on the template, adding approximately 600 μg of V2O5 to the capsule, and closing the 

capsule by folding it. Step-by-step procedures are given in Appendix C. The time requirement for sample 

preparation is approximately 1 to 5 days.

Performing the Analysis and Time Requirements 

All samples are prepared and analyzed in batches of a maximum of 80 per day, and all samples are 

analyzed in duplicate. Six aliquots of three internationally distributed isotopic reference materials with 

different δ34S values are analyzed at the beginning of a batch. Four of them are depleted in 34S, two are 

enriched in 34S, and one has an intermediate value. A set of these three reference materials is also 

interspersed among the samples. At least one reference material set is analyzed for every 10 unknowns. 

The amount of sulfur in the reference materials should be in the same range as that of the samples. 

Therefore, every sample must be preanalyzed to obtain its S concentration unless it is provided by the 

customer. If the S concentration is unknown and cannot be determined before isotopic analysis, a 

sequence of reference materials containing different amounts of S must be analyzed to determine a massdependent correction factor. The C or N concentration also may be necessary to apply the correct dilution 

with He to the CO2 or N2 to avoid peak interference of the SO2 peak. 

The procedure involves loading the autosampler carousel with capsules that contain an appropriate 

amount of sample in sequence according to the “Template” (Appendix D), loading a new sample heading 

(including sample weights) into the “Sequence Table” in ISODAT 2.0 of the IRMS software, choosing 

the appropriate “Method,” and starting sequence acquisition (see Appendix E). After the analyses are 

completed, the data are exported (Appendix F) to a Zip disk or “memory stick” from the ISODAT 2.0 

database and transferred (Appendix G) to the LIMS-LSI and the Data Back-Up computer. Final daily

correction factors are determined with the LIMS-LSI (Appendix H), based on the daily analyses of 

reference materials using equations 3, 4, and 5, which are presented with example numerical values: 

–34.05 ‰ = m × δ34S IAEA-SO-6 - workingref.gas + b (3) 

+0.50 ‰ = m × δ34S IAEA-SO-5 - workingref.gas + b (4) 

 +21.10 ‰ = m × δ34S NBS127 - workingref.gas + b (5) 

The values –34.05 ‰, +0.50 ‰, and +21.1 ‰ are the assigned values of the international reference 

materials IAEA-SO-6, IAEA-SO-5, and NBS 127, respectively. The δ34Sref – workingrefgas values in equations 

3, 4, and 5 are the mean daily delta values of the respective international reference materials relative to 

the working reference gas; b is the additive correction factor, and m is the expansion coefficient 

correction factor. When two or more reference materials with different δ34S values are analyzed, the 

correction for sample blank does not need to be applied if the magnitude of the blank in the samples and 

reference materials is identical. However, if a single reference material is analyzed, only one-point 

Prepared by: Kinga Révész and Haiping Qi RSIL SOP: 1800 

Approved by: T. B. Coplen Page 6 Effective: March 3, 2004
calibration is possible; therefore, a blank should be interspersed with unknowns and a blank correction 

should be applied. 

If replicates do not agree within acceptable tolerances, they are analyzed until acceptable statistics are 

achieved. The computerized LIMS-LSI will not release data until the statistics are acceptable. The time 

required for performing the analyses is a minimum of 2 days. 

No correction is made for the effect of the δ18O value of the SO2 gas on the δ34S determination. Fry

and others (2002) have reported that the δ34S of plants, animals, and soils can be as much as 1 to 3 ‰ to 

positive, particularly for samples with high n(C)/n(S) values. V2O5 is added to each sample to buffer the 

δ18O of SO2 gas and minimize this error (Yanagisawa and Sakai, 1983). 

The systematic procedure is listed in the “Lab Procedures” binder at the RSIL. The supervisor 

reviews suggested changes before they are adopted. 

Problematic Samples 

Problematic samples include those that do not have sulfur concentration before isotopic analysis. In 

that case, the S concentration needs to be determined by a preliminary EA analysis to be able to determine 

the amount of sample needed for analysis. The amounts of C and N may need to be established to 

determine whether CO2 or N2 gases must be diminished by He dilution in the ConFlo before it reaches the 

IRMS to prevent overlap with the SO2 gas. 

Interferences 

There are no known interferences with this analytical technique. However, it should be pointed out 

that if samples contain a mixture of different sulfur sources, reported isotope-ratio values represent the 

isotopic composite of the total sulfur in the sample. The δ34S values of specific S species cannot be 

provided with this analytical technique. 

The δ34S of plants, animals, and soils with high n(C)/n(S) values may be too positive (Fry and others, 

2002). To minimize this interference, V2O5 is added to each sample to buffer the δ18O of SO2 gas. 

Troubleshooting and Bench Notes 

The most common problems with this analytical technique are (1) incomplete combustion; 

(2) leakage in the system, particularly in the EA; and (3) insufficient linearity of the IRMS. The fact that 

the reaction tube temperature is only 1020°C can create insufficient combustion. The “flash point” has a 

higher temperature, approximately 1800°C, (because the tin oxidation reaction is exothermic); therefore, 

it is critical to create a sharp, sudden, bright, single flash. This should be done by coordinating (1) He 

pressure and flow rate, (2) oxygen pressure and flow rate, and (3) sample “start time.” The system is so 

sensitive that even a 1-second difference in the sample dropping time can make a difference in the 

brightness of the flash, peak shape, peak area and, consequently, the δ34S result. The optimum set-up 

parameters of the RSIL EA are as follows: cycle = 100, oxy = 60 (O2 flow stops flowing into

autosampler), sample start = 10, and sample stop = 40. The helium regulator is set for 150 kPa, and He 

flow setup is 95 mL/min, which actually measures 120 mL/min at the vent. The oxygen regulator is set 

for 150 kPa, and the oxygen flow rate is 54 mL/min at purge. The oxygen loop is 5 mL. Oven temperature 

of the GC is 90°C. Sample size commonly ranges between 0.5 mg and 5 mg (Révész, 1998). To improve 

analytical precision, 0.6 mg V2O5 is added to each sample (Yanagisawa and Sakai, 1983). 

Even a tiny leak can interfere with the result; it can create double peaks, an unstable analysis, and so 

forth. The high He flow rate makes the system more sensitive to leaks (Bernoulli principle). Leaks can 

cause uncontrollable changes in the flow rate, which could interfere in the quantitative combustion, in the 

Prepared by: Kinga Révész and Haiping Qi RSIL SOP: 1800 

Approved by: T. B. Coplen Page 7 Effective: March 3, 2004
peak shape, in the peak area, and consequently, in the δ34S value. Ash accumulation is also critical. 

Although tin oxide serves as a catalyst in the reaction, it also partially “clogs” the system, interfering with 

the flow rate, although not necessarily in a measurable manner. However, this assumes a nonrandom

interference that causes a shift in δ34S value. By frequently analyzing isotopic reference materials, this 

shift can be corrected. However, after approximately 50 samples (one carousel), it is advisable to remove 

the ashes (Révész, 1998). The leak-checking procedure is given in Appendix I. A leak is indicated in the 

IRMS when m/z 28 and 29 are high and the ratios of m/z 28, 32, and 40 (N2, O2, and Ar) reflect 

atmospheric compositions. Acceptable levels for m/z 28 and 29 are approximately 0.15 and 0.015 V, 

respectively, with typical IRMS settings (see “Daily Checklist” in Appendix J). 

The IRMS should be focused carefully. The analyst should start with the original factory settings. In 

the RSIL, the settings (in priority order) are as follows: Extraction = 7.00; X focusing = 4.8; Voltage = 

8.00; Trap = 5.7; Electron = 7.8; Y1 focusing = 3.00; Y2 focusing = 3.8; X deflection = 6.4; Extraction = 

5.6; X-focusing symmetry = 3. Emission current is critical. The higher it is, the higher the signal will be, 

but the poorer the linearity will be. The IRMS is temperature sensitive; therefore, it must be operated in a 

temperature-controlled environment with all of the side panels on. The resistor–capacitor combination at 

the low-mass cup is 3 × 108 Ω and 680 pF. At the high-mass cup, the combination is 3 × 1010 Ω and 5 pF. 

The instrument is capable of measuring m/z 64 and 66 simultaneously (fig. 3). 

An internal precision check needs to be conducted using the “Zero Enrichment” method (standard gas 

on/off 10 times), and it must give a standard deviation of ±0.1 ‰ or better. The “Ratio Linearity” test 

must give 0.12 ‰/V or better linearity. An external precision check needs to be performed as needed, 

approximately every week or so; samples of the same amount (within ±0.010 mg) need to be analyzed. 

The 1–σ standard deviation must be ±0.2 ‰ or better for n = 10. If either of these criteria has not been 

met, the IRMS cannot be used and must be refocused. 

Maintenance and Maintenance Records 

Routine maintenance is necessary for the upkeep of the IRMS vacuum system, including

(1) checking the pump performance from time to time, (2) changing the pump oil, and (3) changing the 

oil cartridge in each turbomolecular pump at 6-month intervals. Pump conditions, including date of oil 

changes, problems, and repairs in the pump, are listed in the pump database (file path: LIMS 

C:\RSIL\vacuum pumps). Maintenance of the EA includes (1) changing the insertion tube every day 

(Appendix K), (2) changing the water trap approximately every 200 samples (Appendix L), (3) changing 

the reaction tube about every 200 to 250 analyses (Appendix M), and (4) cleaning the sample carousel 

every week. The IRMS also requires a daily check (Appendix J). A logbook is kept for each IRMS, where 

notes of maintenance checks, history of normal settings, problems, and repairs are listed. 

Maintenance of ISODAT 2.0 includes importing (transferring) results from the ISODAT 2.0 database 

to the LIMS-LSI computer hard disk and the Data Back-Up computer hard disk (Appendix G). 

Sample Retention Time and Disposal 

Samples are retained in the RSIL for at least 4 months after reporting data. Samples are then 

discarded unless the submitter has requested that the samples be returned. 

The ISODAT sample file from the IRMS computer is kept indefinitely on two different hard disks of 

the Data Back-Up computer. Paper reports are kept for a few weeks. Analytical results from the IRMS are 

transmitted to LIMS-LSI and kept indefinitely. No data are entered by hand, and no manual calculations 

are performed on the data. 

Prepared by: Kinga Révész and Haiping Qi RSIL SOP: 1800 

Approved by: T. B. Coplen Page 8 Effective: March 3, 2004
Data Acquisition, Processing, Evaluation, Quality Control, and Quality 

Assurance 

Laboratory Information Management System for Light Stable Isotope (LIMS-LSI) 

In the RSIL, the LIMS-LSI (Coplen, 2000) is used for data processing and evaluation. This system is 

a database program capable of (1) storing information about samples, (2) storing the results of mass 

spectrometric delta values of samples after importing from the ISODAT database, (3) calculating 

analytical results using standardized algorithms stored in a database, (4) normalizing delta values using 

isotopic reference materials, and (5) generating templates for convenient sample placement to facilitate 

loading of automated mass-spectrometer sample preparation manifolds and carousels. With this system, 

the following can be ensured: (1) quality assurance (QA), (2) laboratory efficiency, (3) reduction of 

workload and errors owing to the elimination of retyping of data by laboratory personnel, and 

(4) decrease of errors in data reported to sample submitters. This database provides a complete record of 

information on how laboratory reference materials have been analyzed and provides a record of what 

correction factors have been used. It provides an audit trail for the RSIL. 

Quality Control (QC) Samples 

Samples are prepared and analyzed in batches—a maximum of 80 daily. Each batch contains 

approximately six reference materials (QC samples) at the beginning: four enriched in 34S, one with an 

intermediate value, and one depleted in 34S. One set of three (depleted, intermediate, and enriched in 34S) 

is analyzed for every 10 samples. The last analyses of a batch is that of one set reference materials. The 

preparation and analytical cost of these isotopic reference materials is the responsibility of RSIL. Both 

RSIL and NWQL monitor these results. Quarterly or when requested, the RSIL prepares a summary of 

results and provides it to NWQL. 

Daily, the analyst (1) examines the computer printouts for indications of analytical problems, 

(2) determines the daily additive and expansion correction factors using the LIMS-LSI, and (3) applies 

corrections factors to isotopic data. These values with dates and analyses number ranges are recorded 

manually in the laboratory “δ34S Correction Factor” three-ring binder even though the data are already in 

the LIMS-LSI. After printing the list of δ34S values from the “Table of Samples in Progress,” the analyst 

reviews the results and determines which samples need to be analyzed a third time to achieve acceptable 

results (that is, ∆δ ≤ 0.2 ‰). 

Acceptance Criteria for All QC Samples 

Acceptance criteria for QC samples are the same as acceptance criteria for the samples. The rules are 

as follows: 

• If standard deviation is ≤ 0.2 ‰, use mean delta. 

• If there are three or more analyses, delete the outlier and recalculate. 

• If standard deviation of this recalculation is ≤ 0.2 ‰, use mean from this recalculation. 

• If none of the above is the case, the result is not accepted and corrective action is required. 

Prepared by: Kinga Révész and Haiping Qi RSIL SOP: 1800 

Approved by: T. B. Coplen Page 9 Effective: March 3, 2004
Corrective Action Requirements 

If the analyst finds any problem with the daily reference-sample data, the analyst contacts the 

supervisor. This process requires an evaluation and reanalysis of certain samples to ascertain the origin of 

the problem. 

If samples do not give satisfactory results after three or more separate analyses, the analyst averages 

all the data and reports the mean value. This analytical result is indicated with a comment, and the 

customer is advised by e-mail or other means. If the sample was submitted through the NWQL, it is the 

responsibility of the customer to determine whether the data need to be qualified. If so, the NWQL will 

mark the result in USGS databases appropriately. 

Responsible Parties for All QC/QA Functions for Procedures Covered in RSIL SOPs 

The analyst, with supervisory approval, is responsible for qualifying data and notifying customers. 

Data Management and Records 

In addition to evaluating daily sample analyses, every week an analyst evaluates the data project by

project, reports results to the customers, and files final project data reports in the laboratory

“Correspondence” binder (Appendix N). 

Health, Safety, and Waste-Disposal Information 

Applicable Health and Safety Issues 

Personal Protection 

Safety glasses and protective gloves are recommended whenever samples are handled, especially

when the samples are of biological origin. For other precautions and safety procedures, consult Material 

Safety Data Sheets (MSDSs); they are on file in the laboratory; http://www.ilpi.com/msds/#Manufacturers

provides links to MSDSs of most chemical companies. 

Electrical Hazards 

Electrical systems must conform to the National Electric Code, National Fire Protection Association 

Code (NFPA 70-1971), and the American National Standards Institute (ANSI) Code (C1-1971). Consult

the U.S. Geological Survey’s Safety and Environmental Health Handbook (U.S. Geological Survey, 

2002). 

Shock hazards exist inside the instruments. Only an authorized service representative or an individual 

with training in electronic repair must remove panels or circuit boards where voltages are greater than 

20 V. The instruments require a third-wire protective grounding conductor. Three-to-two wire adapters 

are unsafe for these instruments. 

Prepared by: Kinga Révész and Haiping Qi RSIL SOP: 1800 

Approved by: T. B. Coplen Page 10 Effective: March 3, 2004
Chemical Hazards 

The hazardous chemicals used in the process are Cr2O3 and Co3O4, which are used in the oxidation 

reaction tube, and V2O5, which is used to boost combustion. Sometimes the reaction tube cracks, and the 

packing material leaks out. When this happens, protective gloves and a full-face mask are required during 

the cleanup process. All the materials, including gloves and any cleaning towels, need to be collected in a 

plastic bag and disposed of as hazardous waste. When handling V2O5, protective gloves and a full-face 

mask also are required. All samples must be carefully inspected upon receipt for obvious indications of 

hazards. 

The SO2 reference gas is colorless and has a suffocating odor. Exposure to SO2 can cause respiratory

tract burns. Therefore, an appropriate ventilation unit must be installed in the ConFlo unit. A leak test on 

the tank of gas and the line carrying SO2 to the ConFlo must be performed routinely. 

Gas Cylinder Handling 

Compressed gas cylinders must be handled and stored according to the Safety and Environmental 

Health Handbook (U.S. Geological Survey, 2002). Each cylinder must be (1) carefully inspected when 

received; (2) securely fastened at all times with an approved chain assembly or belt; (3) capped at all 

times when not in use; (4) capped when transported; (5) transported only by a properly designed vehicle 

(hand truck); and (6) stored separately with other full, empty, flammable, or oxidizing tanks of gas, as 

appropriate. 

Specific Waste-Disposal Requirements 

Used reaction tubes containing Cr2O3, CO3O4, and V2O5 must be collected in a closed container and 

must be given to the safety, health, and environment officer for disposal. 

Prepared by: Kinga Révész and Haiping Qi RSIL SOP: 1800 

Approved by: T. B. Coplen Page 11 Effective: March 3, 2004
Revision History 

Publication Series and Series Number: Techniques and Methods 10-C1 (Book 10, Section C, Chapter 4) 

Publication Title: Determination of the δ(

34S/32S) of Total Sulfur in Solids: RSIL Lab Code 1800 

Publication Authorship: Révész, Kinga, and Qi, Haiping 

First Version and Date of First Release: July 2006 

Current Version and Date of Current Release: July 2007 

Summary of Product Components 

Component Description 

Last Revised 

In Publication Version 

Date of 

Last Revision 

List of Revisions (latest version first): 

Prepared by: Kinga Révész and Haiping Qi RSIL SOP: 1800 

Approved by: T. B. Coplen Page 12 Effective: March 3, 2004
References Cited 

Brenna, J. T., Corso, T. N., Tobias, H. J., and Caimi, R. J., 1997, High-precision continuous-flow isotoperatio mass spectrometry: Mass Spectrometry Reviews, v. 16, p. 227–258. 

Clark, I., and Fritz, P., 1997, Environmental Isotopes in Hydrogeology: Lewis Publishers, 328 p. 

Coplen, T. B., 2000, A guide for the laboratory information management system (LIMS) for light stable 

isotopes—Version 7 and 8: U. S. Geological Survey Open-File Report 00-345, 121 p. 

Coplen, T. B., and Krouse H. R., 1998, Sulfur isotope data consistency improved: Nature, v. 392, p. 32. 

Fry, B., Silva, S. R., Kendall, C., and Anderson, R. K., 2002, Oxygen isotope corrections for online δ34S 

analysis: Rapid Communications in Mass Spectrometry, v. 16, p. 1–5. 

Krouse, H. R., and Coplen, T. B., 1997, Reporting of relative sulfur isotope-ratio data: Pure and Applied 

Chemistry, v. 69, p. 293–295. 

Robinson, B. W., 1995, Sulfur Isotope Standards: Reference and intercomparison materials for stable 

isotopes of light elements, Proceedings of a consultants meeting held in Vienna, 1–3 December, 1993, 

IAEA-TECDOC 825, p. 39–45. 

Révész, K., 1998, Carbon and Nitrogen isotope ratios of organic and inorganic bulk samples: Instrument 

performance and Intercalibration: The 5th Canadian Continuous-Flow Isotope-ratio Mass Spectrometry

Workshop, Ottawa Ontario, August 16–19, 1998. 

U.S. Geological Survey, 2002, USGS Handbook 445-3-H, Safety and Environmental Health Handbook,

435 p. 

Yanagisawa, F. and Sakai, H., 1983, Thermal decomposition of barium sulfate—vanadium pentoxide—

silica glass mixtures for preparation of sulfur dioxide in sulfur isotope ratio measurements: Analytical 

Chemistry, v. 55, p. 985–987. 

Prepared by: Kinga Révész and Haiping Qi RSIL SOP: 1800 

Approved by: T. B. Coplen Page 13 Effective: March 3, 2004
Appendix A. Step-by-Step Procedure to Log-In Samples to LIMS-LSI 

1. For samples submitted through NWQL: 

a. Match up information on sample bottles with information on ASR forms by spreading out ASR 

forms and placing each bottle on its respective ASR form. Check for broken bottles. 

b. Assign NWQL #s based on the Julian date of the Monday following the submission date. Check 

note on bulletin board for “Next NWQL #.” Write NWQL #s on ASR forms, then update “Next 

NWQL #” on bulletin board. 

c. Use “New Project Log-In” in LIMS-LSI to assign S-#s; field IDs are the Station IDs. Submission 

date is the date samples are logged in. 

d. Enter all ASR information into LIMS-LSI, sample by sample. 

e. Print out two Project Reports, Labels (two for each sample), and Sample Range forms. 

f. Put a label on a sample bottle and on the corresponding ASR form; crosscheck Field IDs between 

bottles and ASR forms. 

g. Make one photocopy of each ASR form. 

h. Enter S-# range into the appropriate template. 

i. Proofread information on Sample Range forms against ASR forms (recruit help if necessary). 

Make corrections in LIMS-LSI, if necessary and print out corrected Sample Range Forms. Initial 

and date both Project Reports to indicate that proofreading is complete. 

j. In LIMS-LSI, save NWQL Headings to a diskette. 

k. In ISOTOPES e-mail on the common-use PC, copy headings into new message from diskette by

opening headings-file in Notepad and copying/pasting to new message. Print copy of headings 

and e-mail to each project chief for information review and NWQL [Attn: Jeanne Hatcher 

(jhatcher@usgs.gov)].

1. Mail copies (not originals) of ASR forms and corrected Sample Range forms to NWQL [National 

Water Quality Laboratory, Attn: Jeanne Hatcher, U.S. Geological Survey, P.O. Box 25708, MS

407, Building 95, Denver Federal Center, Denver, CO 80225-0608 (Tel: 303-236-3481)].

Envelope should be mailed every Friday.

m. Punch holes in original ASRs and put in “Central Lab” binder along with project reports and date 

on piece of tape. Punch holes in NWQL headings and other project report and place in “Samplesin-Progress” binder. 

n. Add samples to the “Table of Samples to Be Analyzed” in LIMS-LSI. 

i. Click the “Projects” button of LIMS-LSI. 

ii. Select the project that was logged in. 

iii. Click the “Templates” button. 

iv. Select “EA for S.” 

v. Click “Add” and close LIMS-LSI. 

o. Put samples in cabinets for storage until analyzed. 

2. For samples submitted directly to RSIL:

a. For sample submitter: 

i. Download “RSIL Excel Worksheet” from RSIL website at http://isotopes.usgs.gov/. 

ii. Fill out the requested sample information. 

iii. Send diskette and a hard copy along with the samples. 

b. For RSIL personnel: 

i. Match up information on sample bottles with submitted “Excel Worksheet.” 

ii. Enter all Excel Worksheet information into LIMS-LSI by loading the diskette. Submission 

date is the date samples are logged in. 

iii. Use “New Project Log-In” in LIMS-LSI to assign S-#s; field IDs are the Station IDs. 

iv. Print out one Project Reports and container labels (one for each sample). 

Prepared by: Kinga Révész and Haiping Qi RSIL SOP: 1800 

Approved by: T. B. Coplen Page 14 Effective: March 3, 2004
v. Put a label on a sample bottle and crosscheck Field ID’s between bottles and Excel 

Worksheet forms. 

vi. Enter S-# range into the appropriate template. 

vii. Punch holes in original Excel Worksheet and all the information for the project and put in 

“Samples-in-Progress” binder. 

viii. Add samples to the “Table of Samples to Be Analyzed” in LIMS-LSI. 

1. Click the “Projects” button of LIMS-LSI. 

2. Select the project that was logged in. 

3. Click the “Templates” button. 

4. Select “EA for S.” 

5. Click “Add” and close LIMS-LSI. 

ix. Put samples in cabinets for storage until analyzed. 

Prepared by: Kinga Révész and Haiping Qi RSIL SOP: 1800 

Approved by: T. B. Coplen Page 15 Effective: March 3, 2004
Appendix B. Step-by-Step Procedure to Generate an Excel Sample 

Workbook or to Print a Template and a Samples-to-Be-Analyzed List 

Excel Sample Workbook 

1. Use default worksheet-weighing template and add samples to be analyzed. 

2. Fill the appropriate amount in the cells of the rows labeled “Set weight mg.” 

3. Print first worksheet in workbook. 

4. Write the tray ID and the date on both the diskette and paper template. 

5. Put them near the balance. 

Template 

1. Use “Print Template” in LIMS-LSI. 

2. Select “appropriate template” for EA and “Delta Plus” for mass spectrometer. 

3. Select “New Template” (dialog box informs you how many samples are waiting to be analyzed). 

4. Click “OK.” 

5. Click “Print.” 

6. Insert diskette to receive sample headings. 

7. Click “OK.” 

8. Write the day of the week that these samples should be analyzed on both the diskette and paper 

template. 

9. Put them near the balance. 

10. Exit LIMS-LSI.

Prepared by: Kinga Révész and Haiping Qi RSIL SOP: 1800 

Approved by: T. B. Coplen Page 16 Effective: March 3, 2004
Worksheet 1. Weighing template.

[International reference materials are in bold font.]

 1 2 3 4 5 6 7 8 9 10 11 12 

Our Lab ID S-97 S-97 S-97 S-97 S-1301 S-1302 S-9031 S-9031 S-9032 S-9032 S-9033 S-9033

A Set weight

mg 

0.3 0.3 0.3 0.3 0.3 0.3 0.3 0.3 0.3 0.3 0.3 0.3

Actual

weight, mg 

0.3 0.29 0.31 0.31 0.304 0.298 0.299 0.302 0.305 0.303 0.305 0.303

Comment

Our Lab ID S-9034 S-9034 S-9035 S-9035 S-97 S-1301 S-1302 S-9037 S-9037 S-9038 S-9038 S-9039

B Set weight

mg 

0.3 0.3 0.3 0.3 0.3 0.3 0.3 0.3 0.3 0.3 0.3 0.3

Actual

weight, mg 

0.301 0.302 0.295 0.303 0.299 0.295 0.301 0.299 0.293 0.304 0.301 0.304

Comment

Our Lab ID S-9039 S-9040 S-9040 S-9041 S-9041 S-97 S-1301 S-1302 S-9043 S-9043 S-9044 S-9044

C Set weight

mg 

0.3 0.3 0.3 0. 3 0.3 0.3 0.3 0.3 0.3 0.3 0.3 0.3

Actual

weight, mg 

0.301 0.301 0.295 0.306 0.297 0.302 0.3 0.305 0.304 0.297 0.304 0.301

Comment

Our Lab ID S-9045 S-9045 S-9046 S-9046 S-9047 S-9047 S-97 S-1301 S-1302 S-9049 S-9049 S-9050

D Set weight

mg 

0.3 0.3 0.3 0.3 0.3 0.3 0.3 0.3 0.3 0.3 0.3 0.3

Actual

weight, mg 

0.295 0.303 0.32 0.299 0.298 0.296 0.303 0.305 0.305 0.297 0.302 0.296

Comment

Our Lab ID S-9050 S-9051 S-9051 S-9052 S-9052 S-9053 S-9053 S-97 S-1301 S-1302

E Set weight

mg 

0.3 0.3 0.3 0.3 0.3 0.3 0.3 0.3 0.3 0.3

Actual

weight, mg 

296 0.296 0.295 0.299 0.305 0.305 0.299 0.302 0.297 0.304

Comment

Prepared by: Kinga Révész and Haiping Qi RSIL SOP: 1800 

Approved by: T. B. Coplen Page 17 Effective: March 3, 2004
Worksheet 2. Samples to be analyzed.

[International reference materials are in bold font]

Line Identifier Port Comment Amount Amt Unit 

1 S-97 A1 0.3 mg

2 S-97 A2 0.29 mg

3 S-97 A3 0.31 mg

4 S-97 A4 0.31 mg

5 S-1301 A5 0.304 mg

6 S-1302 A6 0.298 mg

7 S-9031 A7 0.299 mg

8 S-9031 A8 0.302 mg

9 S-9032 A9 0.305 mg

10 S-9032 A10 0.303 mg

11 S-9033 A11 0.305 mg

12 S-9033 A12 0.303 mg

13 S-9034 B1 0.301 mg

14 S-9034 B2 0.302 mg

15 S-9035 B3 0.295 mg

16 S-9035 B4 0.303 mg

17 S-97 B5 0.299 mg

18 S-1301 B6 0.295 mg

19 S-1302 B7 0.301 mg

20 S-9037 B8 0.299 mg

21 S-9037 B9 0.293 mg

22 S-9038 B10 0.304 mg

23 S-9038 B11 0.301 mg

24 S-9039 B12 0.304 mg

25 S-9039 C1 0.301 mg

26 S-9040 C2 0.301 mg

27 S-9040 C3 0.295 mg

28 S-9041 C4 0.306 mg

29 S-9041 C5 0.297 mg

30 S-97 C6 0.302 mg

31 S-1301 C7 0.3 mg

32 S-1302 C8 0.305 mg

33 S-9043 C9 0.304 mg

34 S-9043 C10 0.297 mg

35 S-9044 C11 0.304 mg

36 S-9044 C12 0.301 mg

37 S-9045 D1 0.395 mg

38 S-9045 D2 0.303 mg

39 S-9046 D3 0.32 mg

40 S-9046 D4 0.299 mg

41 S-9047 D5 0.298 mg

Prepared by: Kinga Révész and Haiping Qi RSIL SOP: 1800 

Approved by: T. B. Coplen Page 18 Effective: March 3, 2004
Line Identifier Port Comment Amount Amt Unit 

42 S-9047 D6 0.296 mg

43 S-97 D7 0.303 mg

44 S-1301 D8 0.305 mg

45 S-1302 D9 0.305 mg

46 S-9049 D10 0.297 mg

47 S-9049 D11 0.302 mg

48 S-9050 D12 0.296 mg

49 S-9050 E1 0.296 mg

50 S-9051 E2 0.296 mg

51 S-9051 E3 0.295 mg

52 S-9052 E4 0.299 mg

53 S-9052 E5 0.305 mg

54 S-9053 E6 0.305 mg

55 S-9053 E7 0.299 mg

56 S-97 E8 0.302 mg

57 S-1301 E9 0.297 mg

58 S-1302 E10 0.304 mg

Prepared by: Kinga Révész and Haiping Qi RSIL SOP: 1800 

Approved by: T. B. Coplen Page 19 Effective: March 3, 2004
Appendix C. Step-by-Step Procedure for Weighing and Storing Samples 

1. Samples should be homogenized and dried. 

2. Insert Template diskette in the computer connected to the microbalance. 

3. Condition balance (this step should be done once a day): 

a. Place empty capsule on balance and close door. Wait for reading to stabilize (the “mg” on the 

display appears). Tare the balance. 

b. Remove and replace capsule and make sure the stabilized weight is 0.000 mg. 

c. Repeat these steps until the balance is stable. 

4. Remove capsule from balance, add sample and weigh the filled capsule. Repeat until you have 

sufficient mass to yield 40 μg of sulfur. 

5. Enter sample weight on the template. 

6. Add 600 μg ± 100 μg of V2O5 to sample. 

7. Fold cup; secure sample in it. 

8. Repeat steps 4 to 7 for every sample. 

9. Note: 

a. Do not cross-contaminate samples. 

b. Make sure the spatula and sample area are cleaned using Kimwipes between each sample. 

c. Always allow balance to stabilize before removing capsule. 

Prepared by: Kinga Révész and Haiping Qi RSIL SOP: 1800 

Approved by: T. B. Coplen Page 20 Effective: March 3, 2004
Appendix D. Step-by-Step Procedure of Zero Blank Autosampler 

Operation 

1. Before opening the lid, make sure the isolation valve (between sample chamber and reaction tube) is 

closed (arrow towards you) and make sure the He purge isolation valve (on the left) is closed. 

2. Open the purge vent on the top of the autosampler to vent the sample chamber.

3. Release the three fittings holding the lid close and open the lid. 

4. Place your samples and close the lid. Load 49 samples for a 50-position carousel, leave the first hole 

empty. 

5. Secure the lid with three bolts. Start all three bolts, and then lightly tighten two at a time, moving 

around the lid until they are all completely tight. 

6. Open the He purge isolation valve (screw down), purge the sample chamber for 5 min at He flow rate 

of 298 mL/min. Make sure the purge vent valve (on top) is open. Press your finger on top of the vent 

valve for 2 s, then release; you should hear the sound of a pressure release. 

7. Close the He purge vent valve (screw down), wait for 2 min for gas pressure at sample chamber and 

He flow rate to stabilize. Close He purge isolation valve. 

8. Open the isolation valve (arrow toward up). Wait for 2 min for stabilized baseline. Normally when 

the emission current set at 0.5 mA/0.48 mA, with He carrier flow rate of 90 mL/min, one should see 

m/z 28 on cup 1 at about 50 mV, m/z 29 on cup 2 at about 38 to 50 mV and m/z 30 on cup 3 at about 

600 mV to 1 V (Appendix J). 

Prepared by: Kinga Révész and Haiping Qi RSIL SOP: 1800 

Approved by: T. B. Coplen Page 21 Effective: March 3, 2004
Appendix E. Step-by-Step Procedure to Add Sample Information to 

Sequence Table 

1. Insert diskette with “Weighing Template” on it. 

2. Open “Sequence File” under “EA configuration.” 

3. Open “Weighing Template” in Excel. 

4. “Copy” and “Paste” the list of Sample ID, sample weight from template to sequence table. 

5. Select appropriate “method” for each sample. 

6. Define reference line and blank line. 

7. Start. 

8. Give Folder Name: Comment 

a. Select pre: “Date.” 

9. Give File Name: 

a. Select pre: “Analyzes #.” 

b. Select post: “Identifier 1.” 

c. Select: “Print Result.” 

10. Click OK. 

11. Wait for first sample to be analyzed. 

Prepared by: Kinga Révész and Haiping Qi RSIL SOP: 1800 

Approved by: T. B. Coplen Page 22 Effective: March 3, 2004
Appendix F. Step-by-Step Procedure to Retrieve Data from ISODAT 2.0 

for LIMS-LSI and for Data Back-Up 

1. For LIMS-LSI: 

a. Select “Result” in ISODAT 2.0. 

b. Select the result folder you wish to export data from.

c. Select all the individual analyses you want to retrieve by right clicking the selected file. 

d. Select “Reprocess.” 

e. Give a file name. 

f. Add export template previously designed.

g. Open. 

h. Click OK. (Reprocessing takes 1–2 min.) 

i. Open Excel. 

j. Find the file you reprocessed (E-drive, Finnigan, ISODAT 2.0, Global, User, CONFLO II, 

Interface, Result: File name). 

k. Open it in Excel. 

1. Save as: “A” drive. Keep in Lotus format. 

m. Define all reference peaks by adding #1 under column “Is Ref.?.” 

n. Now the file can be imported to LIMS-LSI. 

2. For Data Back Up Computer: 

a. Go to Windows explorer in ISODAT 2.0 computer. 

b. Find the drive where the data are (D). 

c. Choose: “Finnigan.” 

d. Choose: “User.” 

e. Choose the inlet system where you have data (Gas Bench or EA). 

f. Choose “Result folder.” 

g. Transfer data to Zip disk or “memory stick.” 

Prepared by: Kinga Révész and Haiping Qi RSIL SOP: 1800 

Approved by: T. B. Coplen Page 23 Effective: March 3, 2004
Appendix G. Step-by-Step Procedure to Transfer Data to LIMS-LSI, to 

Transfer Data to Back-Up Computer, and to Reevaluate Old Data

1. Transfer data to LIMS-LSI: 

a. Start LIMS. 

b. Choose “Import Analysis.”

c. Choose mass spectrometer “Delta Plus.” 

d. Click “Import.” 

e. Select the file that will be imported. 

f. Select columns containing δ34S data. Check the boxes to import these two columns. 

g. Click Import. Note: Sample ID, sample weight, Peak Area, Analyses #s are automatically

imported to LIMS-LSI. 

2. Transfer data to Data Back Up computer: 

a. Go to Windows Explorer in the Data Back Up computer. 

b. Find the drive your back ups are stored. 

c. Choose: “RSIL.” 

d. Choose: “Mass. Spec. Analysis Back Up.” 

e. Choose: “P.” (Stands for DeltaPlus MS). 

f. Under that folder create a new folder. The name of the folder should be the date range when those 

analyses were done that you want to back up. 

g. Transfer data to that folder. 

h. Make back ups every 2 weeks or so, as required. 

3. Reevaluate old data: 

a. Find your samples in the Data Back Up computer. 

b. Transfer data by a Zip disk to the computer where a virtual version of ISODAT 2.0 is installed. 

c. Reevaluate your data. 

Prepared by: Kinga Révész and Haiping Qi RSIL SOP: 1800 

Approved by: T. B. Coplen Page 24 Effective: March 3, 2004
Appendix H. Step-by-Step Procedure to Determine and Apply Correction 

Factors and Evaluate Data 

1. Open “Correction Factors and Normalization Equations” in LIMS-LSI. 

2. Select MS (DeltaPlus) and element. 

3. Select “Query.” 

4. Double click on the last sample analyzed on that day.

5. Evaluate data of the reference materials. 

6. Choose “Normalize with all References.” 

7. Accept “Expansion Correction and Additive Correction factors.” 

8. Print out correction factor sheet. 

9. Report daily reference values and correction factors along with date and range of analysis number to 

the “EA” binder. 

10. Go back to LIMS-LSI main menu by closing open windows. 

11. Choose “Print Samples in Progress,” 

a. Open “Sample in Progress.” 

b. Choose appropriate isotope. 

c. Choose appropriate prefix (W for water, N for nitrogen, S for sulfur). 

d. Put in sample ID range from “Samples-to-Be-Analyzed” sheet. Click Print. 

12. Review results; determine repeats. 

13. Put repeats back to Table of Samples to Be Analyzed. 

a. Go back to LIMS-LSI main menu. 

b. Open “Print Templates.” 

c. Select appropriate template name for the mass spectrometer the samples are analyzed. 

d. Find the sample in the “List of samples.” 

e. Change “Repeats” from 0 to 1. 

f. Close Windows and exit LIMS-LSI. 

Prepared by: Kinga Révész and Haiping Qi RSIL SOP: 1800 

Approved by: T. B. Coplen Page 25 Effective: March 3, 2004
Appendix I. Step-by-Step Procedure to Check Elemental Analyzer for 

Leaks 

1. Close the VENT carrier output using the proper cap (provided). 

2. Adjust the He pressure to 150 kPa (regulator is on the front central panel), wait 3 min to equilibrate 

gas in the system. 

3. Close He inlet valve by turning the above regulator counter clockwise. 

4. If the gauge needle does not move, there is no leak. 

5. If the gauge needle moves, indicating the lost of pressure, there is a leak in the system. The 

decreasing pressure rate accounts for the degree of leakage. 

6. Locate the leak by separating and testing the system segment by segment, using the He detector. 

Prepared by: Kinga Révész and Haiping Qi RSIL SOP: 1800 

Approved by: T. B. Coplen Page 26 Effective: March 3, 2004
Appendix J. Daily Checklist 

Analyst in charge: ______________________Date: ______________________

Weekly: 

1. Change working reference gas tank and He gas tank if the pressure is < 500 psi. Order new ones for a 

spare; reference gas is SO2 ANHY by Matheson, He carrier is zero grade, O2 is research grade.

2. Change water and CO2 trap after approximately 8,000 samples, or when it is necessary. 

3. Check and clean autosampler carousel. 

4. Change the reaction tube after approximately 200 or 250 samples, or when it is necessary. 

THESE ITEMS ARE TO BE CHECKED OFF AS YOU CHECK THEM DAILY! 

1. Check He, O2, and reference gas flow. [ ] 

2. Check EA reaction-tube temperature (1020 °C) 

3. Change insertion tube (ash-collector liner) in the reaction tube. [ ]

4. Check background masses. [ ]

At emission Current: 0.34 mA/0.33 mA 

Cups Mass Intensity (V) Mass Intensity (V) Mass Intensity (V) Resistor (Ω) Capacity (pF) 

1 28 0.15 44 0 64 0.002 3 × 108 680 

2 29 0.015 45 0 66 0.002 3.5 x 1010 5 

3 30 0.05–0.3 46 0.002 3 × 1011 2 

5. Perform Ref on/off method three times to stabilize IRMS. [ ]

6. Check peak center. If it is off default value by more than 50, do mass calibration. [ ]

7. Analyze Ref on/off method 10 times to stabilize IRMS (standard deviation should be better than 

±0.1 ‰). [ ]

Optimal ConFlo Pressure Setting SO2 

(bar) 

SO2 signal (V) Mass 66 on Cup 2 

0.50 3.000

8. Check paper in printer. [ ]

Prepared by: Kinga Révész and Haiping Qi RSIL SOP: 1800 

Approved by: T. B. Coplen Page 27 Effective: March 3, 2004
Appendix K. Changing the Insertion Tube 

The insertion tube needs to be changed before a template is run. 

1. Manually close needle valve near the ion source. 

2. On the menu of the Model 2500 EA under “Spc. Fun.,” choose “Std By” and press “enter.” The O2

and He should be turned off. 

3. Unscrew the metal seals under the sample carousel to access the reaction tube. 

4. Using the heat protective glove and the wire tool, remove the insertion tube from the reaction tube 

and place in the metal can. Be aware that the tube will be very hot! 

5. Insert clean tube that has 0.5 cm of quartz wool packed at the bottom, and tap it down with the wire 

tool. 

6. Replace the carousel and tighten the metal seals with a wrench. 

7. Turn the O2 and He back on by pressing “enter” and return the screen to the temperature readout by 

pressing “Spc. Fun.” 

8. Open the needle valve. 

Prepared by: Kinga Révész and Haiping Qi RSIL SOP: 1800 

Approved by: T. B. Coplen Page 28 Effective: March 3, 2004
Appendix L. Changing the Water Trap 

Change the water trap after every 200 samples. 

1. Retrieve quartz turnings, quartz wool, magnesium perchlorate, and a clean water trap from Delta

Plus

supplies. 

2. Under a hood, pack one end of the clean water trap with 1 cm of quartz wool. 

3. On a piece of wax paper, create a mix of approximately 70 % magnesium perchlorate and 30 % 

quartz turnings, pack the mix into the water trap tube, leaving 1 cm of empty space. 

4. Pack the open end of the water trap with quartz wool. 

5. Unscrew the red plastic ends from the used water trap and replace it with the clean water trap; be sure 

to replace the rubber O-rings on the ends of the clean water trap and tighten the red ends. 

6. Insert the plug into the vent and watch for any decrease in pressure to check for a leak in the system. 

If everything looks acceptable after 5 min, replace the vent line. 

7. Under the “Spc. Fun.” menu of the model 2500 EA, choose “CNT” (counter) and zero “D,” to set 

back the water-trap counter. 

8. Clean the water trap by pushing all the mixture out of the tube into the trash can and use a clean 

cotton swab to wipe out the inside of the tube. Rinse the tube with DIW, and dry it in the oven. 

Return this tube to the water trap bag in the drawer. 

Prepared by: Kinga Révész and Haiping Qi RSIL SOP: 1800 

Approved by: T. B. Coplen Page 29 Effective: March 3, 2004
Appendix M. Changing the Reaction Tube 

The reaction tube should be changed approximately every 200 to 250 samples. 

1. Manually close the needle valve near the ion source. 

2. Turn the Model 2500 EA to “Std By” with both gases off. 

3. Lower the reaction tube temperature to less than 900 °C. 

4. Retrieve the reaction tube from the cabinet. 

5. Insert the insertion tube into the top of the reaction tube; there will already be a plastic tube in the 

reaction tube that should be removed. The bottom of the reaction tube has copper in it. 

6. Place a black O-ring on the top of the reaction tube. Make sure that all O-ring connections are clean 

and free of any dust. 

7. Loosen the top metal seal and remove the bottom metal seal. Go back and completely remove the top 

seal. It will be very hot! Use oven gloves! 

8. Remove quartz reaction tube and place in metal can, place clean reaction tube in column. Make sure 

the O-ring is clean; then replace the top. 

9. On the bottom, put on the metal piece with the metal O-ring first and then add the clean rubber Oring. Raise the bottom portion and screw together. Then, tighten the connection with wrenches, and 

put the metal support back in place. 

10. Turn the gases back on; then, go to “CNT” in the menu under “Spc. Fun.” and zero “B,” the oxidation 

reaction tube as well as “A” and “C,” to set back the counter. 

11. Insert the plug into the vent and watch for any decrease in the pressure to check for a leak in the 

system. If everything looks okay after 3 min, replace the vent line. 

12. Open the needle valve. 

Prepared by: Kinga Révész and Haiping Qi RSIL SOP: 1800 

Approved by: T. B. Coplen Page 30 Effective: March 3, 2004
Appendix N. Step-by-Step Procedure to Report Data 

1. Open “Store Samples in Progress” in LIMS-LSI. 

2. Choose the appropriate isotope. 

3. Choose sample ID range from “Sample in Progress” print out. 

4. Store data. 

5. Go back to the LIMS-LSI main menu. 

6. Open “Project” and find the appropriate project in the list. 

7. Select “Print Report” and check whether the project report contains all the results. If not, search for 

the missing results in the database. 

8. Select “Results,” transfer data in Excel format or (and) text format to a diskette, and report data to 

customer through e-mail. 

9. Click “Print Report” to print a project report and put it in the “Correspondence” binder along with all 

other documents in the “Samples In Progress” binder that are related to this project. 

10. If the samples were submitted through the NWQL, click “NWQL Export” and transfer data in NWQL 

format to a disc; report these data to the NWQL by e-mail. Print a copy of the NWQL export file and 

save in the “Correspondence” binder with the project report printed in the step above. 

Prepared by: Kinga Révész and Haiping Qi RSIL SOP: 1800 

Approved by: T. B. Coplen Page 31 Effective: March 3, 2004