QA/QC and Method Performance 

Considerations for Chemical TesConsiderations for Chemical Tes

Samples Impacted by HF Fluids

EPA Hydraulic Fracturing Technical Workshop EPA Hydraulic Fracturing Technical WorkshopArlington, VirginiaFebruary 24 - 25, 2011David Thal – Senior Technical Chemist Environmental Standards, Inc.
Today’s Discussion

 QA/QC for EPA-funded projects as a model Critical elements of environmental testing QA/Q Types of analytical methods being routinely app Types of QA/QC demonstrations and QA/QC sa Rough Guide: What QA/QC is needed? Specific information on interferences encountere Summary

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Elements of QA/QC

 Guidance on Systematic Planning Using the 

Quality Objectives Process EPA QA/G-4

 “The principal DQIs are precision, bias (accurac

representativeness, completeness, comparabilitsensitivity.”

 EPA Requirements for Quality Assurance Pro

Plans EPA EPA QA/R-5 

 References “PARCC” parameters

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Are the PARCC Parameters Sufficie

Precision (Test-retest reliability)Accuracy (Comparison of result to consensus value)Representativeness (Does sample reflect population?) epresentativeness (Does sample reflect population?)Completeness (Data of good quality on a sufficient percenta

samples?) 

Comparability (Does the data set make sense within broade

omparability (Does the data set make sense within broade

sets?)

 What about 

Sensitivit

y? 

(EPA QA/G-4 mentions it. Among 10 states and agency gdocuments checked only Connecticut lists it – as PARCC

 What about 

Selectivity? 

(B i d i th th d th i d f l ti l h i t (Burie

d in the meth

o

ds or the min

ds o

f analytical c

hemis

t

 SPARCCS would be a better mnemonic. 4
Frequently Encountered Types of Meth

Related to Shale Gas Related to Shale Gas

 Classical Chemistry - pH, TKN, Anions, Alkalinity, Hardne

and grease)

 G Ch t h Gas Chroma

tograp

hy 

- M th Eth G li Di 

M

ethane, Ethane, 

Gasoline, Dies

Range Organics, 

 Metals Determinations - Alkali Metals. Divalent and other 

i l di M including 

Mercury. 

(ICP-AES, ICP-MS & CVAA)

 NORM - Gamma Spectrometry, Gross alpha, Gross beta.

 Specialties

– Alkoxyalkylphenols, organic acids other orga

(GC-MS, LC-MS/MS)

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Types of QA/QC Samples and Demonst

 I iti l D t ti f C bilit Initi

al Demons

tration o

f

Capabilit

y

 Method Detection Limit Studies Standard Reference Materials (Natural matrix if ava

Standard Reference Materials (Natural matrix if ava

 Blind Performance Evaluation Samples Trip Blanks (VOCs) Equipment Blanks Instrument Blanks Laboratory Method Blanks Laboratory Method Blanks Laboratory Control Samples Matrix Spikes

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 Laboratory Duplicates or Matrix Spike Duplicates
QA/QC – Expect Good Practices

QA/QC Check Classical Chemistry GC-VOC (&GRO) GC- SVOC ICP-AES /ICP-MS NO

Initial Demonstration of Capability Yes Yes Yes Yes So

Method Detection Limit Studies Most Yes Yes Yes (M

Standard Reference Materials Yes Yes Yes Yes Y

Blind PE Samples Yes Yes Yes Yes So

Trip Blanks (VOCs) Yes

Equipment Equipment Blanks Rare Yes Yes Yes R

Instrument Blanks Yes Yes Yes 

Method Blanks Yes Yes Yes Yes Y

Laboratory Control Samples Yes Yes Yes Yes Y

Matrix Spikes. Some Yes Yes Yes Y

Laboratory Dup or Matrix Spike Dups. Yes Yes Yes Yes Y

Dilution Check Yes

Post Dilution Spike Yes

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Post Dilution Spike Yes
Example Data Set

 T tA i N h ill id d d t t i l d

TestAmerica Nashville provided a data set includ

(depending on the analysis) up to 542 samples.

 Samples were from 5 sites across the Marcellus 

Samples were from 5 sites across the Marcellus 

formation.

 Most frequent test was Chloride.

 Oth t t t i l d d M t l GRO D

Other test parameters included: Metals, GRO, D

ORO, 2-butoxyethanol, alkalinity, ammonia as niarsenic, barium, bicarbonate, btu content, HEM, 

Oil and Grease, Sulfate, Sulfide, TSS, TDS, TPH

 These samples were examined for potential inte

listed in methods and based on experience

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listed in methods, and based on experience.
Interferences

 Dissol ed Solids Dissolved Solids - Highl minerali ed aters containing 

Highly mineralized waters containing 

concentrations of calcium, magnesium, chloride and/or su

 Total residue should be limited to about 200 mg. (On a 10

this would be 2000 mg/L 3 4% of the anecdotal samples this would be 2000 mg/L, 3.4% of the anecdotal samples.

 Alkalinity - (Titrimetric Method 310.1) and pH. Oil and gre

coat the electrode causing sluggish response.

 For samples having high concentrations of mineral acids, 

For samples having high concentrations of mineral acids, 

modifications are needed (titrate to an electrometric endpo3.9,using ASTM Standard, D- 067, Method D or supersed

 Anions (Chloride, Fluoride, Bromide, Nitrite, Nitrate, P

Sf ) ul ate) - Any species with a retention time similar to tha

desired anion will interfere. Example, high levels of organmay interfere with inorganic anion analysis may be presen

organic acid homopolymers polymers and telomers are u

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organic acid homopolymers, polymers and telomers are u

fracturing fluids.
Interferences (Cont.)

 Total Kjeldahl Nitrogen (Automated Colorimetry 351.2) - High 

concentrations (10X or more than the TKN level) result in low TIon Selecitve Electrode 351.4): The reaction between nitrate acan b t d b th f i h i ( hl 

be prevente

d

by the use of an anion exc

hange resin (chlo

remove the nitrate prior to the TKN analysis.

 Barium (ICP-AES or MS, e.g. 200.7, 6010, 6020) - The total 

sample digestion procedure will sample digestion procedure will solubilize solubilize and hold in solution 

and hold in solution 

concentrations of barium in the presence of free sulfate.

 Metals by ICP-AES (e.g., 200.7, 6010) - High viscosity and lo

tension can impair sample nebulization and transport processe

significant inaccuracies esp. in samples w/ high dissolved solidacid concentrations.

 Barium can be an interference above the SIC level for ICP-AE

can cause interferences both in the metals analysis and the N

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can cause interferences both in the metals analysis and the N

analyses. (Co-precipitation.)
Interferences (Cont.)

ICP-MS Interference Check Standard (concentration in chCa (300 mg/L); Fe (250 mg/L); Mg (100.0 mg/L); Na (250 250.0; K (100 mg/L); Cl (2000 mg/L). 3.0% of 439 samples exceeded the Ca check standard 

Higher literature values exceed the check standard conc

100-fold.

 One of 74 samples exceeded the Fe check standard lev 1.3% of 381 samples exceeded the Mg check standard 

Higher values reported in the literature exceed 25 times Higher values reported in the literature exceed 25 times 

interference check standard level.

 10% of the samples exceeded the Na check standard le

 4% exceeded the K check standard level

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4% exceeded the

K check standard level.

 1.8% of the 542 samples exceeded the Cl check standa
Summary – and some thoughts to 

discussion

 M t d d l ti l th d l h th ill f 

Many stan

dar

d analytical meth

o

ds apply; 

however, they will perfor

some cases involving high levels of interferents. The interferences characterized, but a careful evaluation of the entire data set is neeunderstand the 

potential biases.

 For Metals, ICP-MS alone is not a good fit. 

 ICP-Atomic Emission Spectrometry is needed to overcome many inte

 Total Dissolved Solids data should be scrutinized. 

 Use field duplicates and evaluate carefully.

 If anion data set does not make sense, consider method of standa Watch barium levels.

 If th t i t t hi h i l ti l h i t 

If they are not consistent, or hi

g

h engage a senior analytical c

hemist 

 Watch sulfate levels. 

 They can cause a low bias in barium.

 Watch nitrate levels

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Watch nitrate levels. 

 They can cause low bias in TKN.
Questions?

E i t l St d d I Environmental Standards, Inc.

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Ten

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