ASTM D3694-96(2024)

Standard Practices for Preparation of Sample Containers and for Preservation of Organic Constituents

SIGNIFICANCE AND USE
4.1 There are four basic steps necessary to obtain meaningful analytical data: preparation of the sample container, sampling, sample preservation, and analysis. In fact these four basic steps comprise the analytical method and for this reason no step should be overlooked. Although the significance of preservation is dependent upon the time between sampling and the analysis, unless the analysis is accomplished within 2 h after sampling, preservation is preferred and usually required.
SCOPE
1.1 These practices cover the various means of (1) preparing sample containers used for collection of waters to be analyzed for organic constituents and (2) preservation of such samples from the time of sample collection until the time of analysis.  
1.2 The sample preservation practice is dependent upon the specific analysis to be conducted. See Section 9 for preservation practices listed with the corresponding applicable general and specific constituent test method. The preservation method for waterborne oils is given in Practice D3325. Use of the information given herein will make it possible to choose the minimum number of sample preservation practices necessary to ensure the integrity of a sample designated for multiple analysis. For further considerations of sample preservation, see the Manual on Water.2  
1.3 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.  
1.4 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use. For specific hazard statements, see 6.7, 6.24, and 8.1.3.  
1.5 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.

General Information

• Status: Published
• Publication Date: 31-Mar-2024
• ICS: 71.040.20 - Laboratory ware and related apparatus
• Technical Committee: D19 - Water
• Drafting Committee: D19.06 - Methods for Analysis for Organic Substances in Water

Relations

• Replaces: ASTM D3694-96(2017) - Standard Practices for Preparation of Sample Containers and for Preservation of Organic Constituents
• Effective Date: 01-Apr-2024
• Refers: ASTM D5316-98(2024) - Standard Test Method for 1,2-Dibromoethane and 1,2-Dibromo-3-Chloropropane in Water by Microextraction and Gas Chromatography
• Effective Date: 01-Apr-2024
• Refers: ASTM D3871-84(2024) - Standard Test Method for Purgeable Organic Compounds in Water Using Headspace Sampling
• Effective Date: 01-Apr-2024
• Refers: ASTM D5315-04(2024) - Standard Test Method for Determination of N-Methyl-Carbamoyloximes and N-Methylcarbamates in Water by Direct Aqueous Injection HPLC with Post-Column Derivatization
• Effective Date: 01-Apr-2024
• Refers: ASTM D5412-93(2024) - Standard Test Method for Quantification of Complex Polycyclic Aromatic Hydrocarbon Mixtures or Petroleum Oils in Water
• Effective Date: 01-Apr-2024
• Refers: ASTM D4839-03(2024) - Standard Test Method for Total Carbon and Organic Carbon in Water by Ultraviolet, or Persulfate Oxidation, or Both, and Infrared Detection
• Effective Date: 01-Apr-2024
• Refers: ASTM D5175-91(2024) - Standard Test Method for Organohalide Pesticides and Polychlorinated Biphenyls in Water by Microextraction and Gas Chromatography
• Effective Date: 01-Apr-2024
• Refers: ASTM D2908-91(2024) - Standard Practice for Measuring Volatile Organic Matter in Water by Aqueous-Injection Gas Chromatography
• Effective Date: 01-Apr-2024
• Refers: ASTM D3973-85(2024) - Standard Test Method for Low-Molecular Weight Halogenated Hydrocarbons in Water
• Effective Date: 01-Apr-2024
• Refers: ASTM D5316-98(2017) - Standard Test Method for 1,2-Dibromoethane and 1,2-Dibromo-3-Chloropropane in Water by Microextraction and Gas Chromatography
• Effective Date: 15-Dec-2017
• Refers: ASTM D4839-03(2017) - Standard Test Method for Total Carbon and Organic Carbon in Water by Ultraviolet, or Persulfate Oxidation, or Both, and Infrared Detection
• Effective Date: 15-Dec-2017
• Refers: ASTM D3973-85(2017) - Standard Test Method for Low-Molecular Weight Halogenated Hydrocarbons in Water
• Effective Date: 15-Dec-2017
• Refers: ASTM D5175-91(2017)e1 - Standard Test Method for Organohalide Pesticides and Polychlorinated Biphenyls in Water by Microextraction and Gas Chromatography
• Effective Date: 15-Dec-2017
• Refers: ASTM D3871-84(2017) - Standard Test Method for Purgeable Organic Compounds in Water Using Headspace Sampling
• Effective Date: 15-Dec-2017
• Refers: ASTM D2908-91(2017) - Standard Practice for Measuring Volatile Organic Matter in Water by Aqueous-Injection Gas Chromatography
• Effective Date: 15-Dec-2017

Overview

ASTM D3694-96(2024), Standard Practices for Preparation of Sample Containers and for Preservation of Organic Constituents, is a key international standard developed by ASTM International. This standard outlines best practices for preparing sample containers and preserving water samples that are to be analyzed for organic constituents. By following ASTM D3694, laboratories, environmental professionals, and regulatory agencies can ensure sample integrity and generate reliable analytical data for organic chemical analysis in water.

Effective preservation and proper sample container preparation are critical steps for achieving accurate results in water quality testing, especially when analysis cannot occur within two hours of sampling. The standard applies to various water matrices and provides broad guidance adaptable to multiple testing scenarios.

Key Topics

• Sample Container Preparation:
  • Instructions for cleaning and preparing borosilicate glass and HDPE bottles for sample collection.
  • Use of appropriate closures, such as PTFE-faced caps, to prevent sample contamination.
  • Cleaning protocols, including detergent, acid, acetone, and chromic acid treatments.
• Sample Preservation Techniques:
  • Guidance on selecting preservatives (e.g., sulfuric acid, hydrochloric acid, sodium bisulfate, mercuric chloride) based on the target organic constituents.
  • Recommendations for adjusting sample pH to inhibit biological or chemical degradation.
  • Procedures for hermetic sealing and minimizing headspace in volatile organic analyses.
  • Special precautions for avoiding photodecomposition and managing samples containing chlorine, sulfides, or high carbonate content.
• Sample Holding Times:
  • Maximum allowable holding times for common test methods are listed, supporting compliance with both ASTM and U.S. EPA regulations.
  • Advice to discard samples exceeding recommended holding times to avoid compromised results.
• Safety and Compliance:
  • Adherence to safety, health, and environmental practices.
  • User responsibility for complying with applicable regulatory limits and hazard guidelines.

Applications

ASTM D3694 is widely applied across industries and regulatory settings where water quality monitoring and environmental compliance are required, such as:

• Environmental Laboratories:
  Ensuring consistent practices for the preparation and preservation of water samples for organic compound analyses.
• Regulatory Compliance:
  Supporting U.S. EPA and international guidelines for water pollutant testing, including holding time requirements in 40 CFR Part 136.
• Industrial Water Monitoring:
  Preserving water samples for process control, discharge compliance, and environmental impact assessments.
• Research and Academic Studies:
  Providing a standard reference for preservation when studying organic pollutants in various water bodies.

Implementing this standard ensures high-quality water sample collection, minimized degradation of organic constituents, and reliable data for decision-making.

Related Standards

The following ASTM standards support and complement ASTM D3694 practices for water analysis and sample handling:

• ASTM D1129 – Terminology Relating to Water
• ASTM D1193 – Specification for Reagent Water
• ASTM D3325 – Practice for Preservation of Waterborne Oil Samples
• ASTM D1252, D1783, D2036, D2579, D3534, D3590, etc. – Various methods for determining organic compounds, phenols, cyanides, PCBs, and more in water
• ASTM D4515 and D4841 – Practices for estimating sample holding times
• EPA 40 CFR Part 136 – Guidelines for establishing test procedures for water pollutant analysis

Keywords

sample preservation, sample container preparation, water analysis, organic constituents, ASTM D3694, holding times, environmental testing, laboratory best practices, water sample integrity, regulatory compliance

ASTM D3694-96(2024) forms the backbone of best practices for reliable water sampling and preservation in environmental and laboratory contexts. Following this international standard helps maintain analytical accuracy and supports global water quality initiatives.

Standards Content (Sample)

This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the
Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
Designation: D3694 − 96 (Reapproved 2024)
Standard Practices for
Preparation of Sample Containers and for Preservation of
Organic Constituents
This standard is issued under the fixed designation D3694; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope 2. Referenced Documents
2.1 ASTM Standards:
1.1 These practices cover the various means of (1) preparing
sample containers used for collection of waters to be analyzed D1129 Terminology Relating to Water
D1193 Specification for Reagent Water
for organic constituents and (2) preservation of such samples
from the time of sample collection until the time of analysis. D1252 Test Methods for Chemical Oxygen Demand (Di-
chromate Oxygen Demand) of Water
1.2 The sample preservation practice is dependent upon the
D1783 Test Methods for Phenolic Compounds in Water
specific analysis to be conducted. See Section 9 for preserva-
D2036 Test Methods for Cyanides in Water
tion practices listed with the corresponding applicable general
D2330 Test Method for Methylene Blue Active Substances
and specific constituent test method. The preservation method
D2579 Test Method for Total Organic Carbon in Water
for waterborne oils is given in Practice D3325. Use of the
(Withdrawn 2002)
information given herein will make it possible to choose the
D2580 Test Method for Phenols in Water by Gas-Liquid
minimum number of sample preservation practices necessary
Chromatography (Withdrawn 2021)
to ensure the integrity of a sample designated for multiple
D2908 Practice for Measuring Volatile Organic Matter in
analysis. For further considerations of sample preservation, see
2 Water by Aqueous-Injection Gas Chromatography
the Manual on Water.
D3113 Test Methods for Sodium Salts of EDTA in Water
1.3 The values stated in SI units are to be regarded as
(Withdrawn 2005)
standard. No other units of measurement are included in this
D3325 Practice for Preservation of Waterborne Oil Samples
standard.
D3371 Test Method for Nitriles in Aqueous Solution by
Gas-Liquid Chromatography (Withdrawn 2002)
1.4 This standard does not purport to address all of the
D3534 Test Method for Polychlorinated Biphenyls (PCBs)
safety concerns, if any, associated with its use. It is the
in Water (Withdrawn 2003)
responsibility of the user of this standard to establish appro-
D3590 Test Methods for Total Kjeldahl Nitrogen in Water
priate safety, health, and environmental practices and deter-
D3695 Test Method for Volatile Alcohols in Water by Direct
mine the applicability of regulatory limitations prior to use.
Aqueous-Injection Gas Chromatography
For specific hazard statements, see 6.7, 6.24, and 8.1.3.
D3856 Guide for Management Systems in Laboratories
1.5 This international standard was developed in accor-
Engaged in Analysis of Water (Withdrawn 2024)
dance with internationally recognized principles on standard-
D3871 Test Method for Purgeable Organic Compounds in
ization established in the Decision on Principles for the
Water Using Headspace Sampling
Development of International Standards, Guides and Recom-
D3921 Test Method For Oil and Grease and Petroleum
mendations issued by the World Trade Organization Technical
Hydrocarbons in Water (Withdrawn 2013)
Barriers to Trade (TBT) Committee.
D3973 Test Method for Low-Molecular Weight Halogenated
Hydrocarbons in Water
These practices are under the jurisdiction of ASTM Committee D19 on Water
and are the direct responsibilities of Subcommittee D19.06 on Methods for Analysis For referenced ASTM standards, visit the ASTM website, www.astm.org, or
for Organic Substances in Water. contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM
Current edition approved April 1, 2024. Published April 2024. Originally Standards volume information, refer to the standard’s Document Summary page on
approved in 1978. Last previous edition approved in 2017 as D3694 – 96 (2017). the ASTM website.
DOI: 10.1520/D3694-96R24. The last approved version of this historical standard is referenced on
Manual on Water, ASTM STP 442, ASTM International, 1969. www.astm.org.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
D3694 − 96 (2024)
D4129 Test Method for Total and Organic Carbon in Water D5790 Test Method for Measurement of Purgeable Organic
by High Temperature Oxidation and by Coulometric Compounds in Water by Capillary Column Gas
Chromatography/Mass Spectrometry
Detection
D5812 Test Method for Determination of Organochlorine
D4165 Test Method for Cyanogen Chloride in Water
Pesticides in Water by Capillary Column Gas Chromatog-
D4193 Test Method for Thiocyanate in Water
raphy (Withdrawn 2011)
D4281 Test Method for Oil and Grease (Fluorocarbon Ex-
tractable Substances) by Gravimetric Determination
4 3. Terminology
(Withdrawn 2012)
3.1 Definitions:
D4282 Test Method for Determination of Free Cyanide in
3.1.1 For definitions of terms used in this standard, refer to
Water and Wastewater by Microdiffusion
Terminology D1129.
D4374 Test Methods for Cyanides in Water—Automated
Methods for Total Cyanide, Weak Acid Dissociable
4. Significance and Use
Cyanide, and Thiocyanate (Withdrawn 2012)
4.1 There are four basic steps necessary to obtain meaning-
D4515 Practice for Estimation of Holding Time for Water
ful analytical data: preparation of the sample container,
Samples Containing Organic Constituents (Withdrawn
sampling, sample preservation, and analysis. In fact these four
2006)
basic steps comprise the analytical method and for this reason
D4657 Test Method for Polynuclear Aromatic Hydrocarbons
no step should be overlooked. Although the significance of
in Water (Withdrawn 2005)
preservation is dependent upon the time between sampling and
D4744 Test Method for Organic Halides in Water by Carbon
the analysis, unless the analysis is accomplished within 2 h
AdsorptionMicrocoulometric Detection (Withdrawn
4 after sampling, preservation is preferred and usually required.
2002)
D4763 Practice for Identification of Chemicals in Water by
5. Apparatus
Fluorescence Spectroscopy
5.1 Forced Draft Oven, capable of operating at 275 °C to
D4779 Test Method for Total, Organic, and Inorganic Car-
325 °C.
bon in High Purity Water by Ultraviolet (UV) or Persul-
fate Oxidation, or Both, and Infrared Detection (With-
5.2 Sample Bottle, borosilicate or flint glass.
drawn 2002)
NOTE 1—High density polyethylene (HDPE) bottles and caps have been
D4839 Test Method for Total Carbon and Organic Carbon in
demonstrated to be of sufficient quality to be compatible for all tests
Water by Ultraviolet, or Persulfate Oxidation, or Both, and except pesticides, herbicides, polychlorinated biphenyls, and volatile
organics. However, this bottle cannot be recycled.
Infrared Detection
D4841 Practice for Estimation of Holding Time for Water
5.3 Sample Bottle Cap, TFE-fluorocarbon or aluminum
Samples Containing Organic and Inorganic Constituents foil-lined.
D4983 Test Method for Cyclohexylamine, Morpholine, and
NOTE 2—Even these liners have some disadvantages. TFE is known to
Diethylaminoethanol in Water and Condensed Steam by
collect some organic constituents, for example, PCBs. Aluminum foil will
Direct Aqueous Injection Gas Chromatography (With- react with samples that are strongly acid or alkaline. Clean TFE liners as
described in 7.1. Replace aluminum foil with new foil after each use.
drawn 2002)
D5175 Test Method for Organohalide Pesticides and Poly- 5.4 Sample Vial, glass.
chlorinated Biphenyls in Water by Microextraction and
5.5 Septa, PTFE-faced with screw cap lid and matching
Gas Chromatography
aluminum foil disks.
D5176 Test Method for Total Chemically Bound Nitrogen in
Water by Pyrolysis and Chemiluminescence Detection
6. Reagents and Materials
D5315 Test Method for Determination of N-Methyl-
6.1 Purity of Reagents—Reagent grade chemicals shall be
Carbamoyloximes and N-Methylcarbamates in Water by
used in all tests. Unless otherwise indicated, it is intended that
Direct Aqueous Injection HPLC with Post-Column De-
all reagents shall conform to the specifications of the Commit-
rivatization
tee on Analytical Reagents of the American Chemical Society.
D5316 Test Method for 1,2-Dibromoethane and 1,2-
Other grades may be used, provided it is first ascertained that
Dibromo-3-Chloropropane in Water by Microextraction
the reagent is of sufficiently high purity to permit its use
and Gas Chromatography
without lessening the accuracy of the determination.
D5317 Test Method for Determination of Chlorinated Or-
6.2 Purity of Water—Unless otherwise indicated, reference
ganic Acid Compounds in Water by Gas Chromatography
to water shall be understood to mean reagent water conforming
with an Electron Capture Detector
D5412 Test Method for Quantification of Complex Polycy-
clic Aromatic Hydrocarbon Mixtures or Petroleum Oils in
ACS Reagent Chemicals, Specifications and Procedures for Reagents and
Standard-Grade Reference Materials, American Chemical Society, Washington,
Water
DC. For suggestions on the testing of reagents not listed by the American Chemical
D5475 Test Method for Nitrogen- and Phosphorus-
Society, see Analar Standards for Laboratory Chemicals, BDH Ltd., Poole, Dorset,
Containing Pesticides in Water by Gas Chromatography
U.K., and the United States Pharmacopeia and National Formulary, U.S. Pharma-
with a Nitrogen-Phosphorus Detector (Withdrawn 2011) copeial Convention, Inc. (USPC), Rockville, MD.
D3694 − 96 (2024)
to Specification D1193, Type II and demonstrated to be free of of H SO (1 + 1). (Warning—Prepare and use this reagent in
2 4
specific interference for the test being performed. a well ventilated hood to avoid exposure to SO fumes.)
6.3 Acetic Acid Buffer Solution (pH 4)—Dissolve 6.0 g of
6.27 Sodium Sulfite Solution (0.1 M)—Transfer approxi-
sodium acetate in 75 mL of water. Add 30 mL of glacial acetic
mately 10.3 g of sodium sulfite to a 1 L volumetric flask. Dilute
acid, with stirring.
to volume with water.
6.4 Acetone.
6.28 Sodium Thiosulfate.
6.5 Acid Buffer Solution (pH 3.75)—Dissolve 125 g of
6.29 Sodium Hydroxide Pellets.
potassium chloride and 70 g of sodium acetate trihydrate in
6.30 Mercuric Chloride (10 mg/mL)—Dissolve 100 mg of
500 mL of water. Add 300 mL of glacial acetic acid and dilute
HgCl in reagent water and dilute to 10 mL.
to 1 L.
6.31 Sulfuric Acid (1 + 1)—Slowly and carefully add 1 vol
6.6 Ascorbic Acid.
of sulfuric acid (see 6.27) to 1 vol of water, stirring and cooling
6.7 Chromic Acid Cleaning Solution—To a 2 L beaker, add
the solution during addition.
35 mL of saturated sodium dichromate solution followed by
1 L of sulfuric acid (sp gr 1.84) with stirring. (Warning—Use
7. Preparation of HDPE Sample Bottles
rubber gloves, safety goggles, and protective clothing when
preparing and handling this corrosive cleaning agent that is a 7.1 Wash the bottles with two 100 mL portions of HCl
powerful oxidant. Store the reagent in a glass bottle with a
(1 + 2) and rinse with three 100 mL portions of water. These
glass stopper.) volumes of wash and rinse portions are recommended for 1 L
sample bottles; therefore, use proportionate volumes for wash-
6.8 Detergent, formulated for cleaning laboratory glass-
ing and rinsing sample bottles of a different volume.
ware.
6.9 Hydrochloric Acid—Concentrated HCl (sp gr 1.19).
8. Preparation of Glass Sample Bottles and Vials
6.10 Hydrochloric Acid (1 + 2)—To 200 mL of water, care-
8.1 Solvent-Detergent/Chromic Acid Preparation of Glass
fully add 100 mL of hydrochloric acid (see 6.9). Store in a
Sample Bottles:
glass-stoppered reagent bottle.
8.1.1 Rinse the container with 100 mL of dilute detergent or
6.11 Ice, crushed wet.
acetone. For some residues, a few alternative detergent and
acetone rinses may be more satisfactory. Then rinse at least
6.12 Lead Acetate Test Paper.
three times with tap water followed by a reagent water rinse to
6.13 Lead Acetate Solution—Dissolve 50 g of lead acetate
remove the residual detergent or acetone, or both.
in water and dilute to 1 L.
8.1.2 Rinse the container with 100 mL of chromic acid
6.14 Lead Carbonate, powdered. solution, returning the chromic acid to its original container
after use. Then rinse with at least three 100 mL portions of tap
6.15 Lime, Hydrated, powdered.
water followed by a reagent water rinse.
6.16 Mercuric Chloride.
8.1.3 Rinse the container with 100 mL of NaHSO solution
6.17 Monochloroacetic Acid Buffer (pH 3)—Prepare by to remove residual hexavalent chromium. (Warning—Carry
out this step in a hood to prevent exposure to SO fumes.)
mixing 156 mL of chloroacetic acid solution (236.2 g/L) and
100 mL of potassium acetate solution (245.4 g/L).
8.1.4 Rinse the container with water until sulfurous acid and
its vapors have been removed. Test rinsings for acid with a pH
6.18 Nitric Acid—Concentrated HNO (sp gr 1.42).
meter or an appropriate narrow range pH paper. Rinsings
6.19 Phosphate Buffer—Dissolve 138 g of sodium dihydro-
should have a pH approximately the same as the water used for
gen phosphate in water and dilute to 1 L. Refrigerate this
rinsing.
solution.
8.1.5 When the last trace of NaHSO has been removed,
6.20 Phosphate Solution—Dissolve 33.8 g of potassium di- wash with three additional 100 mL portions of water. Allow to
hydrogen phosphate in 250 mL of water.
drain. This procedure is for 1 L sample containers, therefore,
use proportionate volumes for washing and rinsing sample
6.21 Phosphoric Acid—Concentrated H PO (sp gr 1.83).
3 4
containers of a different volume.
6.22 Phosphoric Acid Solution (1 + 1)—Dilute 1 vol of
8.1.6 Heat for a minimum of 4 h (mouth up) in a forced draft
phosphoric acid (sp gr 1.83).
oven at 275 °C to 325 °C. Upon cooling, fit the bottles with
6.23 pH Paper, narrow range for pH < 2, pH > 12, and pH caps and the vials with septa.
5 to 7.
NOTE 3—For some tests, heating may not be required. Refer to the
6.24 Potassium Iodide–Starch Test Paper. individual method to determine the necessity for this treatment.
6.25 Sodium Bisulfate. 8.2 Machine Washing Glass Sample Bottles and Vials:
6.26 Sodium Bisulfite Solution—Dissolve 2 g of sodium
NOTE 4—Machine washing of narrow mouth sample bottles may not
bisulfite in 1 L of water and adjust to pH 2 by the slow addition yield acceptable results.
D3694 − 96 (2024)
TABLE 2 Recommended Preservation Practice for Specific
8.2.1 Rinse the container with 100 mL of chromic acid
Organic Constituent Test Methods
solution, returning the chromic acid to its original container
Test Method(s) Recommended Practice
after use. Then rinse with at least three 100 mL portions of tap
D1783 Phenolic compounds by 9.1.3 refrigeration and 9.1.1.1 sulfuric acid
water.
4-AAP or 9.1.1.3 sodium bisulfate or 9.1.1.2 hy-
8.2.2 Machine wash in accordance with the machine manu-
drochloric acid or 9.1.1.5 phosphoric acid
A
facturer’s instructions using a detergent and 90 °C water. D2036 Cyanide 9.1.1.4 sodium hydroxide and in presence
of chlorine 9.1.2 chlorine removal
8.2.3 Remove the bottles from the machine and rinse them
D2330 Alkyl benzene sulfonate 9.1.1.1 sulfuric acid or 9.1.1.3 sodium bisul-
with two 100 mL portions of HCl (1 + 2), followed with three
fate
100 mL portions of water. D2580 Phenols by gas liquid chro- 9.1.3 refrigeration
matography
8.2.4 Heat for a minimum of 4 h (mouth up) in a forced draft
D2908 Volatile organic matter in 9.1.3 refrigeration and 9.1.1.1 sulfuric acid
oven at 275 °C to 325 °C. Upon cooling, fit the bottles with
water by aqueous injection gas or 9.1.1.3 sodium bisulfate
chromatography (DAIGC)
caps and the vials with septa (see Note 3).
D3856 Pesticides, organochlorine 9.1.3 refrigeration
D3113 Ethylenediaminetetraace- 9.1.3 refrigeration
9. Sample Preservation
tate
D3371 Nitriles by DAIGC 9.1.3 refrigeration and 9.1.1.1 sulfuric acid
9.1 Depending upon the type of analysis required, use any
or 9.1.1.3 sodium bisulfate
one or a combination of the following methods of sample
D3534 Polychlorinated biphenyls 9.1.3 refrigeration
D3590 Total nitrogen, Kjeldahl 9.1.3 refrigeration and 9.1.1.1 sulfuric acid
preservation (see Tables 1-3, Annex A1, and Annex A2).
D3695 Volatile alcohols by DAIGC 9.1.3 refrigeration and 9.1.1.1 sulfuric acid
9.1.1 Adjust the pH. An adjustment to neutral pH is usually
or 9.1
...