ASTM D4128-06(2012)

NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
Contact ASTM International (www.astm.org) for the latest information
Designation:D4128 −06 (Reapproved 2012)
Standard Guide for
Identification and Quantitation of Organic Compounds in
Water by Combined Gas Chromatography and Electron
Impact Mass Spectrometry
This standard is issued under the fixed designation D4128; 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 all modes of sample introduction, including injection of or-
ganic extracts, direct aqueous injection, and purge and trap
1.1 This guide covers the identification and quantitation of
techniques.
organic compounds by gas chromatography/mass spectrometry
(GC-MS) (electron impact) that are present or extracted from 1.4 The guide is applicable to either packed or capillary
water and are capable of passing through a gas chromatograph column gas chromatography, including wide-bore capillary
without alteration. The guide is intended primarily for solu- columns. Because of their greatly enhanced resolution, capil-
tions for which 1 ng or more of any component of interest can lary columns are strongly recommended.
be introduced onto a gas chromatographic column. This guide
1.5 This standard does not purport to address all of the
has the advantage of providing tentative identifications of
safety concerns, if any, associated with its use. It is the
volatile and semi-volatile organics, but is restricted to (a)
responsibility of the user of this standard to establish appro-
compoundsforwhichreferencespectracanbeobtainedand(b)
priate safety, health, and environmental practices and deter-
compoundsthatcanbeseparatedbygaschromatography(GC).
mine the applicability of regulatory limitations prior to use.
These restrictions are imposed on the guide, but are not a
1.6 This international standard was developed in accor-
limitation of the technique. The guide is written for, but not
dance with internationally recognized principles on standard-
restricted to, analysis using automated data acquisition and
ization established in the Decision on Principles for the
handling.
Development of International Standards, Guides and Recom-
mendations issued by the World Trade Organization Technical
1.2 Guidelines have been included for quantitation using
Barriers to Trade (TBT) Committee.
ASTM Test Methods D3871, D3973, and other GC-MS
volatile/semivolatile procedures used for environmental analy-
2. Referenced Documents
sis . A detection amount of 1 ng can only be considered
approximate. The actual detection limits for each component
2.1 ASTM Standards:
must be determined in each laboratory. Actual detection
D1066 Practice for Sampling Steam
amounts will vary with the complexity of the matrix, the kind
D1129 Terminology Relating to Water
and condition of the GC-MS system, the sample preparation
D1192 Guide for Equipment for Sampling Water and Steam
technique chosen, and the application of cleanup techniques to
in Closed Conduits (Withdrawn 2003)
the sample extract, if any. Lower levels of detection can be
D1193 Specification for Reagent Water
achieved using modern sensitive instruments or with selected
D2908 Practice for Measuring Volatile Organic Matter in
ion monitoring (SIM). To determine the interlaboratory detec-
Water by Aqueous-Injection Gas Chromatography
tion estimate (IDE) and the interlaboratory quantitation esti-
D3370 Practices for Sampling Water from Closed Conduits
mate (IQE), follow Practices D6091 and D6512.
D3694 Practices for Preparation of Sample Containers and
for Preservation of Organic Constituents
1.3 The guide is applicable to the identification of many
D3871 Test Method for Purgeable Organic Compounds in
organic constituents of natural and treated waters. It includes
Water Using Headspace Sampling
D3973 TestMethodforLow-MolecularWeightHalogenated
This guide is under the jurisdiction ofASTM Committee D19 on Water and is
the direct responsibility of Subcommittee D19.06 on Methods for Analysis for
Organic Substances in Water For referenced ASTM standards, visit the ASTM website, www.astm.org, or
Current edition approved June 15, 2012. Published August 2012. Originally contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
published in 1982. Last previous edition approved in 2006 as D4128 – 06. DOI: Standards volume information, refer to the standard’s Document Summary page on
10.1520/D4128-06R12. the ASTM website.
2 4
U.S. EPA Methods 624 and 8260 (volatiles) and U.S. EPA Methods 625 and The last approved version of this historical standard is referenced on
8270 (semivolatiles) are suitable for quantitation. www.astm.org.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
D4128−06 (2012)
Hydrocarbons in Water elution of the sample component at the same retention time as
D5175 Test Method for Organohalide Pesticides and Poly- the standard component as shown by co-injection or standard
chlorinated Biphenyls in Water by Microextraction and addition, and (2) correspondence of the sample component and
Gas Chromatography the standard component mass spectrum. If co-elution of inter-
D5316 Test Method for 1,2-Dibromoethane and 1,2- fering components prohibits accurate assignment of the sample
Dibromo-3-Chloropropane in Water by Microextraction componentretentiontimefromthetotalionchromatogram,the
and Gas Chromatography retention time should be assigned by using extracted ion
D5317 Test Method for Determination of Chlorinated Or- currentprofilesforionsuniquetothecomponentofinterest.To
ganicAcid Compounds in Water by Gas Chromatography meet the second criteria, all ions present in the authentic mass
with an Electron Capture Detector spectra at a relative intensity greater than 10 % (whereas the
D5789 Practice for Writing Quality Control Specifications most abundant ion in the spectrum equals 100 %) must be
for Standard Test Methods for Organic Constituents present in the sample spectrum; the relative intensities of these
(Withdrawn 2002) ions must agree within6 20 % between the standard and
D6091 Practice for 99 %/95 % Interlaboratory Detection sample spectra. (As an example, for an ion with an abundance
Estimate (IDE) for Analytical Methods with Negligible of 50 % in the standard spectra, the corresponding sample
Calibration Error abundance must be between 30 % and 70 %.) However, there
D6512 Practice for Interlaboratory Quantitation Estimate may be additional peaks in the sample mass spectrum caused
E260 Practice for Packed Column Gas Chromatography by co-eluting interfering components that are not present in the
E355 Practice for Gas ChromatographyTerms and Relation- reference mass spectrum.
ships
3.1.5 confirmed identification—in order to confirm a tenta-
2.2 U.S. Environmental Protection Agency:
tive identification, both the GC retention time and the mass
SW-846 Method 8270c Semivolatile Organic Compounds
spectrum of a compound shall uniquely match those of a
5,6
by Gas Chromatography (GC-MS)
reference compound as demonstrated by co-injection of the
SW-846Method8260b VolatileOrganicCompoundsbyGas
authentic standard with the tentatively identified compound.
5,6
Chromatography (GC-MS)
3.1.6 reconstructed gas chromatogram (see Note 1)
Methods for the Determination of Organic Compounds in
(RGC)—an RGC is the computer output representing either the
Drinking Water-Supplement I, EPA/600/4-90/020, July
summed intensities of all scanned ion intensities or a sample of
the total current in the ion beam for each spectrum scan plotted
Methods for the Determination of Organic Compounds in
against the corresponding spectrum number. Generally, it can
Drinking Water-Supplement II, EPA/600/R-92/129, Au-
be correlated with a flame ionization detector gas chromato-
gust 1990
gram.
3. Terminology
NOTE 1—There are many synonyms in common use for RGC. These
3.1 Definitions of Terms Specific to This Standard:
include: total ionization plot, total ionization current trace, reconstructed
3.1.1 volatile organic compound—an organic compound
ion chromatogram, total ion current profile, and total ion chromatogram.
that can be readily separated from water by inert gas sparging
3.1.7 reference compounds—these are authentic materials
and thermally desorbed onto a GC column or is readily
used to obtain mass spectra, gas chromatographic retention
amenabletodirectaqueousinjectionGC.Thecompoundsmust
data, and response factors. The operator can prepare the
elute from the column within its temperature range without
standards or they can be prepared commercially. Quality
alteration of the structure of the compound.
control solutions should be prepared independently from the
3.1.2 semi-volatile organic compound—an organic com-
calibration solutions. Quantitation methods may also require
pound that can be separated from water by extraction, either
surrogate spiking solutions to determine extraction efficiency.
liquid/liquid or solid phase, undergo volume adjustment, and
3.1.8 mass chromatogram (see Note 2)—a limited mass
be injected onto a GC. The compounds must elute from the
RGC, or mass chromatogram, represents the intensities of ion
column within its temperature range without alteration of the
currents for only those ions having particular mass to charge
structure of the compound.
ratios. It is a means of quickly scanning a complex RGC plot
3.1.3 tentative identification—all identifications are consid-
to locate peaks which could be specific compounds or types of
ered tentative until confirmed by co-injection of an authentic
compounds. However, a complete mass spectrum is required
reference compound showing identical retention time and
for tentative identification.
similar mass spectra. (Tentative identification based on library
NOTE 2—There are several synonyms in current use for mass chro-
matches only are subjected to false positives.)
matogram. These include: mass fragmentogram, extracted ion current
3.1.4 match—two criteria must be satisfied to verify a
profile, and limited mass reconstructed gas chromatogram.
comparison of a sample component to a standard match: (1)
3.1.9 characteristic ion—usually the primary ion in the
mass spectrum used to measure response for quantitation
Available from National Technical Information Service (NTIS), 5285 Port
purposes. When there are interferences in the mass chromato-
Royal Road, Springfield, VA 22161.
6 gram of a primary ion, a secondary characteristic ion must be
SW 846 can be found online at http://www.epa.gov/epaoswer/hazwaste/test/
main.htm. used for quantitation.
D4128−06 (2012)
3.2 Definitions: of the major mass spectral peaks in the candidate spectrum.
3.2.1 For definitions of terms relating to water used in this Frequently, the occurrence of contaminated spectra can be
guide, refer to definitions in D1129. For definitions of terms determinedbynotingdifferencesintheprofilesofseveralmass
relating to gas chromatography used in this guide, refer to chromatograms that do not exactly fit the profiles of the peaks
Practice E355. of the compound of interest. These may be co-eluting interfer-
ences.However,itisrarelypossibletocompletelyeliminateall
4. Summary of Practice
interferences from complex samples, and the analyst must be
aware of this in interpreting unknowns against reference
4.1 The guide consists of the introduction of organic com-
spectra.
pounds from water into a GC-MS for mass spectral identifica-
tionandguidelinestodetermineconcentration.Volatileorganic
7. Apparatus
compounds are typically introduced through a purge-and-trap
sample introduction device, although volatile compounds can
7.1 GC-MS/DS—A gas chromatograph interfaced to a mass
also be introduced by direct aqueous injection. Semi-volatile
spectrometer having electron impact ionization capability is
compoundsaretypicallyintroducedasorganicextractsfroman
used. Most modern GC-MS systems are typically controlled
extracted sample by syringe. A component’s spectrum is
by a data system for computerized instrument control of data
recorded as the component elutes from the chromatographic
acquisitionanddatareduction.Capillarycolumnsarepreferred
column. The tentative identification of a sample component is
with most GC-MS systems although packed GC columns may
based on its mass spectrum and supported by its GC retention
be used.
data. This tentative identification may be confirmed by co-
7.2 Apparatus required to extract organic compounds from
injection of an authentic standard yielding an identical reten-
water and concentrate them in a small volume of organic
tion time and a similar mass spectrum.
solvent—This apparatus includes a 2-L separatory funnel for
batch extractions or 1-L continuous liquid-liquid extractor and
5. Significance and Use
facilities for Kuderna-Danish concentration. Liquid-liquid ex-
5.1 With the common occurrence in water of organic
traction for volatile organic constituents can be conducted
compounds, some of which are toxic, it is often necessary to
using the apparatus specified in Test Method D3973.
identify the specific compounds present and to determine the
7.3 Apparatus for purge-and-trap GC-MS sample
concentration.
introduction—See Test Method D3871 or EPA Method 524.2.
6. Interferences
7.4 Microsyringe, 10-µL.
6.1 Sample alteration and losses of the component of
interest are not true interferences, but are a source of trouble in 8. Reagents and Materials
performing a qualitative GC-MS analysis. Examples of com-
8.1 Purity of Reagents—Reagent grade chemicals shall be
ponent loss are: decomposition, polymerization, adsorption,
used in all tests. Unless otherwise indicated, it is intended that
and both volatilization prior to introduction into the GC and
all reagents shall conform to the specifications of the Commit-
non-volatilization after introduction into the GC. In addition, 8
teeonAnalyticalReagentsoftheAmericanChemicalSociety.
GC-MS interface plugging can lead to apparent losses.
For trace analysis using organic solvents for liquid-liquid
6.2 Chromatographically unresolved compounds or instru- extraction or elution from solid sorbents, solvents specified as
mental background which co-elutes with the compounds of
distilled-in-glass, nano-grade, or pesticide-grade frequently
interest can interfere with this guide. These interferences can have lower levels of interfering impurities. In all cases,
change the apparent mass spectrum of the compound of sufficientreagentblanksmustbeprocessedwiththesamplesto
interest, thereby making tentative identification difficult.
ensure that all compounds of interest are not present in blanks
d
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