ASTM D7645-10
(Test Method)Standard Test Method for Determination of Aldicarb, Aldicarb Sulfone, Aldicarb Sulfoxide, Carbofuran, Methomyl, Oxamyl and Thiofanox in Water by Liquid Chromatography/Tandem Mass Spectrometry (LC/MS/MS)
Standard Test Method for Determination of Aldicarb, Aldicarb Sulfone, Aldicarb Sulfoxide, Carbofuran, Methomyl, Oxamyl and Thiofanox in Water by Liquid Chromatography/Tandem Mass Spectrometry (LC/MS/MS)
SIGNIFICANCE AND USE
This test method has been developed in support of the National Homeland Security Research Center, US EPA by Region 5 Chicago Regional Laboratory (CRL).
The N-methyl carbamate (NMC) pesticides: aldicarb, carbofuran, methomyl, oxamyl, and thiofanox have been identified by EPA as working through a common mechanism. These affect the nervous system by reducing the ability of enzymes. Enzyme inhibition was the primary toxicological effect of regulatory concern to EPA in assessing the NMC’s food, drinking water, and residential risks. In most of the country, NMC residues in drinking water sources are at levels that are not likely to contribute substantially to the multi-pathway cumulative exposure. Shallow private wells extending through highly permeable soils into shallow, acidic ground water represent what the EPA believes to be the most vulnerable drinking water. Aldicarb sulfone and aldicarb sulfoxide are breakdown products of aldicarb and should also be monitored due to their toxicological effects.
This method has been investigated for use with reagent, surface, and drinking water for the selected carbamates: aldicarb, aldicarb sulfone, aldicarb sulfoxide, carbofuran, methomyl, oxamyl and thiofanox.
SCOPE
1.1 This test method covers the determination of aldicarb, aldicarb sulfone, aldicarb sulfoxide, carbofuran, methomyl, oxamyl, and thiofanox (referred to collectively as carbamates in this test method) in water by direct injection using liquid chromatography (LC) and detected with tandem mass spectrometry (MS/MS). These analytes are qualitatively and quantitatively determined by this method. This method adheres to multiple reaction monitoring (MRM) mass spectrometry.
1.2 The Detection Verification Level (DVL) and Reporting Range for the carbamates are listed in Table 1.
1.2.1 The DVL is required to be at a concentration at least 3 times below the Reporting Limit (RL) and have a signal/noise ratio greater than 3:1. Fig. 1 displays the signal/noise ratios of the primary single reaction monitoring (SRM) transitions, and Fig. 2 displays the confirmatory SRM transitions at the DVLs for the carbamates.
1.2.2 The reporting limit is the concentration of the Level 1 calibration standard as shown in Table 2 for the carbamates.
1.3 Units—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 and health practices and determine the applicability of regulatory limitations prior to use.
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Designation: D7645 – 10
Standard Test Method for
Determination of Aldicarb, Aldicarb Sulfone, Aldicarb
Sulfoxide, Carbofuran, Methomyl, Oxamyl and Thiofanox in
Water by Liquid Chromatography/Tandem Mass
Spectrometry (LC/MS/MS)
This standard is issued under the fixed designation D7645; 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.
TABLE 1 Detection Verification Level and Reporting Range
1. Scope
DVL Reporting Range
1.1 This test method covers the determination of aldicarb,
Analyte
(ng/L) (µg/L)
aldicarb sulfone, aldicarb sulfoxide, carbofuran, methomyl,
Aldicarb 250 1-100
oxamyl, and thiofanox (referred to collectively as carbamates
Aldicarb Sulfone 250 1-100
in this test method) in water by direct injection using liquid
Aldicarb Sulfoxide 250 1-100
Carbofuran 250 1-100
chromatography (LC) and detected with tandem mass spec-
Methomyl 250 1-100
trometry (MS/MS). These analytes are qualitatively and quan-
Oxamyl 250 1-100
titatively determined by this method. This method adheres to
Thiofanox 250 1-100
multiple reaction monitoring (MRM) mass spectrometry.
1.2 The Detection Verification Level (DVL) and Reporting
Range for the carbamates are listed in Table 1.
D1193 Specification for Reagent Water
1.2.1 The DVL is required to be at a concentration at least
D2777 Practice for Determination of Precision and Bias of
3 times below the Reporting Limit (RL) and have a signal/
Applicable Test Methods of Committee D19 on Water
noise ratio greater than 3:1. Fig. 1 displays the signal/noise
D3694 Practices for Preparation of Sample Containers and
ratios of the primary single reaction monitoring (SRM) transi-
for Preservation of Organic Constituents
tions, and Fig. 2 displays the confirmatory SRM transitions at
D3856 Guide for Good Laboratory Practices in Laborato-
the DVLs for the carbamates.
ries Engaged in Sampling and Analysis of Water
1.2.2 The reporting limit is the concentration of the Level 1
D4841 Practice for Estimation of Holding Time for Water
calibration standard as shown in Table 2 for the carbamates.
Samples Containing Organic and Inorganic Constituents
1.3 Units—The values stated in SI units are to be regarded
D5847 Practice for Writing Quality Control Specifications
as standard. No other units of measurement are included in this
for Standard Test Methods for Water Analysis
standard.
E2554 Practice for Estimating and Monitoring the Uncer-
1.4 This standard does not purport to address all of the
tainty of Test Results of a Test Method in a Single
safety concerns, if any, associated with its use. It is the
Laboratory Using a Control Sample Program
responsibility of the user of this standard to establish appro-
2.2 Other Documents:
priate safety and health practices and determine the applica-
EPApublication SW-846 Test Methods for Evaluating Solid
bility of regulatory limitations prior to use.
Waste, Physical/Chemical Methods
EPAMethod 531 Measurement of N-Methyl Carbamoylox-
2. Referenced Documents
imes and N-Methyl Carbamates in Drinking Water by
2.1 ASTM Standards:
Direct Aqueous Injection HPLC with Post Column De-
D1129 Terminology Relating to Water
rivatization
EPA Method 531.2 Measurement of
This test method is under the jurisdiction of ASTM Committee D19 on Water N-Methylcarbamoyloximes and N-Methylcarbamates in
andisthedirectresponsibilityofSubcommitteeD19.06onMethodsforAnalysisfor
Water by Direct Aqueous Injection HPLC with Postcol-
Organic Substances in Water.
umn Derivatization
Current edition approved June 1, 2010. Published July 2010. DOI: 10.1520/
D7645-10.
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM Available from National Technical Information Service (NTIS), U.S. Depart-
Standards volume information, refer to the standard’s Document Summary page on ment of Commerce, 5285 Port Royal Road, Springfield, VA, 22161 or at http://
the ASTM website. www.epa.gov/epawaste/hazard/testmethods/index.htm.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
D7645 – 10
FIG. 1 Example Primary SRM Chromatograms Signal/Noise Ratios
FIG. 2 Example Confirmatory SRM Chromatograms Signal/Noise Ratios
D7645 – 10
TABLE 2 Concentrations of Calibration Standards (PPB)
Analyte/Surrogate LV 1 LV 2 LV 3 LV 4 LV 5 LV 6 LV 7 LV 8
Aldicarb 1 5 10 25 35 50 75 100
Aldicarb Sulfone 1 5 10 25 35 50 75 100
Aldicarb Sulfoxide 1 5 10 25 35 50 75 100
Carbofuran 1 5 10 25 35 50 75 100
Methomyl 1 5 10 25 35 50 75 100
Oxamyl 1 5 10 25 35 50 75 100
Thiofanox 1 5 10 25 35 50 75 100
Carbofuran- C (Surrogate) 1 5 10 25 35 50 75 100
13 15
Methomyl- C , N (Surrogate) 1 5 10 25 35 50 75 100
EPA Method 538 Determination of Selected Organic Con- NMC residues in drinking water sources are at levels that are
taminants in DrinkingWater by DirectAqueous Injection- not likely to contribute substantially to the multi-pathway
Liquid Chromatography/Tandem Mass Spectrometry cumulative exposure. Shallow private wells extending through
(DAI-LC/MS/MS) highly permeable soils into shallow, acidic ground water
represent what the EPA believes to be the most vulnerable
3. Terminology
drinking water. Aldicarb sulfone and aldicarb sulfoxide are
breakdown products of aldicarb and should also be monitored
3.1 Definitions:
due to their toxicological effects.
3.1.1 carbamates, n—in this test method, aldicarb, aldicarb
5.3 This method has been investigated for use with reagent,
sulfone, aldicarb sulfoxide, carbofuran, methomyl, oxamyl,
surface, and drinking water for the selected carbamates:
and thiofanox collectively.
aldicarb, aldicarb sulfone, aldicarb sulfoxide, carbofuran,
3.1.2 detection verification level, DVL, n—a concentration
methomyl, oxamyl and thiofanox.
that has a signal/noise ratio greater than 3:1 and is at least 3
times below the Reporting Limit (RL).
6. Interferences
3.1.3 reporting limit, RL, n—the concentration of the
lowest-level calibration standard used for quantification. 6.1 Method interferences may be caused by contaminants in
3.2 Abbreviations: solvents, reagents, glassware, and other apparatus producing
-3
3.2.1 mM—millimolar, 1 3 10 moles/L discrete artifacts or elevated baselines. All of these materials
3.2.2 ND—non-detect are demonstrated to be free from interferences by analyzing
3.2.3 ppt—parts per trillion, ng/L laboratory reagent blanks under the same conditions as
samples.
4. Summary of Test Method
6.2 All glassware is washed in hot water with detergent and
rinsed in hot water followed by distilled water. The glassware
4.1 This is a performance based method, and modifications
is then dried and heated in an oven at 250°C for 15 to 30
are allowed to improve performance.
minutes. All glassware is subsequently cleaned with acetone
4.2 For carbamate analysis, samples are shipped to the lab
followed by methanol.
acidified between 0°C and 6°C and analyzed within 14 days of
6.3 All reagents and solvents should be pesticide residue
collection. In the lab, the samples are spiked with surrogates,
purity or higher to minimize interference problems.
filtered using a syringe driven filter unit, and analyzed directly
6.4 Matrix interferences may be caused by contaminants in
by LC/MS/MS.
13 15
the sample. The extent of matrix interferences can vary
4.3 The carbamates, methomyl- C , N (surrogate) and
considerably from sample source depending on variations of
carbofuran- C (surrogate)areidentifiedbyretentiontimeand
the sample matrix.
two SRM transitions. The target analytes and surrogate are
quantitated using the primary SRM transitions utilizing an
7. Apparatus
external calibration. The final report issued for each sample
lists the concentration of carbamates and the surrogate recov- 7.1 LC/MS/MS System:
eries. 7.1.1 Liquid Chromatography (LC) System—A complete
LC system is needed in order to analyze samples. Any system
5. Significance and Use
that is capable of performing at the flows, pressures, controlled
temperatures, sample volumes, and requirements of the stan-
5.1 This test method has been developed in support of the
dard may be used.
National Homeland Security Research Center, US EPA by
7.1.2 AnalyticalColumn–Waters—ACQUITYUPLCtBEH
Region 5 Chicago Regional Laboratory (CRL).
C18, 2.1 3 100 mm, 1.7 µm particle size was used to develop
5.2 The N-methyl carbamate (NMC) pesticides: aldicarb,
carbofuran, methomyl, oxamyl, and thiofanox have been iden-
tifiedbyEPAasworkingthroughacommonmechanism.These
AdditionalinformationaboutCarbamatepesticidescanbefoundontheInternet
affect the nervous system by reducing the ability of enzymes.
at http://www.epa.gov (2010).
Enzyme inhibition was the primary toxicological effect of
A Waters ACQUITY UltraPerformance Liquid Chromatography (UPLCt)
regulatory concern to EPA in assessing the NMC’s food,
System was used to develop this test method.All parameters in this test method are
drinking water, and residential risks. In most of the country, based on this system and may vary depending on your instrument.
D7645 – 10
13 15 13 15
this test method.Any column that achieves adequate resolution 8.16 Methomyl- C , N (acetohydroxamate- C , N,
2 2
may be used. The retention times and order of elution may CAS # (unlabeled) 16752-77-5 ).
13 13
change depending on the column used and need to be moni- 8.17 Carbofuran- C (Ring- C , CAS # (unlabeled) 1563-
6 6
tored. 66-2).
NOTE 1—Any column that can achieve baseline resolution of these
9. Hazards
analytes may be used. Baseline resolution simplifies data analysis and can
9.1 Normal laboratory safety applies to this method. Ana-
reducethechanceofionsuppression,leadingtohigherlimitsofdetection.
lysts should wear safety glasses, gloves, and lab coats when
7.1.3 Tandem Mass Spectrometer (MS/MS) System—A
working in the lab.Analysts should review the Material Safety
MS/MS system capable of MRM analysis. Any system that is
Data Sheets (MSDS) for all reagents used in this method.
capable of performing at the requirements in this standard may
be used.
10. Sampling
7.2 Filtration Device:
10.1 Sampling and Preservation—Grab samples should be
7.2.1 Hypodermic Syringe—A Lock Tip Glass Syringe ca-
collected in $25 mL pre-cleaned amber glass bottles with
pable of holding a Millext HV Syringe Driven Filter Unit
Teflont lined caps demonstrated to be free of interferences.All
PVDF 0.22 µm or similar may be used.
samples are acidified with glacial acetic acid to pH#3.8 upon
7.2.1.1 A 25 mL Lock Tip Glass Syringe size is recom-
collection.Afew drops or less of glacial acetic acid is required
mended since a 25 mL sample size is used in this test method.
per 40 mL water sample collected. Chlorinated drinking water
7.2.2 Filter—MillextHVSyringeDrivenFilterUnitPVDF
samples are also dechlorinated with ascorbic acid; 10 mg of
0.22 µm (Millipore Corporation, Catalog # SLGV033NS) or
ascorbic acid is added to each 40 mL volume of water prior to
similar may be used.
collection.Drinkingwatersamplesmustbedechlorinatedupon
collection.Aldicarb oxidizes when residual chlorine is present
8. Reagents and Materials
in the sample. This test method is based on a 25 mL sample
8.1 Purity of Reagents—High Performance Liquid Chroma-
size per analysis. If different sample sizes are used, spiking
tography (HPLC) pesticide residue analysis and spectropho-
solution amounts and preservatives will need to be modified.
tometry grade chemicals shall be used in all tests. Unless
Conventional sampling practices should be followed. Refer to
indicated otherwise, it is intended that all reagents shall
GuideD3856andPracticesD3694.Storesamplesbetween0°C
conform to the Committee on Analytical Reagents of the
and 6°C from the time of collection until analysis.Analyze the
American Chemical Society. Other reagent grades may be
sample within 14 days of collection.
used provided they are first determined to be of sufficiently
NOTE 2—Less sample volume is acceptable, but the spike amounts and
highpuritytopermittheirusewithoutaffectingtheaccuracyof
sample preservatives must be adjusted accordingly.
the measurements.
10.1.1 EPAMethod 531.2 demonstrated that carbamates are
8.2 Purity of Water—Unless otherwise indicated, references
towatershallbeunderstoodtomeanreagentwaterconforming more stable under acidic conditions. Potassium dihydrogen
citrate buffer is used in Method 531.2 to bring the pH to ~3.8,
toType 1 of Specification D1193. It must be demonstrated that
this water does not contain contaminants at concentrations but this buffer is incompatible with LC/MS/MS.Therefore, the
pH adjustment is accomplished with acetic acid in this test
sufficient to interfere with the analysis.
8.3 Gases—Ultrapure nitrogen and argon. method. EPA Method 531.2 demonstrated that carbamates
under acidic conditions are stable for at least 28 days. EPA
8.4 Acetonitrile (CAS # 75-05-8).
8.5 Methanol (CAS # 67-56-1). Method 531 demonstrated that oxamyl and methomyl are
stable for at least 70 days at pH 3 60.2. Holding time is
8.6 Acetone (CAS # 67-64-1).
8.7 Ammonium Formate (CAS # 540-69-2). dependent upon your individual matrix and will vary. Practice
D4841 may be used to conduct a holding time study on your
8.8 Acetic Acid (Glacial, CAS # 64-19-7).
individual matrix.
8.9 Aldicarb (CAS # 116-06-3).
8.10 Aldicarb Sulfone (CAS # 1646-88-4).
11. Preparation of LC/MS/MS
8.11 Aldicarb Sulfoxide (CAS # 1646-87-3).
11.1 LC Chromatograph Operating Conditions:
8.12 Carbofuran (CAS # 1563-66-2).
11.1.1 Injection volumes of all calibration standards and
8.13 Oxamyl (CAS # 23135-22-0).
samples are made at 50 µL volume using a full loop injection.
8.14 Methomyl (CAS # 16752-77-5).
If a 50 µL volume loop is installed in the LC, a “full loop”
8.15 Thiofanox (CAS # 39196-18-4).
mode is the preferred technique when performing fast, quali-
tative analyses. This mode should be used whenever accuracy
and precision are the primary concerns. The first sample
A Waters Quattro Premiery XE tandem quadrupole mass spectrometer was
usedtodevelopthistestmethod.Allparametersinthistestmethodarebasedonthis
analyzed after the calibration curve is a blank to ensure there is
system and may vary depending on your instrument.
no carry-over.The gradient conditions for the liquid chromato-
Reagent Chemicals, American Chemical Society Specifications, American
graph are shown in Table 3.
Chemical Society, Washington, D.C. For Suggestions
...
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