Halosulfuron-methyl (PC 128721)
MRIDs 49798401/49983101
Analytical method for halosulfuron-methyl (HSM) and its transformation products
halosulfuron-methyl rearrangement ester (RRE), 3-chlorosulfonamide acid methyl ester
(CPSA or CSE), 2-amino-4,6-dimethoxypyrimidine (AP), halosulfuron acid (HS), 3-
chlorosulfonamide (CSA), halosulfuron acid guanidine (CSAG) and halosulfuron ester
guanidine (CSEG) in water
Reports: ECM: EPA MRID No.: 49798401. Shen, H. and T. Arndt. 2015. Development
and Validation of a Method for the Determination of Halosulfuron-methyl
(HSM) and its Degradates in Surface/Ground Water. Report prepared by
PTRL West (a division of EAG, Inc.), Hercules, California, sponsored and
submitted by Gowan Company, Yuma, Arizona; 203 pages. PTRL Study No:
2679W. Final report issued December 1, 2015.
ILV: EPA MRID No.: 49983101. MacGregor, J.A. andE.S. Bodle. 2016.
INDEPENDENT LABORATORY VALIDATION OF METHODS FOR THE
DETERMINATION OF HALOSULFURON-METHYL (HSM) AND ITS
DEGRADATES IN SURFACE/GROUND WATER BY LC/MS/MS. Report
prepared by EAG Laboratories, Easton, Maryland, sponsored and submitted
by Canyon Group LLC, Yuma, Arizona and Gowan Company, Yuma,
Arizona; 201 pages. EAG Laboratories Project No: 334C-131. Final report
issued July 27, 2016.
MRIDs 49798401 & 49983101
850.6100
ECM: The study was conducted in compliance with USEPA FIFRA Good
Laboratory Practice (GLP) standards (p. 3 of MRID 49798401). Signed and
dated Data Confidentiality, GLP and Quality Assurance statements were
provided (pp. 2-4). The statement of authenticity was included with the QA
statement.
ILV: The study was conducted in compliance with USEPA FIFRA GLP
standards (p. 3 of MRID 49983101). Signed and dated Data Confidentiality,
GLP and Quality Assurance statements were provided (pp. 2-4). The statement
of authenticity was not included.
Classification: This analytical method is classified as supplemental. In the ILV, the
composition of the ground water matrix was unclear. For analyte AP, method
recoveries did not meet OCSPP Guideline 850.6100 criteria for precision and
accuracy for ground water matrix at the LOQ in the ILV and for surface water
matrix at the LOQ and lOxLOQ in the ECM. For analytes CSA and CSAG,
method RSDs in ground water matrix at the LOQ did not meet OCSPP
Guideline 850.6100 criteria for precision and accuracy for both ions in the
ECM. In the ILV, linearity was not satisfactory for HS and CSA. In the ECM,
the LOQ chromatograms for CSA and CSAG in both water matrices showed
baseline interferences with peak resolution or integration. The LODs for the
analytes were not reported in the ILV.
PC Code: 128721
Page 1 of21
Document No.:
Guideline:
Statements:
-------
Halosulfuron-methyl (PC 128721)
MRIDs 49798401/49983101
EFED Final
Reviewers:
CDM/CSS-
Dynamac JV
Reviewers:
Zoe Ruge, Physical Scientist Signature
Mohammed Ruhman, Ph.D.,
Senior Scientist
Lisa Muto,
Environmental Scientist
Kathleen Ferguson, Ph.D.,
Environmental Scientist
Signature:
Date:
9/27/18
Signature:
' V-iฆ
Date:
9/27/18
Signature:
/{"*>
Date:
3 nm
Signature:
Date:
3/7/17
This Data Evaluation Record may have been altered by the Environmental Fate and Effects
Division subsequent to signing by CDM/CSS-Dynamac JV personnel.
Executive Summary
The analytical method, PTRL Study No: 2679W, is designed for the quantitative determination of
halosulfuron-methyl (HSM) and its transformation products halosulfuron-methyl rearrangement
ester (RRE), 3-chlorosulfonamide acid methyl ester (CPSA or CSE), 2-amino-4,6-
dimethoxypyrimidine (AP), halosulfuron acid (HS), 3-chlorosulfonamide (CSA), halosulfuron acid
guanidine (CSAG) and halosulfuron ester guanidine (CSEG) in water using HPLC/MS/MS. In
water, the method is quantitative for halosulfuron-methyl and RRE at the stated LOQ of 0.05 ppb
and for CPSA, AP, HS, CSA, CSAG and CSEG at the LOQ of 0.2 ppb. The LOQs are greater than
the lowest toxicological level of concern in water (EC25 = 0.045 jag ai/L; NOAEC = 0.023 jag ai/L).
Characterized ground (well) water and natural surface water were used for the ECM validation; the
specific water source type of the surface water was not reported. Characterized ground (well) water
and natural surface water were used for the ILV validation; however, two sources of ground water
were used for one ground water matrix. The ECM method was validated by the ILV with
insignificant modifications to the sample processing procedure and the analytical method. The
method for HSM/RRE/CPSA (CSE)/AP was validated by the ILV in the third trial with surface and
ground water matrices. The method for CSA/HS was validated by the ILV in the second trial with
surface and ground water matrices. The method for CSAG/CSEG was validated by the ILV in the
first trial with surface and ground water matrices. All ILV data regarding repeatability, accuracy,
and precision were satisfactory for all analytes in both matrices, except for AP in ground water. In
the ILV, linearity was not satisfactory for HS and CSA. All ILV data regarding specificity were
satisfactory for all analytes in both matrices; only quantitation ion chromatograms were provided.
The LODs for the analytes were not reported in the ILV. All ECM data regarding repeatability,
accuracy, and precision were satisfactory for all analytes in both matrices, except for AP in surface
water and CSA and CSAG in ground water. All ECM data regarding specificity were satisfactory
for all analytes in both matrices, except that baseline interferences affected the resolution and
integration of the LOQ peaks for CSA and CSAG in both matrices.
Page 2 of 21
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Halosulfuron-methyl (PC 128721)
MRIDs 49798401/49983101
Table 1. Analytical Method Summary
Analyte(s)
by Pesticide1
MRID
EPA Review
Matrix
Method Date
(dd/mm/yyyy)
Registrant
Analysis
Limit of
Quantitation
(LOQ)
Environmental
Chemistry
Method
Independent
Laboratory
Validation
Halosulfuron-
methyl
(HSM)
RRE
497984012
499831013
Supplemental
Water
01/12/2015
Gowan
Company,
LLC
Canyon
Group
LLC
LC/MS/MS
0.05 ppb
CPSA (CSE)
AP
CSA
HS
CSAG
CSEG
0.2 ppb
1 HSM = Methyl 3-chloro-5-(4,6-dimethoxypyrimidin-2-ylcarbamoylsulfamoyl)-l-methylpyrazole-4-carboxylate. RRE
= Halosulfuron-methyl rearrangement ester; Methyl 3-chloro-5-[(4,6-dimethoxypyrimidin-2-yl)amino]-l-methyl-
pyrazole-4-carboxylate. CPSA/CSE = 3-Chlorosulfonamide acid methyl ester; Methyl-3-chloro-l-methyl-5-
sulfamoylpyrazole-4-carboxylate. AP = Aminopyrimidine; 2-Amino-4,6-dimethoxypyrimidine. HS = Halosulfuron
acid; 3- Chloro-5-(4,6-dimethoxypyrimidin-2-ylcarbamoylsulfamoyl)-l-methlypyrazole-4-carboxylic acid. CSA= 3-
Chlorosulfonamide; 3-Chloro-l-methyl-5-sulfamoyl-pyrazole-4-carboxylic acid. CSAG = Halosulfuron acid
guanidine; 5-(Carbamimidoylcarbamoylsulfamoyl)-3-chloro-l-methyl-pyrazole-4-carboxylic acid. CSEG =
Halosulfuron ester guanidine; Methyl 5-(carbamimidoylcarbamoylsulfamoyl)-3-chloro-l-methyl-pyrazole-4-
carboxylate.
2 In the ECM, ground (well) water (2706W-032; pH 7.3, hardness 627 mg equiv. CaCCh/L. total dissolved solids 960
ppm) and natural surface water (2440W-083; pH 6.3, total dissolved solids 68 ppm) were used(p. 22; Appendix C, pp.
184-185 of MRID 49798401). Sources not specified.
3 In the ILV, two sources of ground (well) water were used for the ground water sample: PTRL West ground water (the
matrix used in the ECM; 2706W-032; pH 7.3, hardness 627 mg equiv. CaCCh/L. total dissolved solids 960 ppm) and
EAG Laboratories ground water (pH 7.95; hardness 136 mg/L as CaCCh: p. 14; Appendices III-V, pp. 176-179 of
MRID 49983101). The natural surface water (pH 7.00; hardness 64.0 mg/L as CaCOs,) was obtained from Tuckahoe
Lake, Tuckahoe Lake State Park, Ridgely, Maryland.
Page 3 of 21
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Halosulfuron-methvl (PC 128721)
MRIDs 49798401/49983101
I. Principle of the Method
Extraction procedure for HSM/RRE/CPSA (CSEVAP: Water (100 mL; pH 5.5-7.5, adjusted with
HC1 or NaOH if necessary) in a 250-mL separatory funnel was fortified with 0.02 or 0.20 mL of
250 ng/mL HSM and RRE fortification solutions or 0.04 or 0.40 mL of 500 ng/mL CPSA (CSE)
and AP fortification solutions (pp. 22-23, 30-31; Figure 1, p. 53 of MRID 49798401).
Dichloromethane (40 mL) and sodium chloride (ca. 1 g) were mixed with the water sample via
shaking vigorously for 2 minutes. After 5 minutes to allow the phases to separate, the
dichloromethane layer (lower) was drained and filtered through a filter funnel containing ca. 5.5 g
of sodium sulfate. The filter was rinsed with 10 mL of dichloromethane. The remaining water
sample was extracted with ethyl acetate (40 mL) via shaking vigorously for 2 minutes. After 3
minutes to allow the phases to separate, the ethyl acetate layer was drained and combined with the
dichloromethane extract. The combined extracts were reduced to ca. 5 mL via rotary evaporation at
150 mbar and 30ฐC. The residue was transferred to a 15-mL disposable glass tube. The flask was
rinsed with 5 mL of ethyl acetate which was combined with the residue in the disposable glass tube.
The solvent was evaporated under a gentle stream of nitrogen to a volume of ca. 0.2-0.4 mL at
30ฐC. The residue was reconstituted in 2.0 mL of acetonitrile:water (1:1, v:v) and mixed via vortex
prior to LC/MS/MS analysis.
Extraction procedure for CSA/HS: Water (10 mL) in a 50-mL disposable plastic centrifuge tubes
was fortified with 0.04 or 0.40 mL of 50 ng/mL HS and CSA fortification solutions (pp. 22-23, 30-
32; Figure 2, p. 54 of MRID 49798401). The water was extracted with 1% acetic acid in acetonitrile
(10 mL) and Restek Q100 unbuffered extraction salts (1 g NaCl, 4 g MgSCU) with 4 4-mm SS
grinding balls via shaking for 2 minutes on SPEX GenoGrinder at 1500 rpm. After centrifugation (5
minutes at 3000 rpm) using the Sorvall RT-7, the supernatant was transferred to amber vials. An
aliquot was transferred to an autosampler vial for LC/MS/MS analysis.
Extraction procedure for CSAG/CSEG: Water (10 mL) in a 50-mL disposable plastic centrifuge
tubes was fortified with 0.10 or 1.00 mL of 20 ng/mL CSAG and CSEG fortification solutions (pp.
22-23, 30, 32; Figure 3, p. 55 of MRID 49798401). The water was extracted with acetonitrile (10
mL), concentrated HC1 (1 mL) and Restek Q100 unbuffered extraction salts (1 g NaCl, 4 g MgSCU)
with 4 4-mm SS grinding balls via shaking for 2 minutes on SPEX GenoGrinder at 1500 rpm. After
centrifugation (5 minutes at 3000 rpm) using the Sorvall RT-7, the supernatant was transferred to
amber vials. An aliquot was transferred to an autosampler vial for LC/MS/MS analysis.
LC/MS/MS: Samples are analyzed using an AB Sciex API 5500 Series Triple Quad Mass
Spectrometer with Thermo Scientific Agilent 1260 series Liquid Chromatograph (p. 22 of MRID
49798401). The following LC conditions were used (pp. 33-36): Phenomenex Synergiฎ 4jli Hydro-
RP column (2.0 mm x 75 mm, column temperature 30ฐC), Phenomenex Security Guardฎ Aqueous
cl8 guard column (4 mm x 2 mm), mobile phase of (A) 0.1% formic acid in HPLC grade water and
(B) 0.1% formic acid in HPLC grade acetonitrile, and injection volume of 5 |iL. LC mobile phase
gradient and MS multiple reaction monitoring (MRM) conditions varied depending on analyte.
HSM/RRE/CPSA (CSEVAP: The following mobile phase gradient was used (pp. 33-34 of MRID
49798401): percent A:B (v:v) at 0.0-1.0 min. 100:0, 5.0-9.0 min. 0:100, 9.5-13 min. 100:0. The
MRM parameters were ESI positive mode for AP (Experiment 1), ESI negative mode for CPSA
(CSE; Experiment 2), and ESI positive mode for HSM and RRE (Experiment 3). Two ion pair
transitions were monitored for each analyte (quantitation and confirmation, respectively): m/z
Page 4 of 21
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Halosulfuron-methvl (PC 128721)
MRIDs 49798401/49983101
434.9^182.2 and m/z 434.9^139.1 for HSM, m/z 328.0^295.9 and m/z 328.0^197.0 for RRE,
in z 156.1 >99.9 and m/z 156.1^57.0 for AP, and m/z 252.0^187.9 and m/z 252.0^219.8 for
CPSA (CSE). Expected retention times were 5.28, 4.99, 3.51, and 4.37 minutes for HSM, RRE, AP,
and CPSA (CSE), respectively (Figure 11, pp. 112-115).
CSA/HS: The following mobile phase gradient was used (pp. 35-36 of MRID 49798401): percent
A:B (v:v) at 0.0-1.0 min. 100:0, 5.0-6.0 min. 0:100, 6.5-10 min. 100:0. The MRM parameters were
ESI negative mode. Two ion pair transitions were monitored for each analyte (quantitation and
confirmation, respectively): m/z 419.0>194.0 and m/z 419.0>238.0 for HS, and m/z 238.0>78.0
and m/z 238.0>194.0 for CSA. Expected retention times were 3.69 and 4.70 minutes for CSA and
HS, respectively (Figure 11, pp. 116-117).
CSAG/CSEG: The following mobile phase gradient was used (pp. 36-37 of MRID 49798401):
percent A:B (v:v) at 0.0-1.0 min. 100:0, 5.0-6.0 min. 0:100, 6.5-10 min. 100:0. The MRM
parameters were ESI negative mode. Two ion pair transitions were monitored for each analyte
(quantitation and confirmation, respectively): m/z 322.9>193.8 and m/z 322.9>237.8 for CSAG,
and m/z 337.0>251.9 and m/z 337.0>77.9 for CSEG. Expected retention times were 3.56 and 3.78
minutes for CSAG and CSEG, respectively (Figure 11, pp. 118-119).
ILV: The ILV performed the ECM methods for each analyte as written, except for insignificant
equipment and procedure modifications and insignificant modifications to the analytical method for
CSA/HS (pp. 19-23; Tables 1-3, pp. 31-33 of MRID 49983101). The LC/MS/MS instrument and
parameters were the same as those of the ECM, with the exception that the mobile phase gradient
for CSA/HS matched that of HSM/RRE/CPSA (CSE)/AP instead of that of CSAG/CSEG. Two ion
pair transitions were monitored for each analyte (quantitation and confirmation, respectively): m/z
435>182 and m/z 435^139 for HSM, m/z 328^296 and m/z 328^197 for RRE, m/z 156^100
and m/z 156>57 for AP, m/z 252>188 and m/z 252>220 for CPSA (CSE), m/z 419>194 and m/z
419>238 for HS, m/z 238^78.0 and m/z 238^194 for CSA, m/z 323^194 and m/z 323^238 for
CSAG, and m/z 337>252 and m/z 337>77.9 for CSEG (see Reviewer's Comment #8; Tables 1-3,
pp. 31-33; Figures 4-27, pp. 69-92). Expected retention times were ca. 6.4, 6.3, 5.0, 5.8, 5.0, 5.8, 5.0
and 5.2 minutes for HSM, RRE, AP, CPSA (CSE), CSA, HS, CSAG and CSEG, respectively.
The following critical steps were noted by the ILV: in the method for HSM/RRE/CPSA (CSE)/AP,
care must be taken to minimize the length of time sample extracts are allowed to remain at dryness
when on the nitrogen evaporator system; and in the method for CSA/HS, the fortification stock
solution should be prepared in acetonitrile:water (1:1, v:v) to ensure stability and constant solubility
of the CSA/HS analytes, especially the HS component (Appendix VII, p. 198 of MRID 49983101).
LOO and LOD: In the ECM and ILV, the Limits of Quantification (LOQ) were 0.05 ppb for HSM
and RRE and 0.2 ppb for CPSA (CSE), AP, HS, CSA, CSAG and CSEG (p. 10 of MRID 49798401.
pp. 12, 20 of MRID 49983101). In the ECM, the Limits of Detection (LOD) were 0.01 ppb for
HSM and RRE, 0.02 ppb for CPSA (CSE) and AP, 0.01 ppb for HS and CSA and 0.08 ppb for
CSAG and CSEG. The LODs for the analytes were not reported in the ILV.
Page 5 of 21
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Halosulfuron-methyl (PC 128721)
MRIDs 49798401/49983101
II. Recovery Findings
ECM (MRID 49798401): Mean recoveries and relative standard deviations (RSDs) were within
guidelines (mean 70-120%; RSD <20%) for analysis of halosulfuron-methyl (HSM) and its
transformation product RRE at fortification levels of 0.05 ppb (LOQ) and 0.5 ppb (lOxLOQ), for its
transformation products CPSA, AP, HS, CPA, CSAG and CSEG at 0.2 ppb (LOQ) and 2.0 ppb
(lOxLOQ) in the surface water matrix, except for mean recoveries of AP which were 44-53% at the
LOQ and lOxLOQ (ions combined; Tables I-II, pp. 45-50). Mean recoveries and RSDs were within
guidelines for analysis of halosulfuron-methyl (HSM) and its transformation product RRE at
fortification levels of 0.05 ppb (LOQ) and 0.5 ppb (lOxLOQ), for its transformation products
CPSA, AP, HS, CPA, CSAG and CSEG at 0.2 ppb (LOQ) and 2.0 ppb (lOxLOQ) in the ground
(well) water matrix, except for the RSDs of CSA and CSAG at the LOQ which were 25%
(quantification ion) and 24% (confirmation ion), respectively. Two ion pair transitions were
monitored for each analyte using LC/MS/MS in either positive or negative ESI mode. The
quantification and confirmation ion data was comparable or fairly comparable for all analytes in
both matrices, except for HS, CSA (LOQ only) and CSAG (LOQ only) in the ground water matrix.
Ground (well) water (2706W-032; pH 7.3, total dissolved solids 960 ppm) and natural surface water
(2440W-083; pH 6.3, hardness 627 mg equiv. CaC03/L, total dissolved solids 68 ppm) were
characterized by Agvise Laboratories, Northwood, North Dakota (p. 22; Appendix C, pp. 184-185).
The specific water source type of the surface water was not reported.
ILV (MRID 49983101): Mean recoveries and RSDs were within guidelines for analysis of
halosulfuron-methyl (HSM) and its transformation product RRE at fortification levels of 0.05 ppb
(LOQ) and 0.5 ppb (lOxLOQ), for its transformation products CPSA, AP, HS, CPA, CSAG and
CSEG at 0.2 ppb (LOQ) and 2.0 ppb (lOxLOQ) in the surface water matrix (Tables 4-35, pp. 34-
65). Mean recoveries and RSDs were within guidelines for analysis of halosulfuron-methyl (HSM)
and its transformation product RRE at fortification levels of 0.05 ppb (LOQ) and 0.5 ppb
(lOxLOQ), for its transformation products CPSA, AP, HS, CPA, CSAG and CSEG at 0.2 ppb
(LOQ) and 2.0 ppb (lOxLOQ) in the ground (well) water matrix, except for the mean recovery of
AP at the LOQ which was 69.3-69.5%) (ions combined). Two ion pair transitions were monitored
for each analyte using LC/MS/MS in either positive or negative ESI mode. The quantification and
confirmation ion data was comparable or fairly comparable for all analytes in both matrices, except
for RRE (LOQ only) in the surface water matrix. Two sources of ground (well) water were used for
the ground water sample: PTRL West ground water (the matrix used in the ECM; 2706W-032; pH
7.3, hardness 627 mg equiv. CaC03/L, total dissolved solids 960 ppm) and EAG Laboratories
ground water (pH 7.95; hardness 136 mg/L as CaC03; see Reviewer's Comment #2; p. 14;
Appendices III-V, pp. 176-179). The natural surface water (pH 7.00; hardness 64.0 mg/L as CaC03)
was obtained from Tuckahoe Lake, Tuckahoe Lake State Park, Ridgely, Maryland. All water
matrices were characterized by Agvise Laboratories, Northwood, North Dakota and EAG
Laboratories. The method was validated with insignificant modifications to the sample processing
procedure and the analytical method (pp. 13, 19-23; Tables 1-3, pp. 31-33). The method for
HSM/RRE/CPSA (CSE)/AP was validated in the third trial with surface and ground water matrices
(Appendix VII, pp. 196-199). The method for CSA/HS was validated in the second trial with
surface and ground water matrices. The method for CSAG/CSEG was validated in the first trial
with surface and ground water matrices.
Page 6 of 21
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Halosulfuron-methyl (PC 128721)
MRIDs 49798401/49983101
Table 2. Initial Validation Method Recoveries for Halosulfuron-methyl (HSM) and Its
Transformation Products RB
IE, CPSA, AP, HS, CSA, CPAG and CPEG in Wa
ter
Analyte1
Fortification
Level (ppb)
Number
of Tests
Recovery
Range (%)
Mean
Recovery (%)
Standard
Deviation (%)
Relative
Standard
Deviation (%)
Surface Water2
Quantitation ion3
Halosulfuron-
methyl (HSM)
0.05 (LOQ)
5
84.4-98.0
90
6
6
0.5
5
85.6-88.8
87
1
2
RRE
0.05 (LOQ)
5
92.8-102
97
3
4
0.5
5
89.2-96.4
94
3
3
CPS A (CSE)
0.2 (LOQ)
5
86.5-114.0
104
10
10
2.0
5
93.5-102.0
97
4
4
AP
0.2 (LOQ)
5
33.8-49.6
44
6
14
2.0
5
38.3-62.5
53
9
17
HS
0.2 (LOQ)
5
74.0-94.0
87
8
9
2.0
5
75.5-80.5
78
2
2
CSA
0.2 (LOQ)
5
68.0-95.5
85
13
15
2.0
5
90.0-94.5
93
2
2
CSAG
0.2 (LOQ)
5
99.0-122
109
9
8
2.0
5
81.5-91.5
87
4
5
CSEG
0.2 (LOQ)
5
112-125
118
5
4
2.0
5
84.5-91.5
89
3
3
Confirmation ion3
Halosulfuron-
methyl (HSM)
0.05 (LOQ)
5
93.2-98.8
96
3
3
0.5
5
84.0-87.2
86
1
2
RRE
0.05 (LOQ)
5
92.4-98.4
95
3
3
0.5
5
90.8-94.4
93
2
2
CPS A (CSE)
0.2 (LOQ)
5
88.0-102
94
6
6
2.0
5
92.5-98.5
97
3
3
AP
0.2 (LOQ)
5
31.8-53.0
44
8
18
2.0
5
37.4-61.0
51
9
17
HS
0.2 (LOQ)
5
78.0-94.5
88
7
8
2.0
5
76.0-78.5
77
1
1
CSA
0.2 (LOQ)
5
68.5-105
86
13
15
2.0
5
87.0-93.5
91
3
3
CSAG
0.2 (LOQ)
5
95.0-132
115
13
11
2.0
5
82.5-90.0
86
3
4
CSEG
0.2 (LOQ)
5
106-124
116
7
6
2.0
5
86.0-96.0
91
4
5
Ground (Well) Water2
Quantitation ion3
Halosulfuron-
methyl (HSM)
0.05 (LOQ)
5
99.8-110
105
4
4
0.5
5
98-107
102
3
3
RRE
0.05 (LOQ)
5
90.6-96.6
95
3
3
0.5
5
90.0-93.2
92
1
2
CPS A (CSE)
0.2 (LOQ)
5
80.5-96.5
88
7
8
2.0
5
83.5-87.5
85
2
2
AP
0.2 (LOQ)
5
58.5-69.0
63
4
7
2.0
5
38.4-62.0
53
9
18
Page 7 of 2
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Halosulfuron-methyl (PC 128721)
MRIDs 49798401/49983101
Analyte1
Fortification
Level (ppb)
Number
of Tests
Recovery
Range (%)
Mean
Recovery (%)
Standard
Deviation (%)
Relative
Standard
Deviation (%)
HS
0.2 (LOQ)
5
69.0-82.5
77
5
7
2.0
5
79.0-96.0
84
7
8
CSA
0.2 (LOQ)
5
52.5-108
83
20
25
2.0
5
87.5-93.0
91
2
3
CSAG
0.2 (LOQ)
5
87.0-116
96
12
12
2.0
5
79.5-88.5
84
4
5
CSEG
0.2 (LOQ)
5
101-113
108
4
4
2.0
5
89.0-97.5
92
4
4
Confirmation ion3
Halosulfuron-
methyl (HSM)
0.05 (LOQ)
5
93.2-103
98
4
4
0.5
5
97.2-103
100
3
3
RRE
0.05 (LOQ)
5
91.6-99.0
96
3
3
0.5
5
89.0-94.8
92
2
2
CPSA (CSE)
0.2 (LOQ)
5
79.0-95.0
88
7
8
2.0
5
82.5-96.0
88
5
6
AP
0.2 (LOQ)
5
59.5-68.0
63
4
6
2.0
5
38.6-62.5
53
9
18
HS
0.2 (LOQ)
5
62.5-88.0
70
10
15
2.0
5
62.0-100
80
14
17
CSA
0.2 (LOQ)
5
94.0-116.0
103
9
9
2.0
5
89.5-92.0
91
1
1
CSAG
0.2 (LOQ)
5
60.0-107
78
19
24
2.0
5
81.5-89.5
86
3
3
CSEG
0.2 (LOQ)
5
110-119
112
5
4
2.0
5
89.0-95.5
92
3
3
Data (uncorrected recovery results; pp. 37-38) were obtained from Tables I-II, pp. 45-50 of MRID 49798401.
Red values indicate discrepancies with meeting guideline requirements.
1 HSM = Methyl 3-chloro-5-(4,6-dimethoxypyrimidin-2-ylcarbamoylsulfamoyl)-l-methylpyrazole-4-carboxylate. RRE
= Halosulfuron-methyl rearrangement ester; Methyl 3-chloro-5-[(4,6-dimethoxypyrimidin-2-yl)amino]-l-methyl-
pyrazole-4-carboxylate. CPSA/CSE = 3-Chlorosulfonamide acid methyl ester; Methyl-3-chloro-l-methyl-5-
sulfamoylpyrazole-4-carboxylate. AP = Aminopyrimidine; 2-Amino-4,6-dimethoxypyrimidine. HS = Halosulfuron
acid; 3- Chloro-5-(4,6-dimethoxypyrimidin-2-ylcarbamoylsulfamoyl)-l-methlypyrazole-4-carboxylic acid. CSA= 3-
Chlorosulfonamide; 3-Chloro-l-methyl-5-sulfamoyl-pyrazole-4-carboxylic acid. CSAG = Halosulfuron acid
guanidine; 5-(Carbamimidoylcarbamoylsulfamoyl)-3-chloro-l-methyl-pyrazole-4-carboxylic acid. CSEG =
Halosulfuron ester guanidine; Methyl 5-(carbamimidoylcarbamoylsulfamoyl)-3-chloro-l-methyl-pyrazole-4-
carboxylate.
2 Ground (well) water (2706W-032; pH 7.3, hardness 627 mg equiv. CaCCh/L. total dissolved solids 960 ppm) and
natural surface water (2440W-083; pH 6.3, total dissolved solids 68 ppm) were characterized by Agvise Laboratories,
Northwood, North Dakota (p. 22; Appendix C, pp. 184-185). The specific water source type of the surface water was
not reported.
3 Two ion pair transitions were monitored for each analyte (quantitation and confirmation, respectively): m/z
434.9>182.2 and m/z 434.9^139.1 for HSM, m/z 328.0^295.9 and m/z 328.0^197.0 for RRE, m/z 156.1^99.9
and m/z 156.1^57.0 for AP, m/z 252.0^187.9 and m/z 252.0^219.8 for CPSA (CSE), m/z 419.0^194.0 and m/z
419.0>238.0 for HS, m/z 238.0^78.0 and m/z 238.0^194.0 for CSA, m/z 322.9^193.8 and m/z 322.9^237.8 for
CSAG, and m/z 337.0^251.9 and m/z 337.0^77.9 for CSEG.
Page 8 of 21
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Halosulfuron-methyl (PC 128721)
MRIDs 49798401/49983101
Table 3. Independent Validation Method Recoveries for Halosulfuron-methyl (HSM) and Its
Transformation Products RB
IE, CPSA, AP, HS, CSA, CP AG and CPEG in Wa
ter
Analyte1
Fortification
Level (ppb)
Number
of Tests
Recovery
Range (%)
Mean
Recovery (%)
Standard
Deviation (%)
Relative
Standard
Deviation (%)
Surface Water2
Quantitation ion3
Halosulfuron-
methyl (HSM)
0.05 (LOQ)
5
82.6-92.8
88.0
3.66
4.16
0.5
5
83.7-93.2
88.3
3.79
4.29
RRE
0.05 (LOQ)
5
114-124
120
4.04
3.37
0.5
5
93.7-102
96.8
3.10
3.20
CPS A (CSE)
0.2 (LOQ)
5
79.8-106
92.4
10.4
11.3
2.0
5
91.4-101
95.4
4.21
4.41
AP
0.2 (LOQ)
5
75.3-85.1
80.7
3.84
4.76
2.0
5
73.2-81.9
78.0
3.20
4.10
HS
0.2 (LOQ)
5
96.2-102
99.2
2.10
2.12
2.0
5
91.7-97.3
94.2
2.33
2.47
CSA
0.2 (LOQ)
5
87.4-101
93.8
5.61
5.98
2.0
5
96.5-99.2
97.9
0.997
1.02
CSAG
0.2 (LOQ)
5
85.1-104
95.8
7.41
7.73
2.0
5
87.1-92.5
89.9
2.20
2.45
CSEG
0.2 (LOQ)
5
109-126
117
7.89
6.74
2.0
5
102-108
105
2.17
2.09
Confirmation ion3
Halosulfuron-
methyl (HSM)
0.05 (LOQ)
5
80.4-93.1
87.4
4.68
5.35
0.5
5
84.9-90.4
87.0
2.24
2.57
RRE
0.05 (LOQ)
5
84.1-94.9
90.2
4.75
5.27
0.5
5
96.2-104
98.6
3.13
3.17
CPS A (CSE)
0.2 (LOQ)
5
85.8-105
94.3
7.73
8.20
2.0
5
90.8-97.2
93.5
2.62
2.80
AP
0.2 (LOQ)
5
70.4-85.4
79.0
5.72
7.24
2.0
5
70.6-80.4
76.6
4.01
5.24
HS
0.2 (LOQ)
5
92.8-103
96.4
4.22
4.38
2.0
5
93.9-96.4
95.4
0.992
1.04
CSA
0.2 (LOQ)
5
80.8-107
96.8
11.0
11.4
2.0
5
94.4-102
98.6
3.26
3.31
CSAG
0.2 (LOQ)
5
98.0-107
102
3.81
3.74
2.0
5
85.0-91.4
88.9
2.37
2.67
CSEG
0.2 (LOQ)
5
114-124
118
3.85
3.26
2.0
5
108-110
109
0.837
0.7664
Ground (Well) Water2
Quantitation ion3
Halosulfuron-
methyl (HSM)
0.05 (LOQ)
5
77.7-87.3
85.2
4.18
4.91
0.5
5
82.3-86.4
84.0
1.66
1.98
RRE
0.05 (LOQ)
5
89.1-96.7
92.9
2.95
3.18
0.5
5
97.8-101
98.9
1.47
1.49
CPS A (CSE)
0.2 (LOQ)
5
93.1-106
100
5.86
5.86
2.0
5
95.3-103
98.5
3.36
3.41
AP
0.2 (LOQ)
5
60.1-77.7
69.3
7.37
10.6
2.0
5
70.0-89.8
75.3
8.19
10.9
Page 9 of 2
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Halosulfuron-methvl (PC 128721)
MRIDs 49798401/49983101
Analyte1
Fortification
Level (ppb)
Number
of Tests
Recovery
Range (%)
Mean
Recovery (%)
Standard
Deviation (%)
Relative
Standard
Deviation (%)
HS
0.2 (LOQ)
5
95.8-102
98.9
2.35
2.38
2.0
5
89.8-93.2
91.5
1.30
1.42
CSA
0.2 (LOQ)
5
76.8-91.0
85.1
5.73
6.73
2.0
5
86.8-92.7
88.8
2.39
2.69
CSAG
0.2 (LOQ)
5
88.9-102
95.0
4.72
4.97
2.0
5
87.0-89.6
88.4
1.03
1.17
CSEG
0.2 (LOQ)
5
98.6-114
107
5.64
5.27
2.0
5
93.3-98.5
96.1
2.03
2.11
Confirmation ion3
Halosulfuron-
methyl (HSM)
0.05 (LOQ)
5
80.3-89.1
86.1
3.74
4.34
0.5
5
83.0-87.0
84.4
1.89
2.24
RRE
0.05 (LOQ)
5
89.0-97.0
92.8
2.90
3.13
0.5
5
96.5-102
100
2.13
2.13
CPS A (CSE)
0.2 (LOQ)
5
88.0-100
93.9
5.65
6.02
2.0
5
89.4-101
93.7
4.38
4.65
AP
0.2 (LOQ)
5
58.5-79.6
69.5
8.54
12.3
2.0
5
66.9-88.3
74.2
8.19
11.0
HS
0.2 (LOQ)
5
97.6-110
103
4.93
4.79
2.0
5
90.0-92.2
91.3
0.954
1.04
CSA
0.2 (LOQ)
5
85.8-105
93.9
9.69
10.3
2.0
5
84.0-89.6
86.8
2.00
2.30
CSAG
0.2 (LOQ)
5
84.2-102
92.2
7.46
8.09
2.0
5
85.9-91.0
88.2
1.88
2.13
CSEG
0.2 (LOQ)
5
103-115
108
4.76
4.41
Page 10 of 21
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Halosulfuron-methvl (PC 128721)
MRIDs 49798401/49983101
Analyte1
Fortification
Level (ppb)
Number
of Tests
Recovery
Range (%)
Mean
Recovery (%)
Standard
Deviation (%)
Relative
Standard
Deviation (%)
2.0
5
92.8-98.1
96.2
2.02
2.10
Data (uncorrected recovery results; pp. 23-25) were obtained from Tables 4-35, pp. 34-65 of MRID 49983101.
Red values indicate discrepancies with meeting guideline requirements.
1 HSM = Methyl 3-chloro-5-(4,6-dimethoxypyrimidin-2-ylcarbamoylsulfamoyl)-l-methylpyrazole-4-carboxylate. RRE
= Halosulfuron-methyl rearrangement ester; Methyl 3-chloro-5-[(4,6-dimethoxypyrimidin-2-yl)amino]-l-methyl-
pyrazole-4-carboxylate. CPSA/CSE = 3-Chlorosulfonamide acid methyl ester; Methyl-3-chloro-l-methyl-5-
sulfamoylpyrazole-4-carboxylate. AP = Aminopyrimidine; 2-Amino-4,6-dimethoxypyrimidine. HS = Halosulfuron
acid; 3- Chloro-5-(4,6-dimethoxypyrimidin-2-ylcarbamoylsulfamoyl)-l-methlypyrazole-4-carboxylic acid. CSA= 3-
Chlorosulfonamide; 3-Chloro-l-methyl-5-sulfamoyl-pyrazole-4-carboxylic acid. CSAG = Halosulfuron acid
guanidine; 5-(Carbamimidoylcarbamoylsulfamoyl)-3-chloro-l-methyl-pyrazole-4-carboxylic acid. CSEG =
Halosulfuron ester guanidine; Methyl 5-(carbamimidoylcarbamoylsulfamoyl)-3-chloro-l-methyl-pyrazole-4-
carboxylate.
2 Two sources of ground (well) water were used for the ground water sample: PTRL West ground water (the matrix
used in the ECM; 2706W-032; pH 7.3, hardness 627 mg equiv. CaCCh/L. total dissolved solids 960 ppm) and EAG
Laboratories ground water (pH 7.95; hardness 136 mg/L as CaCCh: p. 14; Appendices III-V, pp. 176-179). The
natural surface water (pH 7.00; hardness 64.0 mg/L as CaCCh) was obtained from Tuckahoe Lake, Tuckahoe Lake
State Park, Ridgely, Maryland. All water matrices were characterized by Agvise Laboratories, Northwood, North
Dakota and EAG Laboratories.
3 Two ion pair transitions were monitored for each analyte (quantitation and confirmation, respectively): m/z 435>182
and m/z 435>139 for HSM, m/z 328>296 and m/z 328>197 for RRE, m/z 156>100 and m/z 156>57 for AP, m/z
252>188 and m/z 252^220 for CPSA (CSE), m/z 419^194 and m/z 419^238 for HS, m/z 238^78.0 and m/z
238>194 for CSA, m/z 323^194 and m/z 323^238 for CSAG, and m/z 337^252 and m/z 337^77.9 for CSEG
(see Reviewer's Comment #8).
4 The reviewer assumed that the value reported in the study report (7.68%) was a typographical error (see DER
Attachment 2). The value listed is the RSD value calculated by the reviewer.
Page 11 of 21
-------
Halosulfuron-methvl (PC 128721)
MRIDs 49798401/49983101
III. Method Characteristics
In the ECM and ILV, the LOQs were 0.05 ppb for HSM and RRE and 0.2 ppb for CPSA (CSE),
AP, HS, CSA, CSAG and CSEG (pp. 10, 38-39, 43 of MRID 49798401; pp. 12, 20; Tables 4-35,
pp. 34-65 of MRID 49983101). In the ECM, the LOQs were defined by their validation in the study.
In the ILV, the LOQs were defined as the lowest level fortified during the method validation set. No
calculations or further justification was provided. In the ECM, the Limits of Detection (LOD) were
0.01 ppb for HSM and RRE, 0.02 ppb for CPSA (CSE) and AP, 0.01 ppb for HS and CSA and 0.08
ppb for CSAG and CSEG. The LOD was defined as the lowest calibrant concentration that gave a
linear response and had a signal intensity above that of the reagent blank or control matrix
responses. The study authors also reported that the LOD was 20% or lower for all analytes, except
CSAG and CSEG. The LOD for CSAG and CSEG was 40% of the LOQ due to the sensitivity of
the LC/MS/MS method. The LODs were 0.05 ng/mL for HSM and RRE and 0.01 ng/mL for all
other analytes. The LOD ppb equivalence was calculated using the following equation:
LOD (ppb equivalence) = [LOD conc. (ng/mL) x final volume (mL) x Dilution Factor] ^ sample
weight (g).
No calculations of the LOD based on standard deviations or background levels were reported in the
ECM. The LODs for the analytes were not reported in the ILV.
Page 12 of 21
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Halosulfuron-methyl (PC 128721)
MRIDs 49798401/49983101
Table 4. Method Characteristics Halosulfuron-methyl (HSM) and Its Transformation Products RRE, CPSA, AP, HS, CSA, CP AG
and CPEG1 in Water
Halosulfuron-
methyl HSM
RRE
CPSA (CSE)
AP
HS
CSA
CSAG
CSEG
Limit of
Quantitation
(LOQ)
ECM
ILV
0.05 ppb
0.2 ppb
Limit of
Detection
(LOD)
ECM
0.01 ppb
0.02 ppb
0.01 ppb
0.08 ppb
ILV
Not reported
Linearity
(calibration
curve r2 and
concentration
range)
ECM2
r2 = 0.9981 (Q)
r2 = 0.9982 (C)
r2 = 0.9987 (Q)
r2 = 0.9990 (C)
r2 = 0.9975 (Q)
r2 = 0.9973 (C)
r2 = 0.9987 (Q)
r2 = 0.9991 (C)
r2 = 0.9999 (Q)
r2 = 0.9997 (C)
r2 = 0.9982 (Q)
r2 = 0.9999 (C)
r2 = 0.9992 (Q)
r2 = 0.9996 (C)
r2 = 0.9988 (Q)
r2 = 0.9995 (C)
Range:
0.05-25 ng/mL
0.1-50 ng/mL
0.01-10 ng/mL
0.04-10 ng/mL
ILV3
r2 = 0.9999 (Q)
r2 = 0.9987 (Q)
r2 = 0.9996 (Q)
r2 = 0.9971 (Q)
r2 = 0.9886 (Q)
r2 = 0.9864 (Q)
r2 = 0.9998 (Q)
r2 = 0.9992 (Q)
Range:
0.05-25 ng/mL
0.1-50 ng/mL
0.04-50 ng/mL
0.04-10 ng/mL
Repeatable
ECM4
Surface
Water:
Yes at LOQ and 10/LOQ.
No; mean
recoveries
44% at LOQ
and 51-53% at
lOxLOQ.
Yes at LOQ and lOxLOQ.
Ground
Water:
Yes at LOQ and 10/LOQ.
Yes at
lOxLOQ.
No at LOQ
(Q), RSD =
25%; Yes at
LOQ (C).
Yes at
lOxLOQ.
No at LOQ
(C), RSD =
24%; Yes at
LOQ (Q).
Yes at LOQ
and lOxLOQ.
ILV5
Surface
Water:
Yes at LOQ and lOxLOQ.
Ground
Water:
Yes at LOQ and lOxLOQ.
Yes at
lOxLOQ.
No at LOQ
Mean = 69.3%
(Q), 69.5% (C).
Yes at LOQ and lOxLOQ.
Reproducible
Yes at LOQ and lOxLOQ in surface and ground
water matrices.
Yes at LOQ
and lOxLOQ
in surface
water matrix.
Yes at
Yes at LOQ and lOxLOQ in surface and ground water matrices.
Page 13 of 21
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Halosulfuron-methvl (PC 128721)
MRIDs 49798401/49983101
lOxLOQ in
ground water
matrix; No at
LOQ in ground
water matrix.
Specific
ECM
Surface
Water:
Ground
Water:
Interferences were <10% of
LOQ, based on peak height, at
analyte retention times.
No matrix interferences were
observed.
No matrix
No matrix
interferences
interferences
No matrix
were observed;
were observed;
interferences
however,
however,
were observed;
analyte peak at
baseline noise
however,
LOQ not well-
interfered with
No matrix
analyte peak at
resolved from
analyte peak
interferences
LOD was
baseline.7 Also,
integration.9
were observed.
barely resolved
analyte peak at
Also, peak at
above the
LOD was
LOD was
baseline.6
barely resolved
barely resolved
above the
above the
baseline.8
baseline.10
ILV
Only quantitation ion chromatograms were provided.
Surface
Water:
Ground
Water:
No matrix interferences were
observed.
No matrix
interferences
No matrix
were observed.
interferences
No matrix
were observed;
interferences
however,
were observed;
baseline noise
however,
was significant
minor baseline
near the analyte
noise was
peak.11
observed near
the analyte
peak.
No matrix interferences were observed.
Data were obtained from pp. 10, 12-15, 38-39, 43; Tables I-II, pp. 45-50 (recovery results); Figures 5-7, pp. 64-87 (reagent blanks and control water chromatograms);
Figure 8, pp. 88-95 (calibration curves); Figures 12-15, pp. 120-151 (LOQ and lOxLOQ chromatograms); Figure 16, pp. 152-159 (LOD chromatograms) of MRID
49798401; pp. 12, 20; Tables 4-35, pp. 34-65 (recovery results); Figures 1-3, pp. 66-68 (calibration curves); Figures 4-27, pp. 69-92 (chromatograms) of MRID
49983101. Q = quantitation ion; C = confirmation ion. All results reported for Q and C ions unless specified otherwise.
Red values indicate discrepancies with meeting guideline requirements.
1 HSM = Methyl 3-chloro-5-(4,6-dimethoxypyrimidin-2-ylcarbamoylsulfamoyl)-l-methylpyrazole-4-carboxylate. RRE = Halosulfuron-methyl rearrangement ester;
Methyl 3-chloro-5-[(4,6-dimethoxypyrimidin-2-yl)amino]-l-methyl-pyrazole-4-carboxylate. CPSA/CSE = 3-Chlorosulfonamide acid methyl ester; Methyl-3-chloro-
l-methyl-5-sulfamoylpyrazole-4-carboxylate. AP = Aminopyrimidine; 2-Amino-4,6-dimethoxypyrimidine. HS = Halosulfuron acid; 3- Chloro-5-(4,6-
dimethoxypyrimidin-2-ylcarbamoylsulfamoyl)-l-methlypyrazole-4-carboxylic acid. CSA = 3-Chlorosulfonamide; 3-Chloro-l-methyl-5-sulfamoyl-pyrazole-4-
Page 14 of 21
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Halosulfuron-methvl (PC 128721)
MRIDs 49798401/49983101
carboxylic acid. CSAG = Halosulfuron acid guanidine; 5-(Carbamimidoylcarbamoylsulfamoyl)-3-chloro-l-methyl-pyrazole-4-carboxylic acid. CSEG = Halosulfuron
ester guanidine; Methyl 5-(carbamimidoylcarbamoylsulfamoyl)-3-chloro-l-methyl-pyrazole-4-carboxylate.
2 Correlation coefficients (r2) were reviewer-calculated based on r values (1/x weighted linear regression analysis) reported in the study report; solvent standards were
used (pp. 25-29; Figure 8, pp. 88-95 of MRID 49798401; DER Attachment 2).
3 Correlation coefficients (r2) were reviewer-calculated based on r values (1/x weighted linear regression analysis) reported in the study report; only one set of
calibration cures was provided (Figures 1-3, pp. 66-68 of MRID 49983101; DER Attachment 2). The reviewer assumed that these curves were for the quantitation ion.
The calibration curves were titled with "GW", seeming to indicate that these were for the ground water set. Calibration standards were prepared in solvent (pp. 17-19).
4 In the ECM, ground (well) water (2706W-032; pH 7.3, hardness 627 mg equiv. CaCCh/L. total dissolved solids 960 ppm) and natural surface water (2440W-083; pH
6.3, total dissolved solids 68 ppm) were characterized by Agvise Laboratories, Northwood, North Dakota (p. 22; Appendix C, pp. 184-185 of MRID 49798401). The
specific water source type of the surface water was not reported.
5 In the ILV, two sources of ground (well) water were used for the ground water sample: PTRL West ground water (the matrix used in the ECM; 2706W-032; pH 7.3,
hardness 627 mg equiv. CaCCh/L. total dissolved solids 960 ppm) and EAG Laboratories ground water (pH 7.95; hardness 136 mg/L as CaCCh: p. 14; Appendices
III-V, pp. 176-179 of MRID 49983101). The natural surface water (pH 7.00; hardness 64.0 mg/L as CaCCh) was obtained from Tuckahoe Lake, Tuckahoe Lake State
Park, Ridgely, Maryland. All water matrices were characterized by Agvise Laboratories, Northwood, North Dakota and EAG Laboratories.
6 Figure 16, p. 157 of MRID 49798401.
7 Figure 12, p. 124; Figure 14, p. 140 of MRID 49798401.
8 Figure 16, p. 156 of MRID 49798401.
9 Figure 12, p. 126; Figure 14, p. 142 of MRID 49798401.
10 Figure 16, p. 158 of MRID 49798401.
11 Figures 11-12, pp. 76-77 of MRID 49983101.
Linearity is satisfactory when r2 > 0.995.
A confirmatory method is not usually required when LC/MS and GC/MS is the primary method.
Page 15 of 21
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Halosulfuron-methvl (PC 128721)
MRIDs 49798401/49983101
IV. Method Deficiencies and Reviewer's Comments
1. ECM MRID 49798401 was originally submitted without an ILV. The ECM was reviewed
without the ILV by CDM Smith primary reviewer Lisa Muto and secondary reviewer
Kathleen Ferguson. The data from the ILV was combined with data from the previous DER.
The DER content regarding the ECM MRID 49798401 was reviewed and adjusted, if
necessary, based on data form the ILV, but, generally, very little modification was done to
the original DER content regarding ECM MRID 49798401.
2. In the ILV, two sources of ground (well) water were used for the ground water sample:
PTRL West ground water and EAG Laboratories ground water, but only one set of ground
water recovery data was reported (p. 14; Appendices III-V, pp. 176-179 of MRID
49983101). The ILV study authors did not specify the way in which these two ground water
sources were used in the study, i.e. if the two samples were mixed evenly to create a
combined ground water sample or if the samples were considered analogous and used
independently in the study for various samples. The characteristics and constitution of the
water matrix/matrices should be clear in the method validations.
3. In the ILV, the analysis of AP did not meet OCSPP Guideline 850.6100 criteria for precision
and accuracy (mean recoveries for replicates at each spiking level between 70% and 120%
and relative standard deviations (RSD) <20%) at the stated LOQ in the ground water matrix
(mean recoveries: 69.3% quantitation ion, 69.5% confirmation ion; Tables 10-11, pp. 40-41
of MRID 49983101). In a 2002 Aerobic Aquatic Metabolism study (MRID 45671701), 4,6-
Dimethoxypyrimidin-2-amine (AP) was found to be a major degradate; the reviewed method
does not meet the guideline requirements for analyzing this degradate.
In the ECM, several compounds did not meet OCSPP Guideline 850.6100 criteria for
precision and accuracy at the stated LOQ and at higher concentrations in both water
matrices. In the surface water matrix, the mean recoveries of AP were 44-53% at the LOQ
and lOxLOQ (quantification and confirmation ions; Tables I-II, pp. 45-50 of MRID
49798401). In the ground water matrix, the RSDs of CSA and CSAG at the LOQ which
were 25% (quantification ion) and 24% (confirmation ion), respectively. Regarding CSAG,
the reviewer noted that a confirmatory method is not typically required where GC/MS
and/or LC/MS methods are used as the primary method(s) to generate study data.
In a 2002 Aerobic Aquatic Metabolism study (MRID 45671701), 4,6-Dimethoxypyrimidin-
2-amine (AP) and 3-Chloro-l-methyl-5-sulfamoyl-pyrazole-4-carboxylic acid (CSA) were
found to be major degradates; does not meet the guideline requirements for analyzing these
degradates.
4. In the ILV, linearity was not satisfactory for HS (r2 = 0.9886) and CSA (r2 = 0.9864; pp. 17-
19; Figure 2, p. 67 of MRID 49983101). Linearity is satisfactory when r2 > 0.995.
Additionally, only one set of calibration cures was provided. The reviewer assumed that
these curves were for the quantitation ion. The calibration curves were titled with "GW",
seeming to indicate that these were for the ground water set, but calibration standards were
prepared in solvent. Since data for the confirmatory ion was reported in the ILV study
report, the corresponding calibration curves used to generate that data should have been
reported. However, the reviewer noted that a confirmatory method is not usually required
when LC/MS and GC/MS is the primary method.
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Halosulfuron-methvl (PC 128721)
MRIDs 49798401/49983101
5. In the ILV, only quantitation ion chromatograms were provided; no chromatograms from the
confirmatory ion analyses were shown (Figures 4-27, pp. 69-92 of MRID 49983101). The
reviewer noted that a confirmatory method is not usually required when LC/MS and GC/MS
is the primary method.
Also, baseline noise was significant near the analyte peak in ILV chromatograms of CPSA
(Figures 11-12, pp. 76-77 of MRID 49983101).
6. In the ECM, the LOQ chromatograms for CSA and CSAG in both water matrices showed
baseline interferences with peak resolution or integration (Figure 12, pp. 124, 126; Figure
14, pp. 140, 142 of MRID 49798401).
7. The determinations of the LOD and LOQ in the ECM and ILV were not based on
scientifically acceptable procedures as defined in 40 CFR Part 136. The LOQ and LOD were
not adequately supported by calculations or comparison to background levels in the ECM
(pp. 10, 38-39, 43 of MRID 49798401; pp. 12, 20; Tables 4-35, pp. 34-65 of MRID
49983101). In the ECM, the LOQs were defined by their validation in the study. In the ILV,
the LOQs were defined as the lowest level fortified during the method validation set. In the
ECM, the LOD was defined as the lowest calibrant concentration that gave a linear response
and had a signal intensity above that of the reagent blank or control matrix responses. The
study authors also reported that the LOD was 20% or lower for all analytes, except CSAG
and CSEG. The LOD for CSAG and CSEG was 40% of the LOQ due to the sensitivity of
the LC/MS/MS method. The reviewer noted that the analyte peak at the LOD was barely
resolved above the baseline for HS, CSA and CSAG (Figure 16, pp. 156-158). The LODs
for the analytes were not reported in the ILV.
8. In the ILV, the reviewer noted several significant typographical errors in the reported
monitored ion pair transitions for HSM, AP and CPSA in Table 1 (Table 1, p. 31; Figures 4-
27, pp. 69-92 of MRID 49983101). Ion transitions for HSM were incorrectly reported as m/z
156> 100 and m/z 156>57 in Table 1 (those for AP), instead of m/z 435>182 and m/z
435>139. Ion transitions for AP and CPSA were interchanged in Table 1.
9. In the ECM, matrix effects were evaluated in all matrices (p. 43; Table IV, p. 52 of MRID
49798401). The study authors determined that matrix effects (>20%) were observed for
CSEG (33.5%), surface water; 63.8%> ground water), RRE (-21.2%, ground water), AP (-
20.8%o, ground water), HS (-22.1%, ground water) and CSAG (-31.9%), ground water). The
study authors did not use matrix-matched standards since they determined that the matrix
effects could be reduced by diluting the final extracts with solvent prior to analysis.
10. The communications between the ILV and study developers and sponsors were detailed;
communications involved failed trial discussions and suggested modifications (Appendix
VII, pp. 199-200 of MRID 49983101).
11. In the ILV, the total time required to perform the method (extraction and analysis) for all
analytes with one sample set was ca. 7 days (Appendix VII, pp. 198-199 of MRID
49983101). One set of 13 samples (one reagent blank, two matrix controls and ten fortified
samples) required ca. 12 hours (processing) and ca. 12 hours (analysis and data processing)
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Halosulfuron-methvl (PC 128721)
MRIDs 49798401/49983101
for the HSM/RRE/CPSA(CSE)/AP method, and ca. 4 hours (processing) and ca. 11 hours
(analysis and data processing) for the HS/CSA method or CSAG/CSEG method.
In the ECM, the total time required to perform the method (extraction and analysis) was ca.
30 hours (p. 39 of MRID 49798401). One set of 13 samples (one reagent blank, two matrix
controls and ten fortified samples) required ca. 8 hours (processing) and ca. 6 hours
(analysis and data processing) for the HSM/RRE/CPSA(CSE)/AP method, and ca. 4 hours
(processing) and ca. 4 hours (analysis and data processing) for the HS/CSA method or
CSAG/CSEG method.
12. The ECM should be edited to account for the following critical steps noted by the ILV: in
the method for HSM/RRE/CPSA (CSE)/AP, care must be taken to minimize the length of
time sample extracts are allowed to remain at dryness when on the nitrogen evaporator
system; and in the method for CSA/HS, the fortification stock solution should be prepared in
acetonitrile: water (1:1, v:v) to ensure stability and constant solubility of the CSA/HS
analytes, especially the HS component (Appendix VII, p. 198 of MRID 49983101).
V. References
U.S. Environmental Protection Agency. 2012. Ecological Effects Test Guidelines, OCSPP
850.6100, Environmental Chemistry Methods and Associated Independent Laboratory
Validation. Office of Chemical Safety and Pollution Prevention, Washington, DC. EPA 712-
C-001.
40 CFR Part 136. Appendix B. Definition and Procedure for the Determination of the Method
Detection Limit-Revision 1.11, pp. 317-319.
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Halosulfuron-methyl (PC 128721)
MRIDs 49798401/49983101
Attachment 1: Chemical Names and Structures
Halosulfuron-methyl (HSM; NC-319)
IUPAC Name:
CAS Name:
CAS Number:
SMILES String:
Methyl 3-chloro-5-(4,6-dimethoxypyrimidin-2-ylcarbamoylsulfamoyl)-l-
methylpyrazole-4-carboxylate
Methyl 3-chloro-5-[[[[(4,6-dimethoxy-2-
pyrimidinyl)amino]carbonyl]amino]sulfonyl]-l-methyl-lH-pyrazole-4-
carboxylate
100784-20-1
COC(=0)c 1 c(Cl)nn(C)c 1 S(=0)(=0)NC(=0)Nc2nc(0C)cc(0C)n2
TY
Halosulfuron-methyl rearrangement ester (RRE; HSMR)
IUPAC Name:
CAS Name:
CAS Number:
SMILES String:
Methyl 3-chloro-5-[(4,6-dimethoxypyrimidin-2-yl)amino]-l-methyl-
pyrazole-4-carboxylate
Not reported
Not found
Cn 1 c(c(c(n 1 )Cl)C(=0)0C)Nc2nc(cc(n2)0C)0C
Page 19 of 21
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Halosulfuron-methvl (PC 128721)
MRIDs 49798401/49983101
3-Chlorosulfonamide acid methyl ester (CPSA or CSE; Chlorosulfonamide)
IUPAC Name:
CAS Name:
CAS Number:
SMILES String:
Methyl-3-chloro-l-methyl-5-sulfamoylpyrazole-4-carboxylate
Not reported
100784-27-8
Cn 1 c(c(c(n 1 )C1)C(=0)0C)S(=0)(=0)N
CH,
NH,
2-Amino-4,6-dimethoxypyrimidine (AP; ADMP; Aminopyrimidine; 620Pd-l)
IUPAC Name: 2-Amino-4,6-dimethoxypyrimidine
Not reported
36315-01-2
COc 1 cc(nc(n 1 )N)OC
CAS Name:
CAS Number:
SMILES String:
H,N
CH,
0
1
CH
3
IUPAC Name:
Halosulfuron acid (HS; Halosulfuron; 319-ACID; NC-319 ACID)
3- Chloro-5-(4,6-dimethoxypyrimidin-2-ylcarbamoylsulfamoyl)-l-
methlypyrazole-4-carboxylic acid
Not reported
135397-30-7
CAS Name:
CAS Number:
SMILES String: Cnlc(c(c(nl)Cl)C(=0)0)S(=0)(=0)NC(=0)Nc2nc(cc(n2)0C)0C
TY
Page 20 of 21
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Halosulfuron-methvl (PC 128721)
MRIDs 49798401/49983101
3-Chlorosulfonamide (CSA; Chlorosulfonamide acid; CSAA; MON5783)
IUPAC Name:
CAS Name:
CAS Number:
SMILES String:
3-Chloro-l-methyl-5-sulfamoyl-pyrazole-4-carboxylic acid
Not reported
Not found
Cn 1 c(c(c(n 1 )C1)C(=0)0)S(=0)(=0)N
IUPAC Name:
Halosulfuron acid guanidine (CSAG; Chlorosulfonamide acid guanidine; CSA-
guanidine; CSA-g)
5-(Carbamimidoylcarbamoylsulfamoyl)-3-chloro-l-methyl-pyrazole-4-
carboxylic acid
Not reported
Not found
Cnlc(c(c(nl)Cl)C(=0)0)S(=0)(=0)NC(=0)NC(=N)N
CAS Name:
CAS Number:
SMILES String:
IUPAC Name:
Halosulfuron ester guanidine (CSEG; Halosulfuron guanidine; Chlorosulfonamide
guanidine; CSE-guanidine; CSE-g)
Methyl 5-(carbamimidoylcarbamoylsulfamoyl)-3-chloro-1 -methyl -
pyrazole-4-carboxylate
Not reported
Not found
Cnlc(c(c(nl)Cl)C(=0)0C)S(=0)(=0)NC(=0)NC(=N)N
CAS Name:
CAS Number:
SMILES String:
Page 21 of 21
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