Etridiazole (PC 084701)
MRIDs 50534504/50584602
Analytical method for etridiazole and its metabolites etridiazole acid and 3-DCMT (DCE) in
soil
Reports: ECM: EPA MRID No. 50534504. DeVellis, S.R. 2018. Validation of the
Analytical Method for the Determination of Etridiazole and its Metabolites
in Soil Matrices by LC-MS/MS and GC-MS. Smithers Viscient Study No.:
14088.6158. Sponsor Study No.: 2017-252. Report prepared by Smithers
Viscient, Wareham, Massachusetts; sponsored and submitted by MacDermid
Agricultural Solutions, Inc., c/o Arysta LifeScience North America, LLC,
Cary, North Carolina; 139 pages. Final report issued January 9, 2018.
Document No.
Guideline:
Statements:
ILV: EPA MRID No. 50584602. Cashmore, A. 2018. Etridiazole -
Independent Laboratory Validation of Analytical Method 14088.6158 for the
Determination of Etridiazole and its metabolites Etridiazole acid and DCE in
Soil. Smithers Viscient (ESG) Ltd. Study No.: 3202057 and Document No.:
2017-357. Report prepared by Smithers Viscient (ESG) Ltd., North
Yorkshire, United Kingdom; sponsored and submitted by MacDermid
Agricultural Solutions, Inc., c/o Arysta LifeScience North America, LLC,
Cary, North Carolina; 108 pages. Final report issued May 9, 2018 (pp. 2-5).
MRIDs 50534504 & 50584602
850.6100
ECM: The study was conducted in accordance with the USEPA FIFRA (40
CFR Part 160) and OECD Good Laboratory Practices (GLP; p. 3 of MRID
50534504). Signed and dated No Data Confidentiality, GLP and Quality
Assurance statements were provided (pp. 2-4). A certification of the
authenticity of the report was included with the QA statement.
Classification:
PC Code:
EFED Final
Reviewer:
CDM/CSS-
Dynamac JV
Reviewers:
ILV: The study was conducted in accordance with the UK GLP and OECD
GLP and was in compliance with the GLP regulation and are suitable for
submission to the US FDA/EPA/Japanese regulatory authorities (p. 3;
Appendix 3, p. 105 of MRID 50584602). Signed and dated No Data
Confidentiality, GLP, Authenticity, and Quality Assurance statements were
provided (pp. 2-5; Appendix 3, p. 105).
This analytical method is classified as not acceptable. To upgrade the study
classification, an updated ECM should be submitted which includes ILV
modifications. Soil extract stability data should be provided for 3-DCMT to
support the ECM. ILV analysis was not satisfactory for etridiazole, 3-DCMT
or 3-Carb-T (etridiazole acid) analysis. ECM linearity was not satisfactory
for 3-DCMT analysis. The specificity of the method was not supported for
3-Carb-T based on ILV representative chromatograms. The suitability of the
ILV matrices could not be determined.
084701
Cheryl Sutton, Ph.D. Signature:
_ . Diqitallysiqned by Sutton,
Sutton, Cheryl
' * nate- ?0
Date: 2018.10.30 0<
Environmental Scientist
TeresaNelis, M.S.,
Environmental Scientist
Lisa Muto, M.S.,
Date: October 24, 2018
Signature:
Date: 9/2^/18
Signature: st***-
Page 1 of 16
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Etridiazole (PC 084701)
MRIDs 50534504/50584602
Environmental Scientist Date: 9/28/18
This Data Evaluation Record may have been altered by the Environmental Fate and Effects
Division subsequent to signing by CDM/CSS-Dynamac JVpersonnel. The CDM/CSS-Dynamac
Joint Venture role does not include establishing Agency policies.
Executive Summary
This analytical method, Smithers Viscient Study No. 14088.6158, is designed for the quantitative
determination of etridiazole and its metabolite 3-DCMT (DCE) in soil at the LOQ of 50 |ig/kg using
GC-MS/EI, and metabolite 3-Carb-T (etridiazole acid) in soil at the LOQ of 50 |ig/kg using LC-
MS/MS. The ECM validated the method for the three analytes using one characterized clay loam
and one characterized silt loam soil matrices, and the ILV validated the method using one
characterized sandy loam and one characterized silt loam soil matrices. In the ECM and ILV, three
ions were monitored for etridiazole and 3-DCMT, and two ion transitions were monitored for 3-
Carb-T analysis. An updated ECM should be submitted which includes ILV modifications: the
use of glass pipets instead of positive displacement pipets (plastic) for handling samples, the use of
fresh soil extracts for 3-DCMT analysis due to stability issues, and the stock dilution preparation of
3-Carb-T by preparing directly into disposable glass vials instead of glass volumetric flasks. The
ILV validated the ECM method for the quantitation and confirmation analyses of etridiazole and 3-
DCMT (lOxLOQ only) in silt loam soil in the first trial; the ILV validated the ECM method for the
quantitation and confirmation analyses of etridiazole and 3-DCMT in sandy loam soil, 3-DCMT at
the LOQ in silt loam soil, and 3-Carb-T in sandy loam and silt loam soil matrices in the second trial.
The ILV modifications were necessary for all trials to succeed. The ILV also noted that 3-DCMT
extracts may be unstable in stored extracts; soil extract stability data should be provided for 3-
DCMT to support the ECM. All ECM and ILV data was satisfactory regarding accuracy and
precision for all analytes. ECM and ILV data was satisfactory regarding specificity for all analytes,
except for 3-Carb-T ILV chromatograms, which showed multiple significant contaminants in all Q
chromatograms, including the reagent blank, controls, and calibration standards. ILV linearity was
not satisfactory for etridiazole, 3-DCMT or 3-Carb-T analysis in at least one matrix. ECM linearity
was satisfactory for all analytes, except 3-DCMT analysis in silt loam soil.
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Etridiazole (PC 084701)
MRIDs 50534504/50584602
Table 1. Analytical Method Summary.
Analyte(s)
by
Pesticide
MRID
EPA
Review
Matrix
Method
Date
Registrant
Analysis
Limit of
Quantitation
(LOQ)
Environmental
Chemistry
Method
Independent
Laboratory
Validation
Etridiazole
50534504
50584602
Soil1-2
01/09/2018
MacDermid
Agricultural
Solutions,
Inc.
c/o Arysta
LifeScience
North
America,
LLC
GC/MS
50.0 ng/kg
3-DCMT
(DCE)
3-Carb-T
LC/MS/MS
1 In the ECM, clay loam soil (SMV Lot No. 12DEC16SOIL-B; 40/28/32 sand/silt/clay, pH 5.4 in 1:1 soikwater ratio,
5.6% organic matter) obtained from Grand Forks, North Dakota, and silt loam soil (SMV Lot No. 13SEP17SOIL-B;
24/60/16 sand/silt/clay), pH 7.2 in 1:1 soikwater ratio, 3.9% organic matter Walkley-Black) obtained from Jackson,
Iowa, were used (USDA soil texture classification not specified; pp. 18-19 of MRID 50534504). Soil characterization
was performed by Agvise Laboratories, Northwood, North Dakota.
2 In the ILV, sandy loam soil (CS 27/16 Speyer 5M; 59/30/11 sand/silt/clay, pH 8.5 in 1:5 soikwater ratio, 1.0%
organic carbon) was obtained from Rheinland-Pfalz, Germany, and supplied by LUFA Speyer, and silt loam soil (CS
30/16 Brierlow; 26/58/16 sand/silt/clay, pH 6.4 in 1:5 soikwater ratio, 2.5% organic carbon) was obtained from
Derbyshire, UK, and supplied by LRA Labsoil (USDA soil texture classification; p. 15; Appendix 2, pp. 103-104 of
MRID 50584602). Soil was characterized by Smithers Viscient (ESG), North Yorkshire, UK, except some of the
analyses on the sandy loam soil was characterized by LUFA Speyer.
I. Principle of the Method
Samples (5.00 g dry weight) were transferred to 45-mL glass vials with teflon-lined caps and
fortified with 0.0250 mL or 0.250 mL of the fortification solutions (10.0 mg/L) of etridiazole and 3-
DCMT in acetonitrile to prepare LOQ (50 |ig/kg) and lOxLOQ (500 |ig/kg) fortified samples,
respectively; samples (ca. 5.00 g dry weight) were transferred to 50-mL Nalgene centrifuge tubes
and fortified with 0.250 mL of the fortification solutions (1.00 or 10.0 mg/L) of 3-Carb-T in
acetonitrile to prepare LOQ (50 |ig/kg) and lOxLOQ, fortified samples, respectively (pp. 20-21, 24-
26 of MRID 50534504). The soil samples fortified with etridiazole and 3-DCMT were extracted
with 30.0 mL of dichloromethane:acetone (75:25, v:v) and placed on a shaker table (150 rpm for 30
minutes) (pp. 26-27 of MRID 50534504). After centrifugation (1200 rpm for 15 minutes), a portion
of each extract was concentrated under a gentle stream of nitrogen to incipient dryness {ca. 100 |iL)
and reconstituted with internal standard diluent to a volume of 10.0 mL for the LOQ and lOxLOQ.
The soil samples (5.00 g dry weight) fortified with 3-CarbT in 50-mL Nalgene centrifuge tubes
were extracted with 20.0 mL of acetonitrile:purified reagent water (20:80, v:v) and placed on a
shaker table (150 rpm for 30 minutes) (pp. 27-29 of MRID 50534504). After centrifugation (3000
rpm for 10 minutes), extracts were transferred to 50.0-mL volumetric flasks, and the extraction and
centrifugation procedure was repeated with an additional 20.0 mL of acetonitrile:purified reagent
water (20:80, v:v). The extracts were combined to a total volume of 50.0 mL, and 5.00 mL of the
final extract was further processed by solid phase extraction. The 5.00 mL aliquots received 1.0 [iL
ammonium hydroxide, were loaded onto Oasis Mixed-Mode Strong Anion Exchange (MAX) SPE
columns (60 mg, 3 mL, pre-conditioned with two column volumes of methanol and two column
Page 3 of 16
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Etridiazole (PC 084701)
MRIDs 50534504/50584602
volumes of purified reagent water) and allowed to flow through under vacuum (1 drop/sec. flow)
(pp. 27-29 of MRID 50534504). Each sample vessel and column were rinsed with 5.00 mL of
purified reagent water, the rinsate loaded onto the column, allowed to flow under vacuum at 1
drop/sec., and then rinsed in a similar manner with 5.00 mL of methanol, and the rinsates discarded.
The columns were quickly dried under full vacuum, and the test substance was eluted from the SPE
columns with 3.00 mL of 2% trifluoroacetic acid in methanol under vacuum at 1 drop/sec. and
collected into glass conical vials. The samples were concentrated to incipient dryness under a gentle
stream of nitrogen at 50.0°C. The residue was reconstituted to 5.00 mL with 20:80:0.1
acetonitrile:purified reagent water:trifluoroacetic acid (v:v:v) via mixing and sonication for five
minutes before analysis via LC-MS/MS.
Etridiazole and 3-DCMT sample extracts were analyzed via GC-MS/EI using an Agilent 6890
series GC and Agilent DB-5MS column (15 m x 0.250 mm x 0.25 |im) using a column temperature
program (initial 50°C and held for 2.00 minutes to post 250°C held for 0.00 minutes) and helium
carrier gas coupled with MS detection (300°C transfer line and 230°C source temperature) (pp. 18,
29-30 of MRID 50534504). Three ions were monitored as follows (quantitation, confirmation 1,
and confirmation 2, respectively): m/z 211.00, 185.00, and 183.00 for etridiazole, and m/z 143.00,
184.00, and 186.00 for 3-DCMT. Reported retention times for etridiazole and 3-DCMT were ca. 6.1
and 5.8 minutes, respectively. Benzophenone was used as the internal standard (p. 17 of MRID
50534504)
3-Carb-T sample extracts were analyzed via LC-MS/MS using a Phenomenex column and MDS
Sciex API 5000 mass spectrometer equipped with a with an ESI Turbo V source (pp. 17-18, 31-32
of MRID 50534504). The LC conditions consisted of a Phenomenex Kinetex 5 |im EVO CI 8
column (50 |im x 2.1 mm, column temperature 35°C), a mobile phase of (A) 0.1% trifluoroacetic
acid in water and (B) 0.1% trifluoroacetic acid in acetonitrile [percent A:B (v:v) at 0.01 min.
98.0:2.0, 0.50 min. 98.0:2.0, 2:00 min. 0:100, 3.00 min. 0:100, 3.10 min. 98.0:2.0, and 4.00 min.
98.0:2.0] and MS/MS detection in positive ion mode (ionization temperature 550°C). Injection
volume was 50 |aL. Two ion transitions were monitored (quantitation and confirmation,
respectively) as follows: m/z 175.16—>147.10 and m/z 175.16—>-129.00. Retention time was ca. 1.5
minutes.
In the ILV, the ECM was performed as written with significant modifications of the use of glass
pipets instead of positive displacement pipets (plastic) for handling samples and of the stock
dilution preparation of 3-Carb-T by preparing directly into disposable glass vials instead of glass
volumetric flasks (pp. 20-23, 30-32; Appendix 4, pp. 106-107 of MRID 50584602). Initially, the
ILV incorporated the substitution of plastic for glass extraction vessels; however, recovery issues
due to the analytes adhering to plastic were identified when plastic vessels were used in the place of
glass equipment. The ILV also discovered that glass pipets should be used instead of positive
displacement pipets (plastic) which were listed in the ECM. During, 3-Carb-T analysis, the ILV
suspected that 3-Carb-T adhered to the glass volumetric flask during the serial dilutions of the
10,000 |ig/L stock for fortification of the LOQ and 10 x LOQ samples and calibration standards.
Recovery issues with 3-DCMT at the LOQ, resulting from storing extracts, was corrected by
preparing fresh soil extracts, and it was noted that 3-DCMT extracts may be unstable. The ILV also
incorporated insignificant modifications of the analytical instrumentation and parameters, and the
use of matrix-matched calibration standards for 3-Carb-T analysis on silt loam soil. The ILV
reported that a Thermo Trace 1300 Gas Chromatograph with ISQ LT single quadrupole mass
spectrometer detector was used for etridiazole and 3-DCMT (similar GC-MS parameters; retention
Page 4 of 16
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Etridiazole (PC 084701)
MRIDs 50534504/50584602
times for etridiazole and 3-DCMT were 5.1 and 4.8 min., respectively) and a Shimadzu Nexera
HPLC system coupled with an AB Sciex API 5000 MS/MS detector (similar LC-MS/MS
parameters; same ionization temperature, 550°C, retention time ca. 1.35 min.) was used for 3-Carb-
T (pp. 15,24-25).
In the ECM and ILV, the method LOQs in soil were 50.0 |ig/kg for etridiazole, 3-DCMT, and 3-
Carb-T (pp. 32-33, 38-43 of MRID 50534504; pp. 12, 30 of MRID 50584602). In the ECM, the
method LODs ranged from 5 to 7 |ig/kg in clay loam soil and 6 to 11 |ig/kg in silt loam soil for
etridiazole; 3 to 18 |ig/kg in clay loam soil and 2 to 20 |ig/kg in silt loam soil for 3-DCMT; and 0.1
to 1 |ig/kg in clay loam soil and 0.5 to 1 |ig/kg in silt loam soil for 3-Carb-T (pp. 35-36 of MRID
50534504). In the ILV, the method LODs ranged from 1.28 to 2.37 |ig/L in sandy loam soil and
3.88 to 24.5 |ig/L in silt loam soil for etridiazole; 3.52 to 4.50 |ig/L in sandy loam soil and 3.89 to
25.7 |ig/L in silt loam soil for 3-DCMT; and 4.15 to 4.49 |ig/L in sandy loam soil and 3.46 to 3.68
|ig/L in silt loam soil for 3-Carb-T (pp. 28-29 of MRID 50584602).
11. Recovery Findings
ECM (MRID 50534504): Mean recoveries and relative standard deviations (RSD) from GC-MS/EI
analysis were within guideline requirements (mean 70-120%; RSD <20%) for etridiazole and its
metabolite 3-DCMT at 50.0 |ig/kg (LOQ) and 500 |ig/kg (lOxLOQ) in two soil matrices (Tables 1-
12, pp. 46-57). Mean recoveries and relative standard deviations from LC-MS/MS analysis were
within guideline requirements for 3-Carb-T at 50.0 |ig/kg (LOQ) and 500 |ig/kg (lOxLOQ) in two
soil matrices (Tables 13-16, pp. 58-61). Performance data (recovery results) from primary and
confirmatory analyses were comparable. Clay loam soil (SMV Lot No. 12DEC16SOIL-B; 40/28/32
sand/silt/clay, pH 5.4 in 1:1 soil:water ratio, 5.6% organic matter) was obtained from Grand Forks,
North Dakota, and silt loam soil (SMV Lot No. 13SEP17SOIL-B; 24/60/16 sand/silt/clay), pH 7.2
in 1:1 soil:water ratio, 3.9% organic matter Walkley-Black) was obtained from Jackson, Iowa
(USDA soil texture classification not specified; pp. 18-19). Soil characterization was performed by
Agvise Laboratories, Northwood, North Dakota.
ILV (MRID 50584602): Mean recoveries and RSDs from GC-MS analysis were within guideline
requirements for etridiazole and its metabolite 3-DCMT at 50.0 |ig/kg (LOQ) and 500 |ig/kg
(lOxLOQ) in two soil matrices (Tables 1-6, pp. 35-40, Tables 9-14, pp. 43-48 of MRID 50584602).
Mean recoveries and RSDs from LC-MS/MS analysis were within guideline requirements for 3-
Carb-T at 50.0 |ig/kg (LOQ) and 500 |ig/kg (lOxLOQ) in two soil matrices (Tables 7-8, pp. 41-42,
Tables 15-16, pp. 49-50 of MRID 50584602). Performance data (recovery results) from primary
and confirmatory analyses were comparable. Sandy loam soil (CS 27/16 Speyer 5M; 59/30/11
sand/silt/clay, pH 8.5 in 1:5 soil:water ratio, 1.0% organic carbon) was obtained from Rheinland-
Pfalz, Germany, and supplied by LUFA Speyer, and silt loam soil (CS 30/16 Brierlow; 26/58/16
sand/silt/clay, pH 6.4 in 1:5 soil:water ratio, 2.5% organic carbon) was obtained from Derbyshire,
UK, and supplied by LRA Labsoil (USDA soil texture classification; p. 15; Appendix 2, pp. 103-
104). Soil was characterized by Smithers Viscient (ESG), North Yorkshire, UK, except some of the
analyses on the sandy loam soil was characterized by LUFA Speyer. The ILV validated the ECM
method for the quantitation and confirmation analyses of etridiazole and 3-DCMT (lOxLOQ only)
in silt loam soil in the first trial and of etridiazole and 3-DCMT in sandy loam soil in the second
trial with significant modifications of the use of glass pipets instead of positive displacement pipets
(plastic) for handling samples (pp. 20-23, 30-32; Appendix 4, pp. 106-107). The ILV validated the
Page 5 of 16
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Etridiazole (PC 084701)
MRIDs 50534504/50584602
ECM method for the quantitation and confirmation analyses of 3-DCMT at the LOQ in silt loam
soil in the second trial with significant modifications of the use of glass pipets instead of positive
displacement pipets (plastic) for handling samples and the use of fresh soil extracts; it was noted
that 3-DCMT extracts may be unstable in stored extracts. The ILV validated the ECM method for
the quantitation and confirmation analyses of 3-Carb-T in sandy loam and silt loam soil matrices in
the second trial with significant modifications of the use of glass pipets instead of positive
displacement pipets (plastic) for handling samples and of the stock dilution preparation of 3-Carb-T
by preparing directly into disposable glass vials instead of glass volumetric flasks. Insignificant
modifications to the analytical instruments were also employed. An updated ECM should be
submitted which specifies the use of glass pipets instead of positive displacement pipets (plastic)
for handling samples, the use of fresh soil extracts for 3-DCMT analysis due to stability issues, and
the stock dilution preparation of 3-Carb-T by preparing directly into disposable glass vials instead
of glass volumetric flasks.
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Etridiazole (PC 084701)
MRIDs 50534504/50584602
Table 2. Initial Validation Method Recoveries for Etridiazole and Metabolites 3-DCMT and 3-
Carb-T in Soil.1'2
Analyte
Fortification
Level (jig/kg)
Number
of Tests
Recovery
Range (%)
Mean
Recovery (%)
Standard
Deviation (%)
Relative Standard
Deviation (%)
Clay Loam Soil
Quantitation ion
Etridiazole
50.0 (LOQ)
5
78.2-94.0
85.9
5.74
6.68
500
5
91.2-102
94.8
4.15
4.37
3-DCMT
50.0 (LOQ)
5
80.3-104
89.2
8.68
9.74
500
5
88.5-104
97.7
5.61
5.74
3-Carb-T
50.0 (LOQ)
5
82.2-92.4
87.2
4.28
4.91
500
5
87.5-92.0
88.8
2.04
2.30
Confirmation ion 1
Etridiazole
50.0 (LOQ)
5
77.4-98.8
86.8
8.37
9.65
500
5
87.2-104
95.0
6.74
7.09
3-DCMT
50.0 (LOQ)
5
71.4-86.3
77.1
5.83
7.57
500
5
87.4-95.6
91.5
3.20
3.49
3-Carb-T
50.0 (LOQ)
5
84.0-88.9
85.5
1.94
2.27
500
5
82.7-87.1
85.7
1.83
2.14
Confirmation ion 2
Etridiazole
50.0 (LOQ)
5
80.6-90.9
85.4
4.07
4.77
500
5
88.9-101
94.2
5.20
5.52
3-DCMT
50.0 (LOQ)
5
75.4-86.4
79.2
4.28
5.40
500
5
89.0-102
93.9
5.06
5.39
Silt Loam Soil
Quantitation ion
Etridiazole
50.0 (LOQ)
5
86.3-95.1
91.6
3.74
4.08
500
5
88.3-96.1
92.6
2.95
3.19
3-DCMT
50.0 (LOQ)
5
88.7-93.6
90.7
1.88
2.07
500
5
78.6-90.5
85.8
4.56
5.32
3-Carb-T
50.0 (LOQ)
5
88.5-92.0
89.5
1.43
1.59
500
5
80.1-100.0
93.0
8.19
8.81
Confirmation ion 1
Etridiazole
50.0 (LOQ)
5
85.2-94.5
90.2
4.13
4.58
500
5
80.8-93.1
89.7
5.09
5.68
3-DCMT
50.0 (LOQ)
5
78.8-85.8
83.3
2.89
3.47
500
5
83.2-95.6
90.5
4.94
5.46
3-Carb-T
50.0 (LOQ)
5
76.9-90.5
84.6
6.08
7.19
500
5
86.6-98.8
92.6
4.67
5.04
Confirmation ion 2
Etridiazole
50.0 (LOQ)
5
86.9-93.9
89.8
3.46
3.85
500
5
86.3-94.6
90.6
2.99
3.30
3-DCMT
50.0 (LOQ)
5
83.3-90.8
86.1
2.95
3.43
500
5
88.0-100
94.5
4.38
4.63
Data (uncorrected recovery results) were obtained from Tables 1-16, pp. 46-61, of MRID 50534504.
1 The clay loam soil (SMVLotNo. 12DEC16SOIL-B; 40/28/32 sand/silt/clay, pH 5.4 in 1:1 soil:water ratio, 5.6%
organic matter) was obtained from Grand Forks, North Dakota, and the silt loam soil (SMV Lot No. 13SEP17SOIL-
B; 24/60/16 sand/silt/clay, pH 7.2 in 1:1 soikwater ratio, 3.9% organic matter Walkley-Black) was obtained from
Jackson, Iowa (USDA soil texture classification not specified; pp. 18-19). Soil characterization was performed by
Agvise Laboratories, Northwood, North Dakota.
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Etridiazole (PC 084701) MRIDs 50534504/50584602
2 For GC-MS/EI: three ions were monitored as follows (quantitation, confirmation 1, and confirmation 2, respectively):
m/z 211.00, 185.00, and 183.00 for etridiazole, and m/z 143.00, 184.00, and 186.00 for 3-DCMT. For LC-MS/MS:
two ion transitions were monitored (quantitation and confirmatory, respectively) as follows: m/z 175.16—>147.10 and
m/z 175.16—>129.00 for 3-Carb-T.
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Etridiazole (PC 084701)
MRIDs 50534504/50584602
Table 3. Independent Validation Method Recoveries for Etridiazole and Metabolites 3-DCMT
and 3-Carb-T in Soil.1'2'3
Analyte
Fortification
Level (jig/kg)
Number
of Tests
Recovery
Range (%)
Mean
Recovery (%)
Standard
Deviation (%)
Relative Standard
Deviation (%)
Sandy Loam Soil
Quantitation ion
Etridiazole
50.0 (LOQ)
5
84-93
89
4.1
4.6
500
5
88-111
97
8.7
9.0
3-DCMT
50.0 (LOQ)
5
73-105
86
12.2
14.2
500
5
84-118
96
13.2
13.7
3-Carb-T
50.0 (LOQ)
5
81-95
88
5.1
5.7
500
5
101-121
110
7.7
7.0
Confirmation ion 1
Etridiazole
50.0 (LOQ)
5
80-94
86
5.8
6.7
500
5
91-101
96
3.9
4.1
3-DCMT
50.0 (LOQ)
5
76-98
85
8.3
9.8
500
5
91-115
99
9.2
9.3
3-Carb-T
50.0 (LOQ)
5
89-93
92
1.9
2.1
500
5
106-118
109
5.2
4.8
Confirmation ion 2
Etridiazole
50.0 (LOQ)
5
78-91
87
5.0
5.8
500
5
87-108
96
7.9
8.2
3-DCMT
50.0 (LOQ)
5
78-99
85
9.0
10.6
500
5
82-107
96
9.1
9.5
Silt Loam Soil
Quantitation ion
Etridiazole
50.0 (LOQ)
5
56-84
71
11.3
15.9
500
5
71-98
82
12.1
14.7
3-DCMT
50.0 (LOQ)
5
86-102
94
7.4
7.9
500
5
60-93
81
12.6
15.6
3-Carb-T
50.0 (LOQ)
5
83-96
92
5.5
6.0
500
5
101-108
105
2.9
2.7
Confirmation ion 1
Etridiazole
50.0 (LOQ)
5
53-87
70
13.6
19.3
500
5
72-92
83
8.9
10.7
3-DCMT
50.0 (LOQ)
5
81-97
87
6.1
7.0
500
5
65-92
78
10.8
13.9
3-Carb-T
50.0 (LOQ)
5
82-96
89
5.1
5.8
500
5
90-113
101
8.2
8.1
Confirmation ion 2
Etridiazole
50.0 (LOQ)
5
78-119
94
15.8
16.9
500
5
79-107
91
11.1
12.2
3-DCMT
50.0 (LOQ)
5
78-103
88
9.3
10.7
500
5
65-86
74
9.3
12.7
Data (uncorrected recovery results) were obtained from Tables 1-16, pp. 35-50, of MRID 50584602.
1 3-DCMT synonym DCE and 3-Carb-T synonym etridiazole acid used in ILV.
2 Sandy loam soil (CS 27/16 Speyer5M; 59/30/11 sand/silt/clay, pH 8.5 in 1:5 soil:water ratio, 1.0% organic carbon)
was obtained from Rheinland-Pfalz, Germany, and supplied by LUFA Speyer, and silt loam soil (CS 30/16 Brierlow;
26/58/16 sand/silt/clay, pH 6.4 in 1:5 soil:water ratio, 2.5% organic carbon) was obtained from Derbyshire, UK, and
supplied by LRA Labsoil (USDA soil texture classification; p. 15; Appendix 2, pp. 103-104). Soil was characterized
Page 9 of 16
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Etridiazole (PC 084701)
MRIDs 50534504/50584602
by Smithers Viscient (ESG), North Yorkshire, UK, except some of the analyses on the sandy loam soil was
characterized by LUFA Speyer.
3 For GC-MS: three ions were monitored as follows (quantitation, confirmation 1, and confirmation 2, respectively):
m/z 211, 185, and 183 for etridiazole, and m/z 143, 184, and 186 for 3-DCMT (DCE). For LC-MS/MS: two ion
transitions were monitored (quantitation and confirmatory, respectively) as follows: m/z 174.9—>146.9 and m/z
174.9—>129.0 for 3-Carb-T (etridiazole acid).
III. Method Characteristics
In the ECM and ILV, the method LOQs in soil were 50.0 |ig/kg for etridiazole, 3-DCMT, and 3-
Carb-T (pp. 32-33, 38-43 of MRID 50534504; pp. 12, 30 of MRID 50584602). In the ECM and
ILV, the LOQ was defined as the lowest fortification level. In the ECM, it was noted that blank
values should not exceed 30% of the LOQ. No calculations or comparisons to background levels
were reported to justify the LOQ for the method in the ECM. In the ECM, the method LODs ranged
from 5 to 7 |ig/kg in clay loam soil and 6 to 11 |ig/kg in silt loam soil for etridiazole; 3 to 18 |ig/kg
in clay loam soil and 2 to 20 |ig/kg in silt loam soil for 3-DCMT; and 0.1 to 1 |ig/kg in clay loam
soil and 0.5 to 1 |ig/kg in silt loam soil for 3-Carb-T (pp. 35-36 of MRID 50534504).
In the ILV, the method LODs ranged from 1.28 to 2.37 |ig/L in sandy loam soil and 3.88 to 24.5
|ig/L in silt loam soil for etridiazole; 3.52 to 4.50 |ig/L in sandy loam soil and 3.89 to 25.7 |ig/L in
silt loam soil for 3-DCMT; and 4.15 to 4.49 |ig/L in sandy loam soil and 3.46 to 3.68 |ig/L in silt
loam soil for 3-Carb-T (pp. 28-29 of MRID 50584602). The ILV calculated LOD generally
supported the LOD of the ECM, with the only exception being the LOD for 3-Carb-T in the ECM
was much lower than the ILV.
The LOD was calculated in the ECM using the following equation:
LOD = (3x(SNcti)/(RespLs) x ConcLs
Where, LOD is the limit of detection of the analysis, SNcti is the mean signal to noise in height of
the control samples (or blanks), RespLs is the mean response in height of the two low calibration
standards, and ConcLs is the concentration of the low calibration standard (p. 34 of MRID
50534504). The ILV, LOD is calculated from 3 x height of control baseline noise x control dilution
factor x calibration standard concentration ([j,g/mL) / height of calibration standard peak (p. 26 of
MRID 50584602).
Page 10 of 16
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Etridiazole (PC 084701)
MRIDs 50534504/50584602
Table 4. Method Characteristics for Etridiazole, 3-DCMT, and 3-Carb-T in Soil.
Analyte1
Etridiazole
3-DCMT
3-Carb-T
Analysis
GC/MS
LC/MS/MS
Limit of
ECM
Quantitation
(LOQ)
ILV
50 ng/kg
50 ng/kg
50 ng/kg
Limit of
Detection
(LOD)
ECM
(calculated)
Clay loam
5^g/kg(Q)
6 ng/kg (CI)
7 (ig/kg (C2)
18 ng/kg (Q)
3 ng/kg (CI)
4 ng/kg (C2)
0.1 ng/kg (Q)
1 lig/kg (C)
Silt loam
6 ng/kg (Q)
11 ^g/kg (CI)
6 f-ig/kg (C2)
30 ng/kg (Q)
2 Hg/kg (CI)
4 ng/kg (C2)
0.5 ng/kg (Q)
1 lig/kg (C)
ILV
(calculated)
Sandy
loam
1.28 (ig/L (Q)
2.35 (ig/L (CI)
2.37 (ig/L (C2)
4.5 (ig/L (Q)
4.02 (ig/L (CI)
3.52 (ig/L (C2)
4.15 (ig/L (Q)
4.49 (ig/L (C)
Silt loam
7.76 (ig/L (Q)
3.88 ng/L(Cl)
24.5 (ig/L (C2)
25.7 (ig/L (Q)
3.91 (ig/L (CI)
3.89 (ig/L (C2)
3.46 (ig/L (Q)
3.68 (ig/L (C)
Linearity
(calibration
curve r2 and
ECM
Clay loam
r2 = 0.99708 (Q)
r2 = 0.99618 (CI)
r2 = 0.99739 (C2)
r2 = 0.99589 (Q)
r2 = 0.99694 (CI)
r2 = 0.99542 (C2)
r2 = 0.99604 (Q)
r2 = 0.99339 (C)
concentration
range)
Silt loam
r2 = 0.99773 (Q)
r2 = 0.99377 (CI)
r2 = 0.99792 (C2)
r2 = 0.99462 (Q)
r2 = 0.99350 (CI)
r2 = 0.99553 (C2)
r2 = 0.99643 (Q)
r2 = 0.99049 (C)
ILV2
Sandy
loam
r2 = 0.9951 (Q)
r2 = 0.9951 (CI)
r2 = 0.9927 (C2)
r2 = 0.9935 (Q)
r2 = 0.9977 (CI)
r2 = 0.9987 (C2)
r2 = 0.9888 (Q- LOQ)
r2 = 0.9819 (Q- lOxLOQ)
r2 = 0.9922 (C- LOQ)
r2 = 0.9920 (C- lOxLOQ)
Silt loam
r2 = 0.9951 (Q- LOQ)
r2 = 0.9871 (Q- lOxLOQ)
r2 = 0.9951 (CI-LOQ)
r2 = 0.9890 (CI- lOxLOQ)
r2 = 0.9927 (C2- LOQ)
r2 = 0.9885 (C2- lOxLOQ)
r2 = 0.9903 (Q)
r2 = 0.9884 (CI)
r2 = 0.9836 (C2)
r2 = 0.9968 (Q- LOQ)
r2 = 0.9976 (Q- lOxLOQ)
r2 = 0.9950 (C- LOQ)
r2 = 0.9946 (C- lOxLOQ)
Range
0.750-7.50 (ig/L
0.750-7.50 (ig/L
1.00-10.0 (ig/L
Repeatable
ECM3
Yes at LOQ and lOxLOQ
(two characterized soils; USD A soil texture classification not specified)
ILV4-5
Yes at LOQ and lOxLOQ
(two characterized soils; USD A soil texture classification)
Reproducible
Yes at LOQ and lOxLOQ
Specific
ECM6
Yes, no peaks were
detected in the controls.
Yes, matrix
interferences were
<10% (clay loam)
and ca. 25% (silt
loam)7 of the LOQ
(Q; based on peak
area).
Yes, matrix interferences
were <1% of the LOQ
(based on peak area). Peak
fronting was observed.
ILV8
Yes, matrix interferences
were <10% of the LOQ
(based on peak area)..
Yes, no matrix
interferences were
observed; however,
Q chromatograms
for silt loam soil
showed significant
baseline noise9
No, multiple significant
contaminants were present
in all Q chromatograms,
including the reagent
blank, controls, and
calibration standards.10
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Etridiazole (PC 084701)
MRIDs 50534504/50584602
Data were obtained from pp. 35-36, 38-43 (LOQ/LOD); Tables 1-16, pp. 46-61 (recovery results); p. 22, Figures 1-66,
pp. 62-127 (chromatograms and calibration curves) of MRID 50534504; pp. 12, 28-29 (LOQ/LOD); Tables 1-16, pp.
35-50 (recovery results); pp. 28-29, Figures 1-79, pp. 58-97 (chromatograms and calibration curves); Tables 17-22, pp.
51-56 (matrix effects) of MRID 50584602; DER Attachment 2. Analytes were identified using one quantitation ion and
two confirmation ions for etridiazole and 3-DCMT and one quantitation and one confirmatory ion transition for 3-Carb-
T. Q = Quantitation ion/ion transition; CI = Confirmation ion 1; C2 = Confirmation ion 2; C = Confirmation ion
transition
1 3-DCMT synonym DCE and 3-Carb-T synonym etridiazole acid used in ILV.
2 In the ILV, two coefficients of determination (r2) values were provided for etridiazole, 3-DCMT, and 3-Carb-T when
LOQ and lOxLOQ were run as separate batches as a result of failed initial validation attempts for one of the levels
(pp. 28-29, Appendix 4, pp. 106-108 of MRID 50586402). The calibration curves for the later validation attempts
were not provided. 3-Carb-T correlation coefficients (r2) values were reviewer-calculated from r values provided in
the study report (pp. 28-29; DER Attachment 2).
3 In the ECM, the clay loam soil (SMV Lot No. 12DEC16SOIL-B; 40/28/32 sand/silt/clay, pH 5.4 in 1:1 soil:water
ratio, 5.6% organic matter) was obtained from Grand Forks, North Dakota, and the silt loam soil (SMV Lot No.
13SEP17SOIL-B; 24/60/16 sand/silt/clay), pH 7.2 in 1:1 soil:water ratio, 3.9% organic matter Walkley-Black) was
obtained from Jackson, Iowa (USDA soil texture classification not specified; pp. 18-19 of MRID 50534504). Soil
characterization was performed by Agvise Laboratories, Northwood, North Dakota.
4 In the ILV, sandy loam soil (CS 27/16 Speyer 5M; 59/30/11 sand/silt/clay, pH 8.5 in 1:5 soikwater ratio, 1.0%
organic carbon) was obtained from Rheinland-Pfalz, Germany, and supplied by LUFA Speyer, and silt loam soil (CS
30/16 Brierlow; 26/58/16 sand/silt/clay, pH 6.4 in 1:5 soikwater ratio, 2.5% organic carbon) was obtained from
Derbyshire, UK, and supplied by LRA Labsoil (USDA soil texture classification; p. 15; Appendix 2, pp. 103-104).
Soil was characterized by Smithers Viscient (ESG), North Yorkshire, UK, except some of the analyses on the sandy
loam soil was characterized by LUFA Speyer.
5 The ILV validated the ECM method for the quantitation and confirmation analyses of etridiazole and 3-DCMT
(lOxLOQ only) in silt loam soil in the first trial and of etridiazole and 3-DCMT in sandy loam soil in the second trial
with significant modifications of the use of glass pipets instead of positive displacement pipets (plastic) for handling
samples (pp. 20-23, 30-32; Appendix 4, pp. 106-107 of MRID 50584602). The ILV validated the ECM method for
the quantitation and confirmation analyses of 3-DCMT at the LOQ in silt loam soil in the second trial with significant
modifications of the use of glass pipets instead of positive displacement pipets (plastic) for handling samples and the
use of fresh soil extracts; it was noted that 3-DCMT extracts may be unstable in stored extracts. The ILV validated
the ECM method for the quantitation and confirmation analyses of 3-Carb-T in sandy loam and silt loam soil matrices
in the second trial with significant modifications of the use of glass pipets instead of positive displacement pipets
(plastic) for handling samples and of the stock dilution preparation of 3-Carb-T by preparing directly into disposable
glass vials instead of glass volumetric flasks. Insignificant modifications to the analytical instruments were also
employed. An updated ECM should be submitted which specifies the use of glass pipets instead of positive
displacement pipets (plastic) for handling samples, the use of fresh soil extracts for 3-DCMT analysis due to stability
issues, and the stock dilution preparation of 3-Carb-T by preparing directly into disposable glass vials instead of glass
volumetric flasks.
6 In the ECM, matrix interferences based on representative peak areas of the control and the LOQ were 0%, <10%, and
<1% for etridiazole, 3-DCMT, and 3-Carbon-T, respectively. Matrix effects assessment performed by the study
author determined matrix effects were minimal for etridiazole, 3-DCMT, and 3-Carb-T in the clay loam and the silt
loam (pp. 38-43 of MRID 50534503); results of the matrix assessment were not provided.
7 Based on Figures 42-43, pp. 103-104 of MRID 50534504. This matrix interference was <50% of the LOD since the
calculated ECM LOD was 60% of the LOQ for the Q analysis (143.00). The reviewer noted that the study author
noted that no peak was present at the RT of 3-DCMT (ca. 5.8 min.) in the controls, but a peak at RT 5.806 min. was
quantified.
8 In the ILV, matrix interference was >20% in matrix-matched standards compared to non-matrix standards for 3-Carb-
T in silt loam soil (Table 22, p. 56 or MRID 50584602); as a result, matrix-matched standards were used for 3-Carb-T
analysis on silt loam soil. Matrix interference was <20% for all other analytes and soils (p. 30, Table 17-22, pp. 51-
56). The ILV indicated etridiazole, 3-DCMT, and 3-Carb-T were found in the controls at <50% of the LOD and
<30% of the LOQ (p. 29 of MRID 50584602).
9 Based on Figure 35, p. 75 of MRID 50584602.
10 Based on Figures 59-68, pp. 87-91 of MRID 50584602.
Linearity is satisfactory when r2 > 0.995.
Page 12 of 16
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Etridiazole (PC 084701)
MRIDs 50534504/50584602
IV. Method Deficiencies and Reviewer's Comments
1. An updated ECM should be submitted which specifies the use of glass pipets instead of positive
displacement pipets (plastic) for handling samples, the use of fresh soil extracts for 3-DCMT
analysis due to stability issues, and the stock dilution preparation of 3-Carb-T by preparing
directly into disposable glass vials instead of glass volumetric flasks. Initially, the ILV
incorporated the substitution of plastic for glass extraction vessels; however, recovery issues due
to the analytes adhering to plastic were identified when plastic vessels were used in the place of
glass equipment. The ILV also discovered that glass pipets should be used instead of positive
displacement pipets (plastic) which were listed in the ECM. During, 3-Carb-T analysis, the ILV
suspected that 3-Carb-T adhered to the glass volumetric flask during the serial dilutions of the
10,000 |ig/L stock for fortification of the LOQ and IOxLOQ samples and calibration standards.
Recovery issues with 3-DCMT at the LOQ, resulting from storing extracts, was corrected by
preparing fresh soil extracts, and it was noted that 3-DCMT extracts may be unstable. The ILV
included a modification of the stock dilution preparation of 3-Carb-T by preparing directly into
disposable glass vials instead of glass volumetric flasks. Without these modifications, ILV
recoveries and linearity were unacceptable, and the method could not be validated. Additionally,
soil extract stability data should be provided for 3-DCMT to support the ECM.
2. For quantitation analysis, ILV linearity was not satisfactory for etridiazole analysis in silt loam,
r2 = 0.9871 (10 x LOQ) (p. 29, Figure 1, p. 58); 3-DCMT in sandy loam and silt loam, r2 =
0.9935 and 0.9903, respectively (pp. 28-29, Figure 28, p. 71); 3-Carb-T in sandy loam, r2 =
0.9888 (LOQ) and r2 = 0.9819 (10 x LOQ) (p. 28, Figure 58, p. 86 of MRID 50586402; DER
Attachment 2)
For quantitation analysis, ECM linearity was not satisfactory for 3-DCMT analysis in silt loam,
r2 = 0.99462 (p. 41, Figure 46, p. 107 of MRID 50534504).
For the confirmation analysis, ILV linearity was not satisfactory for etridiazole in sandy loam
soil, r2 = 0.9927 (C2), or in silt loam soil, r2 = 0.9890 (CI - IOxLOQ), 0.9927 (C2 - LOQ), and
0.9885 (C2 - IOxLOQ); for 3-DCMT in silt loam soil, r2 = 0.9884 (CI) and 0.9836 (C2); and
for 3-Carb-T in sandy loam soil, r2 = 0.9922 (LOQ) and 0.9920 (IOxLOQ), or in silt loam soil,
r2 = 0.9946 (IOxLOQ; pp. 28-29 of MRID 50584602). For the confirmation analysis, ECM
linearity was not satisfactory for etridiazole in silt loam soil, r2 = 0.99377 (CI); for 3-DCMT in
silt loam soil, r2 = 0.99350 (CI); and for 3-Carb-T in clay loam soil, r2 = 0.99339, and silt loam
soil, r2 = 0.99049 (pp. 38-43 of MRID 50534504; DER Attachment 2). In the case of the
confirmation analyses, the reviewer did not consider this guideline deviation to be significant
since 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
Linearity is satisfactory when r2 >0.995.
3. The specificity of the method was not supported for 3-Carb-T based on ILV representative
chromatograms. Multiple significant contaminants were present in all Q chromatograms,
including the reagent blank, controls, and calibration standards (Figures 59-68, pp. 87-91 of
MRID 50584602). Minor baseline noise was observed in the confirmation ion chromatograms
(Figures 70-79, pp. 92-97).
Page 13 of 16
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Etridiazole (PC 084701)
MRIDs 50534504/50584602
4. It could not be determined whether the ILV was provided with the most difficult matrices with
which to validate the method since the percentage of soil organic carbon was 1.0-2.5% for the
two ILV soils (p. 15; Appendix 2, pp. 103-104 of MRID 505084602). Also, it could not be
confirmed if the ILV soil matrices covered the range of soils used in any submitted terrestrial
field dissipation (TFD) studies.
In the ECM, USDA soil texture characterization was not specified (pp. 18-19 of MRID
50534504).
5. For the ILV, the first validation attempts for etridiazole and 3-DCMT in sandy loam soil were
unsuccessful and required replacement of plastic extraction vessels with glass extraction vessels.
The first validation attempts for etridiazole and 3-DCMT in silt loam soils were unsuccessful
and required re-aliquoting extracts with glass pipettes instead of plastic. In addition, the first
validation attempts for 3-Carb-T in sandy loam and silt loam soils were unsuccessful at 10 x
LOQ and were attributed to analyte adhering to the volumetric flasks used to prepare serial
dilutions; as a result, serial dilutions were prepared directly into glass vials. Re-analysis was
completed successfully, however in most cases numerous re-injections and re-aliquoting were
required, indicating that the ILV method as specified may not be reproducible (Appendix 4, pp.
106-107 of MRID 50584602).
6. The ILV reported >20% matrix effects for 3-Carb-T analysis on silt loam soil, but not for the
other analytes or soils (pp. 30, 32; Table 17-22, pp. 51-56 of MRID 50584602); matrix-matched
calibration standards were used for 3-Carb-T analysis on silt loam soil. The ILV matrix
assessment differed from the ECM in concentration of matrix matched standards [2.0 |ig/L
etridiazole and 3-DCMT and 5.0 |ig/L for 3-Carb-T in the ILV (p. 18 of MRID 50584602); and
2.50 |ig/L for etridiazole and 3-DCMT and 5.00 |ig/L for 3-Carb-T in the ECM (p. 23 of MRID
50534504)], and the ILV reported the matrix effect as the difference between the (mean
measured concentration with solvent - mean measured concentration with matrix)/measured
concentration with solvent x 100 (Tables 17-22, pp. 51-56).
In the ECM matrix-matched standards were not used for calibration. The ECM reported matrix
effects were minimal for etridiazole, 3-DCMT and 3-Carb-T in clay loam and silt loam soil but
did not provide matrix effects data (pp. 38-43 of MRID 50534504).
7. In the ILV, the coefficient of determination (r2) data for all of the linear calibration curves
required to validate 3-DCMT (DCE) in the Brierlow silt loam soil did not appear to be provided
in the study report (p. 29; Appendix 4, p. 106-107 of MRID 50584602). The lOxLOQ analysis
passed in Sequences Val 2R and 2Ri; the LOQ analysis passed in Sequence Val 6 (Figures 35-
36, p. 75; Figures 44-45, pp. 79-80; Figures 53-54, p. 84). However, in the reported r2 data on p.
29, only one r2 value was provided for each ion analysis, and only calibration curves from
Sequence Val 5 were provided in the study report (Figures 28, 38, and 46, pp. 71, 76, 80). The
reviewer noted that linearity was unsatisfactory for all provided calibration data for 3-DCMT in
the Brierlow silt loam soil.
8. The reviewer noted that the calculated ECM LOD for 3-DCMT in silt loam was 60% of the
LOQ for the Q analysis (143.00; p. 41 of MRID 50534504).
Page 14 of 16
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Etridiazole (PC 084701)
MRIDs 50534504/50584602
9. In the ILV, one of each of the 1.5, 2.0, and 7.5 |ig/L calibration standards for etridiazole were
deleted from the linear calibration curve for the quantitation ion and both confirmation ions
because these data points were outliers for the corresponding 3-DCMT curves; a result of the
laboratory software used in calculating linear calibration curves for mixed standards (Figures 1,
10, 19, pp. 58, 62, and 67 of MRID 50584602). One of each of the 1.5, 2.0, and 7.5 |ig/L
calibration standards were deleted from the 3-DCMT linear calibration curves because they
deviated from the line (Figure 28, 37, 46, pp. 71, 76, 80 of MRID 50584602).
10. The ECM laboratory is Smithers Viscient Laboratory in Wareham, Massachusetts, and the ILV
laboratory is also a Smithers Viscient Laboratory, but located in Harrogate, North Yorkshire,
United Kingdom. One communication was documented between the two laboratories, and that
was to confirm the SPE cartridge particle size. The other documented communications were
between the Harrogate laboratory and the sponsor MacDermid Agricultural Solutions, Inc.,
concerning schedule and approval to repeat validation of etridiazole and 3-DCMT using glass
extraction vessels and re-aliquoting extracts with a glass pipette, and to repeat preparation of 3-
Carb-T intermediate stock, calibration standards and analysis at the LOQ and lOxLOQ
(Appendix 5, p. 108 of MRID 50584602). The reviewer determined that no collusion occurred.
11. The time required to complete the method for a sample set was not reported in the ECM or ILV.
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.
Page 15 of 16
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Etridiazole (PC 084701)
MRIDs 50534504/50584602
)ER ATTACHMENT 1. Etridiazole and Its Environmental Transformation Products. A
Code Name/ Synonym
Chemical Name
Chemical Structure
Study Type
MRID
Maximum
%AR (day)
Final %AR
(study
length)
PARENT
Etridiazole
IUPAC: Ethyl 3-trichloromethyl-
l,2,4-thiadiazol-5-yl ether
H 3 C C O
H , \
CAS: 5-Ethoxy-3-(trichloromethyl)-
1,2,4-thiadiazole
V
S
\
850.6100
ECM soil
50534504
CAS No.: 2593-15-9
\ ^
NA
NA
Formula: C5H5CI3N2OS
MW: 247.5 g/mol
SMILES:
CCOcl nc(ns 1 )C(C1)(C1)C1
CI /
c
^Cl
850.6100
ILV soil
50584602
Etridiazole acid (3-
Carb-T)
IUPAC: 5-Ethoxy-l,2,4-thiadiazole-
3-carboxylic acid
H 3 C C O
V
s
850.6100
ECM soil
50534504
CAS No.: 67472-43-9
\
N '
.N
NA
NA
Formula: C5H6N2O3S
MW: 174.17 g/mol
SMILES: CCOclnc(nsl)C(=0)0
T
COOH
850.6100
ILV soil
50584602
DCE (3-DCMT; T-03)
IUPAC: 5-Ethoxy-3-
dichloromethy 1-1,2,4-thiadiazole
H 3 C C O
H 2 \
850.6100
50534504
Formula: C5H6CI2N2OS
MW: 213.08 g/mol
SMILES: CCOclnc(nsl)C(Cl)Cl
jr \
ECM soil
NA
NA
850.6100
50584602
CI /
\c,
ILV soil
A AR means "applied radioactivity". MW means "molecular weight". NA means "not applicable". ECM means "environmental chemical methods". ILV means "independent laboratory
validation".
Page 16 of 16
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