Significance and Use
5.1 Organophosphate pesticides affect the nervous system by disrupting the enzyme that regulates acetylcholine, a neurotransmitter. They were developed during the early 19th century, but their effects on insects, which are similar to their effects on humans, were discovered in 1932. Some are poisonous and were used as chemical weapon agents. Organophosphate pesticides are usually not persistent in the environment.4, 5
5.2 This test method is for the analysis of selected organophosphorous-based chemical weapon agent degradation products from Sarin (GB), Soman (GD), Tabun (GA) and VX. This method has been investigated for use with reagent and surface water.
Scope
1.1 This procedure covers the determination of diisopropyl methylphosphonate (DIMP), ethyl hydrogen dimethylamidophosphate (EHDMAP), ethyl methylphosphonic acid (EMPA), isopropyl methylphosphonic acid (IMPA), methylphosphonic acid (MPA) and pinacolyl methylphosphonic acid (PMPA) (referred to collectively as organophosphonates in this test method) in surface water by direct injection using liquid chromatography (LC) and detected with tandem mass spectrometry (MS/MS) using electrospray ionization (ESI). These analytes are qualitatively and quantitatively determined by this method. This method adheres to single reaction monitoring (SRM) mass spectrometry.
1.2 This test method has been developed by US EPA Region 5 Chicago Regional Laboratory (CRL).
1.3 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.
1.4 The detection verification level (DVL) and reporting range for the organophosphonates are listed in Table 1.
1.4.1 The DVL is required to be at a concentration at least three times below the reporting limit (RL) and have a signal/noise ratio greater than 3:1. Fig. 1 displays the signal/noise ratios at the DVLs for the organophosphonates in the ESI positive mode and Fig. 2 in the ESI negative mode.
DIMP
Pos
5
16
4
95.1
65.8
136.0
17.6
19.4
21.3
22.4
DIMP
Pos
10
19
5
98.2
80.0
121.0
6.1
5.5
13.6
13.8
DIMP
Pos
25
26
6
102.9
74.4
128.0
5.6
5.7
14.5
14.1
DIMP
Pos
125
22
5
96.6
80.4
120.0
4.4
4.5
11.0
11.4
DIMP-D14
Pos
25
86
6
102.6
54.8
127.6
9.8
9.5
11.2
10.9
EHDMAP
Neg
5
12
3
57.5
0.0
220.0
31.4
22.3
71.1
123.6
EHDMAP
Neg
10
16
4
47.1
0.0
178.0
13.3
10.8
66.8
142.0
EHDMAP
Neg
25
22
5
84.1
54.0
141.2
6.9
6.6
22.9
27.3
EHDMAP
Neg
125
18
4
87.4
64.2
141.6
5.0
5.1
25.4
29.1
EHDMAP
Pos
5
16
4
77.0
0.0
134.2
7.4
8.0
51.4
66.8
EHDMAP
Pos
10
20
5
70.0
0.0
143.0
7.7
10.0
53.6
76.5
EHDMAP
Pos
25
26
6
89.6
60.0
128.8
5.2
6.2
23.5
26.2
EHDMAP
Pos
125
22
5
87.5
59.0
123.2
5.2
6.0
23.9
27.3
EMPA
Neg
50
16
4
110.1
74.8
170.6
22.4
17.2
25.6
23.3
EMPA
Neg
100
20
5
108.3
87.7
175.0
11.1
8.7
24.8
22.9
EMPA
Neg
250
26
6
104.8
82.0
122.6
6.1
5.5
11.8
11.3
EMPA
Neg
1250
22
5
101.5
87.2
126.4
8.4
8.1
11.2
11.0
EMPA
Pos
50
16
4
95.4
77.6
122.8
12.9
13.3
13.1
13.7
EMPA
Pos
100
20
5
96.0
61.4
132.5
9.5
9.5
15.9
16.6
EMPA
Pos
250
26
6
99.7
70.0
133.2
5.9
5.4
18.2
18.2
EMPA
Pos
1250
21
5
93.9
84.0
108.4
2.7
3.0
7.7
8.2
IMPA
Neg
50
16
4
88.0
56.6
140.4
23.7
26.0
23.5
26.7
IMPA
Neg
100
20
5
88.0
68.5
118.0
12.9
14.3
13.4
15.2
IMPA
Neg
250
26
6
98.1
72.8
144.0
13.1
11.9
19.2
19.6
IMPA
Neg
1250
21
5
90.7
73.1
103.0
5.5
6.1
8.7
9.6
IMPA
Pos
50
16
4
98.3
47.8
139.6
19.2
20.5
27.2
27.7
IMPA
Pos
100
19
5
95.4
72.3
120.5
9.8
10.3
12.4
13.0
IMPA
Pos
250
26
6
97.0
79.2
188.4
7.4
7.6
10.9
11.2
IMPA
Pos
1250
21
5
91.3
70.4
115.5
5.1
5.2
11.4
12.5
MPA
Neg
50
16
4
98.7
3.3
175.0
14.2
25.3
60.5
61.3
MPA
Neg
100
20
5
100.0
41.9
142.0
8.9
9.2
30.8
30.8
MPA
Neg
250
26
6
99.5
66.0
124.5
7.6
7.6
14.5
14.5
MPA
Neg
1250
22
5
102.7
81.8
130.5
10.5
9.9
12.4
12.1
MPA
Pos
50
16
4
68.3
9.8
139.6
13.4
20.3
36.6
53.6
MPA
Pos
100
20
5
80.5
48.4
149.7
14.0
12.6
26.8
33.3
MPA
Pos
250
26
6
91.7
33.9
153.7
8.0
7.8
31.8
34.7
MPA
Pos
1250
22
5
95.8
31.8
208.2
12.6
8.3
43.4
45.3
MPA-D3
Neg
250
84
6
111.2
57.2
190.8
16.2
12.5
30.0
26.9
MPA-D3
Pos
250
68
5
104.4
58.4
151.8
14.3
14.0
18.0
17.3
PMPA
Neg
50
15
4
87.8
77.6
124.4
8.4
8.2
13.8
15.7
PMPA
Neg
100
19
5
91.6
83.6
98.2
2.8
3.0
4.4
4.8
PMPA
Neg
250
26
6
101.0
77.2
123.8
5.0
4.8
12.1
12.0
PMPA
Neg
1250
22
5
99.2
84.8
126.5
4.9
4.8
12.3
12.4
PMPA
Pos
50
16
4
90.8
60.8
148.8
15.8
16.1
25.6
28.2
PMPA
Pos
100
15
4
95.2
86.8
114.0
3.8
4.0
7.9
8.3
PMPA
Pos
250
20
5
103.8
85.2
136.1
4.5
3.8
15.3
14.7
PMPA
Pos
1250
12
3
99.8
88.8
117.5
5.2
5.0
7.5
7.5
PMPA-13C6
Neg
250
83
6
99.5
74.8
128.3
9.4
9.2
11.1
11.1
1.5 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.
