GC-TQMS Application: Simultaneous determination of residual agricultural chemicals in food by GC-MS/MS - Sensitivity of standard solution 1ppb and linearity of calibration curve-

  • Summary

MSTips No.259

As "food safety" is recognized as an increasingly important issue on a global scale, many nations have their own regulations on residual agricultural chemicals in food. In Japan, the positive list system, which was enforced at the end of May 2006, stipulates a uniform standard of 10 ppb as a quantity that is considered safe for human health. Under the positive list system, more agricultural chemicals need to be examined, and as a result, techniques capable of accurately and collectively analyzing residual agricultural chemicals in food are in increasing demand. While mass spectrometry (MS) is known for its high detection sensitivity, MS/MS is becoming the mainstream of pesticide analysis for its superior sensitivity and selectivity.
The JMS-TQ4000GC, JEOL’s latest GC-MS/MS system, has a unique ion storage/ejection mechanism within the MS/MS collision cell and incorporates new firmware to support MS/MS analysis with up to 36,000 transitions. In this work, we report the verified results for pesticide residues sensitivity in food using the JMS-TQ4000GC.

Sample and Method

A pesticide standard solution from FUJIFILM Wako Pure Chemical Corporation (PL series) was used that consisted of equal amounts of PL 1, 2, 3, 4, 5, 6, 11, and 12. Afterwards, the solution was diluted to 1, 5, 10, 50 and 100 ppb. PEG 300 was used to protect the pesticides from thermal decomposition in the GC injection liner. In this work, both the sensitivity and the linearity of the calibration curve were examined for 150 pesticides. Table 1 shows the measurement conditions used for the analysis.

Table 1 Measurement condition

[GC-TQMS condition]

System

JMS-TQ4000GC (JEOL)

Ionization mode EI+: 70eV, 50μA
GC column VF-5ms, 30m x 0.25mm, 0.25μm
Oven temp. 50°C (1min)→25°C/min→125°C→10°C/min→300°C
Inlet temp. 250°C
Inlet mode Splitless, 2μL
He flow 1.0mL/min (Constant Flow)
MS/MS mode Peak Dependent SRM

Results and Discussion

Figure 1 shows the calibration curves from 1-100ppb as well as the SRM chromatograms for 4 pesticides at 1ppb. The JMS-TQ4000GC showed excellent linearity and sensitivity for this range of concentrations. Fig 2 shows the retention times (R.T.), SRM information, and correlation coefficient for 150 pesticide calibration curves. Since the uniform criterion of the positive list system is 10 ppb, when the concentration ratio in the sample pretreatment is equal, the criteria concentration in the measurement sample for GC-MS/MS is also 10 ppb. A number of pesticides were detected with good sensitivity at 1 ppb which is 1/10 of criteria concentration. These results suggest that the JMS-TQ4000GC is the most effective tool for pesticide analysis.

Fig.1  Calibration curves (1-100ppb) and SRM chromatograms for 1ppb data

Fig.1  Calibration curves (1-100ppb) and SRM chromatograms for 1ppb data

Table 2 Calibration curve information for 150 pesticides using 1, 5, 10, 50 and 100 ppb standard solutions (n=3 each)

No. Compound RT (min) Q ion Correlation coefficient, R (1-100ppb)
Precursor ion Product ion

1

Atrazine

12.37 215 200 0.9999
2 Benthiocarb 14.68 100 72 0.9997
3 cis-Permethrin 20.68 183 153 0.9999
4 Diflufenican 18.31 266 218 0.9999
5 Fenamiphos 16.24 303 195 0.9998
6 Fenarimol 20.20 139 111 0.9999
7 Fenpropimorph 14.74 128 110 0.9998
8 Norflurazon 17.94 303 145 0.9997
9 Oxadiazon 16.50 175 112 0.9996
10 Penconazole 15.45 248 192 0.9999
11 Pendimethalin 15.29 252 162 0.9990
12 Procymidone 15.70 283 255 0.9980
13 Spiroxamine 1 13.78 100 72 0.9997
14 Spiroxamine 2 14.31 100 72 0.9995
15 Tefluthrine 12.92 177 127 0.9999
16 Terbufos 12.63 231 175 0.9998
17 Terbutryn 14.31 241 170 0.9999
18 trans-Permethrin 20.68 183 153 0.9999
19 Alachlor 13.84 188 160 0.9994
20 Buprofezin 16.68 172 115 0.9993
21 cis-Chlorfenvinphos 15.49 323 267 0.9998
22 Cyproconazole 1 17.03 139 111 0.9998
23 Cyproconazole 2 17.03 139 111 0.9998
24 Difenoconazole 1 23.10 323 265 0.9998
25 Difenoconazole 2 23.18 323 265 0.9999
26 Ethion 17.34 231 175 0.9998
27 Fenitrothion 14.33 277 260 0.9989
28 Fenthion 14.73 278 245 0.9997
29 Fluridone 22.18 328 259 0.9997
30 Hexazinone 18.24 171 71 0.9997
31 Isofenphos oxon 14.79 229 201 0.9999
32 Isophenphos 15.43 255 185 0.9998
33 Isoprothiolane 16.44 189 145 0.9997
34 Propargite 1 18.31 135 107 0.9996
35 Propargite 2 18.31 135 107 0.9996
36 Propiconazole 1 17.93 173 145 0.9998
37 Propiconazole 2 18.07 173 145 0.9996
38 Propyzamide 12.73 175 147 0.9998
39 Pyriproxyfen 19.72 136 96 0.9999
40 trans-Chlorfenvinphos 15.25 323 267 0.9993
41 Triadimenol 1 15.70 168 70 0.9997
42 Triadimenol 2 15.84 168 70 0.9994
43 Triallate 13.13 268 184 0.9999
44 Vinclozoline 13.76 212 172 0.9997
45 Acetamiprid 18.92 152 116 0.9997
46 Allethrin 1 15.43 123 81 0.9994
47 Allethrin 2 15.51 123 81 0.9991
48 Bitertanol 1 20.66 170 141 0.9999
49 Bitertanol 2 20.76 170 141 0.9997
50 Bromopropylate 19.00 183 155 0.9998
51 Chlorobenzilate 17.19 251 139 0.9998
52 Chlorpyrifos 14.63 197 169 0.9997
53 Oxyfluorfen 16.59 252 196 0.9955
54 Parathion 14.80 291 109 0.9979
55 Pirimiphos methyl 14.24 290 233 0.9998
56 Propanil 13.67 217 161 0.9999
57 Pyridaben 20.87 147 119 0.9999
58 Quinoxyfen 18.00 237 208 0.9998
59 Simazine 12.29 201 173 0.9999
60 Tebuconazole 18.38 250 125 0.9998
61 Triadimefon 14.87 208 181 0.9993
62 Triazophos 17.65 161 134 0.9998
63 Ametryn 14.00 227 170 0.9999
64 Azaconazole 16.83 217 173 0.9998
65 Bupirimate 16.66 273 193 0.9998
66 Butachlor 16.01 176 147 0.9994
67 Chlorthal dimethyl 14.73 299 221 0.9999
68 Dicloran 12.19 206 176 0.9993
69 Diethofencarb 14.63 267 225 0.9999
70 Dimepiperate 15.74 119 91 0.9997
71 Dimethenamid 13.61 230 154 0.9999
72 Etoxazole 19.03 204 176 0.9998
73 Fluacrypyrim 17.38 204 189 0.9999
74 Lenacil 18.14 153 136 0.9998
75 Pyriminobac methyl 1 17.96 302 256 0.9996
76 Pyriminobac methyl 2 17.13 302 256 0.9997
77 Pyroquilon 12.88 173 130 0.9996
78 Tetradifon 19.53 159 131 0.9999
79 Tolclofos-methyl 13.87 265 250 0.9998
80 Uniconazole P 16.61 234 165 0.9996
81 Acetochlor 13.66 146 131 0.9997
82 Benalaxyl 17.83 204 176 0.9996
83 Benfuresate 13.57 256 163 0.9998
84 Cadusafos 11.71 159 131 0.9997
85 Chlorpropham 11.37 213 171 0.9997
86 Diclocymet 1 15.61 277 221 0.9995
87 Diclocymet 2 15.91 277 221 0.9999
88 Dimethametryn 15.40 212 122 0.9997
89 Esprocarb 14.49 222 91 0.9998
90 Etofenprox 21.83 163 135 0.9998
91 Fenothiocarb 16.08 160 72 0.9996
92 Iprobenfos 13.27 204 91 0.9998
93 Isoxathion 16.92 177 130 0.9997
94 Mepronil 17.61 119 91 0.9998
95 Prometryn 14.04 241 184 0.9999
96 Propachlor 10.85 120 92 0.9996
97 Prothiofos 16.41 267 239 0.9990
98 Pyrifenox 1 15.99 262 200 0.9998
99 Pyrimethanil 12.89 198 183 0.9998
100 Simetryn 13.94 213 170 0.9999
101 Terbacil 13.06 161 144 0.9999
102 Tetraconazole 14.82 336 218 0.9998
103 Thenylchlor 18.31 127 99 0.9994
104 Tribufos 16.58 202 147 0.9995
105 Tricyclazole 16.66 189 161 0.9996
106 Zoxamide (decomposed) 15.72 187 159 0.9992
107 Benoxacor 13.40 259 120 0.9995
108 Bromacil 14.44 205 188 0.9996
109 Bromobutide 13.70 119 91 0.9998
110 Butamifos 16.17 286 202 0.9997
111 Dichlofenthion 13.56 279 223 0.9998
112 Diphenamid 15.12 167 152 0.9999
113 Hexaconazole 16.42 214 172 0.9996
114 Mefenoxam 14.00 206 132 0.9998
115 Napropamide 16.33 128 72 0.9997
116 Oxadixyl 17.40 163 132 0.9998
117 Paclobutrazol 16.07 236 125 0.9998
118 Phenothrin 1 19.31 183 153 0.9998
119 Phenothrin 2 19.42 183 153 0.9999
120 Piperophos 18.98 320 122 0.9998
121 Prohydrojasmon 1 12.94 153 97 0.9998
122 Prohydrojasmon 2 13.23 153 97 0.9996
123 Propazine 12.42 214 172 0.9997
124 Pyributicarb 18.63 165 108 0.9998
125 Pyrifenox 2 15.51 262 200 0.9995
126 Quinalphos 15.63 146 118 0.9999
127 Tebufenpyrad 19.16 333 171 0.9998
128 Tolfenpyrad 24.05 197 154 0.9999
129 Aldrin 14.78 263 193 0.9988
130 cis-Chlordane 16.26 375 266 0.9998
131 Dicofol 4.97 139 111 0.9998
132 Dieldrin 16.78 277 206 0.9988
133 Endrin 17.19 263 193 0.9996
134 Heptachlor 14.07 272 237 0.9997
135 trans-Chlordane 16.02 373 266 0.9998
136 1-Naphthylacetamide 14.40 141 115 0.9999
137 Bromophos ethyl 15.87 357 301 0.9998
138 Carboxin 16.80 235 143 0.9999
139 Chlorbenside 15.98 268 125 0.9995
140 Chlorofenson 16.42 175 111 0.9995
141 clomazone 12.47 125 89 0.9998
142 Disulfoton 12.98 88 60 0.9997
143 Epoxiconazole 18.61 192 138 0.9999
144 Ethofumesate 14.37 207 161 0.9997
145 Fenamidone 19.17 268 180 0.9998
146 Flutriafol 16.28 219 123 0.9999
147 Isazophos 12.96 161 119 0.9998
148 Phorate 11.79 121 65 0.9998
149 Picolinafen 18.97 376 238 0.9995
150 Propaphos 15.89 220 140 0.9998
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