## 3 Results and Discussion
### Establishment of GC-MS/MS MRM Conditions
\begin{table}
\begin{tabular}{c c c c c c} \hline \hline \multirow{2}{*}{**Pesticides**} & \multirow{2}{*}{**RT (min)**} & \multicolumn{4}{c}{**Precursor \textgreater{} Product Ion (CE, eV)**} \\ \cline{3-6}  & & \multicolumn{2}{c}{**Quantifier Ion**} & \multicolumn{2}{c}{**Qualifier Ion**} \\ \hline Acrinathrin & 13.525 & 181.00 \textgreater{} 152.10 & 24 & 208.00 \textgreater{} 181.10 & 9 \\ Alachlor & 8.572 & 188.00 \textgreater{} 160.10 & 9 & 188.00 \textgreater{} 131.10 & 21 \\ Aldrin & 9.143 & 263.00 \textgreater{} 192.90 & 30 & 263.00 \textgreater{} 190.90 & 30 \\ Ametoctradin & 13.88 & 246.00 \textgreater{} 188.20 & 27 & 246.00 \textgreater{} 174.10 & 30 \\ Anilofos & 12.748 & 226.00 \textgreater{} 157.00 & 15 & 184.00 \textgreater{} 157.00 & 9 \\ Azaconazole & 10.647 & 217.00 \textgreater{} 173.00 & 15 & 173.00 \textgreater{} 109.10 & 27 \\ Benfuresate & 8.399 & 163.00 \textgreater{} 121.10 & 9 & 256.00 \textgreater{} 163.10 & 9 \\ BHC-alpha & 7.55 & 181.00 \textgreater{} 145.00 & 15 & 219.00 \textgreater{} 183.00 & 9 \\ BHC-beta & 7.891 & 181.00 \textgreater{} 145.00 & 18 & 219.00 \textgreater{} 183.00 & 9 \\ BHC-delta & 8.226 & 181.00 \textgreater{} 145.00 & 15 & 219.00 \textgreater{} 183.00 & 9 \\ BHC-gamma & 7.891 & 181.00 \textgreater{} 145.00 & 15 & 219.00 \textgreater{} 183.00 & 12 \\ Bifenox & 12.784 & 341.00 \textgreater{} 310.00 & 9 & 310.00 \textgreater{} 189.00 & 9 \\ Bifenthrin & 12.448 & 166.00 \textgreater{} 164.10 & 30 & 181.00 \textgreater{} 141.10 & 21 \\ Bromobutide & 8.487 & 232.00 \textgreater{} 176.20 & 9 & 232.00 \textgreater{} 114.10 & 9 \\ Bromopropylate & 12.514 & 341.00 \textgreater{} 183.00 & 21 & 183.00 \textgreater{} 76.10 & 27 \\ Butachlor & 10.036 & 176.00 \textgreater{} 147.10 & 15 & 237.00 \textgreater{} 160.20 & 15 \\ Butatfenacil & 14.426 & 331.00 \textgreater{} 180.00 & 21 & 331.00 \textgreater{} 152.10 & 30 \\ Carbophenathion & 11.51 & 342.00 \textgreater{} 157.10 & 15 & 342.00 \textgreater{} 199.10 & 6 \\ Chlorantaniliprole & 12.676 & 278.00 \textgreater{} 249.00 & 20 & 280.00 \textgreater{} 251.00 & 20 \\ Chlorane-cis & 9.988 & 377.00 \textgreater{} 267.90 & 27 & 377.00 \textgreater{} 266.00 & 24 \\ Chlordane-trans & 10.168 & 377.00 \textgreater{} 267.90 & 27 & 377.00 \textgreater{} 266.00 & 24 \\ Chlorfenapyr & 10.699 & 247.00 \textgreater{} 227.20 & 15 & 247.00 \textgreater{} 200.00 & 27 \\ Chlorfenvinphos (E) & 9.472 & 267.00 \textgreater{} 159.00 & 18 & 323.00 \textgreater{} 266.90 & 18 \\ Chlorfenvinphos (Z) & 9.625 & 267.00 \textgreater{} 159.00 & 18 & 323.00 \textgreater{} 266.90 & 18 \\ Chlorfluazuron & 7.291 & 213.00 \textgreater{} 171.10 & 9 & 171.00 \textgreater{} 127.00 & 15 \\ Chlorobenzzilate and chloropropylate & 10.959 & 251.00 \textgreater{} 111.10 & 27 & 139.00 \textgreater{} 75.10 & 27 \\ Chlorpropham & 7.292 & 127.00 \textgreater{} 65.10 & 21 & 213.00 \textgreater{} 171.00 & 9 \\ Chlor pyrifos-methyl & 8.492 & 286.00 \textgreater{} 93.10 & 24 & 286.00 \textgreater{} 270.90 & 18 \\ Cyfluthrin-1 & 14.632 & 163.00 \textgreater{} 127.00 & 6 & 226.00 \textgreater{} 206.10 & 15 \\ Cyfluthrin-2 & 14.731 & 163.00 \textgreater{} 127.00 & 6 & 226.00 \textgreater{} 206.00 & 15 \\ Cyfluthrin-3 & 14.786 & 163.00 \textgreater{} 127.00 & 6 & 226.00 \textgreater{} 206.10 & 15 \\ Cyfluthrin-4 & 14.83 & 163.00 \textgreater{} 127.00 & 6 & 226.00 \textgreater{} 206.10 & 15 \\ \hline \hline \end{tabular}
\end{table} 
Table 1: MRM conditions for the first 40 pesticides in the GC–MS/MS analysis. MRM conditions for the other 83 pesticides are listed in Table S1.