## 3 Results and Discussion
### Precision of the Method  
We analyzed Group C samples prepared with pooled blank urine (Blank I) at three concentrations (0.5, 5, and 15 \(\mathrm{\SIUnitSymbolMicro g}\)/L) within 24 h to determine the RSD representing the within-day precision. The RSDs for the low concentration (0.5 \(\mathrm{\SIUnitSymbolMicro g}\)/L) ranged between 1.7% and 5.2%, and that for the other two concentrations (5 and 15 \(\mathrm{\SIUnitSymbolMicro g}\)/L) also yielded good results showing no more than 5.2% (Table 4). To confirm the method precision, we used a different source of blank urine (Blank II) to prepare Group D samples for testing. Five samples at 0.5 \(\mathrm{\SIUnitSymbolMicro g}\)/L were analyzed and resulted in RSDs ranging between 1.6% and 4.8% (Table 4), which were similar to those derived from Group CL; The results of Groups C and D and the mutual comparison indicate that the method is precise in analyzing insecticide metabolites in urine which, as a medium, had no effect on or interference with the analysis.  
\begin{table}
\begin{tabular}{c c c c c c c c} \hline \hline \multirow{2}{*}{**Metabolite**} & \multicolumn{3}{c}{**Within-Day RSD (\%)**} & \multicolumn{3}{c}{**Between-Day RSD (\%)**} \\ \cline{2-9}  & **Group CL** & **Group CM** & **Group CH** & **Group D** & **Group EL** & **Group EM** & **Group EH** \\ \hline
3-PBA & 2.6 & 3.9 & 4.6 & 4.5 & 2.9 & 3.2 & 3.1 \\ _cis_-DCCA & 4.7 & 3.4 & 2.3 & 3.7 & 3.5 & 3.6 & 2.6 \\ _trans_-DCCA & 4.6 & 4.5 & 3.5 & 4.8 & 4.2 & 3.2 & 3.1 \\ _cis_-DBCA & 4.1 & 2.8 & 2.6 & 3.6 & 2.8 & 2.4 & 2.5 \\ _trans_-CDCA & 3.8 & 3.3 & 3.7 & 2.8 & 3.4 & 3.7 & 3.7 \\ FPBA & 4.8 & 2.6 & 3.3 & 3.6 & 4.5 & 5.3 & 3.8 \\ DMP & 3.9 & 4.1 & 5.1 & 3.2 & 3.8 & 4.1 & 2.6 \\ DMTP & 5.2 & 3.4 & 3.5 & 3.3 & 2.3 & 3.4 & 3.3 \\ DMDTP & 4.7 & 4.1 & 1.6 & 2.2 & 4.6 & 4.2 & 3.1 \\ DEP & 4.5 & 3.3 & 3.5 & 2.3 & 3.3 & 3.1 & 2.4 \\ DETP & 4.4 & 2.7 & 1.3 & 1.6 & 1.8 & 2.9 & 3.1 \\ DEDTP & 3.6 & 1.2 & 2.4 & 2.8 & 2.9 & 2.3 & 1.7 \\
7-phenol & 1.7 & 2.3 & 1.8 & 3.9 & 1.0 & 1.7 & 1.9 \\ Average & 4.05 & 3.20 & 3.02 & 3.25 & 3.15 & 3.32 & 2.84 \\ \hline \hline Average & 92.34 & 4.14 & 96.37 & 3.14 & 4.13 & 93.39 & 3.92 & 96.11 & 2.81 & 2.86 \\ \hline \hline \end{tabular}  
* L: 0.5 \(\mathrm{\SIUnitSymbolMicro g}\)/L; H: 5 \(\mathrm{\SIUnitSymbolMicro g}\)/L; RR: recovery rate; RSD: relative standard deviation; RE: relative error.  
\end{table}
Table 4: The within-day and between-day precisions of urine samples at different concentrations (\(n=5\)).  
\begin{table}
\begin{tabular}{c c c c c c c c c c} \hline \hline \multirow{2}{*}{**Metabolite**} & \multicolumn{3}{c}{**Group A L**} & \multicolumn{3}{c}{**Group B L**} & \multicolumn{3}{c}{**-**} & \multicolumn{3}{c}{**Group A H**} & \multicolumn{3}{c}{**Group B H**} & \multicolumn{1}{c}{**-**} \\  & **RR (\%)** & **RSD (\%)** & **RR (\%)** & **RSD (\%)** & **RE (\%)** & **RR (\%)** & **RSD (\%)** & **RR (\%)** & **RSD (\%)** & **RE (\%)** \\ \hline
3-PBA & 94.5 & 5.3 & 96.2 & 2.6 & 1.77 & 93.6 & 5.2 & 95.4 & 2.7 & 1.89 \\ _cis_-DCCA & 93.3 & 6.1 & 96.0 & 3.1 & 2.81 & 94.4 & 2.1 & 97.4 & 1.7 & 3.08 \\ _trans_-DCCA & 94.5 & 3.2 & 97.2 & 2.4 & 2.78 & 95.3 & 2.5 & 97.7 & 2.6 & 2.46 \\ _cis_-DBCA & 90.7 & 4.2 & 94.2 & 4.3 & 3.72 & 91.5 & 2.6 & 96.2 & 3.6 & 4.89 \\ _trans_-CDCA & 92.5 & 3.4 & 95.5 & 2.7 & 3.14 & 92.1 & 4.6 & 95.9 & 1.8 & 3.96 \\ FPBA & 89.3 & 6.5 & 93.9 & 3.7 & 4.9  
The between-day precision was determined by Group E samples at three concentrations (0.5, 5, and 15 \(\upmu\)g/L). The precision (RSDs) ranged between 1.0% and 4.6% for 0.5 \(\upmu\)g/L (\(n=10\)), 1.7% and 5.3% for 5 \(\upmu\)g/L (\(n=10\)), and 1.6% and 4.8% for 15 \(\upmu\)g/L (\(n=10\)), and indicates that this method is also precise for analysis up to 10 days, during which the processed samples are stable (Table 4).