Determination of organophosphorus pesticides using rambutan peel-based activated carbon as sorbent

Rambutan peel-based activated carbon (RPAC) was prepared and applied as sorbent for dispersive solid phase extraction (DSPE). In this study, the developed sorbent was successfully characterized by using Scanning Electron Microscopy (SEM). Two selected organophosphorus pesticides (OPPs) namely chlorpyrifos and profenofos were employed as model compounds to evaluate the extraction
performance of the synthesized rambutan peel-based activated carbon. Analysis was performed using UV-Vis Spectrophotometry. Several vital DSPE parameters were
optimized. Under the optimum extraction conditions, the DSPE-RPAC method showed coefficient of determination of r²=O.9674 and r²=O.8844 for chlorpyrifos and profenofos respectively. The limit of detection (LOD) obtained were 5.74 for chlorpyrifos and 6.04 mg kg⁻¹ for profenofos. On the other hand, the limit of quantification (LOQ) was 17.39 and 18.29 mg kg⁻¹ for chlorpyrifos and profenofos
respectively. The developed RPAC dSPE method was successfully applied to real sample analysis of the selected OPPs for lettuce. Excellent RSDs were obtained from the lettuce sample. The RSDs obtained for chlorpyrifos was 0.48% (intra-day) and 3.3% (inter-day) while for profenofos, the RSDs obtained was 1.17% (intra-day) and 2.84% (inter-day). The RPAC sorbent demonstrate the potential as an alternative inexpensive extraction sorbent for OPPs.