Enzymatic reaction modulated hydride generation of arsenic for parathion-methyl monitoring in traditional Chinese medicine by atomic fluorescence spectrometry

Abstract

In the production of traditional Chinese medicine (TCM), the frequent use of organophosphorus pesticides (OPs) will lead to a certain residue and affect the quality of TCM. Therefore, the development of simple and rapid methods for OPs residue monitoring is of great significance for the quality control and evaluation of TCM. In this work, a novel method was developed for the indirect determination of parathion-methyl (PM) residue in TCM by hydride generation atomic fluorescence spectrometry (HG-AFS) based on enzyme modulation. The acetylthiocholine (ATCh) can be hydrolyzed by butyrylcholinesterase (BChE) to produce thiocholine (TCh), which contains − SH that can interact with As(III) and inhibits its HG procedure, further reducing its AFS signal. However, OPs like PM can inhibit the activity of BChE to restore the AFS signal. Therefore, the indirect analysis of PM can be achieved by detecting As(III). A low limit of detection (LOD) of 0.043 μg mL−1 and a relative standard deviation (RSD) of 0.5% were obtained, respectively. The proposed method was successfully applied for the analysis of PM residue in 6 kinds of TCMs commonly used in clinical practice. This present strategy offers a unique alternative for OPs assay with high sensitivity, selectivity, and simple operation.