QuEChERS sample preparation method for rapid screening of malathion in legume vegetables by surface-enhanced Raman spectroscopy

A rapid and environment friendly method was developed for the determination of malathion in legume vegetables using QuEChERS(Quick Easy Cheap Effective Rugged and Safe) sample preparation and SERS(Surface-Enhanced Raman Spectroscopy) technology. The samples were extracted with 0.1% acetic acid in acetonitrile, cleaned up by PSA and C18 couple with PestiCarb adsorbents, analyzed by portable surface-enhance Raman spectroscopy(SERS). It quantified through the intensity of malathion characteristic Raman peak which showed at 760 cm-1 adding external standards. The standard curve of malathion was linear range of 0.1~8.0 μg/mL with correlation coefficients more than 0.99. The average recoveries of malathion were from 79.3% to 102.1% at three spike levels of 0.5, 1.0, 2.0 mg/kg, the relative deviations(RSDs) were between 2.3% and 7.8%; the limit of quantitation(LOQ) by the method was 0.2 mg/kg. By all results, the rapid method is easy for pre-treatment, efficient and environmental, suitable for monitoring the maximum residue limits(MRLs) of malathion in legume vegetables, which could be used in the residual analysis of malathion in legume vegetables.