Screening analysis of pesticide residues in plant foodstuffs by capillary gas chromatography using the DFG multiresidue method S19: a comparison of customary detection by ECD/NPD with the novel atomic emission detector (AED).

Over a period of 7 months nearly 240 plant foodstuffs taken fresh from the market were analysed for pesticide residues using the Deutsche Forschungsgemeinschaft (DFG) multiresidue method (MRM) S19. The analysed foodstuffs were a representative cross-section of different fruits and vegetables offered on sale on the German market. With the slightly modified MRM S19, up to 400 pesticides and metabolites amenable to gas chromatography (GC) can be determined. The screening analysis was performed with the combination GC-electron-capture detector (ECD)/nitrogen-phosphorus detector (NPD) as well as with the combination GC-atomic emission detector (AED) in parallel. Results obtained from both screening systems agree over the whole concentration range observed. With so-called "problem foodstuffs" the combination GC-AED is clearly more suitable. Confirmation of positive results was performed by GC-mass spectrometry (MS) analysis. On account of its higher selectivity and its wide linear dynamic range down to the lowest detectable concentrations, the GC-AED system produces more reliable quantitative results compared to those obtained from the GC-ECD/NPD system.