Residual determination of pyrethrins in Lycium barbarum (goji) by GC-MS/MS and a dietary risk assessment of Chinese goji consumption.

An accurate and simple analytical approach for the determination of residues cinerin I, cinerin II, jasmolin I, jasmolin II, pyrethrin I and pyrethrin II (six active ingredients of pyrethrins) in fresh and dried goji berries was developed and validated for analysis by gas chromatography with tandem mass spectrometry. Good linearity (determination coefficient >0.99), accuracy (average recoveries of 88.3%-111.5%) and precision (intra- and inter-day relative standard deviations of 0.4%-8.3%) were obtained with the optimised determination method. The LODs and LOQs of the six analytes in two goji matrices were 0.24-2.1 mu g/kg and 0.8-7 mu g/kg, respectively. In a field trial, the terminal residual levels of pyrethrins (the sum of the concentrations of the six target analytes) in fresh and dried goji berry samples were <20-304 mu g/kg at harvest, which could provide some information for the establishment of a maximum residue limit of pyrethrins on goji berries in China. Moreover, the risk assessment results indicated that because the risk quotient values were MUCH LESS-THAN100%, the potential dietary risk of pyrethrins on goji berries could be negligible for Chinese consumers. These detection and field results could provide some supporting data for the determination of pyrethrin residues in other crops and the proper application and safety assessment of pyrethrins in goji plants.