Simultaneous determination of three organotin pesticides in fruits and vegetables by high-performance liquid chromatography/tandem mass spectrometry.

Rationale: The presence of organotins in the environment affects food safety, making it important to monitor the levels of organotin pesticides (OTPs) in fruit and vegetable samples.

Methods: In the present study, a simple and low cost method for simultaneous determination of three OTPs (azocyclotin, fenbutatin oxide and triphenyltin hydroxide) in vegetable and fruit samples was developed and validated, based on solid-phase extraction and liquid chromatography/tandem mass spectrometry.

Results: Extraction with acetonitrile containing 0.2% formic acid positively affected the recoveries of the three OTPs. Moreover, the simultaneous purification of the three OTPs was the most efficient using mixed-mode cation-exchange cartridges and 5.0% ammonium hydroxide in methanol as eluent, and, in this case, mild matrix effects (-9.3% to 21.6%) were obtained for the three OTPs monitored. The developed method reached limits of quantification of 1 μg kg , and linearity was satisfactory, with correlation coefficients >0.995. A fortification study showed that when spiked at 1.0-50.0 μg kg the mean trueness values were from 72.3 to 110.0% in all matrices (three vegetables and three fruits). The intra-day precision was <14.1%, and the inter-day precision (n = 11) was <18.2%.

Conclusions: The proposed method was successfully applied to the simultaneous analysis of three OTPs in vegetables and fruits.