Simultaneous Determination of Five Organotins in Tropical Fruits Using Modified QuEChERS Combined with Ultra-high Performance Liquid Chromatography–Tandem Mass Spectrometry

A sensitive, confirmatory ultra-high performance liquid chromatography–tandem mass spectrometry based on modified QuEChERS was developed and validated to detect five organotin compounds (tributyltin chloride (TBT), triphenyltin chloride (TPT), trimethyltin chloride (TMT), azocyclotin and cyhexatin) in classical tropical fruits (mango, pineapple and banana). Fruits samples were ultrasonically extracted with methanol and subsequently purified by graphitized carbon black adsorbents. Five organotins were separated on a C18 column with the mobile phase of a mixture of methanol and 0.1% (v/v) aqueous formic acid, and detected by MS/MS under multiple reaction monitoring mode. The developed method was validated in terms of linearity, limit of detection (LOD), recovery and precision. Results were linear in their corresponding concentration ranges, with coefficients of determination (r) bigger than 0.999. The average LODs (S/N = 3) of the method for TBT, TPT, TMT, azocyclotin and cyhexatin were 1.3, 3.5, 3.2, 5.1 and 1.7 μg/kg, respectively. The average recoveries (n = 5) at three spiked levels (0.01, 0.1 and 0.2 mg/kg) ranged from 69 to 103% with relative standard deviations of 2.1–11.9%. The method is simple, effective, accurate and non-derivatized, and meets the routine monitoring requirements for trace organotins in tropical fruits.