Simultaneous Analysis of Seven Neonicotinoids in Commercial Milk Samples Using an UHPLC-MS/MS Method

A liquid–liquid extraction and ultra high-performance liquid chromatography tandem mass spectrometry (UHPLC–MS/MS) method was developed for simultaneous analysis of the residues of seven neonicotinoid insecticides (NEOs), namely acetamiprid, clothianidin, dinotefuran, imidacloprid, thiacloprid, thiamethoxam, and nitenpyram, in commercial milk samples. The method had a good linearity (R2 > 0.992) and a limit of detection range of 0.004–0.15 μg/kg. The average recovery range was 89–119% with an intraday precision of 1.4–10.3% at spiking levels of 8, 12, and 16 μg/kg. The validated method was employed for routine analysis of the aforementioned seven NEOs in commercial milk samples obtained randomly from a supermarket in Miaoli (Taiwan). The detected thiamethoxam and clothianidin levels were 3.4 and 80 μg/kg, respectively.