Determination of five Alternaria toxins in wolfberry using modified QuEChERS and ultra-high performance liquid chromatography-tandem mass spectrometry

A modified quick, easy, cheap, effective, rugged, and safe method coupled with ultra-high performance liquid chromatography-tandem mass spectrometry was established for the simultaneous detection of five Alternaria toxins (tenuazonic acid, alternariol, alternariol monomethyl ether, altenuene, and tentoxin) in wolfberry. The sample pretreatment conditions including the dilution solvent, the extraction solvent and the QuEChERS purification parameters were optimized. Detection of the five Alternaria toxins was performed in MRM mode under ESI + conditions. The results showed that the five Alternaria toxins exhibited good linearity (1-200 μg/L, with correlation coefficients > 0.999). The limits of detection were 0.07-0.24 μg/kg, and the limits of quantification were 0.32-0.77 μg/kg. The trueness was between 73.8% and 111.5%, and the precision was lower than 10%. The established method was effectively used for the determination of five Alternaria toxins in 155 wolfberry samples from Northwest China.