ABSTRACT
Objective@#To develop an approach for simultaneous detection of multi-mycotoxins in fresh fruits, so as to provide technical supports for mycotoxins surveillance in fresh fruits.@*Methods@#Fresh fruits were collected from markets and homogenized. Then, 2 g of fresh fruits were added with 10 mL of 0.1% formic acid ( 99∶1, v/v ) in acetonitrile and wortexed for 10 min. Following extraction with 1 g of sodium chloride and 4 g of anhydrous sodium sulfate, samples were centrifuged and 5 mL of the supernatant was cleaned up with 25 mg C18. Following centrifugation, the supernatant was dried under nitrogen. The residue was dissolved in 300 μL of methanol-acetonitrile mixture solution ( 1∶1, v/v ), and mixed evenly in 700 μL of the distilled water. Samples were then eluted in gradient series of 0.1% formic acid and 5 mmol ammonium formate and methanol-acetonitrile mixture solution ( 1∶1, v/v ). The 15 mycotoxins were determined using liquid chromatography-tandem mass spectrometry ( LC-MS/MS ) with electrospray ion source (ESI+/ESI-) under multiple reaction monitoring. In addition, a matrix-matched standard curve was employed for quantitative analysis.@*Results@#There was a good linear relationship for 15 mycotoxins at concentrations of 0.25 to 10 ng/mL ( R2>0.992 ), the LC-MS/MS method showed the detection limits of 0.1-1.0 μg/kg, the spiked recovery rates of 71.68%-117.50%, and the relative standard deviations ( RSDs ) of 0.01%-13.60%. The detection rate of mycotoxins was 27.09% in 203 fresh fruits sold in markets.@*Conclusions@#The optimized LC-MS/MS method can be used for simultaneous determination of multi-mycotoxins in fresh fruits.
ABSTRACT
Objective@#To screen and quantify 16 kinds of β-lactam antibiotics in pork by high performance liquid chromatography-quadrupole/electrostatic field orbit trap mass spectrometry（UPLC-Q-Orbitrap）.@*Methods@#The pork samples were extracted by ultrasound with acetonitrile，then the supernatant was centrifuged and purified by HLB solid phase extraction column. The analytes were separated by Waters HSS T3 column（100 mm×2.1 mm，1.8 μm）with gradient elution. Mass spectrometry adopted positive ion scanning and targeted SIM/dd-MS2 monitoring mode to complete the separation of analytes in samples and mass spectrometry analysis within 10 minutes. The chromatographic retention time and fragments in mass spectrometry were compared with prepared standards to determine whether the samples contained the antibiotics tested，then the positive samples were quantified.@*Results@#The 16 kinds of β-lactam antibiotics had good linear relationship in the range of 5-400 ng/mL（all the correlation coefficients >0.99）. The detection limits ranged from 0.08 μg/kg to 0.41 μg/kg，recovery rate ranged from 85.5% to 116.7%，and relative standard deviation（RSD）ranged from 3.6% to 12.8%. One of twenty pork samples detected was found penicillin G（28 μg/kg）and ampicillin（18.5 μg/kg）.@*Conclusion@#UPLC-Q-Orbitrap has high resolution and can reduce matrix interference to improve the accuracy. This method is simple，fast and efficient，thus can be used to screen and quantify β-lactam antibiotics in pork.