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.

According to the level of selenium (Se) and methionine (Met) in diet, Wistar rats were randomly divided into 3 groups, group A (normal Se and normal Met); group B (Low Se and normal Met); group C (low Se and low Met). The animals were sacrificed after 8-week feeding. The results showed that the alteration of myocardial ultrastructure was slight in group B. Decreased activities of cytochrome oxidase and succinate dehydrogcnase of myocardial mitochonria and decreased activities of GSH-Px in the blood, heart and liver in group B were observed, as compared with those in group A. But the level of TBA was higher than that of group A.The above mentioned changes in group C were extremely apparent than group A or B, indicating both Se and Met deficiency in diet may concern the etiology of Keshan disease.

Objective: To quickly determine bongkrekic acid（BKA）in plasma qualitatively and quantitatively by liquid chromatography-tandem mass spectrometry（LC-MS/MS）,and to provide technical support for etiological identification of food poisoning events. Methods: The plasma sample was protein precipitated with acetonitrile,diluted with water and purified with anion exchange solid phase extraction cartridge of PAX. The sample extract was separated by an XBridgeTM BEH C18 chromatographic column. Gradient elution was conducted with the mobile phase of 0.01 %（v/v）ammonia and methanol. Then BKA was detected by LC-MS/MS. Results: The equation of linear regression was y=16 509x+3 134.3. Good linear relationship was obtained for BKA at a range from 1 to 400 ng/mL in plasma,with the correlation coefficient of 0.999 3. The limit of detection（LOD）was 0.5 ng/mL and the limit of quantitation（LOQ）was 1 ng/mL. The average recoveries were 76.0%-96.7% with relative standard deviations（RSDs,n=6）of 5.2%-12.8% at three spiking levels of 1（LOQ）,10（10 times of LOQ）and 200 ng/mL（medium of linear range）. The concentrations of BKA in plasma obtained from two patients suffering from food poisoning were 394 and 92.3 ng/mL. Conclusion The optimized sample pretreatment and chromatographic separation conditions can achieve rapid,accurate,qualitative and quantitative analysis of BKA in plasma.