RESUMO
Objective:To determine the level of manganese and assess potential health risks of lip cosmetics. Methods:Assessment on manganese of lip cosmetics was performed using high-end exposure analysis mode based on the daily dosage. Results:In a total of 264 lip cosmetics samples， manganese was detected in the 249 sample， with a detection rate of 94.3%. Daily exposure was determined to be 3.88×10-5 mg/kg. Safety margin was 3 608 and safety limit was 45 mg/kg. Conclusion:Level of manganese in lip cosmetics remains safe. Health risk is low when appropriately used according to the daily usage. However， it is noted that level of manganese exceeds the limits in approximately 10% of the samples， posing a potential health threat.
RESUMO
Objective To develop a method for the simultaneous determination of 15mycotoxins in peanuts by ultra high performance liquid chromatography-tandem mass spectrometry with QuEChERS EMR-Lipid approach and stable isotope dilution. Methods The samples were extracted by 2% formic acid acetonitrile-water (50 : 50, V/V) and then purified with QuEChERS EMR-Lipid approach.The mycotoxins were fully separated on a pentafluorophenyl column under a gradient elution with methonal-0.01%formic acid aqueous solution.The mycotoxins were analyzed by UPLC-MS/MS with multiple reaction monitoring (MRM) mode and quantified by isotope internal standard method. Results Fifteen mycotoxins had good linear relationship in the certain correlation ranges with the correlation coefficients all above 0.995 and the detection limits were 0.1－10 μg/kg.The mean recoveries ranged from 81.2% to 115.3% with RSD (n=6) varying from 2.1% to 10.7%. Conclusion The method is simple, highly sensitive, practical, and proves to be suitable for quantitative analysis of 15 mycotoxins in peanuts.
RESUMO
Objective To make uncertainty evaluation of total arsenic in pork by using the national food safety standard "GB 5009.11-2014 determination of total arsenic and inorganic arsenic in food", and discuss the influence of each uncertainty component on the determination results so as to improve the accuracy of the experimental results. Methods The uncertainty sources that affected the measurement results in the measurement process, including repeatability measurement, sample weighing, sample dilution, standard concentration, standard curve and so on were evaluated.The uncertainty introduced by the repeatability measurement was evaluated by class A, the uncertainty caused by other factors was evaluated by class B, and the phase was calculated according to each component.The synthetic standard uncertainty and the relative expanded uncertainty were discussed, and so were the influence of the uncertainty components on the measurement results. Results According to the contribution of uncertainty from large to small was the sample standard concentration, standard curve, repeatability determination, sample weighing and sample dilution.The calculated relative composite standard uncertainty was 0.0405, and the relative expanded uncertainty was 0.081 (k=2). Conclusion The experimental results show that the concentration of standard substance has a great influence on the measurement process, so it is necessary to standardize the dilution process and simplify the dilution procedure to improve the accuracy of measurement results.