HPLC-MS/MS法分析乙酰甲喹在海参中的主要代谢物

建立了高效液相色谱-串联质谱(HPLC-MS/MS)法分析乙酰甲喹在海参体壁中可能的代谢产物。采用沉淀法和固相萃取法(SPE)对不同种类的代谢物进行净化和浓缩。以含0.1%甲酸的乙腈和含0.1%甲酸的水为流动相,选取AcquityTMUPLCBEH C18(2.1mm×50mm×1.7μm)色谱柱对代谢物进行梯度洗脱,以电喷雾离子源(ESI)正离子全扫描模式进行检测。通过将样品的一级和二级子离子与标准品比对,确定乙酰甲喹在海参体壁的代谢物中含有3-甲基喹噁啉-2-羧酸(MQCA),同时检测出3种未知代谢物D2、D3、D4,并推测了代谢物可能的裂解途径。     

羧基化高纯单壁碳纳米管修饰电极对乙酰甲喹的高灵敏检测

采用羧基化高纯单壁碳纳米管(c SWCNTs)固载于金电极表面来构筑乙酰甲喹电化学传感器。运用循环伏安法(CV)、差分脉冲伏安法(DPV)和电化学交流阻抗法(EIS)测定传感器的性能。结果显示,该传感器对乙酰甲喹的电化学还原具有显著的催化性能,修饰电极的峰电流达到-128.40μA,是裸电极峰电流的1167倍。通过对传感器性能影响因素的考察,得到最优制备条件为cSWCNTs涂覆量为4μL(质量分数0.10%分散液),搅拌速度1000 r/min,pH=7.0的PBS浓度为0.2 mol/L,-0.5V电压下富集30 min。在该条件下制备的传感器峰电流与乙酰甲喹在1～500nmol/L范围内呈良好的线性关系,相关系数为0.998,方法的检出限为0.76nmol/L。该传感器被成功地应用于实际样品检测,加标回收率在81.7%～124.0%。     

乙酰甲喹在刺参幼参中的代谢及其对成品刺参食用安全性评价

对乙酰甲喹在刺参幼参中的代谢及代谢物对成品刺参食用安全性影响进行研究评价。将刺参幼参分别暴露于2、4、6 mg/L的乙酰甲喹药浴液,浸泡24 h,消除96 h,采集不同时间点样品,用高效液相色谱法检测其中乙酰甲喹及代谢物3-甲基喹噁啉-2-羧酸(3-methyl-quinoxaline-2-carboxylic acid,MQCA)含量。结果表明:刺参幼参对水体中的乙酰甲喹吸收迅速,分别在2.5、1.5、1.5 h达到峰值,分别为0.89、1.73、2.56 mg/kg;各药浴组刺参幼参对乙酰甲喹富集系数分别为0.45、0.43和0.43;其药时曲线下面积值与药浴质量浓度呈正相关(R2=1);乙酰甲喹在刺参幼参中消除迅速,消除0.5 h后,约85%的药物从体内排出或代谢,72 h后无检出。代谢物MQCA最早于药浴15 min产生(6 mg/L组),且含量不断增长,24 h达到最大值29.2μg/kg;MQCA在刺参幼参中消除缓慢,将在刺参体内长时间存在。采用食品安全指数法对成品刺参中MQCA进行食用安全性评价,食品安全指数值为1.23×10-4,即MQCA对成参食用安全性没有影响。     

Physiologically based pharmacokinetic model for quinocetone in pigs and extrapolation to mequindox

ABSTRACT

Physiologically based pharmacokinetic (PBPK) models are scientific methods used to predict veterinary drug residues that may occur in food-producing animals, and which have powerful extrapolation ability. Quinocetone (QCT) and mequindox (MEQ) are widely used in China for the prevention of bacterial infections and promoting animal growth, but their abuse causes a potential threat to human health. In this study, a flow-limited PBPK model was developed to simulate simultaneously residue depletion of QCT and its marker residue dideoxyquinocetone (DQCT) in pigs. The model included compartments for blood, liver, kidney, muscle and fat and an extra compartment representing the other tissues. Physiological parameters were obtained from the literature. Plasma protein binding rates, renal clearances and tissue/plasma partition coefficients were determined by in vitro and in vivo experiments. The model was calibrated and validated with several pharmacokinetic and residue-depletion datasets from the literature. Sensitivity analysis and Monte Carlo simulations were incorporated into the PBPK model to estimate individual variation of residual concentrations. The PBPK model for MEQ, the congener compound of QCT, was built through cross-compound extrapolation based on the model for QCT. The QCT model accurately predicted the concentrations of QCT and DQCT in various tissues at most time points, especially the later time points. Correlation coefficients between predicted and measured values for all tissues were greater than 0.9. Monte Carlo simulations showed excellent consistency between estimated concentration distributions and measured data points. The extrapolation model also showed good predictive power. The present models contribute to improve the residue monitoring systems of QCT and MEQ, and provide evidence of the usefulness of PBPK model extrapolation for the same kinds of compounds.     

超高效液相串联质谱法测定水产品中乙酰甲喹及其代谢物

目的建立一种超高效液相串联质谱法(ultra liquid chromatography tandem mass spectrometry,ULPC-MS/MS)测定水产品中乙酰甲喹及其代谢物的方法。方法组织样品经二氯甲烷/乙酸乙酯提取,正己烷去除脂肪过滤处理后,采用Waters ACQUITY HSS T3色谱柱进行分离,乙腈-5mmol/L乙酸铵水溶液+0.1%甲酸水(V:V)溶液作为流动相进行梯度洗脱,正离子扫描方式下多反应监测模式测定。结果乙酰甲喹及其5种代谢物在1～50 ng/mL线性范围内线性良好,相关系数为0.9991～0.9996;该方法的检出限和定量限分别为0.03μg/kg和0.1μg/kg;鳗鲡、青蛾、虾、蟹肌肉样品中,乙酰甲喹及代谢物在0.1、0.2、1.0μg/kg的加标水平的平均回收率为66.6%～106.6%,日内精密度范围为2.1%～11.1%,日间精密度范围为1.3%～13.2%。结论本方法稳定、准确、灵敏、快速,能够满足水产品中乙酰甲喹及其代谢物残留分析的需求。