同位素内标-液相色谱-串联质谱测定牛奶中加米霉素

Determination of Gamithromycin in Milk by Isotopic Internal Standards-Liquid Chromatography-Tandem Mass Spectrometry

基于同位素内标和液相色谱串联质谱仪,建立牛奶中加米霉素定量检测方法。样品经乙腈提取,净化过膜后,选用乙腈-0.1%甲酸水为流动相进行梯度洗脱,采用正离子多反应监测模式测定,同位素内标法定量。结果表明,加米霉素在0.25~5.00μg/L质量浓度范围内有良好的线性关系(R^(2)>0.99)。方法的测定低限为0.5μg/kg,牛奶中加米霉素在添加水平0.5, 1.0和5.0μg/kg的平均回收率为90.5%~107%,批内(n=6)相对标准偏差(relative standard deviations, SRSD)为1.32%~4.36%,批间(n=18)相对标准偏差为1.98%~2.80%。该方法简单易操作,回收率高,稳定性好,定量准确,基质效应低,可以满足快速测定牛奶中加米霉素残留量的要求。

A quantitative method for the determination of gamithromycin in milk was established based on isotopic internal standard and liquid chromatography tandem mass spectrometer.The samples were extracted with acetonitrile and purified via membranes.Acetonitrile-0.1%formic acid water was used as mobile phase for gradient elution.The isotopic internal standard method was for quantification,and the positive ion multiple reaction monitoring mode was for determination.The results showed that gamithromycin had a good linear relationship in the concentration range of 0.25-5.00μg/L(R^(2)>0.99).The detection limit of the method was 0.5μg/kg.The average recoveries of gamithromycin at the spike levels 0.5,1.0 and 5.0μg/kg in milk were 90.5%-107%,the relative standard deviation(SRsp)of intra(n=6)was 1.32%-4.36%,and SRsD of inter(n-18)was 1.98%-2.80%.The method was simple and easy to operate,with high recovery rate,good stability,accurate quantification and low matrix effect,and able to meet the requirements of rapid determination of gamithromycin residues in milk.