液相色谱-串联质谱法测定牛肉中加替沙星残留量的研究

建立牛肉中加替沙星残留量检测的液相色谱-串联质谱(liquid chromatography-tandem mass spectrometry, LC-MS/MS)方法。牛肉样品经80%(V/V)乙腈溶液提取, Prime HLB固相萃取柱净化。采用0.1%甲酸(V/V)-甲醇溶液(A)和0.1%甲酸(V/V)-水溶液(B)进行梯度洗脱, 电喷雾离子源正离子扫描模式(ESI+),多反应监测(MRM),内标法定量。结果表明,加替沙星进样浓度在1～50 ng/mL范围内与峰面积呈良好的线性关系(r₂^＝0.999)；方法检出限和定量限分别为1.0和2.0 μg/kg；在2.0、4.0、20 μg/kg 3个添加水平上,回收率在64.2%～113.4%之间,相对标准偏差为5.0%～9.7%(n=6)。本方法快速、准确、灵敏,适用于牛肉中加替沙星残留量检测。

Determination of gatifloxacin residues in beef by liquid chromatography-tandem mass spectrometry

To establish a method for determination of gatifloxacin in beef by liquid chromatography-tandem mass spectrometric (LC-MS/MS). Beef samples were extracted with 80% (V/V) acetonitrile solution and then the extracts were purified by the Prime HLB solid phase extraction. The gradient elution was carried out with 0.1%(V/V) formic acid methanol (A) and 0.1%(V/V) formic acid water(B). Positive ion scanning mode of electric spray ion source(ESI_⁺), multiple reaction monitoring(MRM), internal standard method were applied for quantitative analysis.There was a good linear correlation between the peak areas and the concentrations of gatifloxacin at the range of 1-50 ng/mL(r_²＝0.999), the limit of detection and limit of quantification was 1.0 and 2.0 μg/kg. The recovery rates were 64.2%-113.4% and the relative standard deviations were 5.0%-9.7% (n=6)at the addition levels of 2.0, 4.0 and 20.0 μg/kg.This method is fast, accurate and sensitive, can be used for determination of gatifloxacin residues in beef.