A high throughput screening method was developed for the simultaneous determination of twenty representative tranquilizers in dairy products using the combination of ultra-performance liquid chromatography -high resolution time-of-flight mass spectrometry and screening database built with Target Analysis software. The protein and fat in the sample was removed using a two-step precipitation of acetonitrile and acidic acetonitrile, and the supernatant was combined and concentrated with Speedvac concentrator. The chromatographie separation was performed on an ACQUITY BEH column with gradient elutin using 0. 1% formic acid and acetonitrile as mobile phase at a flow rate of 0. 3 mL/min. The monitoring of tranquilizers was achieved by time-of-flight mass spectrometry under positive ionization mode in 9 min. The quantification was performed with matrix-matching method. The linear ranges were 1-500 μg/L or 5-1000 μg/L. The LODs and LOQs were 0.3-1.5 μg/L and 1-5 μg/L, respectively. At 5 and 50 μg/L spiked levels, the average recoveries were 76. l%-108.2% with relative standard deviations of 2.5%-9.0%. The screening result for spiked sample showed all the spiked tranquilizers could be correctly identified with low deviations of retention time (< 0. 1 min) and mass (< 3 mDa) and high degrees of isotope pattern match (> 89. 5%). The developed method was further applied for the analysis of 50 real dairy products, and no positive sample was detected.%利用超高效液相色谱/高分辨飞行时间质谱,结合数据库,建立了乳制品中20种镇静剂的高通量筛查方法.样品以乙腈和酸化乙腈沉淀蛋白质和脂肪,冷冻离心浓缩,经超高效液相色谱分离,采用电喷雾离子源,正离子模式,基质匹配法进行定量分析,可在9 min内对20种镇静剂进行高通量筛查和定量分析.镇静剂的质量浓度在l～ 500 μg/L或5～1000μg/L范围内具有较好的线性关系,检出限为0.3～1.5μg/L,定量限为1～5 μg/L.在5和50 μg/L添加水平时,平均回收率为76.1％ ～ 108.2％,相对标准偏差为2.5％～9.0％.利用TargetAnalysis软件建立镇静剂数据库,并应用于加标样品的筛查分析.通过数据库比对,样品中添加的镇静剂被全部筛查出来,鉴定准确度达到了100％,保留时间偏差小于0.1 min,质量偏差小于3mDa,同位素峰形匹配度大于89.5％.利用本方法对购自超市的8个不同品牌的50余份乳制品进行了筛查分析,均未检出阳性样品.
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