土壤中β-内酰胺类抗生素的全自动固相萃取-超高效液相色谱-串联质谱测定法

Determination of β-lactam antibiotics residues in soil by ultra performance liquid chromatography tandem mass spectrometry after automatic solid phase extraction

目的建立土壤中5种β-内酰胺类抗生素（氨苄西林,阿莫西林、青霉素G、头孢噻呋、头孢噻肟）的全自动固相萃取-超高效液相色谱-串联质谱（SPE-UPLC-MS-MS）测定方法。方法土壤样品经乙腈-磷酸盐缓冲溶液（0.2 mol/L,p H 8.0）（体积比为1∶1）的提取液（含0.1 mol/L乙二胺四乙酸二钠）超声提取,经SAX-HLB串联固相萃取柱净化,以C18超高效色谱柱分离,乙腈-水为流动相,采用串联质谱电喷雾离子源（ESI）,在多反应监测正离子模式下测定,外标法定量。结果在2～200μg/L的浓度范围内,所得5种β-内酰胺类抗生素回归方程的线性关系良好,r〉0.999。方法检出限为0.56～3.63μg/kg,平均回收率在63.1%～118.5%之间,RSD在3.4%～15.7%之间。结论该方法高效、准确、灵敏度高,选择性好,适用于土壤样品中5种β-内酰胺类抗生素的测定。

Objective To develop a method for determining five β-lactam antibiotics residues in soil by ultra liquid chromatography-tandem mass spectrometric after antomatic solid phase extraction. Methods The samples were extracted with extraction solution[acetonitrile-PBS（0.2 mol/L, p H 8.0）（V∶V=1∶1）] containing 0.1 mol/L EDTA and purified by SAX and HLB SPE column.The analytes were separated by Ultra C18 and eluted by acetonitrile and water mobile phase. UPLC-MS/MS analysis was conducted on multiple reaction monitoring mode under positive ion electrospray ionization with the external method. Results The linear range was 2-200 μg/L. The correlation coefficient for each compound was higher than 0.999. The limits of detection were 0.56-3.63 μg/kg. Average recoveries of standard addition were 63.1%-118.5% and RSDs were 3.4%-15.7%. Conclusion The method is efficient,accurate,sensitive and applicable to the determination of five β-lactam antibiotics residues in soil.