固相萃取-液相色谱-三重四极杆串联质谱测定养殖废水中17种氟喹诺酮类抗生素

采用固相萃取-液相色谱-三重四极杆串联质谱(SPE-LC-MS/MS)技术，建立了养殖废水中17种氟喹诺酮类抗生素(FQs)的测定方法。水样在采用固相萃取法富集前，先用 0.45 μm 的聚四氟乙烯滤膜过滤，而后加入5%甲醇(体积比)，用盐酸溶液将水样pH调节至2.0±0.5，经固相萃取柱富集，最后用9 mL 0.1%甲酸甲醇洗脱。以C18柱为分离柱，0.1%甲酸−5 mmol·L⁻¹ 甲酸铵水溶液和甲醇为流动相，采用液相色谱－三重四极杆串联质谱多反应监测离子模式(MRM)对目标化合物进行了检测和分析。在优化实验条件下，17种FQs的线性范围为0.50 -100 μg·L⁻¹时，目标化合物峰面积与内标物质峰面积之比与质量浓度的线性关系良好(R²>0.99)，方法检出限为0.08-0.3 ng·L⁻¹。在加标量为0.01 μg·L⁻¹和0.09 μg·L⁻¹时，空白加标的平均回收率为58.6%-104.2% 和65.3%-91.0%，相对标准偏差(RSD)在2.1%-19.3%(n=6)。以养殖废水为基质，17种FQs的加标回收率在47.8%-118.7%，RSD小于20%(n=6)。应用该方法测定了广州某水产养殖场的养殖废水。结果表明，氧氟沙星检出浓度最高(9.36 ng·L⁻¹)，达氟沙星次之(5.96 ng·L⁻¹)。该方法快速、准确，可适用于养殖废水中17种FQs的测定。

Determination of 17 fluoroquinolones antibiotics in aquaculture wastewater using LC-MS/MS coupled with solid phase extraction

A method was developed for the determination of 17 target fluoroquinolones antibiotics (FQs) in aquaculture wastewater by liquid chromatography/tandem triple quadruple bar mass spectrometry (LC-MS/MS), coupled with solid phase extraction (SPE). Before solid phase extraction, samples were filtered by 0.45 μm polytetrafluoroethylene filter membrane, and then 5% methanol (V:V) was added in filtrate and the pH was adjusted to 2.0 with HCl solution. The analytes were efficiently extracted by SPE column and eluted by 9 mL 0.1% formic acid methanol. The separation was performed on a reverse-phase Cl8 column using a mobile phase consisting of 0.1% formic acid-5mmol·L−1 ammonium formate aqueous solution and methanol. All analytes were quantified by LC-MS /MS under multi-reaction monitoring (MRM) mode. Under the optimal conditions, the calibration curves of all 17 targets were linear in the range of 0.5-100μg·L−1 with the correlation coefficients more than 0. 99. The limits of detection (MDL) were 0.08~0.3 ng·L−1.The average recovery rates were in the ranges of 58.6%~104.2% and 58.0%~107.8% and relative standard deviations (RSDs) ranged from 2.1% to 19.3% (n=6) with two spiked levels of 0.01 and 0.09 μg·L−1, respectively. The average recoveries of 17 FQs in the aquaculture wastewater samples were 47.8%~118.7% with RSDs<20% (n=6). A sample of aquaculture wastewater collected from an aquaculture farm in Guangzhou was detected with this method. The results showed that the ofloxacin had the highest detection concentration (9.36 ng·L−1.) in the sample, followed by danofloxacin (5.96 ng·L−1). This method was simple, rapid and accurate, and could be used to detect 17 FQs residues in aquaculture wastewater．