Tong Lei, Liu Hui, Xie Cong, Li Minjing
School of Environmental Studies, China University of Geosciences, 430074 Wuhan, PR China.
School of Environmental Studies, China University of Geosciences, 430074 Wuhan, PR China.
J Chromatogr A. 2016 Jun 24;1452:58-66. doi: 10.1016/j.chroma.2016.05.027. Epub 2016 May 7.
A highly effective analytical method for multi-residue determination of antibiotics in aquifer sediments was first established in this study. Microwave-assisted solvent extraction (MASE) and solid-phase extraction were used for sample pre-concentration and purification, ultra-high performance liquid chromatography coupled to hybrid quadrupole-high resolution Orbitrap mass spectrometry (UHPLC-Q-Orbitrap) was applied for detection. For high resolution mass spectrometry (HRMS), the target compounds were tentatively identified by retention time and accurate mass which was measured with precursor ions in Target-SIM scan, and then confirmed by the monitoring of daughter ion fragments which were generated in dd-MS(2) scan. The results provided good mass accuracy with mass deviations below 2ppm (except norfloxacin with -2.3ppm) for quantitative analysis of the compounds by HRMS. Reasonable recoveries of all analytes were obtained more than 60% (except doxytetracycline) in fortification samples at concentrations higher than 10μgkg(-1). Relative standard deviations of repeatability and inter-day precision were below 21% and 11%. Limits of detection (LOD) ranged from 0.1 to 3.8μgkg(-1), whereas limits of quantification (LOQ) were established between 0.3-9.0μgkg(-1). The method was applied to analyze real aquifer sediment samples in different aquifer depth of 4.0, 7.5, 13.0 and 18.0m. Chlorotetracycline and ofloxacin were observed at relative high concentrations of 53 and 19μgkg(-1) respectively in 18.0m deepness. The exposure to low doses of these compounds in subsurface environment increases concerns on long-term ecological security of underground system.
本研究首次建立了一种高效的分析方法，用于测定含水层沉积物中的多种抗生素残留。采用微波辅助溶剂萃取（MASE）和固相萃取进行样品预浓缩和净化，应用超高效液相色谱-四极杆-高分辨轨道阱质谱联用仪（UHPLC-Q-Orbitrap）进行检测。对于高分辨质谱（HRMS），目标化合物通过保留时间和精确质量进行初步鉴定，精确质量在目标选择离子监测（Target-SIM）扫描中以前体离子进行测定，然后通过在数据依赖二级质谱（dd-MS(2)）扫描中监测产生的子离子碎片进行确认。通过HRMS对化合物进行定量分析时，结果提供了良好的质量准确性，质量偏差低于2ppm（诺氟沙星除外，为-2.3ppm）。在浓度高于10μgkg(-1)的加标样品中，所有分析物的回收率均合理，超过60%（多西环素除外）。重复性和日间精密度的相对标准偏差分别低于21%和11%。检测限（LOD）范围为0.1至3.8μgkg(-1)，而定量限（LOQ）设定在0.3 - 9.0μgkg(-1)之间。该方法应用于分析不同含水层深度（4.0、7.5、13.0和18.0m）的实际含水层沉积物样品。在18.0m深度处分别观察到相对高浓度的金霉素和氧氟沙星，浓度分别为53和19μgkg(-1)。在地下环境中接触低剂量的这些化合物增加了对地下系统长期生态安全的担忧。
