以全自动固相萃取-超高效液相色谱-串联质谱法测定医化园区周边地表水中地塞米松、泼尼松、炔诺酮、炔雌醇、甲睾酮和米非司酮的残留量。随机采集医化园区周边地表水样,除杂后置于棕色广口瓶中,将其酸度调至pH 7。分取500 mL水样,以10 mL·min^-1流量过活化好的HLB固相萃取柱,用20%(体积分数)甲醇溶液15 mL洗脱,收集洗脱液,于50℃氮吹至近干,残渣用甲醇复溶并定容至1 mL,涡旋30 s,按照优化的仪器工作条件测定。以Agilent Zorbax Eclipse Plus C₁₈色谱柱为固定相,以不同体积比的1 mmol·L^-1乙酸铵溶液和乙腈的混合溶液为流动相进行梯度洗脱,分离所得目标物用三重四极杆串联质谱仪在电喷雾离子源负离子模式以及多反应监测模式下检测,外标法定量。结果显示,6种目标物的质量浓度均在0.005~5 mg·L^-1内与其对应的峰面积呈线性关系,检出限(3S/N)分别为0.24,0.14,0.51,0.16,0.21,0.08 μg·L^-1;对实际样品进行3个浓度水平的加标回收试验,6种目标化合物的回收率为83.9%~105%,测定值的相对标准偏差(n=5)为2.7%~4.1%,在样品中检出了地塞米松和炔雌醇,检出量分别为0.75,1.27 μg·L^-1。

Residues of dexamethasone, prednisone, norethindrone, ethinylestradiol, methyltestosterone and mifepristone in surface water around medical and chemical park by ultra-high performance liquid chromatography-tandem mass spectrometry with automatic solid phase extraction (SPE). Surface water sample around medical and chemical park was randomly collected, and impurities in which were removed. The solution obtained was placed in a brown jar, and its acidity was adjust to pH 7. An aliquot (500 mL) of the water sample was passed through HLB SPE column activated beforehand at flow rate of 10 mL·min^-1, and the column was eluted with 15 mL of 20% (volume fraction) methanol solution. The eluate was collected and blown to nearly dry by nitrogen at 50 ℃, and the residue was redissolved and diluted to 1 mL with methanol. After mixing by vortex for 30 s, the mixed solution was analyzed by the optimized instrument working conditions. Agilent Zorbax Eclipse Plus C₁₈ column was used as the stationary phase, and the mixed solutions composed of 1 mmol·L^-1 ammonium acetate solution and acetonitrile at different volume ratios were used as mobile phase for gradient elution. The separated targets were detected by triple quadrupole tandem mass spectrometer in electrospray ion source negative ion mode and multiple reaction monitoring mode, and quantified by external standard method. It was shown that linear relationships between values of the peak area and the mass concentration of the 6 targets were kept in the same range of 0.005-5 mg·L^-1, with detection limits (3S/N) of 0.24, 0.14, 0.51, 0.16, 0.21, 0.08 μg·L^-1, respectively. Test for the spiked recovery was made on actual samples at the 3 concentration levels, giving recoveries of the 6 targets in the range of 83.9%-105%, with RSDs (n=5) of the determined values ranged from 2.7% to 4.1%, and dexamethasone and ethinylestradiol were detected at 0.75, 1.27 μg·L^-1 in the sample, respectively.