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    固相萃取净化-液相色谱-串联质谱法测定沉积物中五氯酚的含量

    Determination of Pentachlorophenol in Sediment by Solid Phase Extraction Purification and Liquid Chromatography-Tandem Mass Spectrometry

    • 摘要: 针对气相色谱-质谱法测定沉积物中五氯酚时需要衍生化,分析时间长等问题,提出了题示方法。取2.00 g沉积物样品置于50 mL带盖聚丙烯离心管中,加入100 μg·L−113C6-五氯酚同位素内标溶液100 μL,混合均匀,用10 mL含1.0%(体积分数)乙酸的乙腈溶液涡旋振荡5 min,超声提取10 min,离心5 min,并重复提取一次,合并上清液,旋转蒸发至0.5 mL,再用2 mL 75%(体积分数,下同)乙腈溶液复溶,全部通过Captiva EMR-Lipid小柱。过柱后用0.5 mL 75%乙腈溶液润洗,将所有流出液过0.22 μm针式聚四氟乙烯滤膜,在Shim-pack Scepter C18-120色谱柱上分离滤液中的五氯酚,以不同体积比的5 mmol·L−1乙酸铵溶液和乙腈混合液为流动相进行梯度洗脱,以电喷雾离子源负离子模式电离,在多反应监测模式下进行质谱分析。结果表明,五氯酚的标准曲线的线性范围为0.2~20.0 μg·L−1,检出限(3S/N)为0.03 μg·kg−1。按照标准加入法进行回收试验,回收率为88.2%~116%,测定值的相对标准偏差(n=6)小于15%。方法用于分析18个实际沉积物样品,仅1个样品中检出五氯酚,检出量为0.15 μg·kg−1

       

      Abstract: In response to the issues of derivatization and long analysis time required for the determination of pentachlorophenol in sediment by gas chromatography-mass spectrometry, the method mentioned by the title was proposed. The sediment sample (2.00 g) was taken and placed into a 50 mL-polypropylene centrifuge tube with a cap, and 100 μL of 100 μg·L−113C6-labeled pentachlorophenol isotope internal standard solution was added. The mixture was mixed evenly, and then extracted by vortex-mixing for 5 min with 10 mL of acetonitrile solution containing 1.0% (volume fraction) acetic acid, followed by ultrasonic extraction for 10 min and centrifugation for 5 min. This extraction procedure was repeated once. The combined supernatants were concentrated to 0.5 mL via rotary evaporation. The concentrate was reconstituted in 2 mL of 75% (volume fraction, the same below) acetonitrile solution and passed entirely through a Captiva EMR-Lipid cartridge. The cartridge was subsequently rinsed with 0.5 mL of 75% acetonitrile solution. All eluates were filtered through 0.22 μm needle polytetrafluoroethylene filter membrane. Pentachlorophenol was separated on Shim-pack Scepter C18-120 column using a mixture of 5 mmol·L−1 ammonium acetate solution and acetonitrile at different volume ratios as mobile phase for gradient elution. Mass spectrometric analysis was performed using electrospray ionization (ESI) in negative ion mode, operating in multiple reaction monitoring mode. As shown by the results, the linear range of standard curve of pentachlorophenol was 0.2−20.0 μg·L−1, with detection limit (3S/N) of 0.03 μg·kg−1. Test for recovery was made by the standard addition method, giving results in the range of 88.2%−116%, with RSDs of the determined values (n=6) less than 15%. This method was applied to the analysis of 18 actual sediment samples, and pentachlorophenol was detected in only one sample, with detection amount of 0.15 μg·kg−1.

       

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