固相萃取/高效液相色谱法测定水中痕量硝磺草酮

Determination of Trace Amounts of Mesotrione in Water by Solid Phase Extraction and High Performance Liquid Chromatography

建立了一种固相萃取/高效液相色谱（SPE/HPLC）测定水中痕量硝磺草酮的方法。水样用磷酸调至p H 3.0-4.0,经C18固相萃取柱富集、乙腈-水（1∶1）洗脱后,用HPLC/紫外检测器测定。测定条件为：流动相为乙腈-磷酸水溶液（45∶55,p H 3.0）,流速0.5 m L/min,色谱柱为Thermo Hypersil-C18柱（250 mm×4.6 mm,5μm）,柱温30℃,检测波长233 nm。结果表明：在0.4-20μg·L^-1范围内,硝磺草酮的线性良好,方法检出限为0.039μg·L^-1。加标浓度为1,5,10μg·L^-1时,硝磺草酮的回收率为90.3%-94.7%,相对标准偏差为3.5%-4.6%。应用该方法测得实际水样中硝磺草酮的加标回收率为89.9%-93.2%。该方法具有快速、简便、灵敏等优点,可用于水样中痕量硝磺草酮的测定。

A solid phase extraction coupled with high performance liquid chromatographic（ HPLC）method was developed for the determination of trace amounts of mesotrione in water. The p H values of the samples were initially adjusted to 3. 0- 4. 0 with phosphoric acid,and then enriched and purified with a C18solid-phase extraction column. The mesotrione fraction was eluted with acetonitrile- water（ 1 ∶ 1） and then concentrated to 10 m L. Mesotrione was determined by HPLC equipped with a Thermo Hypersil- C18column（ 250 mm × 4. 6 mm,5 μm）,by using a mixture of acetonitrile- phosphoric acid solution（ 45 ∶ 55,p H 3. 0） as mobile phase at a constant flow of 0. 5 m L / min. The column temperature was set at 30 ℃ and the wavelength of ultraviolet（ UV） detection was set at 233 nm.The experimental results showed that a good linear relationship（ r 〉0. 999 7） between peak area and mesotrione concentration was obtained in the range of 0. 4- 20 μg·L^- 1. The method detection limit for mesotrione was 0. 039 μg·L^- 1. The average recoveries were in the range of 90. 3%- 94. 7% at spiked levels of 1,5,10 μg·L^- 1with relative standard deviations of 3. 5%- 4. 6%. The method was applied in the determination of trace amounts of mesotrione in surface water and wastewater with recoveries of 89. 9%- 93. 2% at spiked amounts of 5 μg · L^- 1 and 10 μg · L^- 1. The method showed the advantages of simplicity,rapidness and sensitivity,and was suitable for the determination of trace amounts of mesotrione in water.