反相高效液相色谱法测定水中的甲基磺草酮农药

建立了二氯甲烷萃取浓缩,反相高效液相色谱测定水样中甲基磺草酮农药含量的分析方法.调节水样pH值为4.0后,以二氯甲烷为萃取剂,25℃下重复萃取两次,萃取时间为15min,旋转蒸发仪浓缩近干,乙腈定容.以SPHERI-5RP-18 （5μm）为色谱柱,乙腈-磷酸缓冲溶液（pH值4.0）为流动相,紫外检测波长为220nm.结果表明,在选定的萃取和色谱条件下,甲基磺草酮测定的线性范围为0.5-100.0mg/L,线性相关系数r为0.9996,标准偏差（SD）为0.46,变异系数（CV）为0.47％,平均加标回收率88.9％,检出限为0.03mg/L.此方法可用于实际水样中甲基磺草酮农药含量的测定.

Determination of Mesotrione in Water by Reversed Phase High Performance Liquid Chromatography

Mesotrioe in water samples was extracted by methylene chloride and determined by reversed-phase high-performance liquid chromatography（RP-HPLC）. After the pH value of the water samples was adjusted to 4 by phosphoric acid or sodium hydoxide solution and then extracted twice by methylene dichloride under 25℃ for 15 min. The extract liquor was evaporated by rotary evaporator nearly dry and dissolved in acetonitrile in constant volume finally. HPLC was used to determine mesotrione with a SPHERI-5 RP-18 column,UV detector at 220nm,and acetonitrile-phosphoric acid aqueous solution（pH= 4.0） as the mobile phase. Results showed that linear range of meotrione was 0.5--100.0 mg/L,and the correlation coefficient r was 0. 9996,the standard deviation （SD） was 0.46,the variation coefficient （CV） was 0. 472% ,the average recovery rate was 88.9 % under the optimum condition.