整体柱高效液相色谱法测定草甘膦原药中甲醛含量

建立了衍生化-高效液相色谱法对草甘膦原药中痕量甲醛含量进行测定的方法。样品中残留甲醛经超声波水浴提取，与2，4-二硝基苯肼衍生反应，生成的2，4-二硝基苯腙用反相整体柱色谱进行快速分离，在360nm紫外波长下检测，外标法定量。该分析方法在2．0～200mg/L浓度范围呈良好线性，添加回收率在88％～105％之间，相对标准偏差小于5％。样品中甲醛的最小检测浓度为0．5mg/kg。比较了整体色谱柱和常规C18反相柱分离效果，表明整体色谱柱可在1．5min内实现衍生化产物的快速分离并进行定性定量，同时发现相对于常规柱，采用整体柱提高了检测灵敏度约10倍。

Determination of Formaldehyde in Glyphosate Technical by Monolithic C18 Flash Column Separation and Ultraviolet Detection

An analytical method for determination of formaldehyde impurity in glyphosate technical by offline derivatization-high performance liquid chromatography (HPLC) was developed. The sample was resolved in acetonitrile-water and derivatized with 2,4-dinitrophenyl hydrazine at pH 2.0 and then extracted under ultrasonic bath. The derivatized product was separated on a Merk Co. monolithic flash column (4.6 mm150 mm) with mobile phase consisting of acetonitrile: water (5545, V/V) , flow rate of 3 mL/min and detected by ultraviolet detection at 360 nm. Formaldehyde was determined by a reversed phase HPLC monolithic flash column, off-line derivatization with hydrazine reagent and ultraviolet (UV) detection at 360 nm. The method was shown to be simple, rapid and practical. The method was validated from 2.0 to 200 mg/L with satisfied linear relationship. The recovery rates were between 88% to 105%, with less than 5% of relative standard (deviation). The detection limit is 0.5 mg/L. A comparison was undertaken for regular C_(18) and monolithic (column) in separation time and limit of detection (LOD). With the monolithic column, lower LOD can be (obtained), and the analytical time reduced to 1.5 minutes.