Worobey B L
Health and Welfare Canada, Bureau of Chemical Safety, Ottawa, ON.
J AOAC Int. 1993 Jul-Aug;76(4):881-7.
A liquid chromatographic (LC) method for the determination of diquat and paraquat herbicides/desiccants in potatoes was collaboratively studied in 6 laboratories. Analytes are extracted from 5 g sample with dilute acid by using a microreflux procedure; the hydrolysate is adjusted to pH 9-10 and passed through a disposable silica cartridge for rapid cleanup and preconcentration. Analytes are separated on a reversed-phase LC column and are measured as their heptanesulfonate ion pairs by UV detection. Each collaborator determined diquat and paraquat at 4 levels (0.05, 0.1, 0.5, and 1.0 ppm) in blind duplicate samples plus 2 blind negative control samples. Potatoes, obtained from each participant's region, were spiked by the collaborators with unknown aqueous solutions containing no analyte or a mixture of diquat and paraquat standards. Repeatability and reproducibility relative standard deviations (RSDr and RSDR) averaged 17.1 and 29.0%, respectively, for determination of diquat and 10.8 and 29.5%, respectively, for paraquat. For analysis of standard solutions, RSDr and RSDR values were 6.3 and 12.0%, respectively, for diquat and 7.3 and 13.9%, respectively, for paraquat. Accuracy, measured by comparison with true spiking values (absolute recovery) averaged 77.6 and 76.2% for diquat and paraquat, respectively, and ranged from 71.8 to 88.0% for both compounds. The method was adopted first action by AOAC International.
一种用于测定马铃薯中敌草快和百草枯除草剂/干燥剂的液相色谱（LC）方法在6个实验室进行了协同研究。通过微回流程序用稀酸从5克样品中提取分析物；将水解产物调节至pH 9 - 10，并通过一次性硅胶柱进行快速净化和预浓缩。分析物在反相LC柱上分离，并通过紫外检测作为其庚烷磺酸盐离子对进行测量。每位合作者在重复的盲样以及2个盲样阴性对照样品中，以4个水平（0.05、0.1、0.5和1.0 ppm）测定敌草快和百草枯。合作者用不含分析物或含有敌草快和百草枯标准品混合物的未知水溶液对从每个参与者所在地区获得的马铃薯进行加标。测定敌草快时，重复性和再现性相对标准偏差（RSDr和RSDR）平均分别为17.1%和29.0%，测定百草枯时分别为10.8%和29.5%。对于标准溶液的分析，敌草快的RSDr和RSDR值分别为6.3%和12.0%，百草枯分别为7.3%和13.9%。通过与真实加标值（绝对回收率）比较测得的准确度，敌草快平均为77.6%，百草枯平均为76.2%，两种化合物的范围均为71.8%至88.0%。该方法被美国官方分析化学师协会（AOAC International）首次采用。
