Department of Agricultural Chemistry, C-3 Building, Campus of Rabanales, University of Córdoba, E-14071 Córdoba, Spain.
Talanta. 2010 Oct 15;82(5):1757-62. doi: 10.1016/j.talanta.2010.07.068. Epub 2010 Aug 4.
The evidence that glyoxylate is a biomarker of tolerance or susceptibility to the action of herbicides belonging to the glycine family makes necessary to develop simple methods for the determination of this metabolite. Glyoxylate level allows both to know the presence/absence of members of the glycine family in plants and plant response to these herbicides. With this aim, a colorimetric-screening method has been developed for determination of glyoxylate based on formation of a phenylhydrazone, then oxidised to red coloured 1,5-diphenylformazan. Simultaneous optimization of ultrasound-assisted extraction of glyoxylate from plants and derivatization by a multivariate design has allowed the determination of the target analyte in fresh plants without interferences from pheophytines and compounds with carbonyl groups. Limits of detection and quantification are 0.05 μg ml(-1) and 0.17 μg ml(-1), respectively, with precision, expressed as relative standard deviation, of 3.3% for repeatability and 5.6% for the within-day laboratory reproducibility. Only 50mg of plant is necessary for determination of glyoxylate within 32 min. Confirmatory analysis by capillary electrophoresis-diode array detection in samples of Lolium spp. subjected to treatment with glyphosate shows that the relative error of the proposed method is always lower than 7%.
草甘膦是甘氨酸类除草剂作用的耐受性或敏感性的生物标志物，这一证据使得开发用于测定该代谢物的简单方法变得非常必要。草酰乙酸水平不仅可以确定植物中甘氨酸类化合物的存在/不存在，还可以了解植物对这些除草剂的反应。为此，开发了一种基于草酰乙酸与苯肼形成苯腙，然后被氧化为红色 1,5-二苯基甲腙的比色筛选法来测定草酰乙酸。通过多元设计同时优化植物中草酰乙酸的超声辅助提取和衍生化，使得可以在没有叶绿素和含羰基化合物干扰的情况下，在新鲜植物中测定目标分析物。检测限和定量限分别为 0.05μg/ml 和 0.17μg/ml，精密度（以相对标准偏差表示）为重复性 3.3%，日内实验室重现性 5.6%。仅需 50mg 植物即可在 32 分钟内测定草酰乙酸。对用草甘膦处理的 Lolium spp.样品进行毛细管电泳-二极管阵列检测的确认分析表明，所提出方法的相对误差始终低于 7%。
