期刊
ANALYTICA CHIMICA ACTA
卷 540, 期 1, 页码 3-7出版社
ELSEVIER SCIENCE BV
DOI: 10.1016/j.aca.2004.12.028
关键词
glyphosate; aminomethylphosphonic acid (AMPA); capillary electrophoresis; HPLC; anion-exchange resins; environmental analysis
A previously elaborated capillary electrophoresis (CE) method used for the determination of glyphosate and aminomethylphosphonic acid (AMPA) was slightly modified in order to improve the sensitivity. However, detection limits attained (5 mu g mL(-1) for glyphosate and 4 mu g mL(-1) for AMPA) were still not satisfactory for analytical purposes, thus the addition of a preconcentration step before the CE analysis was proposed. AMBERLITE (R) IRA-900, a strong anion-exchange resin, was used to preconcentrate both analytes in environmental aqueous samples. The experimental conditions optimised in a previous work were readapted, by decreasing the eluent concentration due to CE limitations. Satisfactory results were attained when spiked ultrapure water was applied, with recoveries from 84 to 87% for glyphosate (R.S.D. < 6%) and from 85 to 98% for AMPA (R.S.D. < 5%). Enrichment factors up to 65 were achieved with this system, allowing the determination of 85 ng mL(-1) of Glyphosate and 60 ng mL(-1) of AMPA. The extraction efficiency varied when four different natural water samples of varying conductivity were applied. Especially the strong dependence on ion concentration in samples on AMPA recovery was found. For glyphosate, good recoveries (86-99%) were obtained for samples of low and medium conductivity (0-800 mu S). The effect of sample salt content on extraction efficiency was studied and a linear relationship could be established for AMPA (r(2) = 0.996). An important improvement on recoveries was observed when lower volumes of sample were treated. A HPLC method with UV-vis detection and pre-column derivatisation with p-toluensulphonyl chloride was compared to the CE method. No significant differences in results were found when t- and F-statistical tests were applied. (c) 2004 Elsevier B.V. All rights reserved.
作者
我是这篇论文的作者
点击您的名字以认领此论文并将其添加到您的个人资料中。
推荐
暂无数据