Department of Analytical Chemistry, Campus of Rabanales, University of Córdoba, E-14071 Córdoba, Spain.
Talanta. 2012 May 15;93:224-32. doi: 10.1016/j.talanta.2012.02.022. Epub 2012 Feb 17.
This paper describes a new approach for the determination of monocarboxylic, dicarboxylic and tricarboxylic acids (35 compounds) in water. The analytes, in acid medium (pH ≈ 1.3), were sorbed on an 80 mg LiChrolut EN-Supelclean ENVI-18 (1:1) column and subsequently eluted with methanol. After evaporation of the extract to ≈ 10 μL, the analytes were spiked with 60 μL of the derivatising reagent and derivatised in a household microwave oven for 3 min. Among the reagents tested (BF(3)/1-butanol; acetyl chloride/1-butanol; isobutyl chloroformate/1-butanol; trimethylphenylammonium hydroxide, N,O-bis-(trimethylsilyl)acetamide, N,O-bis-(trimethylsilyl)trifluoroacetamide and trimethylchlorosilane), the best results in terms of reaction yield and stability of the derivatives were obtained with the mixture of 1% trimethylchlorosilane in N,O-bis-(trimethylsilyl)trifluoroacetamide. Microwave assisted derivatisation was used as an alternative heating approach for the rapid silylation of carboxylic acids. The proposed method proved to be a suitable analytical procedure for several types of carboxylic acids in water, with limits of detection within the range 0.6-15 ng L(-1), precision values from 4.0 to 6.0% (as within-day relative standard deviation) and recoveries from 93 to 101% for all the target analytes.
本文介绍了一种测定水中单羧酸、二羧酸和三羧酸（35 种化合物）的新方法。在酸性介质（pH ≈ 1.3）中，分析物被吸附在 80mg LiChrolut EN-Supelclean ENVI-18（1:1）柱上，然后用甲醇洗脱。提取液浓缩至 ≈ 10μL 后，用 60μL 衍生试剂进行衍生化，在家庭微波炉中衍生 3 分钟。在测试的试剂中（BF(3)/1-丁醇；乙酰氯/1-丁醇；异丁基氯甲酸酯/1-丁醇；三甲基苯基氢氧化铵、N,O-双（三甲基硅基）乙酰胺、N,O-双（三甲基硅基）三氟乙酰胺和三甲基氯硅烷），用 1%三甲基氯硅烷在 N,O-双（三甲基硅基）三氟乙酰胺中的混合物得到了最好的反应产率和衍生物稳定性。微波辅助衍生化被用作快速硅烷化羧酸的替代加热方法。该方法被证明是一种适用于水中多种类型羧酸的分析方法，检出限范围为 0.6-15ng/L，精密度值在 4.0-6.0%（日内相对标准偏差）之间，所有目标分析物的回收率为 93-101%。
