Department of Analytical Chemistry, Campus of Rabanales, University of Córdoba, E-14071 Córdoba, Spain.
J Chromatogr A. 2010 Nov 19;1217(47):7440-7. doi: 10.1016/j.chroma.2010.09.075. Epub 2010 Oct 7.
A novel analytical method is reported that combines continuous solid-phase extraction and gas chromatography for the determination of 22 carboxylic acids in water. The highly polar and hydrophilic analytes were preferentially sorbed on a mixture of LiChrolut EN-Supelclean ENVI-18 (1:1) sorbent column and eluted with methanol; this extraction process did not require derivatisation. The extract was analysed by gas chromatography coupled to a flame ionisation detector as well as a mass spectrometer with electron impact (EI) or positive chemical ionisation modes. The highest sensitivity was achieved when using MS-EI, with good linearity in calibration curves and low detection limits (2-40ngL(-1)) for 50mL of sample. The entire procedure from raw aqueous sample to a ready-to-inject methanol solution of the acids requires less than 15min. Another benefit of this method is the good accuracy (recoveries between 93 and 102%) and precision (relative standard deviation, 3.4-6.2%), which allows the determination of carboxylic acids in environmental water and in real chlorinated and ozonated drinking water.
一种新的分析方法被报道，它结合了连续固相萃取和气相色谱法，用于测定水中的 22 种羧酸。高度极性和亲水性的分析物优先被 LiChrolut EN-Supelclean ENVI-18（1:1）混合吸附剂柱吸附，并用甲醇洗脱；这个提取过程不需要衍生化。提取物通过气相色谱与火焰离子化检测器以及电子轰击（EI）或正化学电离模式的质谱仪进行分析。当使用 MS-EI 时，灵敏度最高，校准曲线具有良好的线性，对于 50mL 样品，检测限低至 2-40ngL(-1)。从原始水样到可直接注入甲醇的酸溶液的整个过程不到 15 分钟。该方法的另一个优点是良好的准确性（回收率在 93%到 102%之间）和精密度（相对标准偏差为 3.4-6.2%），这允许在环境水以及实际氯化和臭氧化饮用水中测定羧酸。
