Spanik Ivan, Horvathova Gabriela, Janacova Antonia, Krupcik Jan
Slovak University of Technology, Faculty of Chemical and Food Technology, Institute of Analytical Chemistry, Radlinskeho 9, SK-812 37 Bratislava, Slovak Republic.
J Chromatogr A. 2007 May 25;1150(1-2):145-54. doi: 10.1016/j.chroma.2007.01.070. Epub 2007 Jan 26.
This work focuses on the development of a suitable working procedure for preconcentration of amino acids enantiomers from water samples using a solid phase extraction. The three types of ion exchangers with various capabilities have been used. The effect of experimental conditions in SPE procedure employing strong anion exchange (SAX), weak (WCX) and strong cation exchange (SCX) cartridges (such as sample volume, pH, origin of elution solvent and its volume) on effective preconcentration of the model set of amino acids has been studied in detail. The enantiomers of isolated and preconcentrated amino acids have been analysed by GC on three capillary columns coated with chiral selectors. The different amino acids derivatives have been investigated in order to achieve optimal resolution of biogenic amino acids and their enantiomers. The best separation of amino acid enantiomers has been obtained on a Chirasil-L-Val column analysing their N-TFA methyl esters. It has been shown that SCX-SPE cartridge with sulfonic groups attached on silicagel support is most suitable for isolation and preconcentration of amino acids from water samples. For this sample treatment procedure, the overall recovery of extraction process has been calculated as an average value from three measurements. It has been found, that recoveries are practically identical for both enantiomers of a particular amino acid and varies in the range 75-99% depending on the type of amino acid. The effectivity of this sample preparation and GC method has been verified by preconcentration of amino acids from orange juice fortified by racemic mixture of some selected amino acids.
本工作着重于开发一种合适的工作程序，用于使用固相萃取法从水样中预富集氨基酸对映体。已使用了三种具有不同性能的离子交换剂。详细研究了在采用强阴离子交换（SAX）、弱阳离子交换（WCX）和强阳离子交换（SCX）柱的固相萃取程序中，实验条件（如样品体积、pH值、洗脱溶剂的来源及其体积）对一组模型氨基酸有效预富集的影响。通过气相色谱在三根涂有手性选择剂的毛细管柱上对分离和预富集的氨基酸对映体进行了分析。为了实现生物源氨基酸及其对映体的最佳分离，对不同的氨基酸衍生物进行了研究。在分析其N-TFA甲酯的Chirasil-L-Val柱上获得了氨基酸对映体的最佳分离效果。结果表明，硅胶载体上连接有磺酸基团的SCX-SPE柱最适合从水样中分离和预富集氨基酸。对于该样品处理程序，提取过程的总回收率是通过三次测量的平均值计算得出的。已发现，特定氨基酸的两种对映体的回收率实际上是相同的，并且根据氨基酸的类型，回收率在75%-99%的范围内变化。通过从添加了某些选定氨基酸外消旋混合物的橙汁中预富集氨基酸，验证了该样品制备方法和气相色谱方法的有效性。
