Multiparametric analysis of amino acids and organic acids in rat brain tissues using GC/MS

Using design of experiment (DOE) theory coupled with multivariate statistical analysis, we have developed a simple and reliable GC/MS-based analytical assay for simultaneous analysis of amino acids and organic acids in rat brain tissue samples. The process of water extraction (pH 10.0) was extensively evaluated using brain tissue samples and a set of 21 reference standards. Acceptable calibration curves were obtained over a wide concentration range, 0.2-35.0 microg/mL for standards and 15.0-2.4 mL/g (tissue) for brain tissue samples. The precision was mostly better than 10% for both the mixed standards and the brain tissue samples. The brain tissue samples exhibited good stability within 48 h with RSD generally less than 15%. Furthermore, the developed analytical method was successfully applied in distinguishing the subtle variation among different parts of the brain tissues, such as cerebral cortex, hippocampus, and thalamus.