| Summary: | 碩士 === 高雄醫學大學 === 藥學研究所 === 91 === Analytical derivatization coupled with high-performance liquid chromatography was used for the analysis of isovaleric and valeric acids as biomarkers in metabolic acidosis or as malodorant in organic pollution. The method is based on the derivatization of isovaleric acid and valeric acid with 2-(2-naphthoxy)ethyl 2-(piperidino) ethanesulfonate (NOEPES) in toluene, using potassium carbonate and 18-crown-6 ether as reaction activators. The resulting naphthoxyethyl derivative of isovaleric acid and valeric acid were separated on a C-18 column, using a mixed solvent of methanol : water : tetrahydrofuran (72：22：6, v/v) as the mobile phase. The separated isovaleric acid and valeric acid derivatives were monitored with a fluorimetric detector (lex: 235nm; lem: 350nm), and the peak-areas of isovaleric and valeric acids derivatives were used for quantitative analysis.
The linear range of the method for the determination of isovaleric acid and valeric acid derivative were over 0.5 ~ 10.0 mM. The detection limit (signal to noise ratio = 3, injected amount 20 mL) of isovaleric acid and valeric acid was about 0.07 mM. Several parameters affecting the derivatization of isovaleric and valeric acids were discussed including amount of derivatization reagent, reaction temperature, reaction time, and base catalyst. Application of the method to the analysis of isovaleric and valeric acids in urine is in procession.
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