Turiák G, Volicer L
Department of Pharmacology, Boston University School of Medicine, MA 02118.
J Chromatogr A. 1994 May 13;668(2):323-9. doi: 10.1016/0021-9673(94)80121-5.
RP-HPLC coupled with 16-channel coulometric electrode array detection was used to monitor the decomposition of five amino acid o-phthalaldehyde (OPA)-sulfite derivatives (Ala, Arg, Glu, Ser, Tyr) and their methyl ester derivatives as well. At fixed OPA and sulfite concentrations inclusion of methanol and EDTA in the derivatization media has increased most effectively the room temperature stability of both derivatives measured at pH 9.2 (amino acids) and pH 8.2 (methyl esters). Decreases in product concentrations by 6% have occurred after more than 15 h for amino acid derivatives and 8 h for methyl ester derivatives. The oxidation potential maxima for OPA-sulfite derivatives of amino acids were found at 600 mV while the same methyl ester derivatives had 60-120 mV higher maxima with the exception of tyrosine. The detector responses were found to be linear in the studied 0.1-10 microM concentration range for both derivative forms and their detection limit was 100-200 fmol injected on the column. The RP-HPLC retention of amino acid methyl ester OPA-sulfite derivatives was very similar to the amino acid OPA-2-mercaptoethanol ones while the more polar amino acid OPA-sulfite derivatives were eluted earlier (k' < 1) under the same chromatographic conditions.
采用反相高效液相色谱（RP-HPLC）结合16通道库仑电极阵列检测法，监测5种氨基酸邻苯二甲醛（OPA）-亚硫酸盐衍生物（丙氨酸、精氨酸、谷氨酸、丝氨酸、酪氨酸）及其甲酯衍生物的分解情况。在固定的OPA和亚硫酸盐浓度下，在衍生化介质中加入甲醇和乙二胺四乙酸（EDTA），最有效地提高了在pH 9.2（氨基酸）和pH 8.2（甲酯）条件下测得的两种衍生物的室温稳定性。氨基酸衍生物在15 h以上、甲酯衍生物在8 h以上后，产物浓度下降了6%。氨基酸的OPA-亚硫酸盐衍生物的氧化电位最大值出现在600 mV，而相同的甲酯衍生物除酪氨酸外，最大值高60 - 120 mV。在所研究的0.1 - 10 microM浓度范围内，两种衍生物形式的检测器响应均呈线性，其检测限为进样到柱上100 - 200 fmol。氨基酸甲酯OPA-亚硫酸盐衍生物的RP-HPLC保留情况与氨基酸OPA-2-巯基乙醇衍生物非常相似，而在相同色谱条件下，极性更强的氨基酸OPA-亚硫酸盐衍生物洗脱较早（k' < 1）。
