Ce(Ⅳ)-吐温40-色氨酸化学发光体系的研究与应用

Chemiluminescence Behavior of Ce(Ⅳ)-Tween 40-Tryptophan System and its Application

实验观察到在酸性条件下,色氨酸能够增强Ce(Ⅳ)和吐温40的化学发光反应,其发光强度的增加与色氨酸含量在一定的范围内呈线性关系,据此建立了测定色氨酸的化学发光分析新方法。采用顺序注射技术进样,将试样和试剂的消耗降至微升范围内,明显提高了分析速度。考察了各种实验参数的影响和可能的反应机理,此反应的发光体为Tween40的中间氧化产物。在试样体积70μL、吐温40浓度为5%、试剂Ce(Ⅳ)体积80μL、浓度为1.0mmol/L、检测流速为1.8mL/min的条件下,线性范围为2.0×10-7～1.4×10-5mol/L;检出限(3σ)为8.8×10-8mol/L;对6.0×10-6mol/L色氨酸进行9次测定的相对标准偏差为1.3%。啤酒和血清中色氨酸含量测定的回收率为91.2%～102%。

It was observed that chemiluminescence intensity of the reaction of Ce （Ⅳ） with Tween 40 was greatly enhanced by tryptophan at acidic condition. Based on the observation, a sequential injection procedure with chemiluminescence detection was developed for the determination of tryptophan. The influence of several physical and chemical parameters was evaluated; the possible reaction mechanism was discussed. An intermediate product of Tween 40 oxidized by Ce（Ⅳ） was suggested as the emitter of the reaction. A sample volume of 70μL with Tween 40 of 5% ,a 80 μL of Ce（IV） solution of 1.0 × 10^-3 mol/L,and a 1.8 mL/min of detection flow rate were employed for the determination. Under the selected conditions, an analytical range of 2.0 × 10^-7 - 1.4×10^-5 mol/L, a 30σ detection limit of 8.8 ×10^-8 mol/L and a RSD of 1.3% at 6.0×10^-6 mol/L （n = 9） level was obtained. The method was applied to the determination of tryptophan in amino acid injection, beer and serum, with recoveries of 91.2% - 102%.