在本文中,我们首次观察到氨基磺酸可以显著增强鲁米诺电化学发光,而且鲁米诺电化学发光的强度随着氨基磺酸浓度在0.1 μmol·L^-1至500 μmol·L^-1范围增加而线性增加。同时,我们观察到多巴胺可以显著猝灭鲁米诺-氨基磺酸电化学发光。基于该猝灭现象,我们建立了多巴胺的电化学发光分析方法,该方法的线性范围为0.5至20 μmol·L^-1,检出限为30 nmol·L^-1。该方法具有较好的选择性,尿酸、抗坏血酸、糖和一些氨基酸对电化学发光影响较小。采用标准加入法,成功地将鲁米诺-氨基磺酸体系用于尿液中多巴胺的电化学发光测定,回收率为103% ~ 105%。另外,我们还考察了多巴胺的猝灭机理,并用Stern-Volmer方程计算了的动态猝灭常数。

Herein, sulfamic acid (SA) was utilized, for the first time, to enhance significantly the luminol electrochemiluminescence (ECL). With the SA concentration increased from 0.1 μmol·L^-1 to 500 μmol·L^-1 the ECL intensity increased proportionally. The developed luminol/SA ECL system was employed to detect dopamine (DA) based on its prominent quenching effect. The Stern-Volmer equation of I_o/I= 1+K_sv[DA] could be applied to express well the quenching mechanism of DA in the luminol/SA ECL system. The calibration plot showed that the increase in the DA concentration from 0.5 to 20 μmol·L^-1 decreased linearly the ECL intensity with a detection limit of 30 nmol·L^-1. The luminol/SA ECL system was successfully carried out for DA detection in urine real sample by employing the standard addition method with the excellent recoveries of 103% ~ 105%. Selectivity of the as-developed ECL system was also investigated by using uric acid, ascorbic acid, sugars and amino acids. The results indicated that the ECL intensities changed negligibly in the presence of other substances.