在HAc-NaAc缓冲溶液中,葡萄糖氧化酶(COD)催化葡萄糖与溶解氧反应生成H2O2;辣根过氧化物酶(HRP)催化H2O2氧化过量的KI生成I3-,I3-分别与罗丹明S(RhS),罗丹明6G(Rh6G),丁基罗丹明B(b-RhB),罗丹明B(RhB)结合形成缔合物微粒,使得4体系分别在556,556,584和584nm处的荧光峰强度线性降低。在最佳条件下,葡萄糖的浓度分别在0.0839.99,0.17~8.33,0.33~8.33,0.33~9.99μmol·L^-1范围内与RhS,Rh6G,b-RhB,RhB四体系的荧光猝灭强度呈良好的线性关系,其回归方程、相关系数、检出限分别为△F=40.0c+3.0,△F=23.9c+8.1,△F=25.6c+4.2,△F=18.4c+0.8;0.9951,0.9973,0.9960,0.9965;0.059,0.17,0.21,0.16μmol·L^-1RhS催化体系最灵敏、稳定,将其用于人血清中葡萄糖的检测,结果满意。
In acetate buffer solution and in the presence of glucose oxidase (GOD), glucose reduced the dissolved oxygen to form H2 02 that oxidized catalytically the excess KI to from I3- by horseradish peroxidase (HRP). The I3- combines respectively with rhodamine S (RhS), rhodamine 6G(Rh6G), butyl-rhodamine B(b-RhB) and rhodamine B(RhB) to form RhS-Ia, Rh6G-I3, b-RhB-I3 and RhB-I3 associated particles that result in fluorescence quenching at 556, 556, 584 and 584 nm, respectively. Under the optimal conditions, the concentration of glucose in the range of 0. 083-9.99, 0.17-8.33, 0. 33-8. 33 and 0. 33-9.99μmol·L^-1 is linear with their fluorescence quenching at 556, 556, 584 and 584 nm, with detection limits of 0. 059, 0.17, 0. 21 and 0. 16μmol·L^-1 glucose. And the regression equation was △F=40.0c+3.0,△F=23.9c+8.1,△F=25.6c+4.2,△F=18.4c+0.8, respectively. The RhS system was the most sensitive and stable, and was chosen for use. Influence of some foreign substances on the RhS fluorescence quenching determination of 6.67 μmol·L^-1 glucose was examined, with a relative error of ~ 10M. Results showed that 1 000-fold Mg2+ and Cu2+ , 300-fold Mn2+ , 100-fold Zn2+ , AP+ and Co2+ , 60-fold L-tyrosine, urea and nicotinic acid, 50-fotd Fe3+ , HSA and BSA, 10-fold sucrose, vitamin 132, L-lysine, L-glutamic acid and L-cystine did not interfere with the determinatiorL This RhS fluorescence quenching assay was applied to the determination of glucose in the serum samples with satisfactory results.