流动体系中维生素B~1的电致化学发光研究

在0.1mol/LNaOH水溶液中(pH12.6),维生素B~1的水解产物在玻碳电极上于+0.88V(vs.Ag/AgCl,下同)处被氧化,其氧化产物在+1.20V处与被氧化的Ru(bpy)~3^2^+反应,生成激发态的Ru(bpy)~3^2^+^*而发光,发光波长为609nm,研究结果表明水溶液的pH值影响了维生素B~1的水解速率,从而引起发光强度的明显差异。

Electrochemiluminescent behaviour of vitamin B~1 (thiamine) and tris (2, 2'-bipyridyl) ruthenium in a flow system

Upon the electrochemical oxidation of tris(2, 2'-bipyridyl) ruthenium(II) Ru(bpy)~3^2^+] and vitamin B~1 (thiamine) in 0.1mol/L NaOH (aqueous solution), a bright electrochemiluminescence (ECL) was observed. Vitamin B~1 was transformed into a yellow pseudo-base and a colorless thiol formed when treated with 0.1mol/L NaOH for 5 and 20min, respectively. The thiol form was oxidized at +0.88V (vs. Ag/AgCl) to produce a free radical, which reacted with Ru(bpy)~3^3^+ at a glassy carbon electrode. The light emission at wavelength 609nm was caused by the transition of the excited state of Ru(bpy)~3^2^+ to its ground state. The pH of solution effected the hydrolysis of vitamin B~1, which caused the different light emission intensity of Ru(bpy)~3^2^+ and vitamin B~1 solution. ECLs of some coexisting substances such as amino acids, sugars, hydroxyl carboxylic acids, vitamin B~2, B~6 were also detected in this flow system.