在pH 5.0的柠檬酸盐缓冲溶液及0.15 mol·L-1 KCl底液中,维生素B1在-1.40 V处出现灵敏的极谱波,据此提出了测定保健食品中维生素B1的快速而灵敏的示波极谱法.在pH 4.7-5.2的范围内,可得到对称的二阶导数峰.峰电流(ip)与维生素B1浓度在0.1-8.0 mg·L-1间呈线性关系,其检出限为0.078 mg·L-1,连续测定6天,每天测定6次,对方法的精密度作了检验,所得结果的日内RSD值小于4.78%,日间RSD值为5.76%,回收率的测得值在920%及107.2%之间,对五种保健食品,用此法及国家标准法分别测定,所得分析结果用t-检验法进行检验,表明相互间无显著差异(t=1.76,P>0.05).

In a citrate buffer of pH 5 and a base solution of 0.15 mol·L-1 KCl,a sensitive polarographic wave of vitamin B1 was observed at -1.40 V.Based on this phenomenon,a rapid and sensitive oscillopolarographic method for the determination of vitamin B1 in hygienic foodstuffs was proposed.In the pH range of 4.7-5.2,a symmetric 2nd derivative peak was obtained.Linear relationship between the peak current (ip) and the concentration of vitamin B1 in the range of 0.1-8.0 mg·L-1 was obtained with a detection limit of 0.078 mg·L-1.The within-day and between-day RSD′s were determined in 6 days successively,and 6 times every day,and the values obtained were less than 4.78% and 5.76% respectively.Recoveries in the range from 92.0% to 107.2% were found.By analyzing 5 foodstuff samples both by the present method and the national standard method,no significant differences were found in the analytical results tested by the t-test (t=1.76,P>0.05).