摘要
本文利用KBrO3和KBr的氧化还原反应与茶单宁的溴代反应间的速度差异，将动力学分析法与示波电位法结合起来，提出了测定痕量茶单宁的新方法。在0．032mol／LHCl介质中，KBrO3和KBr浓度为0．0005和0．001mol／L时，方法的检出限为3．8μg／L，相对标准偏差为2．8％。调整上述试剂浓度，可使测定范围延伸几个数量级（从ng级到mg级）。该方法灵敏、简便、快速，且不受颜色等干扰。用于饮料、体液和茶树样品中茶单宁的测定，结果与酒石酸铁比色法相差—7．9％～5．5％。
A new method for the determination of tea tannin is developed on the basis of thespeed difference between the redox reaction of bromate with bromide and the bromination of tea tannin and of the combination of oscillographic potentiometry with kinetic analysis. When the concentration of hydrochloric acid, bromate and bromide is 0.032,0. 0005 and 0.001 mol/L respectively, the detection limit is 3. 8 μg/L and the relative standard deviation is 2. 8%. If the concentrations are appropriately adjusted, the determination range can be widened from nanogram to milligram level. The proposed method is sensitive, simple, fast and indifferent to solution color. It has been applied to the determination of tea tannin in beverage, urine, serum and tea tree samplcs. The deviation between the results obtained by this method and by the colorimetry using iron tartrate is -7. 9%~5. 5%.
出处
《分析化学》
SCIE
EI
CAS
CSCD
北大核心
1996年第5期506-509,共4页
Chinese Journal of Analytical Chemistry
