铅离子选择性电极检测终点间接电位测定大蒜中大蒜辣素含量.pdfVIP

噩fl!.幢噩忡II:!，亨位朋 PTCA( PART B: CHEM. ANAL.) 铅离子选择性电极检测终点间接电位测定 大蒜中大蒜辣素含量 崔铜川，提爱泳l (1.江南大学食品学院，无锡 214036; 2. 盐城工学院，盐城 224003) 摘要:取新鲜蒜瓣试样若千，捣成糊状。称取约 50.00 g ，加浓硝酸 20 mL 处理使其中所含亚 腻a 基氧化成 SC:X一，加水，过滤并定容。分取此滤波一份(约十分之一)，置于漓足杯中，用氢氧化纳 溶液调酸皮至 pH 5-6 ，加入一倍体积的乙醇，以铅离子选择电极指示终点，用铅标准漓走路液进 行电住满足。终点电位预先用二二次微商法求得。方法所测得结果的 RSD 为 0.44% ，且与莹莹法 测定结果相比允显著差异。 关键词:电位漓定法;铅离子选择也极;大昂殊索g 大蒜 中团分类号: 0657.1 文献栋i只码:A 文章编号: 1001-4020(2006)04-0289--0 2 INDIRECT PO丁ENTIOMETRIC 丁ITRA丁ION OF ALLICIN IN GARLIC USING Pb( II) ION SELEC丁lVE ELEC丁RODE AS END POINT INDICATOR CUI Gang1 2 , QIU Ai-yon旷 • (1. Schoolo/ P，∞d Sc的zce ， Jiangna;钝 Uni悦γsity ， Wuxi 2140毡， China; 2. Ya 1Ícheng Institute 0/ E吨ineering ， Yancheng 224003 , China) Abstract: Sample of fresh garlíc was ground into slurry and a definite amount (about 50. 00 g) of the slurry was taken and treated with 20 mL of ∞nc. HN03 to oxidize the sulfoxide in the sample into sulfate ion. The su日pension was diluted with water , filtered and made up to a definìte volume. An alìquot of the filtrate (ca. 1/10) was taken and it acidity adjusted to pH 5-6 with sodium hydroxide solutìon , and an equal volume of 巳thanol was added to the solutíon. Titrate the 段:自由 in the solutíon with standard lead nìtrate titratìng solutìon , using Pb( II )-ìon selective electrode to indicate the end point , the potential of which was determined by the method of 2nd derivation. RSD s of this method was shown as O. 44 %, and no signifìcant difference were found between the r巳sults obtained by this method and by the gravimetric method.