摘要
本实验研究了铅与非水溶性试剂meso-四(4-硝基苯基)卟啉(TNPP)的显色反应。采取分光光度法,测定了温度、酸碱度、辅助络合剂的添加等多个方面的因素对络合物的生成量及稳定性的影响,确定了反应进行的最适条件,建立起一种新型的测定蜂胶原料中铅污染程度的分析方法。实验发现,用邻二氮菲、酒石酸钾钠溶液作联合遮蔽剂,在盐酸羟胺存在的条件下,meso-四(4-硝基苯基)卟啉(TNPP)能与铅生成淡黄色络合物,该反应需在50℃水浴中加热20min即可生成完全。实验测得,该络合物的最大吸收波长在673nm处,络合比为1:1,且当铅含量在0～10μg/ml范围内时,测得的标准工作曲线呈线性关系,相关系数为R=0.9865,服从比尔定律。本实验通过传统的干法灰化法消化样品,以达到富集铅离子的目的,操作简单,重现性好,可将其用于食品中痕量铅的测定,结果令人满意。
The color reaction of lead and non-water soluble reagent meso-tetrakis （4-nitryl） porphyrin （TNPP） was studied for propolis assay with spectrophotometric method. The effects of temperature, pH and time etc. on stability of this complex were assayed. An excellent method that can be used to determine the lead in food or medicine has been ascertained. The experimental results indicated that in the presence of hydroxylamine hydrochloride, with ortho-dinitrogenous ptenanthrene, NH4SCN and seignette saltat as masking agents, meso-tetrakis-（4-nitryl） porphyrin and lead can produce light yellow complex. This response can be produced completly by being heated in 50 ℃ water baths for 20 minutes. A stable 1：1 （M：L） complex forms. The Soret band of the complex is at 673 nm. Beer＇s law is obeyed in the range between 0~10 μg of lead per ml with r=0.9865. In order to achieve the lead ions enrichment, this experiment can be carried into effect through traditional ashing digest method. It is easy to operate and the repeatability is good, so it can be use for the determination of plumbous trace amount in the medicines. The result is satisfactory. This method has also been used to determine the trace of lead in food with satisfactory results.
出处
《食品科学》
EI
CAS
CSCD
北大核心
2007年第7期379-384,共6页
Food Science
基金
河北省自然科学基金资助项目(203147)
