分光光度法测定大豆中的锌含量  

Determination of Zinc in Soybean by Spectrophotometry

作　　者：金文斌[1] JIN Wen-bin(Department of Chemical and Biological Engineering,Nantong Vocational University,Nantong 226007,China)

机构地区：[1]南通职业大学化学与生物工程学院,江苏南通226007

出　　处：《南通职业大学学报》2018年第3期88-91,共4页Journal of Nantong Vocational University

摘　　要：依据3-[(4,6-二溴-2-羧基苯)偶氮]-6-[(2-胂酸基苯)偶氮]-4,5-二羟基-2,7-萘二磺酸(二溴羧基偶氮胂DBKKA)与Zn(Ⅱ)的显色反应,建立了测定微量锌的光度分析法,讨论了显色反应的最佳条件:在pH=9.5的氢氧化钠-硼砂缓冲溶液中,以溴化十六烷基吡啶(CPB)微乳液为活性剂,二溴羧基偶氮胂(DBKKA)与锌形成稳定的蓝紫色配合物。在最佳测定波长685 nm下,该配合物的表观摩尔吸光系数为6.8×104(L·mol-1·cm-1),锌含量在0~0.6μg/mL范围内符合比尔定律。运用该法测定大豆中的锌含量,相对标准偏差(n=6)为1.4%~2.1%,加标回收率为98%~104%,本法测定结果与原子吸收法测定值相符合。On the basis of the color reaction of Dibromo-carboxy-arsenazo with Zn(Ⅱ),a new spectrophotometric method for the determination of tracing zinc is established and the optimum condition for colour re-action is analyzed.In sodium hydroxide-borax buffer of pH 9.5,Cetyl pyridine bromide(CPB)microemulsion used as active agent,Dibromo-carboxyl-azo-arsone(DBKKA)forms a stable blue-purple complex with zinc.Under the condition of optimal measurement wavelength of 685 nm,the molar absorptivity is 6.8×104 L·mol-1·cm-1.Beer’s law is obeyed for 0~0.6 mg/L for Zn(Ⅱ).The method is applied to determination of Zn(Ⅱ)in soybean,and the values of zinc amount found were checked quite well with the results found by the AAS,RSD of 1.4%~2.1%and recovery of 98.0%~104.0%

关 键 词：二溴羧基偶氮胂 分光光度法 锌含量 溴化十六烷基吡啶 

分 类 号：O657.3[理学—分析化学]