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在pH5.7的NaAc-HAc缓冲溶液中,Zn2+与邻菲啰啉(phen)和亮黄(BY)反应生成稳定的离子缔合物[Zn(phen)3]BY,使BY褪色,492 nm处出现正吸收峰,379 nm处出现负吸收峰。选定测量波长为492 nm,参比波长为379 nm,建立了双波长光度法测定微量锌的新方法。表观摩尔吸光系数为3.01×104L.mol-1.cm-1,线性范围为0~1.5μg/mL,检出限为18.5μg/L。方法用于测定锌强化营养盐和健康平衡盐中锌,相对标准偏差为0.69%~0.87%(n=5),回收率为98.4%~99.3%。
In NaAc-HAc buffer solution at pH5.7, Zn2 + reacts with phen and bright yellow (BY) to form stable ion association [Zn (phen) 3] BY, Positive absorption peak appears at 379 nm at the negative absorption peak. A new method of dual-wavelength spectrophotometry for the determination of trace zinc was established with the selected measurement wavelength of 492 nm and the reference wavelength of 379 nm. The apparent molar absorptivity was 3.01 × 104L.mol-1.cm-1, the linear range was 0 ~ 1.5μg / mL and the detection limit was 18.5μg / L. The method was applied to the determination of zinc in zinc fortified salt and healthy balance salt with relative standard deviations of 0.69% -0.87% (n = 5) and recoveries of 98.4% -99.3%.