摘要
在聚乙烯醇(PVA)存在下,丁基罗丹明B(BRB)与铜钨杂多酸形成离子缔合物。缔合物的形成条件为cH2SO4=1.2mol/L,cWO2-4=6.1×10-5mol/L,cBRB=3.8×10-5mol/L和PVA0.08%。缔合物的最大吸收波长位于570nm,摩尔吸光系数ε=1.66×106L·mol-1·cm-1,铜量在每25mL0~0.5μg范围内服从比耳定律,检测限为每mL0.65ng(n=12),对每mL18ngCu测定的RSD为0.85%(n=10)。缔合物至少稳定150h,其摩尔比为Cu∶W∶BRB=1∶12∶5,红外图谱表明铜钨杂多酸具有Keggin结构。考察了40多种共存离子的影响,大多数常见元素不干扰。本法已用于天然水、自来水、降水、人发、中药和蔬菜中铜的测定,结果满意。
A new spectrophotomteric method for the determination of microamounts of copper was studied.The method is based on the reaction of butyl rhodamine B (BRB) cation with tungstocoppate heteropoly acid anion to form an ion association complex in the presence of polyvinyl alcohol (PVA).The optimum concentrations of H 2SO 4,tungstate,BRB and PVA for the determination of copper are 1.2,6.1×10 5,3 8×10 -5 mol/L and 0.08%,respectively,The maximum absorbance of the ion association complex is at 570nm.The apparent molar absorptivity is 1.66×10 6L·mol -1 ·cm -1 .Beer's law is obeyed in the range of 0~0 05μg/25mL for copper .The detection limit is 0.65 μg/mL( n =12) and relative standard deviation is 0.85% ( n =10).The ion association complex was stable for at least 150h.The molar ratio of Cu to W to BRB in the ion association complex was established to be 1∶12∶5.The influence of 45 diverse ions was examined.Most common ions do not interfere.The method can be applied to the spectrophotometric determination of microamounts of copper in some natural waters,running water,precipitation,human hairs,carrot and Coptis with satisfactory results.
出处
《分析试验室》
CAS
CSCD
1997年第6期6-9,共4页
Chinese Journal of Analysis Laboratory
关键词
丁基罗丹明B
铜钨杂多酸
光度法
Butyl rhodamine B
tungstocoppate heteropoly acid
spectrophotometry