β-环糊精交联聚合树脂相光度法测定紫菜中痕量Co(Ⅱ)

Determination of trace cobalt(Ⅱ) in laver by β-cyclodextrin polymer resin phase spectrophotometry

以β-环糊精(β-CD)和环氧氯丙烷为交联剂,合成了β-环糊精交联聚合树脂(β-CDP),将钴与水杨醛缩氨基硫脲(HBDHT)形成的有色络合物包结在β-CDP上,采用树脂相分光光度法测定痕量钴(Ⅱ)。确定了最佳测定条件,并对干扰离子及其消除进行了讨论。树脂相上络合物的最大吸收波长为432nm,表观摩尔吸光系数4.23×105L·mol/cm,钴(Ⅱ)的含量在0～700μg/L范围内符合比耳定律,方法检出限为3.34μg/L。方法用于紫菜中钴(Ⅱ)的测定,相对标准偏差小于2.57%,测定过程中无需加入掩蔽剂,结果令人满意。

A new method for the determination of trace Co（Ⅱ） ion by β-cyclodextrin polymer resin phase spectrop-hotometry was developed. The colored complex formed by Co（Ⅱ） ion and hydroxybenzaldehyde thiosemicar-bazone（HBDHT） is concentrated on the β-cyclodextrin polymer resin,and then Co（Ⅱ） ion can be determined directly by the β-cyclodextrin polymer resin at 432 nm. Most other coexisting ions didn’t interfere in the determination. Beer＇s law is obeyed in the range of 0～700 μg/L for Co（Ⅱ） ion. The detection limit is 3.34 μg/L. The method has been successfully applied to determine Co（Ⅱ） ion in laver with RSD of 2.2%～2.6% and recovery of 97.6% ～101.9%.