摘要：
在pH=5.7的NaAc-HAc缓冲溶液中,Cd2+与邻菲啰啉(phen)和刚果红(CR)反应生成稳定的离子缔合物[Cd(phen)3](CR)2,体系吸光度明显增强,建立了分光光度法测定痕量镉的新方法。试验了酸度、试剂用量、表面活性剂、反应温度和时间的影响,确定了最佳反应条件。最大吸收峰位于561 nm。镉质量浓度在0～2.5 mg/L范围内符合比尔定律,表观摩尔吸光系数为4.51×104 L/(mol·cm),检出限为19.6μg/L。采用巯基棉分离富集,测定化工废水中的镉,相对标准偏差为0.34%～0.94%(n=5),回收率为97.3%～102.5%。
关键词:
分光光度法,
镉,
离子缔合物,
邻菲啰啉,
刚果红
Abstract:
A new method for the determination of trace cadmium by spectrophotometry has been developed.The method is based on the reaction of Cd2+ with phen and congo red(CR) to form a stable ion-association complex [Cd(phen)3](CR)2 in NaAc-HAc buffer solution at pH=5.7,which results in great enhancement of absorbance with the maximum absorption peak at 561 nm.The effects of acidity,reagent dosage,surfactant,reaction temperature and time are examined,and the optimum reaction conditions for the determination of trace Cadmium are confirmed.When the cadmium concentration is in the range of 0-2.5 mg/L,it accords with Beer’s law.The molar absorption coefficient is 4.51×104 L/(mol·cm) and its detection limit is 19.6 μg/L.After separation and enrichment with sulfhydryl cotton,the cadmium in chemical industrial wastewater is determinated.RSDs are 0.34%-0.94%(n=5),and recovery rates are 97.3%-102.5%
Key words:
spectrophotometry,
cadmium,
ion-association complex,
phen,
congo red
中图分类号:
李人宇, 李咏梅, 卢洋, 黄勇波. 离子缔合体系分光光度法测定化工废水中的镉[J]. 工业水处理, 2010, 30(9): 69-72.
Li Renyu, Li Yongmei, Lu Yang, Huang Yongbo. Spectrophotometric determination of cadmium in chemical industrial wastewater with ion-association system[J]. INDUSTRIAL WATER TREATMENT, 2010, 30(9): 69-72.