摘要
在阿拉伯树胶存在下,在pH 5.7 HAc-NaAc缓冲溶液中,Zn(Ⅱ)与硫氰酸钾和中性红(NR)反应生成稳定的离子缔合物[NR]4[Zn(SCN)6],使NR退色,在462 nm处出现正吸收峰,575 nm处出现负吸收峰。选定测定波长为462和575 nm,建立了双波长光度法测定微量锌。结果表明:锌含量在0.0～1.0μg/mL内符合比尔定律,表观摩尔吸光系数为5.67×104 L.mol-1·cm-1,方法用于测定电镀废水中微量锌,结果与5-Br-DMPAP光度法相符。实际样品分析结果的相对标准偏差<4%,加标回收率为98.0%～102.5%。
A new method for determination of trace zinc by double-wavelength spectrophotometry was developed using 462 nm and 575 nm as the detection wavelength.In presence of arabic gum,Zn（Ⅱ） reacts with potassium thiocyanate and neutral red（NR） to form a stable ion-association complex 4[Zn（SCN）6] in HAc-NaAc buffer solution at pH 5.7,which leads to the fading of NR.As a result,there were a positive absorption peak at 462 nm and a negative absorption peak at 575 nm.The results showed that Beer′s law was obeyed in range of 0.0～1.0 μg/mL for zinc,and its apparent molar absorptivity of 5.67×104 L·mol-1·cm-1.when this method was applied to the determination of trace zinc in electroplating wastewater,the results were in good agreement with those provided by 5-Br-DMPAP spetrophotometric method.The relative standard deviation was less than 4% and the recoveries of samples were between 98.0% and 102.5%.
出处
《化学试剂》
CAS
CSCD
北大核心
2011年第7期637-639,共3页
Chemical Reagents
关键词
双波长分光光度法
锌
中性红
离子缔合物
电镀废水
double-wavelength spectrophotometry
zinc
neutral red
ion-association complex
electroplating wastewater
