摘要
本文以2-氯-4-硝基苯重氮氨基偶氮苯(CNDAA)为显色剂,研究了镉的高灵敏显色体系及表面活性剂的作用机理。研究结果表明:对于Cd(Ⅱ)-CNDAA配合物,非离子型、阴离子型及阴-非混合型表面活性剂对此有显著的增溶增敏作用;并以Cd(Ⅱ)-ONDAA-SF显色体系建立了光度法测定微量镉的高灵敏新方法,并对几种测定方法进行了比较,筛选出显色条件宽容、选择性好的体系。该体系用于铝合金样品中镉的测定,结果满意。另外,还提出了Gd(Ⅱ)-CNDAA配合物的结构。对表面活性剂对体系的作用作了描述,并阐明了试剂的酸性离解常数(pK_a)与显色酸度以及方法的选择性三者之间的关系。
A highly sensitive color reaction of Cadmium and the action mechanism of surfactants were studied by using 2-chloro-4-nitrobenzenediazoaminoazobenzeno(CND AA) as chromogenic reagent. It was shown that Cd(Ⅱ)-CND AA complex could be solubilized and sensitized by nonionic surfactants, anionic surfactants and nonionicanionic mixed surfactants. Four new methods for spectrophotometric determination of trace Cadmium were built on the system of Cd(Ⅱ)-GND AA-SF. The proposed method has a high sensitivity, good selectivity and a wide acidity range of color reaction and were used for determination of trace Cadmium in ahminium alloy with satisfactory results. Moreover, the structure of Cd(Ⅱ)-OND AA complex was investigated. The relationship between the dissociation constant of reagent(pK_a), acidity of color reaction and the selectivity of neighed were also described.
出处
《化学学报》
SCIE
CAS
CSCD
北大核心
1993年第11期1106-1111,共6页
Acta Chimica Sinica
