Dalziel J A, Slawinski A K
Department of Chemistry, Chelsea College of Science and Technology, Manresa Road, London S.W. 3 U.S.A.
Talanta. 1968 Apr;15(4):367-72. doi: 10.1016/0039-9140(68)80244-9.
A new, more stable reagent, S-2-(3-mercaptoquinoxalinyl)thiuronium chloride (MQT), is proposed for the simultaneous absorptiometric determination of cobalt and nickel. It is hydrolysed rapidly to quinoxaline-2,3-dithiol (QDT) in ammonia buffer at pH 10. In the presence of zinc(II), QDT is stabilized by complex formation and the reagent blanks are reduced. Samples containing cobalt(II) and nickel(II) react with the mixture on warming to give 1:3 cobalt and 1:2 nickel complexes, with maximum absorbances at 472 and 520 mmu respectively. The sensitivity of the method is high, 0.0017 and 0.0028 mug cm (2) for cobalt and nickel respectively, and there is a significant improvement in accuracy and precision, which is about +/-1 % over a 15-fold change in cobalt to nickel ratio. The selectivity is moderate; Ag(I), Cu(II), Pd(II), Cd(II), Hg(II), Sn(II), Pb(II), Bi(III) and Pt(IV) cause significant interference but most other common cations and anions can be tolerated.
一种新型、更稳定的试剂，即氯化S - 2 -（3 - 巯基喹喔啉基）硫脲（MQT），被提议用于钴和镍的同时吸光测定。在pH 10的氨缓冲液中，它会迅速水解为喹喔啉 - 2,3 - 二硫醇（QDT）。在锌（II）存在下，QDT通过形成络合物而稳定，试剂空白值降低。含有钴（II）和镍（II）的样品在加热时与该混合物反应，生成1:3的钴络合物和1:2的镍络合物，最大吸收波长分别在472和520毫微米处。该方法灵敏度高，钴和镍的灵敏度分别为0.0017和0.0028微克/厘米²，在钴与镍的比例变化15倍的情况下，准确度和精密度有显著提高，约为±1%。选择性中等；银（I）、铜（II）、钯（II）、镉（II）、汞（II）、锡（II）、铅（II）、铋（III）和铂（IV）会产生显著干扰，但大多数其他常见阳离子和阴离子可以耐受。
