A spectropolarimetric titrimetric method for the determination of cadmium, mercury, lead and bismuth

✍ Scribed by R.J. Palma Sr.; K.H. Pearson

• Publisher: Elsevier Science
• Year: 1970
• Tongue: English
• Weight: 439 KB
• Volume: 49
• Category: Article
• ISSN: 0003-2670
• DOI: 10.1016/s0003-2670(00)86826-9

✦ Synopsis

Spectropolarimetric titrimetry is a new analytical technique first described by KXRSC~NER ASD BHATNAGAR 1 in X963. A photoelectric polarimeter is used to monitor the change in optical rotation of a solution upon the addition of titrant. A recognizable change in optical rotation of the solution must occur at the titration end-point, Applications of this technique to the determination of metal ions have been limited.

Only three metal ion-ligand titrations have been described to date: the titration of L-( +)-histidine monohydrochloride with copper(II) chloride1, the titration of disodium EDTA with zinc(II) nitrate using L-(+)-histidine as the asymmetric indicator 2, and the titration of D-(--)-I,z-propylenediamine with nickel(II) perchlorate e.

The titrimetric procedures are rapid, simple, and require no external indicators to mark the end-point. A strong stereospecific chelating agent, D-(--)-i,2-propylenediaminetetraacetic acid (D(--)PDTA), was selected as the titrant. It has been estimated that the free energy difference caused by a methyl-acetate interaction in the n~ L o .j