Novel Reactions for the Simple and Sensitive Spectrophotometric Determination of Traces of Selenium in Environmental Samples

✍ Scribed by Kailasa Suresh Kumar; Kanchi Suvardhan; Lingaladinne Krishnaiah; Pattium Chiranjeevi

• Publisher: John Wiley and Sons
• Year: 2005
• Tongue: German
• Weight: 72 KB
• Volume: 88
• Category: Article
• ISSN: 0018-019X
• DOI: 10.1002/hlca.200590018

✦ Synopsis

Two rapid, highly sensitive, and selective spectrophotometric methods for the determination of traces of selenium(IV) were studied. The methods are based on either the oxidation of 4-aminoantipyrine ( 4-amino-1,2-dihydro-1,5-dimethyl-2-phenyl-3H-pyrazol-3-one; 4-AAP; 1) by selenium in basic medium and coupling with N-(naphthalen-1-yl)ethane-1,2-diamine dihydrochloride (NEDA; 2 ´2 HCl) to give a violet derivative 3 or on the oxidation of dopamine hydrochloride ( 4-(2-aminoethyl)benzene-1,2-diol hydrochloride; DPH; 4 ´HCl) by selenium in H 2 SO 4 medium and coupling with 1 to yield a red derivative 5 (see Scheme). The violet derivative 3 with l max 563 nm is stable for 8 days and the red derivative 5 with l max 495 nm for more than a week. Beers law is obeyed for selenium in the concentration range 0.03 ± 3.5 mg ml À1 (violet derivative 3) and 0.07 ± 2.5 mg ml À1 (red derivative 5), respectively. The optimum reaction conditions and other important analytical parameters were established. Interference due to various non-target ions were also investigated. The proposed methods, were applied to the analysis of selenium in polluted water, natural water, plant material, soil samples and synthetic mixtures. The results of the analyses were superior in precision to those obtained by reported methods.