Sequential Injection Photometric Determination of Molybdenum Using Organic Wetting Film Extraction

✍ Scribed by Shigenori Nakano; Yongyi Luo; David Holman; Jaromir Ruzicka; Gary D. Christian

• Book ID: 102618299
• Publisher: Elsevier Science
• Year: 1997
• Tongue: English
• Weight: 89 KB
• Volume: 55
• Category: Article
• ISSN: 0026-265X
• DOI: 10.1006/mchj.1996.1401

✦ Synopsis

Wetting film extraction was combined with colorimetry to determine nanogram amounts of molybdenum(VI). The simple extraction procedure enhanced sensitivity and selectivity while maintaining a high sample throughput. Extraction and back extraction steps were exploited to exclude interference from the 31 metal species and 11 anions tested. In the first step, molybdenum(VI) was extracted into a toluene film as an ion paired complex. Molybdenum(VI) reacted with thiocyanate to form anionic molybdenum(V) and/or molybdenum(VI) thiocyanate complexes. The complexes were extracted into a toluene film containing tetraheptylammonium bromide as ion pairing reagent. The thiocyanate ligands were displaced by 1,5-diphenylcarbazone (DPC) to form a more intensely colored complex (l max Å 540 nm). DPC was introduced in the back extraction solvent, methanol. The relative standard deviation was 2.5% for 50 ng ml 01 of molybdenum(VI) (n Å 10) at a rate of 25 samples h 01 . The detection limit (3 1 baseline noise) was 2.5 1 10 08 M.