Chemiluminescence of cobalt(II)-catalysed auto-oxidation of sulphite and its application to cobalt analysis.
The oxidation of sulphite by dissolved oxygen in aqueous solution catalysed by cobalt(II) was investigated. A weak chemiluminescence (CL) emission was observed when the reaction took place in a strong alkaline solution without any special CL reagent. Further studies showed that in the presence of fluorescein sodium the CL signal was enhanced significantly. The CL emission is linear with Co(II) concentration in the range 0.6-80 nmol/L and the detection limit is 0.3 nmol/L. In addition to Co(II), other transition metal ions were also tested, and the results showed that the proposed system was highly selective for Co(II). The method was successfully applied to the determination of Co(II) in pharmaceutical preparations. The possible CL mechanism was also discussed.
Yang
Xiao-Feng
XF
Institute of Analytical Science, Northwest University, Xi'an 710069, China.
Li
Hua
H
D002384:Catalysis; D003035:Cobalt / Q000032:analysis* / Q000737:chemistry*; D005456:Fluorescent Dyes / Q000737:chemistry; D007700:Kinetics; D008163:Luminescent Measurements / Q000379:methods*; D010084:Oxidation-Reduction; D010100:Oxygen / Q000737:chemistry*; D004364:Pharmaceutical Preparations / Q000032:analysis / Q000737:chemistry; D012680:Sensitivity and Specificity; D012972:Sodium Hydroxide / Q000737:chemistry; D013447:Sulfites / Q000032:analysis / Q000737:chemistry*; D014867:Water / Q000737:chemistry
D005456:Fluorescent Dyes; D004364:Pharmaceutical Preparations; D013447:Sulfites; D014867:Water; D003035:Cobalt; D012972:Sodium Hydroxide; D010100:Oxygen