Indirect determination of chloride and sulfate ions in alcohol fuel by capillary electrophoresis.
A capillary zone electrophoresis method using indirect UV detection for the analysis of chloride and sulfate in alcohol fuel samples was developed. The anions were analyzed in less than 3 min using an electrolyte containing 10 mmol l(-1) chromate and 0.75 mmol l(-1) hexamethonium bromide (HMB) as electroosmotic flow modifier. Coefficients of variation were better than 0.6% for migration time ( n=10) and between 2.05 and 2.82% for peak area repeatabilities. Analytical curves of peak area versus concentration in the range of 0.065-0.65 mg kg(-1) for chloride and 0.25-4.0 mg kg(-1) for sulfate were linear with coefficients of correlation higher than 0.9996. The limits of detection for sulfate and chloride were 0.033 and 0.041 mg kg(-1), respectively. Recovery values ranged from 85 to 103%. The method was successfully applied for the quantification of sulfate and chloride in five alcohol fuel samples. The concentration of sulfate varied from 0.45 to 3.12 mg kg(-1). Chloride concentrations were below the method's LOD.
Instituto de Química, Universidade de Sao Paulo, Av. Prof. Lineu Prestes 748, Bloco 11 superior, 05508-900 São Paulo, Brazil. ealves@iq.usp.br
Elisabete A
EA
Pereira
Alessandra
A
Stevanato
Arnaldo A
AA
Cardoso
Marina F M
MF
Tavares
D000438:Alcohols / Q000737:chemistry*; D002712:Chlorides / Q000032:analysis*; D019075:Electrophoresis, Capillary / Q000379:methods; D013056:Spectrophotometry, Ultraviolet / Q000379:methods; D013431:Sulfates / Q000032:analysis*
D000438:Alcohols; D002712:Chlorides; D013431:Sulfates