Spectrophotometric determination of sulphate in automotive fuel ethanol by sequential injection analysis using dimethylsulphonazo(III) reaction

• Author(s): Oliveira, Fábio Santos de ; Korn, Mauro ; Oliveira, Fábio Santos de ; Korn, Mauro
• Date: 2013
• Origin: Oasisbr
• Subject(s): Sulphate determination; Automotive fuel ethanol; SIA; Ethanol combustion
• Document Type: Journal article
• Language: English

Description

Texto completo: acesso restrito. p.992–999

Submitted by Edileide Reis ([e-mail]) on 2013-09-04T13:36:51Z No. of bitstreams: 1 1-s2.0-S003991400500408X-main.pdf: 188667 bytes, checksum: fa22ac6a99d0a2be76c3bd371e487888 (MD5)

Made available in DSpace on 2013-09-04T13:36:51Z (GMT). No. of bitstreams: 1 1-s2.0-S003991400500408X-main.pdf: 188667 bytes, checksum: fa22ac6a99d0a2be76c3bd371e487888 (MD5) Previous issue date: 2006

A sensitive SIA method was developed for sulphate determination in automotive fuel ethanol. This method was based on the reaction of sulphate with barium–dimethylsulphonazo(III) leading to a decrease on the magnitude of analytical signal monitored at 665 nm. Alcohol fuel samples were previously burned up to avoid matrix effects for sulphate determinations. Binary sampling and stop-flow strategies were used to increase the sensitivity of the method. The optimization of analytical parameter was performed by response surface method using Box–Behnker and central composite designs. The proposed sequential flow procedure permits to determine up to 10.0 mg SO42− l−1 with R.S.D. <2.5% and limit of detection of 0.27 mg l−1. The method has been successfully applied for sulphate determination in automotive fuel alcohol and the results agreed with the reference volumetric method. In the optimized condition the SIA system carried out 27 samples per hour.