Determination of chloride and sulfate in bio-ethanol by ion chromatography

Abstract

<span style="mso-ansi-language:EN-US" lang="EN-US">Bio-ethanol is produced from biomass or biodegradable waste and is used as a blending component in commercial gasoline fuel. Bio-ethanol can be contaminated with chloride and sulfate ions which can cause various unwanted side effects. European norm, EN 15376 defines the maximum permitted level of ions present and by that maximum chloride and sulfate content should not exceed 6.0 mg·kg^-1and 4.0 mg·kg^-1, respectively. The optimization and validation of ion chromatography method for the quantitative determination of chloride and sulfate ions in bio-ethanol by direct injection ion chromatography using anion-exchange stationary phase, carbonate/hydrogen carbonate mobile phase and conductivity detection has been described. The method is optimized regarding mobile phase composition and flow rate as well as the length of the chromatographic column. Validation of the method has been performed in order to confirm its applicability. <span style="mso-fareast-font-family:GulliverRM;mso-ansi-language:EN-US" lang="EN-US">The developed method is applied for the determination of chloride and sulfate ions in <span style="mso-bidi-font-size:10.0pt; mso-ansi-language:EN-US" lang="EN-US">real<span style="mso-bidi-font-size: 10.0pt;mso-ansi-language:EN-US" lang="EN-US"> bio-ethanol samples used for <span style="mso-ansi-language:EN" lang="EN">inter-laboratory <span style="mso-ansi-language: EN" lang="EN">comparative <span style="mso-ansi-language:EN" lang="EN">testing<span style="mso-fareast-font-family:GulliverRM;mso-ansi-language:EN-US" lang="EN-US">. The obtained <span style="mso-bidi-font-size:10.0pt;mso-ansi-language: EN-US" lang="EN-US">results are compared with the official tests results and <i style="mso-bidi-font-style:normal">z</i>-score has been determined. For chloride determination <span style="mso-ansi-language:EN" lang="EN">higher <i style="mso-bidi-font-style:normal"><span style="mso-ansi-language:EN" lang="EN">z</span></i><span style="mso-ansi-language:EN" lang="EN">-scores <span style="mso-ansi-language:EN" lang="EN">is obtained (from 1.4 to >3) than for the determination of <span style="mso-fareast-font-family:GulliverRM;mso-ansi-language:EN-US" lang="EN-US">sulfate<span style="mso-ansi-language:EN" lang="EN"> (from -0.9 to 0.1). <span style="mso-ansi-language:EN-US" lang="EN-US">

</span></span></span></span></span></span></span></span></span></span></span></span></span></span></span>