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Simultaneous determination of free and total glycerol in biodiesel by capillary electrophoresis using multiple short‐end injection
Author(s) -
Spudeit Daniel Alfonso,
Piovezan Marcel,
Dolzan Maressa D.,
Vistuba Jacqueline Pereira,
Azevedo Mônia Stremel,
Vitali Luciano,
Leal Oliveira Marcone Augusto,
Oliveira Costa Ana Carolina,
Micke Gustavo Amadeu
Publication year - 2013
Publication title -
electrophoresis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.666
H-Index - 158
eISSN - 1522-2683
pISSN - 0173-0835
DOI - 10.1002/elps.201300371
Subject(s) - saponification , biodiesel , glycerol , chromatography , chemistry , castor oil , extraction (chemistry) , biodiesel production , periodate , analytical chemistry (journal) , organic chemistry , catalysis
A rapid method for the simultaneous determination of free glycerol ( FG ) and total glycerol ( TG ) in biodiesel by CE using a short‐end multiple injection ( SE / MI) configuration system is described. The sample preparation for FG involves the extraction of glycerol with water and for TG a saponification reaction is carried out followed by extraction as in the case of FG . The glycerol extracted in both cases is submitted to periodate oxidation and the iodate ions formed are measured on a CE ‐ SE / MI system. The relevance of this study lies in the fact that no analytical procedure has been previously reported for the determination of TG (or of FG and TG simultaneously) by CE . The optimum conditions for the saponification/extraction process were 1.25% KOH and 25°C, with a time of only 5 min, and biodiesel mass in the range of 50.0–200.0 mg can be used. Multiple injections were performed hydrodynamically with negative pressure as follows: 50 mbar/3s ( FG sample); 50 mbar/6s (electrolyte spacer); 50 mbar/3s ( TG sample). The linear range obtained was 1.55–46.5 mg/L with R 2 > 0.99. The LOD and LOQ were 0.16 mg/L and 0.47 mg/L, respectively for TG . The method provides acceptable throughput for application in quality control and monitoring biodiesel synthesis process. In addition, it offers simple sample preparation (saponification process), it can be applied to a variety biodiesel samples (soybean, castor, and waste cooking oils) and it can be used for the determination of two key parameters related to the biodiesel quality with a fast separation (less than 30 s) using an optimized CE‐SE/MI system.