Simultaneous determination of free and total glycerol in biodiesel by capillary electrophoresis using multiple short‐end injection |
| |
Authors: | Daniel Alfonso Spudeit Marcel Piovezan Maressa D Dolzan Jacqueline Pereira Vistuba Mônia Stremel Azevedo Luciano Vitali Marcone Augusto Leal Oliveira Ana Carolina Oliveira Costa Gustavo Amadeu Micke |
| |
Institution: | 1. Department of Chemistry, Federal University of Santa Catarina, , Florianopolis, SC, Brazil;2. Department of Food Science Technologies, Federal University of Santa Catarina, , Florianopolis, SC, Brazil;3. Department of Chemistry, Federal University of Juiz de Fora, , Juiz de Fora, MG, Brazil |
| |
Abstract: | 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 R2> 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. |
| |
Keywords: | Biodiesel CE Free glycerol Short‐end multiple injections Total glycerol |
|
|