title: Automatized flow-batch method for fluorescent determination of free glycerol in biodiesel samples using on-line extraction.
abstract: An automatic method, based on flow-batch (FB), for determining glycerol in biodiesel was developed. The FB systems draw upon the useful features of flow, batch and multi-commutation approaches. The standards and samples preparation, as well as, derivatization and analysis were fully automated. For that purpose, a homemade chamber was built. The proposed method is based on liquid-liquid extraction of glycerol and simultaneous oxidation with periodate, generating formaldehyde that reacts with acetylacetone. A fluorescent product of 3,5-diacetyl-1,4-dihydrolutidine was obtained. The fluorescence signal was recorded at λ(ex) =417 nm and λ(em) = 514 nm. A linear response was observed from 0.10 to 5.00 mg L(-1) glycerol, variation coefficient 1.5%, sampling rate 14 h(-1) and detection limit 0.036 mg L(-1) glycerol. The procedure was successfully applied to the analysis of biodiesel samples, and the results agreed with the reference method (ASTM D6584-07) at 95% confidence level.
authors.affiliation: Universidade Federal da Paraíba, CCEN, Departamento de Química, Caixa Postal 5093, CEP 58051-970, Cidade Universitária, João Pessoa, Paraíba, Brazil.
authors.forename: Marcelo B
authors.initials: MB
authors.lastname: Lima
authors.forename: Matías
authors.initials: M
authors.lastname: Insausti
authors.forename: Claudia E
authors.initials: CE
authors.lastname: Domini
authors.forename: Marcelo F
authors.initials: MF
authors.lastname: Pistonesi
authors.forename: Mário C Ugulino
authors.initials: MC
authors.lastname: de Araújo
authors.forename: Beatriz S Fernández
authors.initials: BS
authors.lastname: Band
mesh_terms: D057205:Automation, Laboratory; D056804:Biofuels / Q000032:analysis*; D004095:Dihydropyridines / Q000032:analysis*; D005453:Fluorescence; D005557:Formaldehyde / Q000737:chemistry; D005990:Glycerol / Q000032:analysis*; D057230:Limit of Detection; D059625:Liquid-Liquid Extraction / Q000379:methods; D010084:Oxidation-Reduction; D010422:Pentanones / Q000737:chemistry; D010504:Periodic Acid / Q000737:chemistry; D013050:Spectrometry, Fluorescence / Q000295:instrumentation / Q000379:methods*
chemical_list: D056804:Biofuels; D004095:Dihydropyridines; D010422:Pentanones; D010504:Periodic Acid; D005557:Formaldehyde; C003953:3,5-diacetyl-1,4-dihydrolutidine; C008790:acetylacetone; C009288:metaperiodate; D005990:Glycerol