A flow injection procedure based on solenoid micro-pumps for spectrophotometric determination of free glycerol in biodiesel.
A flow system designed with solenoid micro-pumps is proposed for fast and greener spectrophotometric determination of free glycerol in biodiesel. Glycerol was extracted from samples without using organic solvents. The determination involves glycerol oxidation by periodate, yielding formaldehyde followed by formation of the colored (3,5-diacetil-1,4-dihidrolutidine) product upon reaction with acetylacetone. The coefficient of variation, sampling rate and detection limit were estimated as 1.5% (20.0 mg L(-1) glycerol, n=10), 34 h(-1), and 1.0 mg L(-1) (99.7% confidence level), respectively. A linear response was observed from 5 to 50 mg L(-1), with reagent consumption estimated as 345 μg of KIO(4) and 15 mg of acetylacetone per determination. The procedure was successfully applied to the analysis of biodiesel samples and the results agreed with the batch reference method at the 95% confidence level.
Instituto de Química, Universidade de São Paulo, PO Box 26077, 05513-970, São Paulo, SP, Brazil.
Sidnei G
SG
Silva
Fábio R P
FR
Rocha
D056804:Biofuels; D004867:Equipment Design; D017022:Flow Injection Analysis / Q000295:instrumentation* / Q000379:methods; D005557:Formaldehyde / Q000737:chemistry; D005990:Glycerol / Q000032:analysis* / Q000737:chemistry; D006863:Hydrogen-Ion Concentration; D009930:Organic Chemicals / Q000737:chemistry; D010504:Periodic Acid / Q000737:chemistry; D015203:Reproducibility of Results; D012997:Solvents / Q000737:chemistry; D013053:Spectrophotometry / Q000379:methods*; D013997:Time Factors
D056804:Biofuels; D009930:Organic Chemicals; D012997:Solvents; D010504:Periodic Acid; D005557:Formaldehyde; C009288:metaperiodate; D005990:Glycerol