Poster
Presentation 1B-34
A Sequential
Enzymatic Micro Reactors System for Ethanol Detection of Gasohol Mixtures
E. M. Alhadeff,2 A.M.
Salgado,2 N. Pereira Jr.2 and B. Valdman1*
1 Departamento de Engenharia Química - Escola de
Química –
Universidade Federal do Rio de Janeiro
C.T., Bl. E, sl 201
Rio de
Janeiro – Brasil
E-mail: belkis@eq.ufrj.br
2 Departamento de
Engenharia Bioquímica - Escola de Química - Universidade Federal do Rio de
Janeiro, C.T., Bl. E, sl 203,Rio de
Janeiro – Brasil
A sequential enzymatic double micro
reactor system with dilution line was developed for quantifying ethanol from
gasohol mixtures, using a colorimetric detection method. Alcohol oxidase (AOD) and Horseradish peroxidase
(HRP) immobilized on glass beads, one in each micro reactor, were used with
phenol and 4-aminophenazone and the red colored product was detected with a
spectrophotometer at 555 nm. Good
results were obtained with the immobilization technique used for both AOD and
HRP enzymes, with retention efficiencies of 95.9 % and 73.9 %, respectively. The two micro reactors were used to analyze
extracted ethanol from gasohol blends in the range 1 – 30 % v/v, with and
without dilution line. A calibration
curve was obtained in the range 0.001 – 0.06 g ethanol/L and the linearity
being in the range of 0.001 – 0.023 g ethanol/L, with a correlation coefficient
of 0.9897. The samples concentrations
were also determined by gas chromatography (GC) and high pressure liquid
chromatography (HPLC) methods and the results compared with the proposed
sequential system measurement.