An integrated platform for gas-diffusion separation and electrochemical determination of ethanol on fermentation broths.
An integrated platform was developed for point-of-use determination of ethanol in sugar cane fermentation broths. Such analysis is important because ethanol reduces its fuel production efficiency by altering the alcoholic fermentation step when in excess. The custom-designed platform integrates gas diffusion separation with voltammetric detection in a single analysis module. The detector relied on a Ni(OH)2-modified electrode. It was stabilized by uniformly depositing cobalt and cadmium hydroxides as shown by XPS measurements. Such tests were in accordance with the hypothesis related to stabilization of the Ni(OH)2 structure by insertion of Co(2+) and Cd(2+) ions in this structure. The separation step, in turn, was based on a hydrophobic PTFE membrane, which separates the sample from receptor solution (electrolyte) where the electrodes were placed. Parameters of limit of detection and analytical sensitivity were estimated to be 0.2% v/v and 2.90 μA % (v/v)(-1), respectively. Samples of fermentation broth were analyzed by both standard addition method and direct interpolation in saline medium based-analytical curve. In this case, the saline solution exhibited ionic strength similar to those of the samples intended to surpass the tonometry colligative effect of the samples over analyte concentration data by attributing the reduction in quantity of diffused ethanol vapor majorly to the electrolyte. The approach of analytical curve provided rapid, simple and accurate analysis, thus contributing for deployment of point-of-use technologies. All of the results were accurate with respect to those obtained by FTIR method at 95% confidence level.
Microfabrication Laboratory, Brazilian Nanotechnology National Laboratory (LNNano), Brazilian Center for Research in Energy and Materials (CNPEM), Campinas, SP 13083-970, Brazil; Department of Analytical Chemistry, Institute of Chemistry - UNICAMP, Campinas, SP 13083-970, Brazil; National Institute of Science and Technology of Bioanalytics, Institute of Chemistry - UNICAMP, Campinas, SP 13083-970, Brazil.
Gabriela Furlan
GF
Giordano
Microfabrication Laboratory, Brazilian Nanotechnology National Laboratory (LNNano), Brazilian Center for Research in Energy and Materials (CNPEM), Campinas, SP 13083-970, Brazil.
Luis Carlos Silveira
LC
Vieira
Microfabrication Laboratory, Brazilian Nanotechnology National Laboratory (LNNano), Brazilian Center for Research in Energy and Materials (CNPEM), Campinas, SP 13083-970, Brazil.
Angelo Luiz
AL
Gobbi
Microfabrication Laboratory, Brazilian Nanotechnology National Laboratory (LNNano), Brazilian Center for Research in Energy and Materials (CNPEM), Campinas, SP 13083-970, Brazil; Department of Analytical Chemistry, Institute of Chemistry - UNICAMP, Campinas, SP 13083-970, Brazil; National Institute of Science and Technology of Bioanalytics, Institute of Chemistry - UNICAMP, Campinas, SP 13083-970, Brazil.
Renato Sousa
RS
Lima
Department of Analytical Chemistry, Institute of Chemistry - UNICAMP, Campinas, SP 13083-970, Brazil; National Institute of Science and Technology of Bioanalytics, Institute of Chemistry - UNICAMP, Campinas, SP 13083-970, Brazil. Electronic address: kubota@iqm.unicamp.br.
Lauro Tatsuo
LT
Kubota
Ethanol; Nickel electrode; Point-of-use; Rapid test; X-ray photoelectron spectroscopy