Direct Methanol (or Ethanol) Fuel Cell as Enzymatic or Non-Enzymatic Device, Used to Check Ethanol in Several Pharmaceutical and Forensic Samples.

It was already demonstrated by our research group that a direct catalytic methanol (or ethanol) fuel cell (DMFC) device can be used also for analytical purposes, such as the determination of ethanol content in beverages. In the present research we extended the application to the analysis of several ethanol-based pharmaceutical products, i.e., pharmaceutical tinctures (dyes) and disinfectants. In recent work we have also shown that the use of alcohol dehydrogenase enzyme as a component of the anodic section of a direct catalytic methanol (or ethanol) fuel cell significantly improves the performance of a simple DMFC device, making it more suitable to measure ethanol (or methanol) in real samples by this cell. At the same time, we have also shown that DMFC can respond to certain organic compounds that are more complex than methanol and ethanol and having R(R')CH-OH group in the molecule. Firstly, pharmaceutical dyes were analyzed for their ethanol content using the simple catalytic DMFC device, with good accuracy and precision. The results are illustrated in the present paper. Additionally, a detailed investigation carried out on commercial denatured alcoholic samples evidenced several interferences due to the contained additives. Secondly, we hypothesized that by using the enzymatic fuel cell it would be possible to improve the determination, for instance, of certain antibiotics, such as imipenem, or else carry out determinations of ethanol content in saliva and serum (simulating forensic tests, correlated to drivers "breath test"); even if this has already been hypothesized in previous papers, the present study is the first to perform them experimentally, obtaining satisfactory results. In practice, all of the goals which we proposed were reached, confirming the remarkable opportunities of the enzymatic (or non-enzymatic) DMFC device.

Further development on DMFC device used for analytical purpose: real applications in the pharmaceutical field and possible in biological fluids.

The analytical research devoted to the utilization of the direct methanol fuel cell (DMFC) for analytical purposes has been continued. The research reported in this paper concerns two points, one of which was the possibility of improving the features, from the analytical point of view, of a catalytic fuel cell for methanol and ethanol, by introducing an enzyme, immobilized into a dialysis membrane small bag, in the anodic area of the fuel cell. This objective has been fully achieved, particularly using the enzyme alcohol dehydrogenase, which has increased the sensitivity of the method and reduced dramatically the response time of the cell. The second point concerned the opportunity to determine two particular antibiotics having an alcohol functional group in their molecule, that is, imipenem and chloramphenicol. Also, this goal has been reached, even if the sensitivity of the method is not so high. Graphical abstract Imipenem and Chloramphenicol determination using the DMFC and Ethanol determination using the enzymatic DMFC.