Three Electrodes Biosensor for Alcohol in Whole Blood Based on Multi-wall Carbon-nanotube

A novel disposable three electrodes blood alcohol biosensor strip was fabricated by a screen printing technique. Multi-wall carbon nanotube (MWCNT), Meldola's (MB), alcohol dehydrogenase (ADH) and nicotinamide adenine dinucleotide cofactor (NAD) were modified on the surface of the carbon working electrode. Then hydrophilic membrane was stuck in the outermost of the three electrodes to make a reaction camera of 5 mu L. Experimental results indicated that the biosensor possessed good accuracy and stability, the linear response range was 0.5 - 20 mmol/L with correlation coefficient of 0.9949, detection limit was 0.22 mmol/L, and the response time was less than 15 s. Some influencing factors to the biosensor were investigated, such as the pH, temperature and interferences. Correlation analysis showed that there was a significant correlation between the methods of biosensor and the headspace vapor phase chromatography in 10 whole blood samples (r = 0.97583). Small volume whole blood sucked using siphonage to detect blood alcohol directly and quantitatively was the obvious character of the biosensor.