DEVELOPMENT OF ELECTROCHEMICAL SENSOR FOR DETERMINATION OF GLUCOSAMINE USING DROPLET MICROFLUIDIC SYSTEM

Abstract

A droplet-based electrochemical sensor for direct measurement of D-glucosamine was developed using carbon paste electrodes (CPEs) modified with gold nanoparticles (AuNPs) and polyaniline (PANI). Central composition design (CCD) was employed as a powerful method for optimization of parameters for electrode fabrication. The optimized amounts of AuNPs and PANI were determined as 300 and 3,000 mg L-1, respectively. In addition, the optimum pH of buffer was found to be pH 4. For batch measurements, two linear ranges of glucosamine were observed. The first and second linear ranges were 0.05-40 mM and 40–100 mM, respectively. Using the first linear range, limits of detection and quantitation (LOD and LOQ) were calculated as 2.8 and 9.4 µM, respectively. Coupled with a droplet microfluidic system, the analysis of glucosamine was performed in a high-throughput manner with a sample throughput of at least 60 samples h-1. In addition, the adsorption of the analyte on the electrode surface was prevented due to compartmentalization in droplets. Linearity of the proposed system was found to be in the range of 0.5–5 mM with LOD and LOQ of 0.45 and 1.45 mM, respectively. High intra-day and inter-day (evaluated among 3 days) precisions for the detection of 50 droplets containing glucosamine were obtained with %RSD less than 3%. The system was successfully used to determine the amounts of glucosamine in supplementary products with error percentage and relative standard deviation less than 3%. In addition, the amounts of glucosamine measured using the developed sensors were in good agreement with those obtained from a traditional CE method. These indicate high accuracy and precision of the proposed system for determination of glucosamine in supplementary products.