Chemiluminescence microfluidic system on a chip to determine vitamin B1 using platinum nanoparticles triggered luminol-AgNO3 reaction

A novel and sensitive chemiluminescence (CL) method on a microchip has been presented for the determination of vitamin B1 (VB1). The microchip was fabricated by soft lithographic procedure using polydimethyl siloxane (PDMS) having four inlets and one outlet with a 200 μm wide, 250 μm height, 6 mm diameter and 100 mm long microchannel. The method is based on the enhanced CL intensity of luminol by its oxidation with AgNO3 in the presence of platinum nanoparticles (PtNPs). It was found that the oxidation of luminol with AgNO3 by PtNPs produced strong CL signal at about 425 nm which meant that the luminophore was still 3-aminopthalate. The CL intensity of the luminol-AgNO3-PtNPs system was further increased with the addition of VB1. Under optimum conditions, the CL intensity was increased by increasing the concentration of VB1 in the range of 1.0 × 10−7 to 4.0 × 10−5 mol L−1 with a correlation coefficient of 0.9992. The limit of detection was found to be 4.8 × 10−9 mol L−1 with the relative standard deviation of 1.06%. The method was successfully applied to determine VB1 in vitamin B1 tablets and vitamin B complex tablets. The interaction mechanism of the CL system has been proposed by UV-vis spectra and CL emission spectra.