Sensors and Actuators B 185 (2013) 301–308 Contents lists available at SciVerse ScienceDirect Sensors and Actuators B: Chemical journal h om epage: www.elsevier.com/locat e/snb Chemiluminescence microfluidic system on a chip to determine vitamin B1 using platinum nanoparticles triggered luminol–AgNO 3 reaction Mohammad Kamruzzaman a , Al-Mahmnur Alam a , Sang Hak Lee a,∗ , Trung Dung Dang b a Department of Chemistry, Kyungpook National University, Daegu 702-701, South Korea b School of Mechanical Engineering, Yeungnam University, Gyeongbuk 712-749, South Korea a r t i c l e i n f o Article history: Received 3 September 2012 Received in revised form 15 March 2013 Accepted 8 April 2013 Available online 2 May 2013 Keywords: Lab-on-a-chip Chemiluminescence Luminol Vitamin B1 AgNO3 Platinum nanoparticles a b s t r a c t 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 m wide, 250 m height, 6 mm diameter and 100 mm long microchannel. The method is based on the enhanced CL intensity of luminol by its oxidation with AgNO 3 in the presence of platinum nanoparticles (PtNPs). It was found that the oxidation of luminol with AgNO 3 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–AgNO 3 –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 rel- ative 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. © 2013 Elsevier B.V. All rights reserved. 1. Introduction Vitamin B1 (VB1), also called thiamine is a water soluble vitamin of B complex present in most plant and animal tissues. It consists of an aminopyrimidine ring and a thiazole ring with methyl and hydroxyethyl side chains linked by a methylene bridge. VB1 is a biologically and pharmaceutically essential compound for the car- bohydrate metabolism and maintenance of neural activity [1]. All living organisms need VB1 for their metabolism. It is also neces- sary for the proper functioning of the nervous, muscle, heart and cardiovascular systems of the body [2,3]. It can also be used for the prevention and treatment of beriberi or Wernicke–Korsakoff [1]. Due to the functions and stability factors of VB1 in the body, it is necessary to develop a simple, low cost and sensitive analyt- ical method to determine VB1 in clinical analysis, food processing and pharmaceutical formulations. There have been several reports on the determination of VB1 including spectrophotometry [4–7], gravimetric analysis [8], electrochemical analysis [9–13], spec- trofluorimetry [1,14–18], high performance liquid chromatography [19–23], capillary electrophoresis [24–26], gas chromatography [27,28], and chemiluminescence [29,30]. ∗ Corresponding author. Tel.: +82 53 950 5338; fax: +82 53 950 6330. E-mail address: shlee@knu.ac.kr (S.H. Lee). Among the above methods, the chemiluminescence (CL) method represents high sensitivity with simple instrumentation, wide linear range and detection limit, rapidity in signal detection and has been frequently used for the determination of phar- maceutical and biological samples. Recently metal nanoparticles have attracted much attention in the field of analytical chemistry because of their excellent physical and chemical properties. In the CL system, nanoparticles can participate as catalysts, reduc- tants or luminophores. Metal nanoparticles have been extensively used as catalysts in the CL reaction to boost up the CL signal arising from the electronically excited states of the CL species. Several CL methods have already been presented describing the catalytic activity of metal nanoparticles on CL reactions [31–38]. The results of these studies demonstrate the potential application of metal nanoparticles catalyzed CL systems in analytical chem- istry. In this study, we have presented a PtNPs catalyzed CL system using a luminol–AgNO 3 system on a microfluidic chip to determine VB1 for the first time. In recent years, microfluidic devices have been used in a variety of applications including molecular biology, small-molecule organic synthesis, immunoassays, pharmaceutical analysis and cell manipulation. Microfluidic chip-based CL system has been shown to have significant advantages over the macroscale analogs including improved efficiency with regard to reagent con- sumption, response times, analytical performance, integration, 0925-4005/$ – see front matter © 2013 Elsevier B.V. All rights reserved. http://dx.doi.org/10.1016/j.snb.2013.04.029