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چکیده
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The determination of vitamin C (Ascorbic acid, AA) content in different real samples is of significance since it plays an important role in the maintenance of the good health of human beings. Flow Injection Analysis (FIA) based on UV-Vis and Chemiluminescence Spectroscopy, Amperometry, and Voltammetry is the most frequently used method for AA determination. The utilization of Microchip Analytical technology (μTAS) for carrying out chemical and biochemical analysis has attracted much attention over the past few decades [1]. In the proposed method, Microchannels having a cross-section of 250 X 100 μm were fabricated in a quarts glass chip as a component of the integrated FIA system for flow, mixing, reaction, and detection steps in the analysis system [2]. The chemical reaction system was the well-established coupled redox-complexation between AA and a 1, 10 phenanthroline – Fe (III) mixture. Sample solutions were introduced into microchannels by a micro syringe pump, and the reagents were mixed through molecular diffusion. A photothermal microscope [3] was used for the ultra-sensitive detection of the non-fluorescent reaction product. The proposed method allows for the determination of AA with a linear range of up to 40 μM. The RSD for 25 μM AA (n=5) is 1% with an LOD of 0.1μM. The method was successfully applied to determine of AA content of urine and AA in vitamin C tablets and the results agreed well with those of reference methods
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