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چکیده
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Catecholamines (CA) are used as markers to diagnose various diseases, aging, and stress, and also as a treatment after cardiac surgery, as well as drugs for bronchial asthma, myocardial infarction, and neural disorders such as Parkinson's disease. Several reviews have described numerous methods for the determination of these biologically important compounds in pharmaceutical formulations and biological specimens [1, 2]. Spectrophotometric, fluorimetric, titrimetric, and kinetic methods are among the widely used methods for the determination of CA. Typical oxidants used in spectrophotometric methods are sodium metaperiodate, sodium bismutate, potassium-hexacyanoferrate, and potassium bromate. A novel integrated microchip technology [3] is proposed for the determination of CA. Thermal lens microscopy is an ultra-sensitive detection system. Mixing, reaction, and detection steps of the analysis, were accomplished throughout the microchannels within the microchip with cross-sections of 250 X 100 μm. The chemical reaction system of the proposed method was the CA oxidation by sodium metaperiodate to form colored aminochromes “which is then determined by a thermal lens microscope (TLM). The sensitivity of the system was comparable for the four CA requiring only 15 seconds for mixing of samples and reagents. The calibration lines indicated excellent linearity in the concentration range of 5-20 μm. The RSD for 10 μg ml-1 CA was between 1.08 – 2.5 %. CA in pharmaceutical injections was also determined and the results obtained, correlated very well with normal values
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