A simple design and low cost miniaturized reactor integrated with interchangeable thin film TiO 2 nanolayer was successfully fabricated for the photocatalytic degradation of azo dyes. The TiO 2 nanofilms were prepared by sol-gel dip-coating method, while the miniaturized reactor was fabricated on poly methyl methacrylate (PMMA) substrates, using a laser cutting machine. The performance of the miniaturized reactor for the photocatalytic degradation process was investigated for the degradation of a commercial dye (Novacron Red C-2BL). About 98% degradation of the commercial dye was achieved after 100 min in a stopped flow system, and 15% in a continuous flow system. The effect of different operating variables such as pH, initial flow rate, light intensity, layers of the nanoparticles, and temperature on the photocatalytic degradation was studied and the optimum operating conditions were determined to be: inlet flow rate of 0.05 ml/s, pH of 7, UV power 82 W and using a multilayer of TiO 2 thin film in the miniaturized reactor. The reaction kinetics was described as pseudo first order kinetics and rationalized using the Langmuir-Hinshelwood model.

An integrated microfluidic/electrochemical sensor with a dual working electrode configuration was fabricated for voltammetric and electrochemiluminescence (ECL) applications. The fabrication method integrates the two techniques of injection molding and screen printing for the first time. Injection molding is used to fabricate the flow cell with integrated electrical and fluidic connectors. Screen printing was used to print the electrodes directly onto the injection molded base plate. An over molding procedure followed by ultrasonic welding was used to form the complete sensor. The electrochemical and ECL performance of the sensors was assessed by applying different electrochemical methods such as cyclic voltammetry (CV), anodic stripping voltammetry (ASV) and chronoamperometry. The attractive analytical performance demonstrates good capability of the disposable sensors for routine online electrochemical and ECL measurements.

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