The purpose of this thesis is to design and test a new microfluidic device based on impedance cytometry principles for detecting and quantifying microplastics in droplets. To measure the size and concentration of microplastics, we created a flow-focusing droplet generator with coplanar electrodes. Polystyrene microbeads of four distinct sizes and three different concentrations were employed. The impedance measurements were taken with a lock-in amplifier at three distinct frequencies:​ 4.4 MHz, 11 MHz, and 22.5 MHz. ANOVA and k-NN classification were used to examine the findings. The signal phase at low and medium frequencies was proven to best differentiate between different sizes and concentrations. The functional groups (for example, carboxyl groups) on the surface of microplastics can significantly interfere with the signal phase. The ANOVA and KNN classification findings demonstrated that the microfluidic device is highly sensitive to the concentration of non-carboxylated polystyrene beads and can classify concentration levels with 95.0% accuracy. According to a proposed equivalent circuit, the presence of microplastics in droplets can significantly influence the properties of the double-layer capacitance produced at the interface of the droplet and the electrode, making lower frequencies better for discriminating between different concentrations. The prominence of parasitic capacitance at high frequencies makes measurements indeterminate. Finally, it was demonstrated that the droplets' resistive behaviour does not alter as much as the double-layer capacitance behaviour, making medium frequencies less discriminative.