Electrokinetic detection of organic contaminants using molecularly imprinted polymer particles in microchannels

A novel analytical technique for organic contaminants was developed based on the electrokinetic motion of submicron molecularly imprinted polymer (MIP) particles. As the electrokinetic velocity of the MIP particles changes after selective adsorption of organic contaminant from the aqueous sample, the concentration of the contaminant can be determined by measuring the variation of the electrokinetic velocity of the MIP particles in a microchannel. Following the investigations of the synthesis of size-controlled MIP particles, characterization of the adsorption capability, and mechanism of the electrokinetics of the porous particles, the electrokinetic analytical technique was demonstrated by applying this method in analyzing sulfamethoxazole (SMX) as a representative antibiotic organic contaminant. This technique showed an excellent linear response to the logarithmic SMX concentrations in the range of 1 to 1000 µM with LOD = 0.17 µM, which also indicated promising adaptability for practical applications with the recovery of 76-101% for lake water and 93-111% for sea water. This method can be readily extended to other organic contaminants by employing the corresponding target molecules as templates during MIP synthesis. Owing to its simplicity and efficiency, the electrokinetic analytical approach holds great potential for miniaturization into portable onsite sensors by integrating particle velocity measurement techniques.