An ultra-selective and non-enzymatic colorimetric sensor based on imprinted polymer for ephedrine assay in urine samples

A novel non-enzymatic, rapid, and portable molecularly imprinted polymer (MIP)-based colorimetric sensor was developed for ephedrine (EPD) assay in urine samples. The EPD-imprinted polymer was provided via the precipitation polymerization method and applied to fabricate an EPD colorimetric sensor utilizing the carbon disulfide and Cu2+ reagents. The calibration curve for different concentrations of EPD was obtained using the captured images on a cell smartphone and associated RGB data. Some effective parameters including pH of the EPD extraction, time of data collection after adding the reagents, and reagents sequence were investigated and optimized. The selectivity of the sensor was studied using different similar structural compounds, which proved the favorable capability of this method for the selective determination of EPD. This sensor platform with a relatively wide linear calibration range (1-100 μM), and the detection limit of 0.6 μM represents the efficient, reliable, and easy approach for EPD assay in urine samples.