A solid-phase luminescence sensor based on molecularly imprinted polymer-CdSeS/ZnS quantum dots for selective extraction and detection of sulfasalazine in biological samples.

A new solid phase luminescence sensor (SPLS) based on molecularly imprinted polymer (MIP) as recognition element and semi-conductor CdSeS/ZnS alloyed quantum dots (QDs) as fluorophore has been synthesized and developed for the determination of sulfasalazine. The surface modified quantum dot was attached to the surface of the glass slide. MIP and Non-imprinted polymer (NIP) with the recognition site for Sulfasalazine (SSZ) were synthesized and attached to the immobilized QDs. A trace amount of sulfasalazine was determined using fluorescence spectroscopy method based on quenching effect of sulfasalazine on the QDs luminescence with a fluorescence resonance energy transfer (FRET) mechanism. The MIP-QDs based sensor showed high recognition capability of sulfasalazine in comparison with the NIP-QDs based sensor. Various experimental parameters affecting fluorescence intensity such as the reactions time and pH were investigated and optimized. Under optimal conditions, the MIP-QDs sensor showed good linearity for sulfasalazine in the range of 0.02-1.5 µmol L-1 with a determination coefficient (R2) of 0.9986. The limit of detection (S/N = 3) and limit of quantification (S/N = 10) were found to be 0.0071 and 0.024 µmol L-1, respectively. The intra-day and inter-day RSDs were 2.6-5.1% and 3.5-6.9%, respectively. The MIP-QDs based sensor was successfully used to the determination of sulfasalazine in human plasma and urine with the recoveries in the range of 90-107%, offering reliability and applicability of the sensor to the complex matrices.