A molecularly imprinted modified CdSeS/ZnS core–shell quantum dot embedded glass slide for highly selective and sensitive solid phase optosensing of trace amounts of lidocaine in biological samples

Abstract

An optosensing material based on surface functionalization of a glass slide with quantum dots (QDs) and molecularly imprinted polymer (glass slide@QDs@MIP) with unique optical properties of QDs and selective recognition of MIPs was fabricated for the determination of lidocaine in biological samples. Firstly, CdSeS/ZnS quantum dots were covalently attached to a glass slide surface. Then a molecularly imprinted polymer layer, using lidocaine as the template, was embedded onto the modified surface of the glass slide@QDs by copolymerization to prepare a solid phase glass slide@QDs@MIP sensor. The proposed sensor was more strongly quenched by lidocaine than the non-imprinted polymer (glass slide@QDs@NIP) indicating selective recognition of lidocaine by glass slide@QDs@MIP. The main parameters affecting the extraction and recognition of lidocaine such as the pH of the sample solution and reaction time were investigated and optimized. Under optimal conditions, the synthesized MIP optosensing sensor offered good response for lidocaine with the linear range varying from 0.002–1.0 μM and a correlation coefficient of 0.9991. The limit of detection (3S_b/m) of the method and the limit of quantification (10S_b/m) were 6.3 × 10⁻⁴ and 2.0 × 10⁻³ μM, respectively. The intra-day and inter-day RSDs were 1.9% and 4.4%, respectively. The proposed sensor was practically applicable to the detection of a trace amount of lidocaine in real biological samples (urine and plasma) with satisfactory recoveries in the range of 96.7–105.4% and RSDs between 1.8 and 4.9%. The sensor showed obvious advantages such as photostability, simple and rapid detection of lidocaine in complex matrices and specific recognition toward lidocaine.