Portable and green solid contact potentiometric sensor for the rapid and direct assay of clozapine in post-mortem rat liver and dosage forms: An analytical approach to forensic and pharmaceutical samples

Abstract

This work is devoted to fabricating and validating a portable potentiometric sensor for in-site clozapine (CLZ) assay in tablets and post-mortem rat liver. The outcomes marking the overall sensor performance were defined to be (Nernstian slope, quantification limit, and correlation coefficients). A polyaniline-coated glassy carbon electrode was used as support for the sensors. The optimized sensor was composed of PVC (30.85 % w/w) plasticized with 2-nitrophenyl phenyl ether NPPE (64.32 % w/w) incorporating phosphotungstic acid PT (1.61 % w/w) as a cationic exchanger and calix-8-arene CX-8 (3.22 % w/w) as an ionophore, where the membrane thickness was 100 µm. The developed membrane works over the pH range of 2.3–6, providing a dynamic response time of 8 s. A computational docking approach was implemented, and the ionophore-CLZ complex interactions were studied to identify the best-fit complex. The docking study demonstrates that CX-8 is the optimum choice since it binds with CLZ+ by forming four bonds with −4.36 as binding free energy, reflecting the expected high stability of the developed complex. Validation of the proposed sensor illustrates that CLZ follows a linear response over the range of 1.8 × 10−5–1 × 10−2 M, yielding a correlation coefficient value of 0.9989 and a limit of detection LOD of 2.0 × 10−6 M. Moreover, the constructed membrane sensor proves to be of acceptable accuracy as reflected by the recovery percentage (97.48 %) and provides satisfactory precision as shown by the low relative standard deviation values; 0.114 for intermediate precision and 0.772 for repeatability. The greenness profile of the proposed method was assessed by the Green Analytical Procedure Index (GAPI), compared with the reported HPLC method, and found superior.