In this work, ZnS loaded onto sponge-activated carbon (ZnS-NSAC) was fabricated and applied for the adsorption of benzodiazepines (BDs) from aqueous and biological samples. Various analyses, including FESEM, TEM, and BET, were performed on the synthesized adsorbent. Then, ZnS-NSAC was used in a dispersive ultrasound-assisted microextraction (DUAM) method to extract clonazepam (CLO) and chlordiazepoxide (CHLO) from aqueous and biological samples, and their concentrations were determined by HPLC. In the first step of optimization, seven parameters, including the amount of ZnS-NSAC (mg), pH, vortex time, time and temperature of the ultrasonic, ionic strength, and volume of desorption solvent (mL), were investigated by Plackett-Burman design, and in the second step, the significant parameters were optimized by central composite design. To obtain optimal conditions for extracting the drugs mentioned above, linear regression and desirability functions were used. After optimization, the linear range and limit of detection of the proposed method were determined. At optimum conditions, the method has a linear response over 0.005–10 μg mL−1, with detection limits of 0.0014-0.0016 μg mL−1, quantification limits of 0.0047-0.0054 μg mL−1, and relative standard deviations (RSDs) of 5.3–5.6 % (n = 5).
Talebianpoor et al. (Sun,) studied this question.