Dispersive solid-phase microextraction of antiemetic drugs using a bio-based sorbent modified with carbon dots

Herein, for the first time, the wasted cockle shells were modified with N, S: carbon dots (N, S:CDs) after carbonization and used as a suitable bio-based adsorbent for the extraction of ondansetron (ON) and domperidone (DP), which are the most important antiemetic drugs. The extraction and separation process was performed based on vortex assisted dispersive solid-phase microextraction and high-performance liquid chromatography-ultraviolet detection (HPLC-UV). Various techniques such as Fourier-transform infrared (FT-IR), fluorescence (FL), field emission scanning electronic microscope (FESEM), thermogravimetric analysis (TGA), Brunauer-Emmett-Teller (BET), X-ray powder diffraction (XRD), and energy-dispersive spectra (EDS) were used to characterization the chemical composition of carbonized cockle shells and to confirm the loading of N, S: CDs dots in the final modified composite. After examining the factors affecting the extraction efficiency and access to the optimal points using the response surface methodology (RSM), the linearity was in the range of ۵ to ۳۵۰ μg/L with acceptable coefficients of determination(R۲>۰.۹۹۳). The limits of detection (LODs) and the limits of quantification (LOQ) were in the range of ۱.۵-۱.۷ μg/L and ۴.۹-۵.۲ μg/L, respectively. In the end, the proposed method was applied for the quantitative determination of trace levels of ON and DP from pharmaceutical tablets and human urine. The recoveries were more than ۹۴.۴%, indicating the proposed method's excellent accuracy. The cockle shells used as an adsorbent are not only economical but also a waste product available. Using biomass as efficient adsorbents can help solve their disposal problem. We found that the performance of carbonized cockle shells increased after modifying with N, S: CDs due to the addition of functional groups and a dramatic increase in the surface area. The BBD experimental design was used to optimize the extraction conditions of ON and DP with a minimum number of experiments. The advantages of this method are low consumption of bio-based sorbent, short extraction time, economical and environmentally friendly.