Preparation of biochar-based surface molecularly imprinted polymers and evaluation of their selective adsorption and removal of carbaryl from rice and corn

Selective extraction and determination of chlorpyrifos residues from aqueous samples using biochar-functionalized molecularly imprinted polymer combined with high-performance liquid chromatography

The concentration of chlorpyrifos (CPF) in aqueous samples was determined using a novel molecularly imprinted dispersive solid-phase extraction (MISPE) approach that was presented in this research. Using a non-covalent molecular imprinting technique, a biochar (BC)-functionalized molecularly imprinted polymers (MIPs) (BC-MIPs) was created. These MIPs were used in dispersive solid-phase extraction (DSPE) in conjunction with high-performance liquid chromatography with photodiode array detection (HPLC-PDA) to detect CPF in aqueous samples with high sensitivity. Using methacrylic acid (MAA) as the monomer and ethylene glycol dimethacrylate (EGDMA) as the cross-linker, BC-MIPs were created using CPF as a template. By using the suggested dispersive solid-phase extraction (DSPE) approach, the efficiency of the synthesized BC-MIPs granules was evaluated. Analytical performance of the devised DSPE-HPLC-PDA technique was assessed under optimal settings. The optimized parameters included extraction time, aqueous sample pH, desorption time and desorption reagents. Compared with the traditional method, the established method has better selective adsorption capacity, reusability and sensitivity for CPF. The suggested method presented that limit of detection and limit of quantification were 1.0 ng/mL and 4.0 ng/mL, along with excellent linear range (4.0-1500 ng/mL) with coefficients of determination (R2=0.9982). The established method was successfully used to determination CPF in aqueous samples from the Baisha River in Qingdao, with the advantages of accuracy (recoveries: 81.2 %-103.6 %, RSDs≤9.2 %), speed (CPF-BC-MIPs-DSPE time: 75 min; HPLC-PDA time: 12 min), selectivity (imprinting factor: 4.24), and economy (50 mg of adsorbent synthesized using cheap straw and 1 mL of solvents), which partially conform to the current advanced principle of "3S+2A" in analytical chemistry. The BC-MIPs granules shown potential for CPF preconcentration in complicated samples and were effective carriers for the selective adsorption of CPF.

Magnetic phytic acid-modified kapok fiber biochar as a novel sorbent for magnetic solid-phase extraction of antidepressants in biofluids

BACKGROUND

Therapeutic drug monitoring (TDM) of antidepressants is essential for monitoring patient medication to avoid drug toxicity, complications, or nonadherence. Chromatographic techniques with high sensitivity and reproducibility are the main detection method for antidepressants. Effective pretreatment of biological sample processes is necessary prior to instrumental analysis. Magnetic solid-phase extraction (MSPE) has received much attention for its advantages of simple operation, rapidity, cost-effectiveness and low organic solvent consumption. Therefore, the development of a suitable and green magnetic sorbent for the detection of antidepressants in plasma and urine is apparently necessary. (88) RESULTS: A magnetic phytic acid-modified kapok fiber biochar sorbent (Fe3O4/PAKFBC) was successfully synthesized by pyrolytic impregnation and physical milling methods. Fe3O4/PAKFBC exhibited a large specific surface area (214 m2 g-1) and a rich pore structure (5-10 nm). The extraction equilibrium, using 10 mg Fe3O4/PAKFBC, can be completed in about 1 min. The density functional theory (DFT) results showed that the adsorption mechanism of Fe3O4/PAKFBC on the six antidepressants mainly included electrostatic interactions, van der Waals interactions, π-π interactions and weak hydrogen bonding. Examination using the greenness assessment tools showed that the developed method exhibited excellent greenness. By combining with liquid chromatography-ultraviolet (LC-UV), a quantitative method with good linearity (R2 > 0.993) and relative recoveries (92.4-107.7%) and negligible matrix effect (-11.5-6.0%) was developed. The Fe3O4/PAKFBC successfully detected six antidepressants in plasma and urine samples, requiring no pH adjustment with buffer salts. (142) SIGNIFICANCE: The environmental sustainability of the proposed methods was affirmed by six greenness evaluation tools, all indicating exceptional eco-friendliness. The Fe3O4/PAKFBC demonstrated outstanding greenness in both its creation and analytical application, proving highly effective in real sample applications and showcasing potential for broader use. This study contributes to a deeper and broader understanding of the microscopic adsorption mechanism, which can help in the optimization and development of more green sorbents. (69).