Azarbaijan Shahid Madani University

A novel thin film microextraction (TFME) method was developed for phosalone determination in fruit and vegetable samples using gas chromatography-flame ionization detection (GC-FID). MIL-101 metal-organic framework (MOF) was synthesized via solvothermal condensation and incorporated into alginate (Alg) through solvent blending, forming a monolithic self-supportive thin film. The MIL-101/Alg biocomposite was characterized using XRD, FT-IR, and SEM. The impact of MIL-101 doping on extraction efficiency was assessed, showing significant enhancement. A central composite design (CCD) optimized extraction and desorption conditions. The method exhibited a detection limit of 1.6 ng mL^-1 and a quantification limit of 5.5 ng mL^-1, with a linear range of 5.5-1000 ng mL^-1 (r² = 0.9909). Intra-day, inter-day, and inter-sorbent precisions (n = 6) were 3.6, 4.07, and 9.4 %, respectively. Validation in spiked real samples (apple, celery, cucumber, and tomato) showed relative recoveries above 93.2 %, confirming method accuracy and applicability.

The development of sustainable analytical methods is crucial to minimize environmental impacts and align with green chemistry principles. In this study, a novel chitosan-based molecularly imprinted polymer (CS-MIP) thin film was designed for the selective microextraction of tramadol (TRA) from biological and environmental samples. Chitosan, a biodegradable and renewable polymer, was employed as a green functional monomer and supportive matrix. The integration of molecular imprinting with thin-film solid-phase microextraction (TF-SPME) provides a robust and eco-friendly approach to enhance extraction efficiency and selectivity for trace-level analysis.

The synthesized CS-MIP thin film was thoroughly characterized using SEM, ATR-FTIR, and TGA, confirming its structural stability and imprinting efficiency. The thin film was employed as a selective sorbent for TRA extraction using TF-SPME, coupled with digital image colorimetry (DIC) for on-site detection. The DIC method utilized the colorimetric shift of bromocresol green (BCG) in the presence of TRA, transitioning from green to dark green through an ion-pair production mechanism. Optimal conditions for colorimetric detection were determined using a one-variable-at-a-time approach, while TF-SPME parameters were optimized via central composite design. The method demonstrated a linear dynamic range of 9.9-500 ng mL^-1, with limits of detection and quantification at 3.3 ng mL^-1 and 9.9 ng mL^-1, respectively. High recoveries (80.70 %-106.00 %) were achieved for saliva, urine, and wastewater samples, showcasing the method's accuracy and applicability.

This study introduces a sustainable and selective analytical method combining molecular imprinting and colorimetric detection. The CS-MIP-DIC system represents a breakthrough in green sample preparation and on-site monitoring, offering a practical, cost-effective solution for detecting TRA in various matrices. The proposed methodology sets a precedent for environmentally friendly and efficient analytical applications.

It is challenging for environmental scientists to identify the trace value of arsenite (As(III)) as an essential hazardous material in the presence of arsenate (As(V)) and other metal ions.This paper proposes a method of magnetic solid-phase extraction (MSPE) for the trace anal. of As(III) using magnetite graphene oxide (MGO) covalently functionalised with dimercaptosuccinic acid (DMSA) and putrescine (PUT).The hydrothermally synthesized MGO/DMSA-PUT adsorbent was carefully characterized by using energy-dispersive X-ray spectroscopy anal., Fourier transform IR, dynamic light scattering, SEM, zeta potential analyzer, X-ray diffraction, and vibrating sample magnetometer techniques in detail.Maximum adsorption capacity of MGO/DMSA-PUT for As(III) was determined 144 mg g^-1 which considerably improved vs. graphene oxide with the adsorption capacity of 54.8 mg g^-1.Sample pH of 6 with a volume of 50 mL, contact time of 5 min, initial concentration of 50 μg L^-1, adsorbent dosage of 0.1 g and volume of eluent 3 mL were obtained as the optimized parameters for the developed MSPE procedure.According to exptl. data obtained with hydride generation at. absorption spectroscopy, the linear range and detection limit of the proposed method for As(III) measurement was found to be 0.4-5000 μg L^-1 and 9.914 ng L^-1, resp.According to exptl. results, a preconcentration limit (PL) of 1.72 μg L^-1 was achieved for As(III), corresponding to a preconcentration factor of 965.Statistical anal. of standard reference materials confirmed the accuracy of the method against systematic and constant errors (>95% recovery with <5% RSD).Because of the selectivity of MGO/DMSA-PUT toward the As(III), the developed MSPE procedure is capable for successful speciation and determination of As(III) in water samples with satisfactory anal. results.