Spectrophotometric determination of aflatoxin B1 in food sample: Chemometric optimization and theoretical supports for reaction mechanisms and binding regions

Synthesis, characterization and application of cross-linked functional terpolymer through epoxy group as sorbent for extraction of cadmium from waters and foods: Multivariate optimization

The purpose of this study was to develop a selective sorbent for cadmium ions (Cd(II)) enrichment in orbital shaker assisted solid phase microextraction (OS-SPME) from different aqueous and food samples. A maleic anhydride-styrene-glycidyl methacrylate (MA-St-GMA) terpolymer was synthesized and characterized in detail. Experimental variables of sample preparation step were optimized using a central composite design (CCD). The final determination step was performed using flame atomic absorption spectroscopy (FAAS). The MA-St-GMA sorbent exhibited a high adsorption capacity (195.9 mg g-1) for the Cd(II) ion. The developed method under optimal conditions provides satisfactory performance and a significant improvement compared to other protocols available in the literature. The linear range and detection limit of the method is 0.1-130 ng mL-1 and 0.03 ng mL-1, respectively. The robustness, intraday/interday precision, selectivity, and accuracy of the method were investigated. To further validate the method, a dedicated series of analysis was performed using certified reference materials (CRMs). This part of the study confirmed the applicability of the method for routine analysis. The OS-SPME-FAAS method was validated using water and food samples. Relative standard deviations and recovery for real-world samples were in ranges 1.7-2.2 % and 95.5-98.5 %, respectively. As a result, the MA-St-GMA sorbent showed that it could quantitatively extract Cd(II) ions from aqueous solution.

A Simultaneous Determination Method for the Analysis of Chloride and Nitrate Ions in Air Samples by PLS1

This study describes a multi-ion-selective electrode system for the simultaneous determination of nitrate and chloride ions in air samples by using multivariate calibration methods. The measurement system was constituted of two ion-selective electrodes, an Ag/AgCl double-junction reference electrode and a multi-potentiometer. The measurements were performed at pH 5.0 acetic acid/sodium acetate buffer. The obtained data were evaluated by using Partial Least Squares (PLS1). The system was used to analyze the synthetic samples and fume-hood samples in terms of the amount of chloride and nitrate. The percentage recovery values obtained from fume-hood samples were 93.8% ± 3.8 and 102.4% ± 2.5 for chloride and nitrate, respectively. The presented system could be an easy-to-use approach for monitoring the amount of chloride and nitrate species in the scope of occupational health and safety analysis.

Computational Studies of Aflatoxin B1 (AFB1): A Review

Aflatoxin B₁ (AFB₁) exhibits the most potent mutagenic and carcinogenic activity among aflatoxins. For this reason, AFB₁ is recognized as a human group 1 carcinogen by the International Agency of Research on Cancer. Consequently, it is essential to determine its properties and behavior in different chemical systems. The chemical properties of AFB₁ can be explored using computational chemistry, which has been employed complementarily to experimental investigations. The present review includes in silico studies (semiempirical, Hartree-Fock, DFT, molecular docking, and molecular dynamics) conducted from the first computational study in 1974 to the present (2022). This work was performed, considering the following groups: (a) molecular properties of AFB₁ (structural, energy, solvent effects, ground and the excited state, atomic charges, among others); (b) theoretical investigations of AFB₁ (degradation, quantification, reactivity, among others); (c) molecular interactions with inorganic compounds (Ag⁺, Zn²⁺, and Mg²⁺); (d) molecular interactions with environmentally compounds (clays); and (e) molecular interactions with biological compounds (DNA, enzymes, cyclodextrins, glucans, among others). Accordingly, in this work, we provide to the stakeholder the knowledge of toxicity of types of AFB₁-derivatives, the structure-activity relationships manifested by the bonds between AFB₁ and DNA or proteins, and the types of strategies that have been employed to quantify, detect, and eliminate the AFB₁ molecule.

Optimization of green and rapid analytical procedure for the extraction of patulin in fruit juice and dried fruit samples by air-assisted natural deep eutectic solvent-based solidified homogeneous liquid phase microextraction using experimental design and computational chemistry approach

In this paper, a green and inexpensive air-assisted natural deep eutectic solvent-based solidified homogeneous liquid phase microextraction procedure was optimized for extraction of patulin in fruit juice and dried fruit samples using experimental design prior to its spectrophotometric determination. Four different natural deep eutectic solvent were prepared and applied to ensure efficient, and selective extraction of patulin. The significant variables including Zn(II) amount, cooling time, pH and amount of natural deep eutectic solvent were optimized by using central composite design. Under optimized conditions, working range was 10-750 μg L^-1 with 0.9996 of correlation coefficient. Detection limit and preconcentration factor were 3.5 μg L^-1 and 150, respectively. The repeatability and reproducibility precision were in the range of 3.2-4.6% and 4.3-5.6% respectively. Recoveries ranging from 94% to 104% proved the accuracy of the method. The optimized method was successfully applied to the extraction and identification of patulin in the selected samples.

Development of sensitive and accurate solid-phase microextraction procedure for preconcentration of As(III) ions in real samples

We synthesized the poly(methyl methacrylate-co-2-aminoethyl methacrylate (PMaema) amphiphilic copolymer in a form of solid phase adsorbent. Then it was used for separation, preconcentration and determination of trace amount of As(III) ions from foods and waters with hydride generation atomic absorption spectrometry. The PMaema was characterized by fourier transform infrared spectrometer and nuclear magnetic resonance spectrometer. The adsorption of As(III) to the PMaema was also supported using computational chemistry studies. The experimental parameters (pH, PMaema amount, adsorption time and ethanol volume) were optimized using a three-level Box-Behnken design with four experimental factors. We observed linear calibration curve for the PMaema amount in the 10-500 ng L-1 range (R2 = 0.9956). Limit of detection, preconcentration factor and sorbent capacity of PMaema were equal to 3.3 ng L-1, 100 and 75.8 mg g-1, respectively. The average recoveries (spiked at 50 ng L-1) changes in the range of 91.5-98.6% with acceptable relative standard deviation less than 4.3%. After validation studies, the method was successfully applied for separation, preconcentration and determination of trace amount of As(III) from foods and waters.