A green molecular imprinted solid-phase extraction protocol for bisphenol A monitoring with HPLC-UV to guarantee the quality and safety of walnuts under different storage conditions

Optimization of a Fabric Phase Sorptive Extraction protocol for the isolation of six bisphenols from juice pouches to be analysed by high performance liquid chromatography coupled with diode array detector

Fabric Phase Sorptive Extraction (FPSE) combined with high pressure liquid chromatography using to diode array detection (HPLC-DAD) was applied for the simultaneous determination of bisphenols (BPA, BPB, BPC, BPE, BPF, BPS) in juice pouches. The FPSE procedure was optimized with regards to the critical parameters that affect the performance of the method including the selection of the FPSE membrane type and size, adsorption time, extraction time, solvent volume desorption, magnetic stirring ratio, and salt addition. The FPSE membrane could be reused up to 14 times. The developed FPSE-HPLC-DAD method was validated in terms of linearity, sensitivity, accuracy andprecision. The limits of detection (LODs) were lower than 6.9 ng/mL, while the limits of quantification (LOQs) were lower than 21 ng/mL. The results obtained are satisfactory in terms of precision, accuracy and repeatability, with recoveries above 86% and CV values below 9.5%. The FPSE-HPLC-DAD method was successfully applied in the determination of six bisphenols in juice samples stored in pouches.

Arsenic(III) and Arsenic(V) Removal from Water Sources by Molecularly Imprinted Polymers (MIPs): A Mini Review of Recent Developments

The present review article summarizes the recent findings reported in the literature with regard to the use of molecularly imprinted polymers for the removal of arsenic from water and wastewater. MIPs are polymers in which a template is employed in order to enable the formation of recognition sites during the covalent assembly of the bulk phase, via a polymerization or polycondensation process. The efficiency of both arsenic species and the mechanism of removal are highlighted. The results have shown that under certain conditions, MIPs demonstrated arsenic sorption capacities of up to 130 mg/g for As(V) and 151 mg/g for As(III), while the regeneration ability was found to reach up to more than 20 cycles. The overall results showed that further development of MIPs could result in the formation of promising adsorbents for arsenic removal from waters. The use of MIPs for the removal not only of arsenic but also other inorganic contaminants is considered a very important topic, with great potential in terms of future applications in water treatment. The main advantage of these materials is that they are very selective toward the contaminant of interest. This enhanced selectivity is attributed to the incorporation of specific templates, which can then adsorb the contaminant of interest almost exclusively. Therefore, the main problem in adsorption processes is the competition for adsorption sites by other water components, for example, phosphates, nitrates, carbonates, and sulfates, which can be circumvented by the use of MI-type adsorbents.

Evaluation of three sorbent-phase extraction techniques based on hyper-crosslinked polymer for the extraction of five endocrine disrupters in water

A series of low-cost hyper-crosslinked polymers were prepared by an easy one-step Friedel-Crafts reaction. The synthesized hyper-crosslinked polymers exhibited remarkably porous structure, large surface area, and hydroxyl groups, which can be employed as an ideal adsorbent material for novel sorbent-phase extraction techniques. Based on this, using hyper-crosslinked polymers as sorbent and coating, three novel extraction methods, including micro-solid-phase extraction, dispersive solid-phase extraction, and solid-phase microextraction, were explored and evaluated for simultaneous measurement of five endocrine-disrupting compounds (triclosan and bisphenol A, tetrabromobisphenol A, tetrabromobisphenol A bisallylether, and tetrabromobisphenol A bis(2,3-dibromopropyl ether)) in environment water prior to high-performance liquid chromatography-ultraviolet. The influence of experimental parameters on three extraction techniques such as extraction time, the amount of hyper-crosslinked polymers, extraction temperature, ionic strength, and desorption conditions were optimized. Three previously mentioned methods provided limits of detection ranging from 0.01 to 0.05 μg/L, and high recoveries (85-99%) with relative standard deviations of 1.7-5.6%. This study presented the merits and disadvantages of three proposed extraction methods and their potential for effective monitoring of hazardous pollutants in real water samples.

Computational modeling, fabrication, and characterization of the deep eutectic solvent-based green molecular cage for selective metronidazole extraction from plasma followed by UHPLC with diode array detector determination

Four ternary deep eutectic solvents were computationally designed and synthesized, being used as candidate functional monomers in metronidazole molecular imprinting polymer synthesis, allowing selective extraction and determination by ultra high performance liquid chromatography with diode array detection. In terms of metronidazole selective extraction, the best results were obtained by (deep eutectic solvent)₂ :(ethylene glycol dimethacrylate)₁₁ , in which deep eutectic solvent is the functional monomer constructed by combining three components in 6:6:2 ratios of choline chloride:ethylene glycol:methacrylic acid. The effects of different parameters on molecular imprinted solid-phase extraction of metronidazole were thoroughly explored through screening design and response surface methodology. The adsorption mechanism findings show that the adsorption data are primarily fitted on the Freundlich model based on higher correlation coefficient. Kinetic experiments have shown that the mechanism of adsorption fits the pseudo-second-order model. The best extraction recovery (96.5%) was obtained in 25-min elution time, desorption temperature of 40°C, and 1.0 mL ACN as eluent. Metronidazole was measured by a validated ultra high performance liquid chromatography with diode array detection method. The calibration of the method was linear in the range of 0.1-10 μg/mL with limits of detection and quantification of 0.03 and 0.1 μg/mL, respectively. The method was successfully applied for the determination of metronidazole in human plasma.

Determination of the Toxic and Nutrient Element Content of Almonds, Walnuts, Hazelnuts and Pistachios by ICP-AES

The trace element content of thirty-two nuts including almonds, walnuts, hazelnuts and pistachios available in a Greek market was determined by inductively coupled plasma atomic emission spectrometry (ICP-AES). Wet acid digestion using nitric acid (65%) took place in Teflon autoclaves. The limits of detection (LODs) and limits of quantification (LOQs) ranged between 0.01 (Mg)–2.52 (Cu) μg g−1 and 0.02 (Mg)–8.40 (Cu) μg g−1, respectively. Good method linearity (r2 > 0.9990) was observed for each element at the selected emission lines. The metals were quantified and one-way analysis of variance (ANOVA) was used to examine whether or not there were any statistically significant differences among the metal concentrations inside the different nut species.