Supramolecular imprinted polymeric stir bar sorptive extraction followed by high-performance liquid chromatography for endocrine disruptor compounds analysis

Flexible molecularly imprinted fiber library for the metabolic analysis of bisphenol F and ecological risk evaluation

Bisphenol F (BPF) has evoked global attentions due to its ubiquity and detrimental effects. Herein, a flexible molecularly imprinted fiber library was firstly proposed for the metabolic analysis of BPF in aquatic ecosystems. The library includes flexible single fibers and fiber arrays to precisely identify BPF and its metabolites with a wide range of polarities. Compared to commercial polyacrylate, the performance increased 11.56-570.98-fold. The adsorption capacity and the LogKow value were positively related. These arrays were used for the acquisition of environmental metabolomics data from aquatic ecosystems. In-depth data analysis showed that risk quotient was lower than 0.76, and bioaccumulation factor was lower than 2000 L/kg. Distribution concentration of BPF and its metabolites changed seasonally, and accumulation in sediment was much larger than that in surface water and hydrobionts. The risk is gradually increasing in sediment, but it does not reach high risk. The likelihood of bioaccumulation of parent compounds was greater than its metabolites. The library can be used in the metabolic diagnosis of pollutants with a broad range of polarities, providing a new method to acquire data for further ecological risk assessment, and offering a revolutionary strategy for environmental metabolomics investigation in aquatic ecosystems.

A multi-site recognition molecularly imprinted solid-phase microextraction fiber for selective enrichment of three cross-class environmental endocrine disruptors

Molecularly imprinted solid-phase microextraction fibers with multi-site recognition were prepared for the simultaneous enrichment of three cross-class environmental endocrine disruptors (EEDs) in environmental water. The surface morphology of the multi-site recognition molecularly imprinted fibers was characterized using scanning electron microscopy, atomic force microscopy, Fourier transform infrared spectroscopy, and surface area and pore size analyzer. Under optimal extraction conditions, the molecularly imprinted fibers showed higher extraction capacity to bisphenol F, diethyl phthalate, and methyl paraben than non-imprinted polymer fibers and commercial fibers. Compared with commercial solid-phase microextraction fibers, the multi-site recognition molecularly imprinted fibers showed superior extraction performance at different concentrations of analytes. The selectivity study confirmed that the multi-site recognition molecularly imprinted solid-phase microextraction fibers were highly selective not only for specific template molecules but also for bisphenols, parabens, and phthalates. Furthermore, the method achieved a limit of detection of 0.003-0.02 μg L^-1 for the three cross-class EEDs in environmental water samples with recoveries ranging from 75.76% to 112.69% and relative standard deviations below 11.46%. Thus, the novel MIP fibers with multi-site recognition prepared in this work have provided a promising approach in the field of specific adsorption and a strategy for the simultaneous and sensitive monitoring of multiple cross-class trace EEDs.

β-Cyclodextrin-Based Supramolecular Imprinted Fiber Array for Highly Selective Detection of Parabens

A novel high-throughput array analytical platform based on derived β-cyclodextrin supramolecular imprinted polymer (SMIP) fibers was constructed to achieve selective enrichment and removal of parabens. SMIP fiber arrays have abundant imprinting sites and introduce the host−guest inclusion effect of the derived β-cyclodextrin, which is beneficial to significantly improve the adsorption ability of fiber for parabens. Upon combination with HPLC, a specific and sensitive recognition method was developed with a low limit of detection (0.003−0.02 µg/L, S/N = 3) for parabens analysis in environmental water. This method has a good linearity (R > 0.9994) in the linear range of 0.01−200 µg/L. The proposed SMIP fiber array with high-throughput adsorption capacity has great potential in monitoring water pollution, which also provides a reliable reference for the analysis of more categories of pharmaceutical and personal care product pollutants.

Development of β-cyclodextrin crosslinked citric acid encapsulated in polypropylene membrane protected-μ-solid-phase extraction device for enhancing the separation and preconcentration of endocrine disruptor compounds

Endocrine disruptor compounds (EDCs) such as plasticisers, surfactants, pharmaceutical products, personal care products and pesticides are frequently released into the environmental waters. Therefore, a sensitive and environmentally friendly method is entailed to quantify these compounds at their trace level concentrations. This study encapsulated the β-cyclodextrin crosslinked with citric acid in a polypropylene membrane protected-μ-solid phase extraction (BCD-CA μ-SPE) device for preconcentrating the EDCs (triclosan, triclocarban, 2-phenylphenol, 4-tert-octylphenols and bisphenol A) in real water samples before the analysis by high-performance liquid chromatography. FT-IR and TGA results indicated that BCD-CA was successfully synthesised with the formation of ester linkage (1078.33 cm^-1) and O-H stretching from carboxylic acid (3434.70 cm^-1) with higher thermal stability as compared with native CD with the remaining weight above 72.1% at 500 °C. Several critical parameters such as the sorbent loading, type and amount of salts, extraction time, sample volume, sample pH, type and volume of desorption solvents and desorption time were sequentially optimised and statistically validated. Under the optimum condition, the use of BCD-CA μ-SPE device had manifested good linearity (0.5-500 μg L^-1) with the determination of the coefficient range of 0.9807-0.9979. The p-values for the F-test and t-test (6.60 × 10^-8 - 1.77 × 10^-5) were lesser than 0.05 and low detection limits ranging from 0.27 to 0.84 μg L^-1 for all studied EDCs. The developed technique was also successfully applied for EDC analyses in four distinct real water samples, namely, wastewater, river water, tap water and mineral water, with good EDCs recoveries (80.2%-99.9%), low relative standard deviations (0.1%-3.8%, n = 3) with enrichment factor ranging from 9 to 82 folds. These results signified the potential of the BCD-CA μ-SPE device as an efficient, sensitive, and environmentally friendly approach for analyzing EDCs.

Design, synthesis, and characterization of a series of novel β-cyclodextrin functional monomers

In order to increase its solubility in water and improve β-cyclodextrin combination with guest molecules, chemical modification of β-cyclodextrin is a feasible and effective method. A variety of β-cyclodextrin derivatives are designed and introduced for pharmaceutical complexation and analytical chemistry application. In this study, a series of β-cyclodextrin derivatives containing unsaturated bonds is designed and synthesized. The products are characterized by MS, FTIR, 1H NMR, and 13C NMR. Some of the functional monomers may be used in the preparation of molecularly imprinted polymers, and preliminary studies have shown excellent molecular recognition ability. The prepared β-cyclodextrin functional monomers have potential application value in molecular recognition materials based on polymers.

Cyclodextrin-based dispersive liquid-liquid microextraction for the determination of fungicides in water, juice, and vinegar samples via HPLC

Cyclodextrin-based dispersive liquid-liquid microextraction (CD-DLLME) was developed for the determination of triazole and strobilurin fungicides in water, juice, and vinegar samples using high-performance liquid chromatography-diode-array detection (HPLC-DAD). Undecanol, which is a green solvent, was selected as the extraction solvent. A cyclodextrin aqueous solution was chosen as the dispersion solvent and demulsifier to avoid the use of a toxic dispersion solvent and eliminate the centrifugation step. Dispersion and phase separation were completed within 1 and 60 s, respectively. The linear range of this method was 1 to 100 µg L^-1. The limits of detection were 0.3 μg L^-1 along with the preconcentration factor of 133 and enrichment factor of 124. The recovery was 83.2% to 103.2%. This pretreatment method was fast, simple, and environmentally friendly and was successfully applied to the analysis of triazole and strobilurin fungicide residues in water, juice, and vinegar samples.

A new approach based on inversion of a partial least squares model searching for a preset analytical target profile. Application to the determination of five bisphenols by liquid chromatography with diode array detector

The paper shows a procedure for selecting the control method parameters (factors) to obtain a preset 'analytical target profile' when a liquid chromatographic technique is going to be carried out for the simultaneous determination of five bisphenols (bisphenol-A, bisphenol-S, bisphenol-F, bisphenol-Z and bisphenol-AF), some of them regulated by the European Union. The procedure has three steps. The first consists of building a D-optimal combined design (mixture-process design) for the control method parameters, which are the composition of the ternary mobile phase and its flow rate. The second step is to fit a PLS2 model to predict six analytical responses (namely, the resolution between each pair of consecutive peaks, and the initial and final chromatographic time) as a function of the control method parameters. The third final step is the inversion of the PLS2 model to obtain the conditions needed for attaining a preset analytical target profile. The computational inversion of the PLS2 prediction model looking for the Pareto front of these six responses provides a set of experimental conditions to conduct the chromatographic determination, specifically 22% of water, mixed with 58% methanol and 20% of acetonitrile, keeping the flow rate at 0.66 mL min^-1. These conditions give a chromatogram with retention times of 2.180, 2.452, 2.764, 3.249 and 3.775 min for BPS, BPF, BPA, BPAF and BPZ, respectively, and excellent resolution among all the chromatographic peaks. Finally, the analytical method is validated under the selected experimental conditions, in terms of trueness and precision. In addition, the detection capability for the five bisphenols were: 596, 334, 424, 458 and 1156 μg L^-1, with probabilities of false positive and of false negative equal to 0.05.

Application of a new adhesive elastomeric coating and hydrophilic-lipophilic-balanced sorbent for modified stir-bar sorptive extraction

A new polyurethane adhesive was evaluated to fix a hydrophilic-lipophilic-balanced sorbent and to produce modified stir-bars. It presented high mechanical and chemical resistance, indicating that it is an adequate adhesive. The homemade bars were employed to determine bisphenol A, diclofenac, ibuprofen and triclosan in aqueous medium. Satisfactory figures of merit were observed, with LOD between 0.06 and 0.30 ng mL-1 and enrichment factors between 133 and 195 times, using an extraction time of 2 h. The stir-bars were employed to determine the four analytes in water samples, presenting recovery results from 53 to 135% and RSD between 0.7 and 20%. In general, the results observed here indicated that the adhesive is an appropriate alternative material to fix HLB particles, and could probably be applied to other sorbents.