Simultaneous extraction of four plant growth regulators residues in vegetable samples using solid phase extraction based on thiol-functionalized nanofibers mat

Construction of a physiologically based pharmacokinetic model of paclobutrazol and exposure estimation in the human body

Paclobutrazol (PBZ) is a plant growth regulator that can delay plant growth and improve plant resistance and yield. Although it has been widely used in the growth of medicinal plants, human beings may take it by taking traditional Chinese medicine. There are no published studies on PBZ exposure in humans or standardized limits for PBZ in medicinal plants. We measured the solubility, oil-water partition coefficient (logP), and pharmacokinetics of PBZ in rats and established a physiologically based pharmacokinetic (PBPK) model of PBZ in rats. This was followed by extrapolation to healthy Chinese adult males as a theoretical foundation for future risk assessment of PBZ. The results showed that PBZ had low solubility and high fat solubility. Pharmacokinetic experiments showed that PBZ was absorbed rapidly but eliminated slowly in rats. On this basis, the rat PBPK model was successfully constructed and extrapolated to healthy Chinese adult males to predict the plasma concentration-time curve and exposure of PBZ in humans. The construction of the PBPK model of PBZ in this study facilitates the determination of the standard formulation limits and risk assessment of PBZ residues in medicinal plants.

Hydrophilic molecularly imprinted resin-hexagonal boron nitride composite as a new adsorbent for selective extraction and determination of a carcinoid tumor biomarker in urine

BACKGROUND

The detection of disease biomarkers in biological samples plays an important role in early diagnosis and treatment of carcinoid tumor. However, due to the complexity of biological samples and the extremely low concentration of disease biomarkers, sample pretreatment is still the bottleneck of achieving accurate quantitative determination. In this work, new hydrophilic molecularly imprinted resin-hexagonal boron nitride (HMIR-h-BN) composites were developed and used as a new solid phase extraction (SPE) adsorbent for selective detection of 5-hydroxyindoleacetic acid (5-HIAA), a biomarker of carcinoid tumor, in urine.

RESULTS

Twenty-two types of HMIR-h-BN were successfully synthesized through growing hydrophilic molecularly imprinted resin on surface of activated two-dimensional h-BN nanosheets, and preparation parameters affecting the adsorption performance of HMIR-h-BN were investigated and optimized through adsorption experiments. HMIR-h-BN #19 (the ratio of resorcinol to hexamethylenetetramine: 6:3; the dosage of h-BN: 300 mg; the dosage of dummy template: 0.12 mmol; the imprinting time: 4 h) has demonstrated to be the optimal material for efficient separation and extraction of 5-HIAA. Combined with HPLC-UV, the limit of detection and the limit of quantification of 5-HIAA in real urine samples were 9.4 ng mL-1 and 31.3 ng mL-1, respectively, the coefficient of determination (R2) was 0.9996 in the linear range of 0.1-300 μg mL-1 and the relative recoveries ranged from 86.9 % to 97.7 % with RSD ≤5.1 %. Moreover, after being processed by HMIR-h-BN-SPE, there are no interferences from other peaks at the peak position of 5-HIAA.

SIGNIFICANCE

The HMIR-h-BN composite has been demonstrated to be capable of selective extraction of 5-HIAA from urine samples and have a significant purification effect. Based on the established HMIR-h-BN-SPE-HPLC-UV method, accurate quantitative determination of 5-HIAA in urine samples was achieved, which is expected to be applied in the early diagnostic of carcinoid tumor.

Construction of magnetic hydroxyl group-enriched hyper cross-linked polymers with functional triazine as the core for efficient enrichment of plant growth regulators

The determination of trace plant growth regulators (PGRs) residues in water and food samples make it crucial to develop novel sample pretreatment methods for the enrichment of PGRs. Herein, a novel magnetic hyper cross-linked polymer (M-CTT-9OH-HCP) was constructed and served as a magnetic adsorbent for the efficient extraction of some PGRs from water, watermelon, tomatoes, and milk samples for the first time. Combined with high performance liquid chromatography-fluorescence detection (HPLC-FLD), the established method presented a good linearity (0.03-60.0 ng g-1 (ng mL-1), (r) ≥ 0.9973), satisfactory accuracy with method recoveries (83.0%-119%) and acceptable precision with the intra-day and inter-day variations (expressed as the relative standard deviations (RSDs) ≤ 9.8%). The limits of detection (LODs) and limits of quantitation (LOQs) were in the range of 0.01-1.50 and 0.03-5.00 ng g-1/ ng mL-1. The results show that the established method is sensitive and efficient for the determination of PGRs in real samples.

Polyvinyl alcohol electrospun nanofiber membrane based solid-phase extraction for monitoring administered aminoglycoside antibiotics in various animal-derived foods

This work aims to develop a widely applicable method to monitor administered AGs in various animal-derived food samples to ensure food safety. A polyvinyl alcohol electrospun nanofiber membrane (PVA NFsM) was synthesized and employed as solid-phase extraction (SPE) sorbent, in combination with UPLC-MS/MS, for the simultaneous detection of ten AGs in nine types of animal-derived food samples. PVA NFsM exhibited excellent adsorption performance for the targets (with an adsorption rate of over 91.09%), good matrix purification ability (with a reduction of 7.65%-77.47% in matrix effect after SPE), and good recyclability (can be reused 8 times). The method displayed a linear range of 0.1-25000 μg/kg and attained limits of detection for AGs were 0.03-15 μg/kg. Spiked samples demonstrated a recovery of 91.72%-100.04% with a precision of<13.66%. The practicality of the developed method was verified by testing multiple actual samples.

Recent advances in emerging application of functional materials in sample pretreatment methods for liquid chromatography-mass spectrometry analysis of plant growth regulators: A mini-review

Plant growth regulators (PGRs) are a class of small molecular compounds, which can remarkably affect the physiological process of plants. The complex plant matrix along with a wide polarity range and unstable chemical properties of PGRs hinder their trace analysis. In order to obtain a reliable and accurate result, a sample pretreatment process must be carried out, including eliminating the interference of the matrix effect and pre-concentrating the analytes. In recent years, the research of functional materials in sample pretreatment has experienced rapid growth. This review comprehensively overviews recent development in functional materials covering one-dimensional materials, two-dimensional materials, and three-dimensional materials applied in the pretreatment of PGRs before liquid chromatography-mass spectrometry (LC-MS) analysis. Besides, the advantages and limitations of the above functionalized enrichment materials are discussed, and their future trends have been prospected. The work could be helpful to bring new insights for researchers engaged in functional materials in sample pretreatment of PGRs based on LC-MS.

Novel polymer nanoparticles with core-shell structure for breaking asphaltenes-stabilized W/O and O/W emulsions

HYPOTHESIS

The removal of stable water-in-oil (W/O) or oil-in-water (O/W) emulsions has been a challenging issue in chemical and oil industry for decades. Traditional demulsifiers were generally designed specifically for treating either W/O or O/W emulsions. A demulsifier that is effective for treating both types of emulsions will be highly desired.

EXPERIMENTS

Novel polymer nanoparticles (PBM@PDM) was synthesized as a demulsifier for treating both W/O and O/W emulsions prepared by toluene, water, and asphaltenes. The morphology and chemical composition of synthesized PBM@PDM were characterized. Demulsification performance and interaction mechanisms including interfacial tension, interfacial pressure, surface charge properties and surface forces were systematically studied.

FINDINGS

PBM@PDM could immediately prompt the coalescence of water droplets upon addition and effectively release the water in asphaltenes-stabilized W/O emulsion. In addition, PBM@PDM successfully destabilized asphaltenes-stabilized O/W emulsion. Not only could PBM@PDM substitute the asphaltenes adsorbed at the water-toluene interface, but they could also dominate the water-toluene interfacial pressure in competition with asphaltenes. The steric repulsion between interfacial asphaltene films could be suppressed in the presence of PBM@PDM. Surface charges significantly influenced the stability of asphaltenes-stabilized O/W emulsion. This work provides useful insights into the interaction mechanisms of asphaltene-stabilized W/O and O/W emulsions.

Fabrication of magnetic ordered mesoporous carbon for quantitative analysis of acidic phytohormones in mushroom samples prior to their determination by ultra-high-performance liquid chromatography–tandem mass spectrometry

A novel method was established for analysing trace four acidic phytohormones, namely, indole-3-acetic acid, 3-indolebutyric acid, abscisic acid, and 1-naphthylacetic acid, using magnetic ordered mesoporous carbon (MOMC). MOMC was facilely synthesised via self-assembly strategy with a direct carbonisation process. The properties of MOMC were characterised using various instruments. MOMC exhibited excellent adsorption capacity towards the analytes. Various critical parameters which may influence the enrichment efficiency were evaluated, including amount of MOMC, extraction conditions, and desorption conditions. An efficient method based on MOMC magnetic solid-phase extraction coupled with ultra-high-performance liquid chromatography–tandem mass spectrometry (UHPLC–MS/MS) was developed to analyse the trace four acidic phytohormones, with good correlation coefficients (R 2 = 0.9965–0.9998) and low limits of detection (0.13–9.7 ng L−1, S/N = 3). Trace acidic phytohormones in Agaricus bisporus and Hypsizygus marmoreus samples were determined with satisfactory recoveries (91.8–108%) and reproducibility (2.6–6.3%). The features indicated that MOMC provides an efficient platform for mushroom sampling; the developed method is convenient, promising, and sensitive for the detection of trace phytohormones in complicated mushroom samples.

Effectively removing indole-3-butyric acid from aqueous solution with magnetic layered double hydroxide-based adsorbents

The magnetic layered double hydroxide-based materials (MLDHs) with the metal composition of Mg(II)Al(III) were synthesized by different conditions as the adsorbent for removal of a phytohormone, indole-3-butyric acid (IBA). The morphological characteristics of MLDHs were studied through various characterization methods such as XRD, SEM, TEM, FTIR, BET, Zeta-potential and VSM. The adsorption results showed that the adsorption capacity of MLDH-1 synthesized by co-precipitation method with ammonia as the base source was the best (maximum 522.6 mg/g). The extent of adsorption in the pH range of 3.0-9.0 was observed to be no noticeable change. From the economical point of view, 1.0 g/L MLDH-1 composites were selected as optimum parameter. For a given adsorbent concentration (C_s), its kinetics and adsorption isotherm followed the pseudo-second-order and Liu isotherm model, respectively. The adsorbed sample can be easily magnetically separated and regenerated with NaNO₃. The adsorption process was spontaneous and exothermic, including two path stages: surface adsorption of lamellar and interlayer anion exchange. The research makes a contribution to evaluating the ability of MLDHs in IBA removal and helping the public to understand the mechanism of adsorption process.

Development and perspectives of rapid detection technology in food and environment

Food safety become a hot issue currently with globalization of food trade and food supply chains. Chemical pollution, microbial contamination and adulteration in food have attracted more attention worldwide. Contamination with antibiotics, estrogens and heavy metals in water environment and soil environment have also turn into an enormous threat to food safety. Traditional small-scale, long-term detection technologies have been unable to meet the current needs. In the monitoring process, rapid, convenient, accurate analysis and detection technologies have become the future development trend. We critically synthesizing the current knowledge of various rapid detection technology, and briefly touched upon the problem which still exist in research process. The review showed that the application of novel materials promotes the development of rapid detection technology, high-throughput and portability would be popular study directions in the future. Of course, the ultimate aim of the research is how to industrialization these technologies and apply to the market.

Magnetic boron nitride nanosheets as a novel magnetic solid-phase extraction adsorbent for the determination of plant growth regulators in tomatoes

A novel magnetic boron nitride nanosheets (Fe₃O₄@BNNSs) composite-based magnetic solid-phase extraction (MSPE) method was employed to analyse six plant growth regulators (PGRs) in tomatoes combined with high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS). The novel Fe₃O₄@BNNSs composite was prepared via an in situ chemical coprecipitation process and characterized by scanning electron microscopy (SEM), Fourier transform infrared spectrometry (FT-IR), X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), and vibrating sample magnetometry (VSM). Several factors that may affect the extraction efficiencies were optimized. Under the optimal factors, low limits of detection (0.002-0.010 ng g^-1), good linear ranges (0.05-10 ng g^-1) and satisfactory precisions (intra-day: 1.2%-3.9%; inter-day: 2.1%-6.9%) were achieved. The established approach was successfully employed to extract and determine PGRs in tomatoes, and the spiked recoveries were between 85.2 and 109.0%.

Selective, sensitive, and miniaturized analytical method based on molecularly imprinted graphene oxide composites for the determination of naphthalene-derived plant growth regulators in apples

This paper reports a selective, sensitive, and miniaturized analytical method based on a molecularly imprinted graphene oxide (MIP-GO) composite as adsorbent for miniaturized tip solid-phase extraction (MTSPE) to determine naphthalene-derived plant growth regulators (PGRs) in apples. The proposed method combines the advantages of MIP-GOs (high selectivity), MTSPE (low consumption), and high-performance liquid chromatography-fluorescence detection (high sensitivity). Under optimized conditions, the method exhibited appreciable linearity (2.00-200 ng/g), low detection limits (0.21-0.53 ng/g), high accuracy (absolute recoveries: 87.6-99.5%), and high precision (relative standard deviations ≤ 3.0%), along with low consumption (0.5 mL sample solution and 2.0 mg adsorbent). In addition, the adsorption performance of the MIP-GO adsorbent did not decrease over ten months, highlighting the long storage and operational lifetime of the adsorbent. The proposed method was employed for the analysis of naphthalene-derived PGR residues in apples and exhibited promising potential for application in food safety analysis.

Sodium 4-styrenesulfonate functionalized nanofibers mat as 96-well plate solid-phase extraction adsorbent for quantitative determination of multiple β-agonists residues in pork samples

In this work, sodium 4-styrenesulfonate functionalized polyacrylonitrile nanofibers mat (SS/PAN NFM) was firstly prepared and applied as 96-well plate solid-phase extraction adsorbent for quantitative determination of seven β-agonists residues in pork samples. The functional modification endowed the SS/PAN NFM with superior adsorption performance for target β-agonists. The adsorption process is spontaneous (ΔG < 0), the initial adsorption rate can reach 6.03-9.09 mg/g/min and the maximum adsorption capacity is calculated to be 48.3 mg/g at 298 K. Moreover, SS/PAN NFM can be reused for 12 times without degradation in adsorption capability. Combined with UPLC-MS/MS, the limits of detection can reach 0.006-0.24 μg/kg, the recoveries ranged from 87.2% to 111% and the relative standard deviations of intra-day and inter-day precisions were in the scope of 1.75%-11.6% and 5.08%-13.5%, respectively. The obtained results fully demonstrated the practicability of this method in preventing the hazard of β-agonists residues.