Magnetic solid-phase extraction of four β-lactams using polypyrrole-coated magnetic nanoparticles from water samples by micellar electrokinetic capillary chromatography analysis

Polypyrrole supported Pd/Fe bimetallic nanoparticles with enhanced catalytic activity for simultaneous removal of 4-chlorophenol and Cr(VI)

Nanoscale zerovalent iron (nZVI) represents a promising reduction technology for water remediation, but its broad application is largely hampered by the tendency of nZVI to aggregate and the low electron transferability due to the interfacial charge resistance. Herein, by combining the advantages of polypyrrole (PPY) and nZVI, we prepared a composite material (i.e., PPY supported palladium‑iron bimetallic nanoparticles (Pd/Fe@PPY)) and applied it for the simultaneous removal of 4-chlorophenol (4-CP) and Cr(VI). Our results showed that this material had superior catalytic performances with a complete removal of 4-CP (50 mg·L^-1) and Cr(VI) (10 mg·L^-1) within 60 and 1 min, respectively. As opposed to the bare Pd/Fe nanoparticles, the reactivity of Pd/Fe@PPY with 4-CP was significantly enhanced by nearly 8 times. The enhanced catalytic activity of Pd/Fe@PPY was attributed to the distinctive properties of PPY as i) a good support that resulted in the formation of Pd/Fe nanoparticles with high dispersibility; ii) an adsorbent that increased the accessibility of 4-CP and Cr(VI) with electrons or active species (e.g., H*) on the particles surface; iii) an electron transfer carrier that facilitated the reactivity of Pd/Fe@PPY with contaminants by reducing the interfacial charge resistance. Moreover, by conducting cyclic voltammetry and quenching investigations, we showed that two mechanisms (i.e., direct and H*-mediated indirect electron transfer) were involved in the reductive dehalogenation of 4-CP, while catalytic hydrodechlorination played a dominant role. This work offers an alternative material for the efficient removal of 4-CP and Cr(VI) and provides better understanding of the relationship between structure and catalytic activity of nZVI.

Restricted double access mesoporous polypyrrole as adsorbent in pipette-tip solid phase extraction for simultaneous determination of progesterone, pyriproxyfen, and deltamethrin in chicken eggs

In this study, two sample preparation techniques were evaluated in the simultaneous determination of three compounds with different physicochemical properties, progesterone, pyriproxyfen, and deltamethrin that may be present in the chicken egg. In this procedure, firstly the restricted double access mesoporous polypyrrole was synthesized, which was evaluated as adsorbent in pipette-tip solid phase extraction and dispersive solid phase extraction. After optimizing the extraction parameters, it was found that pipette-tip solid phase extraction was more efficient and, therefore, it was used in the validation and application of the method. The analytical method showed good recoveries, acceptable linearity (r > 0.99), limits of quantification, precision and accuracy, robustness and stability within the limits of the literature. Finally, the developed method was successfully applied in simultaneous determination of analytes in different chicken egg samples. Therefore, this work provided a promising strategy for the extraction of different organic compounds from egg products.

Rapid Determination of Vitamin D3 in Aquatic Products by Polypyrrole-Coated Magnetic Nanoparticles Extraction Coupled with High-Performance Liquid Chromatography Detection

A method using polypyrrole-coated Fe3O4 (Fe3O4@PPy composites) based extraction coupled with high performance liquid chromatography was developed for adsorption and detection of trace vitamin D3 (VD3) in aquatic products. The fabricated Fe3O4@PPy composites were characterized by scanning electron microscopy, transmission electron microscopy, X-ray diffraction, Fourier transform infrared spectroscopy, and thermogravimetric analysis. Fe3O4@PPy composites showed efficient adsorption of VD3 at pH 9.0 and 25 °C with a dose of 25 mg per 10 mL of sample solution and an adsorption time of 11 min. Methanol was selected as the desorption solvent to recover VD3 from Fe3O4@PPy composites after 3 min of static treatment. Fe3O4@PPy composites can be used for VD3 adsorption at least two times. The developed method showed a good linearity for VD3 determination in the range of 0.1-10 μg/mL with a correlation coefficient of 0.9989. The limits of detection and quantification were 10 ng/mL and 33 ng/mL, respectively. The recovery of VD3 in a spiking test was 97.72% with a relative standard deviation value of 1.78%. The content of VD3 in nine aquatic products was determined with this method. Our results show that Fe3O4@PPy composites provide a convenient method for the adsorption and determination of VD3 from the complex matrix of aquatic products.

Conductive Polymer-Based Nanocomposites as Powerful Sorbents: Design, Preparation and Extraction Applications

Conductive polymers as composite materials have been attracted tremendous attention due to their versatile and excellent features such as tunable conductivity, facile synthesis and fabrication, high chemical and thermal stability etc. These characteristics make them versatile and let them being used in numerous fields including microelectronics, optics and biosensors. Throughout the mentioned fields, conductive polymers particularly perform as effective sorbents. Although tremendous efforts have been put into this topic, to the best of our knowledge, a comprehensive up-to-date review on the applications of conductive polymers as efficient sorbents has not been reported. The main objective of this paper is to make a significant contribution to the recent literature toward the synthesis and extraction applications of conductive polymers as efficient sorbents.

Design, Preparation, and Application of Magnetic Nanoparticles for Food Safety Analysis: A Review of Recent Advances

This review (with 126 references) aims at providing an updated overview of the recent developments and innovations of the preparation and application of magnetic nanoparticles for food safety analysis. During the past two decades, various magnetic nanoparticles with different sizes, shapes, and surface modifications have been designed, synthesized, and characterized with the prospering development of material science. Analytical scientists and food scientists are among the ones who bring these novel materials from laboratories to commercial applications. Powerful and versatile surface functional groups and high surface to mass ratios make these magnetic nanoparticles useful tools for high-efficiency capture and preconcentration of certain molecules, even when they exist in trace levels or complicated food matrices. This is why more and more methods for sensitive detection and quantification of hazards in foods are developed based on these magic magnetic tools. In this review, the principles and superiorities of using magnetic nanoparticles for food pollutant analysis are first introduced, like the mechanism of magnetic solid phase extraction, a most commonly used method for food safety-related sample pretreatment. Their design and preparation are presented afterward, alongside the mechanisms underlying their application for different analytical purposes. After that, recently developed magnetic nanoparticle-based methods for dealing with food pollutants such as organic pollutants, heavy metals, and pathogens in different food matrices are summarized in detail. In the end, some humble outlooks on future directions for work in this field are provided.

Abundance and Dynamic Distribution of Antibiotic Resistance Genes in the Environment Surrounding a Veterinary Antibiotic Manufacturing Site

Background: Antibiotics releasing from the manufacturing sites to the surrounding environment has been identified as a risk factor for the development of antibiotic resistance of bacterial pathogens. However, the knowledge of the abundance and distribution of antibiotic resistance genes (ARGs) influenced by antibiotic pollution is still limited. Methods: In this work, the contamination by resistance genes of the environmental media including an urban river and soil along the river located near the sewage outlet of a veterinary antibiotic manufacturing site in Shijiazhuang, China, was assessed. The abundance and dynamic distribution of ARGs in different sampling points and during different seasons were analyzed using fluorescent quantitative PCR method (qPCR). Results: A total of 11 resistance genes, one integron and one transposon were detected in water and soils around the pharmaceutical factory, and among which, the sulfonamide resistance genes sul1 and β-lactam resistance genes blaSHV were the most abundant genes. The relative abundance of ARGs in both river water and soil samples collected at the downstream of the sewage outlet was higher than that of samples collected at the upstream, non-polluted areas (p < 0.05). The mobile genetic elements (MGEs) integron in river was significantly correlated (p < 0.05) with the relative abundance of ARGs. Conclusions: The results indicate that the discharge of waste from antibiotic manufacturing site may pose a risk of horizontal transfer of ARGs.

[Annual review of capillary electrophoresis technology in 2020]

该文为2020年毛细管电泳(capillary electrophoresis, CE)技术年度回顾。归纳总结了以“capillary electrophoresis-mass spectrometry”或“capillary isoelectric focusing”或“micellar electrokinetic chromatography”或“capillary electrophoresis”为关键词在ISI Web of Science数据库中进行主题检索得到的2020年CE技术相关研究论文222篇,以及中文期刊《分析化学》和《色谱》中CE技术相关的研究论文37篇。对2020年影响因子(IF)≥5.0的Analytical Chemistry, Food Chemistry, Analytica Chimica Acta和Talanta等13本期刊的38篇文章报道的科研工作作了逐一介绍;对IF<5.0的期刊中CE技术报道较为集中的Journal of Chromatography A和Electrophoresis两本分析化学类期刊发表40篇文章中的代表性内容作了综合介绍;对重要的中文期刊《分析化学》出版的“核酸适配体专刊”和《色谱》出版的2期CE技术专刊所收录的37篇文章中的工作作了总体介绍。总体来说,2020年CE技术发展趋势仍以毛细管电泳-质谱(CE-MS)的新方法和新应用最为突出,主要集中在CE-MS与电化学检测、固相萃取以及多种毛细管电泳模式的联用方面,CE-MS接口相关的报道较前几年有所减少;常规CE技术则以胶束电动毛细管色谱(MEKC)在复杂样本分析、浓缩富集应用为主,尤其在食品和药品等复杂基质样本分析方面的报道较为集中;此外,我国CE相关领域专家学者的科研成果涵盖了CE在生命科学、临床医学、医药研发、环境科学、天然产物、食品分析等领域的应用,代表了国内CE科研应用水平和现状。

Rapid determination of folic acid and riboflavin in urine by polypyrrole magnetic solid-phase extractant combined ultra-performance liquid chromatography

Determination of folic acid and riboflavin in biological samples is difficult due to their high polarity, low concentration, chemical instability, and complex matrix. In this study, the polypyrrole-coated magnetic nanocomposite (Fe₃O₄@PPy) was synthesized innovatively with the assistance of hexadecyltrimethylammonium bromide. To evaluate the adsorption mechanism and the feasibility of synthesized Fe₃O₄@PPy as an adsorbent, the adsorption capacities, kinetics and thermodynamics of folic acid and riboflavin were investigated systemically. Furthermore, in light of the chemical instability of folic acid and riboflavin a method for rapid extraction and detection of them from human urine within 10 min was developed successfully by combining magnetic solid phase extraction with ultra-performance liquid chromatography (MSPE/UPLC). The adsorption parameters including sorbent amount, pH value, extraction time, desorption solvent and desorption time were studied. Under optimum conditions, the performance of the established determination method was validated with the linearly dependent coefficients (>0.9995), the limits of detection (0.02-0.05 µg/mL), the limits of quantification (0.07-0.18 µg/mL), and the recoveries (92.2-105.1%, with relative standard deviation < 3.3%). The rapid extraction and detection of folic acid and riboflavin from real urine samples were achieved subsequently. The present study suggests that the developed method exhibits a promising application in the analysis of free folic acid and riboflavin in human urine samples, which can provide a reference for the clinical drug monitoring and treatment.

Ultrasonication-facilitated synthesis of functionalized graphene oxide for ultrasound-assisted magnetic dispersive solid-phase extraction of amoxicillin, ampicillin, and penicillin G

A simplistic approach is presented for the synthesis of ultrasonically fabricated graphene oxide functionalized with polyaniline and N-[3-(Trimethoxysilyl)propyl]ethylenediamine. The synthesized nanocomposite was then employed for the facile, green, ultrasound-assisted, magnetic dispersive solid-phase extraction of amoxicillin, ampicillin, and penicillin G in milk samples and infant formula prior to high-performance liquid chromatography-ultraviolet determination. The designed nanocomposites were comprehensively characterized using field emission scanning electron microscopy, energy-dispersive X-ray spectroscopy, transmission electron microscopy, X-ray powder diffraction, and Fourier transform infrared spectroscopy. In order to achieve the best extraction efficiencies, the influential parameters including pH, amount of magnetic sorbent, type and volume of elution solvent, extraction time, sample volume, and desorption time were assessed. At the optimum conditions, linear ranges of 2.5-1000 (μg L^-1) for ampicillin and penicillin G and a linear range of 2.5-750 (μg L^-1) were obtained for amoxicillin at optimum conditions. Moreover, the limits of detection (S/N = 3) of 0.5, 0.8, and 0.9 (μg L^-1) were obtained for amoxicillin, ampicillin, and penicillin G, respectively. The precision (relative standard deviations (%)) values of 3.1, 2.6, and 2.5 at the concentration of 50 μg L^-1 for seven replicates were obtained for ampicillin, amoxicillin, and penicillin G, respectively. The efficiencies of ≤ 96% and relative standard deviations of less than 3.1% were also obtained thereby confirming the high potential of the synthesized nanocomposites for simultaneous preconcentration and separation of the β-lactam antibiotics in complex matrixes. Graphical Abstract.

Simultaneous determination of 11 antiseptic ingredients in surface water based on polypyrrole decorated magnetic nanoparticles

With the emergence and spread of coronavirus COVID-19, the use of personal cleansing, medical and household disinfectant products have increased significantly. In this work, a new magnetic solid-phase extraction (MSPE) method for the determination of 11 antiseptic ingredients in surface water by high performance liquid chromatography-mass spectrometry (HPLC-MS/MS) for 6 months based on Fe3O4@PPy magnetic nanoparticles (MNPs) was established. The MSPE method possessed the advantages of simple processing, little time consumption and less organic solvent consumption, and the MNPs could be reused several times. The analytical parameters influencing the extraction efficiency, such as sample pH, amount of MNPs and extraction time, were optimized in detail. It was indicated that the method had satisfactory linearities in the range of 0.50 to 1000.0 μg L-1 with the correlation coefficients (r) higher than 0.9996. Additionally, satisfactory spiked recoveries were achieved in the range of 80.21-107.33% with relative standard deviations (RSDs) from 1.98% to 8.05%. The limits of detection (LODs) and limits of quantitation (LOQs) were in the range of 0.20 to 2.0 μg L-1 and 0.50 to 5.0 μg L-1. Therefore, the developed MSPE-HPLC-MS/MS method has high selectivity and stability, and satisfactory quantitative capability for the antiseptic ingredients in surface water. Furthermore, this method can provide relevant technical support for the development of surface water standards.

Determination of sulfa antibiotic residues in river and particulate matter by field-amplified sample injection-capillary zone electrophoresis

In the present research, field-amplified sample injection-CZE (FASI-CZE) coupled with a diode array detector was established to determine trace level sulfa antibiotic. Sulfathiazole, sulfadiazine, sulfamethazine, sulfadimethoxine, sulfamethoxazole, and sulfisoxazole were selected as analytes for the experiments. The background electrolyte solution consisted of 70.0 mmol/L borax and 60.0 mmol/L boric acid (including 10% methanol, pH 9.1). The plug was 2.5 mmol/L borax, which was injected into the capillary at a pressure of 0.5 psi for 5 s. Then the sample was injected into the capillary at an injection voltage of -10 kV for 20 s. The electrophoretic separation was carried out under a voltage of +19 kV. The capillary temperature was maintained at 20˚C throughout the analysis, and six sulfonamides were completely separated within 35 min. Compared with pressure injection-CZE, the sensitivity of FASI-CZE was increased by 6.25-10.0 times, and the LODs were reduced from 0.2-0.5 to 0.02-0.05 μg/mL. The method was applied to the determination of sulfonamides in river water and particulate matter samples. The recoveries were 78.59-106.59%. The intraday and interday precisions were 2.89-7.35% and 2.77-7.09%, respectively. This provides a simpler and faster method for the analysis of sulfa antibiotic residues in environmental samples.