Contaminants In Environmental Samples Research Articles

Use of Particle Induced X-Ray Emission (PIXE), Particle Induced Gamma–Ray Emission (PIGE), Energy Dispersive X-Ray Analysis (EDXRF) for Detecting Trace Elements in Soil Sample

This review paper provides a comprehensive overview of trace element analysis utilizing ion-atom interaction techniques, focusing on the principles, applications, and recent advancements in the field. Ion- atom interaction techniques, including Particle Induced X- Ray Emission (PIXE), Particle Induced Gamma–Ray Emission (PIGE), Energy Dispersive X-Ray Analysis (EDXRF), Rutherford backscattering spectroscopy (RBS), and ion beam analysis (IBA), offer unique capabilities for trace element analysis with high sensitivity and minimal sample preparation requirements. The paper begins by discussing the fundamental principles underlying ion-atom interaction techniques, such as the interaction of energetic ions with matter and the subsequent detection of emitted X-rays or backscattered particles. It explores the various analytical parameters that influence the sensitivity, resolution, and depth profiling capabilities of these techniques. Furthermore, the review highlights the diverse applications of ion-atom interaction techniques in fields such as environmental monitoring, forensic science, biomedical research, and materials science. It showcases how these techniques have been utilized to address specific analytical challenges, such as the detection of trace contaminants in environmental samples or the characterization of thin films and semiconductor materials.

A non-targeted analysis workflow for the identification of organic contaminants in a sludge water based on fragmentation matching score and metadata

ABSTRACT Non-targeted analysis (NTA) methods have been increasingly used to discover organic contaminants in environmental samples. The identification efficiency of conventional NTA workflow is often very low due to many factors such as low fragmentation score between experimental MS2 data and reference MS2 data/in-silico MS2 data. Additionally, the prioritisation of possible candidates is also challenging due to the large number of candidates obtained from MS acquisitions. In this study, a multiplatform data processing workflow applicable to non-targeted LC-MS data is proposed to improve the identification accuracy of organic contaminants in water. This workflow consists of (1) scanning quadrupole data-independent acquisition (SONAR) to acquire relatively clean MS1 and MS2 data, (2) data deconvolution using Progenesis QI Software to filter/select the appropriate ions (MS1 data), (3) the selected MS1 data matching against U.S. EPA Chemistry Dashboard to get a list of the environmentally related candidates with metadata (e.g., data sources, toxicity, and exposure), (4) experimental MS2 data matching against in-silico fragmentation data of the obtained candidate by MetFrag to obtain a fragmentation score, (5) compound identification through ranking the candidates by MetFrag based on fragmentation score and metadata. The identification efficiency of the metadata-based NTA workflow was evaluated using a 33-component mixture of chemicals in a complex sludge water. Out of 33 spiked compounds, 26 compounds had been identified using the defined NTA workflow. Most of the 26 identified compounds were recognized as 1st hit of the candidates obtained from the library searching. Overall, the incorporation of fragmentation score and metadata to rank the candidates has significantly improved the accuracy of the organic contaminant identification in the sludge water, compared to the conventional NTA workflow based solely on the fragmentation score.

Novel biosensor for high-throughput detection of progesterone receptor-interacting endocrine disruptors

Progesterone receptor (PR)-interacting compounds in the environment are associated with serious health hazards. However, methods for their detection in environmental samples are cumbersome. We report a sensitive activity-based biosensor for rapid and reliable screening of progesterone receptor (PR)-interacting endocrine disrupting chemicals (EDCs). The biosensor is a cell line which expresses nuclear mCherry-NF1 and a green fluorescent protein (GFP)-tagged chimera of glucocorticoid receptor (GR) N terminus fused to the ligand binding domain (LBD) of PR (GFP-GR-PR). As this LBD is shared by the PRA and PRB, the biosensor reports on the activation of both PR isoforms. This GFP-GR-PR chimera is cytoplasmic in the absence of hormone and translocates rapidly to the nucleus in response to PR agonists or antagonists in concentration- and time-dependent manner. In live cells, presence of nuclear NF1 label eliminates cell fixation and nuclear staining resulting in efficient screening. The assay can be used in screens for novel PR ligands and PR-interacting contaminants in environmental samples. A limited screen of river water samples indicated a widespread, low-level contamination with PR-interacting contaminants in all tested samples.

Chiral Analysis of Pesticides and Emerging Contaminants by Capillary Electrophoresis-Application to Toxicity Evaluation.

Chiral analysis is a very relevant topic in environmental chemistry. This is due to the different properties of the stereoisomers of chiral compounds. In the case of agrochemicals, the desired activity, degradation rate, or toxicity, among other characteristics, may differ between stereoisomers, and the same is true for emerging contaminants, such as pharmaceuticals and cosmetics. Therefore, the development of chiral analytical methodologies enabling their determination in samples of environmental interest is paramount. Although other techniques have been widely employed to carry out chiral separations, such as HPLC, GC, and SFC, capillary electrophoresis (CE) has attracted a lot of attention in the field of chiral analysis due to its simplicity, flexibility, and low cost. In fact, chromatographic columns are not needed, and the consumption of reagents and samples is very low due to the small dimensions of the separation capillaries. This article reviews the characteristics of the chiral methodologies developed by CE for the stereoselective analysis of pesticides and emerging contaminants in environmental samples (water and soil), as well as pesticides in food samples and commercial agrochemical formulations. Applications of the developed CE methodologies in stability and toxicity studies of these chiral contaminants are also reviewed.

Development and Validation of Spectrophotometric and Spectrofluorimetric Methods for Glufosinate-Ammonium Herbicide and Carbofuran Insecticide Contamination in Environmental Samples

Development and Validation of Spectrophotometric and Spectrofluorimetric Methods for Glufosinate-Ammonium Herbicide and Carbofuran Insecticide Contamination in Environmental Samples

Determination of Stable Hydrogen Isotopic Composition and Isotope Enrichment Factor at Low Hydrogen Concentration.

Determination of stable hydrogen isotopic compositions (δ2H) is currently challenged to achieve a high detection limit for reaching the linear range where δ2H values are independent of concentration. Therefore, it is difficult to assess precise δ2H values for calculating the hydrogen isotope enrichment factor (εH) and for field application where the concentrations of contaminants are relatively low. In this study, a data treatment approach was developed to obtain accurate δ2H values below the linear range. The core concept was to use a logarithmic function to fit the δ2H values below the linear range and then adjust the δ2H values below the linear range into the linear range by using the fitted logarithmic equation. Moreover, the adjusted δ2H values were calibrated by using laboratory reference materials, e.g., n-alkanes. Tris(2-chloroethyl) phosphate (TCEP) and hexachlorocyclohexane (HCH) isomers were selected as examples of complex heteroatom-bearing compounds to develop the data treatment approach. This data treatment approach was then tested using δ2H values from a TCEP transformation experiment with OH radicals. Comparable δ2H values and εH between the low-concentration experiment and the reference experiment were obtained using the developed approach. Therefore, the developed data treatment approach enables a possibility of determining the hydrogen isotopic compositions of organic components in low concentrations. It is especially valuable for determining organic contaminants in environmental samples, which are usually present in low concentrations.

Distribution of Inorganic Contaminants Along the Coast of Ciudad de la Costa, Uruguay.

The aim of this work was to study the distribution of relevant inorganic contaminants in environmental samples from Ciudad de la Costa, the second most populated city of Uruguay. For this task aluminum (Al), cadmium (Cd), chromium (Cr), nickel (Ni) and lead (Pb) levels were determined in sand, water, and plant material from six beaches that are located in the area. Analytical methods were successfully validated. Accuracy was ensured by using certified reference materials and spiking procedures. Average metal concentrations in sand and water samples were compared with the maximum limits established by international or national regulations (when available), being far below these limits in all cases. This may indicate that the inorganic contamination in the studied area is rather low, despite the rapid increase in anthropic activities in recent years. To give a deeper characterization of the ecosystem, metal accumulation and mobility within a common plant of the zone, Ammophila arenaria, were studied. Results showed that concentrations in roots were one order of magnitude higher in comparison to aerial parts. In addition, the bioaccumulation coefficient (BAC) showed that the plant accumulates Cd, Cr and Ni, while a low accumulation for Pb was observed. Finally, a Cr(VI) speciation analysis in Ammophila arenaria was performed, showing Cr(VI) percentages below 4.6%, which is relevant from the (eco)toxicological point of view due to the high environmental mobility and bioavailability of this valence state. This work constitutes the first environmental surveillance report of this kind, regarding this populated area of the country.

Microplastics are overestimated due to poor quality control of reagents

Microplastics are widely distributed in the environment and pose potential ecological risks, increasing to be one of the most important environmental pollutants. However, when assessing the characteristics of microplastic contamination in environmental samples, inadequate quality control measures for the working solutions may introduce additional microplastic contamination and lead to an overestimation of microplastic abundance in the samples. In this study, we evaluated the microplastic contamination characteristics in commonly used flotation and digestion reagents to assess errors caused by microplastics in the reagents. The results showed that the abundance of microplastics in the reagents ranged from 0.8 to 43.4 items/g, with the abundance of microplastics in flotation reagents being lower than that in digestion reagents. The shapes of the detected microplastics included particles, fibers, and fragments, and their size and outline were generally small, with most being below 100 µm. The most common types of polymers detected were polyethylene and polypropylene. In order to improve the universality and readability of the results, the detected microplastic abundances were converted into the actual application concentration of the working fluid. It was found that the potential contamination of microplastics in untreated flotation solutions ranged from 1.5 to 30.8 items/mL, while in digestion solutions ranged from 0.1 to 2.3 items/mL. Our study emphasizes the need for quality control measures, such as suction filtration, when evaluating microplastics in environmental samples or conducting chemical and biological tests related to microplastics.

Design of a Whole-Cell Biosensor Based on Bacillus subtilis Spores and the Green Fluorescent Protein To Monitor Arsenic.

A green fluorescent protein (GFP)-based whole-cell biosensor (WCB-GFP) for monitoring arsenic (As) was developed in Bacillus subtilis. To this end, we designed a reporter gene fusion carrying the gfpmut3a gene under the control of the promoter/operator region of the arsenic operon (Pars::gfpmut3a) in the extrachromosomal plasmid pAD123. This construct was transformed into B. subtilis 168, and the resultant strain was used as a whole-cell biosensor (BsWCB-GFP) for the detection of As. The BsWCB-GFP was specifically activated by inorganic As(III) and As(V), but not by dimethylarsinic acid [DMA(V)], and exhibited high tolerance to the noxious effects of arsenic. Accordingly, after 12 h exposure, B. subtilis cells carrying the Pars::gfpmut3a fusion exhibited 50 and 90% lethal doses (LD50 and LD90) to As(III) of 0.89 mM and As 1.71 mM, respectively. Notably, dormant spores from the BsWCB-GFP were able to report the presence of As(III) in a concentration range from 0.1 to 1,000 μM 4 h after the onset of germination. In summary, the specificity and high sensitivity for As, as well as its ability to proliferate under concentrations of the metal that are considered toxic in water and soil, makes the B. subtilis biosensor developed here a potentially important tool for monitoring environmental samples contaminated with this pollutant. IMPORTANCE Arsenic (As) contamination of groundwater is associated with serious worldwide health risks. Detection of this pollutant at concentrations that are established as permissible for water consumption by WHO is a matter of significant interest. Here, we report the generation of a whole-cell biosensor for As detection in the Gram-positive spore former B. subtilis. This biosensor reports the presence of inorganic As, activating the expression of the green fluorescent protein (GFP) under the control of the promoter/operator of the ars operon. The biosensor can proliferate under concentrations of As(III) that are considered toxic in water and soil and detect this ion at concentrations as low as 0.1 μM. Of note, spores of the Pars-GFP biosensor exhibited the ability to detect As(III) following germination and outgrowth. Therefore, this novel tool has the potential to be directly applied to monitor As contamination in environmental samples.

Irreversible fluorine covalent organic framework based probe nanoelectrospray ionization mass spectrometry for direct and rapid determination of perfluoroalkyl carboxylic acids

Probe nanoelectrospray ionization mass spectrometry (PESI-MS) is practically desirable for rapid and ultra-sensitive analysis of trace contaminants in environment, but limited with the stable and selective probe coating. Herein, we show the design and preparation of irreversible fluorine-based covalent organic framework (TFPPA-F4) covalently bonded probe to couple with ESI-MS (TFPPA-F4-PESI-MS) for direct and rapid determination of perfluoroalkyl carboxylic acids (PFCAs) in environmental water. Chemical bonding coating of irreversible crystalline TFPPA-F4 not only improved stability of the probe, but also offered accessible multiple interactions including hydrophobic, hydrogen bonding and F-F interactions to promote the kinetics and selectivity for PFCAs. The proposed TFPPA-F4-PESI-MS realized rapid determination of PFCAs (about 4 min) with low limits of detection of 0.06–0.88 ng L−1 and wide linear range of 1–5000 ng L–1 (R2 of 0.9982–0.9998). Recoveries for the spiked lake and pond water were 85.9–111.1 %. TFPPA-F4 based probe can maintain the extraction performance after 100 times of extraction. This work shows the great potential of the irreversible covalent organic framework based PESI-MS in rapid and ultra-sensitive determination of contaminants in environmental samples.

Electrochemical molecularly imprinted polymer sensor for ultrasensitive indoxacarb detection by tin disulfide quantum dots/carbon nitride/multiwalled carbon nanotubes as a nanocomposite

Unsuitable use of agricultural pesticides has caused excessive pollution of the environment. Therefore, it is very important to identify the remaining contamination in environmental samples. Indoxacarb (IDC) as an oxadiazine fungicide use on large part of corps. In this work, we reported voltammetric sensor-based molecularly imprinted polymers (MIP) film on a tin disulfide quantum dots-carbon nitride-multiwalled carbon nanotubes (MIP@SnS2 QDs/pg-C3N4/MWCNTs) nanocomposite for ultrasensitive detection of IDC. Cyclic and differential pulse voltammetry (CV and DPV), electrochemical impedance spectroscopy (EIS), UV-Vis absorption spectroscopy, photoluminescence spectroscopy, Fourier transform infrared spectroscopy (FT-IR), field emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM), dynamic light scattering (DLS), X-ray diffraction (XRD), energy dispersive X-ray (EDX), elemental mapping used for characterization of the proposed electrode. Under optimum conditions, the current response for IDC was obtained in the linear range of 20.0 nmol L−1 to 10.0 µmol L−1 and a detection limit of 7.1 nmol L−1. Using this MIP sensor, IDC has been determined in samples of Zayandeh Rood river water and apple. Several advantages of the proposed sensor were demonstrated, including its sensitivity, selectivity, and simplicity.

Biomimetic Material for Quantification of Methotrexate Using Sensor Based on Molecularly Imprinted Polypyrrole Film and MWCNT/GCE

This study investigates biomimetic sensors for the detection of methotrexate contaminants in environmental samples. Sensors inspired by biological systems are the focus of this biomimetic strategy. Methotrexate is an antimetabolite that is widely used for the treatment of cancer and autoimmune diseases. Due to the widespread use of methotrexate and its rampant disposal into the environment, the residues of this drug are regarded as an emerging contaminant of huge concern, considering that exposure to the contaminant has been found to lead to the inhibition of some essential metabolic processes, posing serious risks to humans and other living beings. In this context, this work aims to quantify methotrexate through the application of a highly efficient biomimetic electrochemical sensor constructed using polypyrrole-based molecularly imprinted polymer (MIP) electrodeposited by cyclic voltammetry on a glassy carbon electrode (GCE) modified with multi-walled carbon nanotubes (MWCNT). The electrodeposited polymeric films were characterized by infrared spectrometry (FTIR), scanning electron microscopy (SEM), and cyclic voltammetry (CV). The analyses conducted using differential pulse voltammetry (DPV) yielded a detection limit of 2.7 × 10-9 mol L-1 for methotrexate, a linear range of 0.01-125 μmol L-1, and a sensitivity of 0.152 μA L mol-1. The results obtained from the analysis of the selectivity of the proposed sensor through the incorporation of interferents in the standard solution pointed to an electrochemical signal decay of only 15.4%. The findings of this study show that the proposed sensor is highly promising and suitable for use in the quantification of methotrexate in environmental samples.

Poliomyelitis outbreak, vaccine, and concern in current clinical surgery

Dear Editor, Poliomyelitis is a fairly old disease, and the vaccination against it has been in use for a long time. The reemergence of poliovirus-related sickness in America draws international attention. A male case from the United States was diagnosed with paralytic poliomyelitis in July 2022.[1,2] The virus discovered in the feces was recognized as a circulating vaccine-derived poliovirus type 2 caused by oral polio vaccination.[2] Routine vaccine administration has decreased globally since the COVID-19 pandemic, with an increasing proportion of areas lacking poliovirus vaccination.[2] The shifting situation in America could be attributable to a variety of factors. Nonetheless, it confirms that the poliovirus and the sickness it causes have never been successfully eradicated. Vaccines are currently regarded as an effective preventive tool against infectious diseases. Sometimes, the fundamental concepts of disease control and sanitation are overlooked. Poliomyelitis has resurfaced not just in the United States but also in emerging countries in South Asia. Sanitation should be a basic principle that is necessary for any situation, independent of the socioeconomic background.[3,4] Concerning the association between COVID-19 and polio, the discovery of contamination in environmental samples from the same location confirms the need for basic sanitation principles as the criteria for any infectious disease prevention. In high-income neighborhoods with adequate sanitation, there is still a risk of disease invasion from outside sources, such as immigrant workers. Therefore, it is time for applying good sanitation measures and infectious controls.[5] Because of the fact that there is a chance of unknown contamination conditions in the environment, some specific patients might have risks. For example, a posttransplantation case is proven for low immunity against poliovirus, and if the patient contacts with the contaminated pathogen, the infection can be expected.[5,6,7] Because of the likelihood of polio recurrence, the surgical ward may have to play a part in care for a patient with positive poliovirus, and good preparation with normal infection control principles must be followed.

A Multiplex Gene Expression Assay for Direct Measurement of RNA Transcripts in Crude Lysates of the Nematode Caenorhabditis elegans Used as a Bioanalytical Tool.

Gene expression profiling in Caenorhabditis elegans has been demonstrated to be a potential bioanalytical tool to detect the toxic potency of environmental contaminants. The RNA transcripts of genes responding to toxic exposure can be used as biomarkers for detecting these toxins. For routine application in environmental quality monitoring, an easy-to-use multiplex assay is required to reliably quantify expression levels of these biomarkers. In the present study, a bead-based assay was developed to fingerprint gene expression in C. elegans by quantitating messenger RNAs (mRNAs) of multiple target genes directly from crude nematode lysates, circumventing RNA extraction and purification steps. The assay uses signal amplification rather than target amplification for direct measurement of toxin-induced RNA transcripts. Using a 50-gene panel, the expression changes of four candidate reference genes and 46 target mRNAs for various contaminants and wastewaters were successfully measured, and the expression profiles indicated the type of toxin present. Moreover, the multiplex assay response was in line with previous results obtained with more time-consuming reverse-transcription quantitative polymerase chain reaction and microarray analyses. In addition, the transcriptomic profiles of nematodes exposed to wastewater samples and extracts prepared from tissues of swimming crabs were evaluated. The profiles indicated the presence of organic pollutants. The present study illustrates the successful development of a multiplex fluorescent bead-based approach using nematode C. elegans crude lysates for gene expression profiling of target RNAs. This method can be used to routinely fingerprint the presence of toxic contaminants in environmental samples and to identify the most biologically active fraction of the contaminant mixture in a toxicity identification and evaluation approach. Environ Toxicol Chem 2023;42:130-142. © 2022 The Authors. Environmental Toxicology and Chemistry published by Wiley Periodicals LLC on behalf of SETAC.

Bioaccumulation Dynamic by Crassostrea gigas Oysters of Viruses That Are Proposed as Surrogates for Enteric Virus Contamination in Environmental Samples.

Oysters are filter-feeders and retain sewage-derived pathogens in their organs or tissues. Since most enteric viruses involved in outbreaks cannot grow in cell culture, studies using viral surrogate models are essential. Some species are proposed as surrogates for enteric viruses in environmental samples, including in bivalve mollusk samples, such as murine norovirus type 1 (MNV-1) and somatic (as φX) or F-specific coliphages (as MS2) bacteriophages. This study evaluated the tissue distribution of viral surrogates for enteric virus contamination after their bioaccumulation by Crassostrea gigas. Oyster tissues were analyzed for the distribution of viral surrogates (MNV-1, φX-174, and MS2) in digestive tissue (DT), gills (GL), and mantle (MT) after 4, 6, and 24h of experimental bioaccumulation. MNV-1 had higher counts at 6h in DT (1.2 × 103 PFU/g), followed by GL and MT (9.5 × 102 and 3.8 × 102 PFU/g, respectively). The bacteriophage φX-174 had a higher concentration in the MT at 4 and 6h (3.0 × 102 PFU/g, in both) and MS2 in the GL after 24h (2.2 × 102 PFU/g). The bioaccumulation pattern of MNV-1 by oysters was similar to the other enteric viruses (more in DT), while that of phages followed distinct patterns from these. Since the MNV-1 is bioaccumulated by C. gigas and is adapted to grow in cell culture, it is an important tool for bioaccumulation and viral inactivation tests in oysters. Although bacteriophage bioaccumulation was not similar to enteric viruses, they can be indicated for viral bioaccumulation analysis, analyzing MT and GL, since they do not bioaccumulate in DT.

First Novel Workflow for Semiquantification of Emerging Contaminants in Environmental Samples Analyzed by Gas Chromatography-Atmospheric Pressure Chemical Ionization-Quadrupole Time of Flight-Mass Spectrometry.

The ionization efficiency of emerging contaminants was modeled for the first time in gas chromatography-high-resolution mass spectrometry (GC-HRMS) which is coupled to an atmospheric pressure chemical ionization source (APCI). The recent chemical space has been expanded in environmental samples such as soil, indoor dust, and sediments thanks to recent use of high-resolution mass spectrometric techniques; however, many of these chemicals have remained unquantified. Chemical exposure in dust can pose potential risk to human health, and semiquantitative analysis is potentially of need to semiquantify these newly identified substances and assist with their risk assessment and environmental fate. In this study, a rigorously tested semiquantification workflow was proposed based on GC-APCI-HRMS ionization efficiency measurements of 78 emerging contaminants. The mechanism of ionization of compounds in the APCI source was discussed via a simple connectivity index and topological structure. The quantitative structure–property relationship (QSPR)-based model was also built to predict the APCI ionization efficiencies of unknowns and later use it for their quantification analyses. The proposed semiquantification method could be transferred into the household indoor dust sample matrix, and it could include the effect of recovery and matrix in the predictions of actual concentrations of analytes. A suspect compound, which falls inside the application domain of the tool, can be semiquantified by an online web application, free of access at http://trams.chem.uoa.gr/semiquantification/.

A novel workflow for semi-quantification of emerging contaminants in environmental samples analyzed by LC-HRMS.

There is an increasing need for developing a strategy to quantify the newly identified substances in environmental samples, where there are not always reference standards available. The semi-quantitative analysis can assist risk assessment of chemicals and their environmental fate. In this study, a rigorously tested and system-independent semi-quantification workflow is proposed based on ionization efficiency measurement of emerging contaminants analyzed in liquid chromatography-high-resolution mass spectrometry. The quantitative structure-property relationship (QSPR)-based model was built to predict the ionization efficiency of unknown compounds which can be later used for their semi-quantification. The proposed semi-quantification method was applied and tested in real environmental seawater samples. All semi-quantification-related calculations can be performed online and free of access at http://trams.chem.uoa.gr/semiquantification/ .

Detection of Mycotoxins in Highly Matrix-Loaded House-Dust Samples by QTOF-HRMS, IM-QTOF-HRMS, and TQMS: Advantages and Disadvantages.

The analysis of (trace) contaminants in environmental samples represents an important tool for exposure assessment and for the evaluation of potential risks to human health. Currently, mass spectrometric detection using triple quadrupole (TQMS) systems is the established method of choice. However, screening methods using high resolution mass spectrometry (HRMS) find increasing application as they provide advantages such as enhanced selectivity. A complex composition of environmental samples is known to have enormous effects on mass analyzers. The present work therefore compares the impact of a highly matrix-loaded sample material like house-dust on the performance of mass spectrometric detection of the emerging indoor contaminant group of mycotoxins by quadrupole time-of-flight (QTOF) and TQMS after ultrahigh-performance liquid chromatographic separation. Furthermore, the role of ionization efficiencies of different ion sources in instrument sensitivity was compared using an electrospray ionization source and a newly developed heated electrospray ion source (Bruker VIP-HESI) during QTOF experiments. Finally, it was evaluated whether an additional dimension of separation enables increased sensitivity in QTOF-HRMS detection by applying mycotoxins in house-dust to an (trapped) ion mobility spectrometry instrument. The sensitivity of the QTOF detection was positively influenced by the application of the VIP-HESI ion source, and overall HRMS instruments provided enhanced selectivity resulting in simplified data evaluation compared to the TQMS. However, all performed experiments revealed strong signal suppression due to matrix components. QTOF results showed more severe effects, enabling a more sensitive detection of mycotoxins in house-dust by applying TQMS detection.

Research progress on lyophilization for pretreatment of emerging organic contaminants in environmental samples

有机新污染物是一类在先进分析技术帮助下新鉴定的、现有法规未管制的、人为源的有机污染物。有机新污染物主要包括药品与个人护理、农药、全氟化合物、内分泌干扰物等,其会产生内分泌干扰效应、诱发抗性基因传播,还对人类和野生生物的生存与发展构成潜在威胁,因此检测环境样品中的有机新污染物浓度对生态环境和人体健康具有重大意义。由于环境样品中的有机新污染物浓度较低,为了达到检测仪器的检测要求,通常需要对环境样品进行前处理,包括样品的净化和浓缩。冷冻干燥技术是一种在真空干燥条件下通过升华方式去除水分的前处理技术,主要包括样品冷冻、初级干燥和再干燥3个阶段,常用于食品和药品行业。在药品行业中,冷冻干燥技术能维持药品的生物活性和化学活性,保持药品的物理化学特性。近年来,冷冻干燥技术逐步用于环境水样中有机新污染物的前处理。其主要的操作步骤包括水样预处理、冷冻干燥、洗脱、吹干、过滤、定容和上机检测。冷冻干燥技术具有操作简单、低成本、样品处理体积少、样品易保存和处理过程中样品损失少等优点,具有广泛应用于环境样品中有机新污染物监测的潜力。该文综述了环境样品中有机新污染物常见的种类,并重点介绍冷冻干燥技术的原理及其在环境样品前处理过程中的应用,提出了冷冻干燥技术在环境分析中的应用前景,为环境样品中有机新污染物的监测提供了参考。

Detection of 2,4-dichlorophenoxyacetic acid herbicide using a FGE-sulfatase based whole-cell Agrobacterium biosensor

2,4-Dichlorophenoxyacetic acid (2,4-D) has been widely used as a herbicide for agricultural purposes. Currently, the available methods for detecting 2,4-D require multi-step sample preparations and expensive instruments. The use of a whole cell biosensor is an interesting approach that is straightforward and simple to use. In this study, we constructed a genetic-based Agrobacterium tumefaciens biosensor based on a cadA promoter and cadR regulator from Bradyrhizobium sp. strain HW13 (2,4-D degrader) with a formylglycine generating enzyme (FGE)-sulfatase as the reporter gene. The performance of the biosensor was further improved through direct evolution of the cadR activator. The detection limit of cadR mutants for phenoxyacetic acid herbicides including 2,4-D and 4-Chlorophenoxyacetic acid (4-CPAA) were 1.56 μM (an eight-fold improvement compared to wild-type CadR). The biosensor could detect 2,4-D contamination in environmental samples without encountering interference from other complex compounds. The Agrobacterium biosensor was also stable after storing in a simple Luria-Bertani (LB) medium at 4 °C for 30 days where the activity remained at 82% when exposed to 100 μM of 2,4-D. This novel biosensor, with its high stability under simple storage conditions, exhibits promising potential to be used as an inexpensive and easy-to-use tool to screen for 2,4-D contamination in environmental sources.