Complex Environmental Samples Research Articles

Ultrasound-assisted magnetic solid phase extraction of lead and thallium in complex environmental samples using magnetic multi-walled carbon nanotubes/zeolite nanocomposite

Magnetic multi-walled carbon nanotubes@zeolite (MWCNT-Fe3O4@Zeo) nanocomposite was facilely synthesized using a one-pot solvothermal method. The MWCNT-Fe3O4@Zeo was characterized by VSM, BET, XRD, TEM and SEM/EDS. The Zeolite-coated multi-walled carbon nanotubes–magnetite was used as an adsorbent in ultrasonic-assisted magnetic solid phase extraction (UA-MSPE) for preconcentration of trace Pb and Tl. The analytes were detected and quantified using inductively coupled plasma optical emission spectrometry (ICP-OES). The optimization of experimental parameters affecting the preconcentration method was achieved using a multivariate approach. Under optimal experimental conditions, the linearity ranged from 0.1 to 500 μg L−1 for lead and 0.1–600 μg L−1 for thallium. Preconcentration factors, limits of detection and quantification for Pb and Tl ranged from 90 to 100, 0.28–0.23 μg L−1, 0.93–0.77 μg L−1. The intraday precisions (repeatability, n = 20) expressed as the relative standard deviation, were found to be 1.6% and 1.4% for Pb and Tl, respectively. In addition, the interday precisions (reproducibility, n = 5) were 2.6% and 3.1% for Pb and Tl, respectively. The accuracy of the method was investigated using standard reference material as well as spiked recovery test and satisfactory recoveries (97–99.3%) were obtained. The maximum adsorption capacities were 37.8 mg g−1 and 44.5 mg g−1, for Pb and Tl, respectively. The developed UA-MSPE/ICP-OES method was effectively applied for simultaneous preconcentration and determination of Pb and Tl in environmental samples.

Matrix-matched standards in the liquid chromatography–mass spectrometry determination of neonicotinoids in soil and sediment

The use of matrix-matched standards with a solid-liquid extraction and salting out without the addition of further cleanup steps or costly cleanup procedures associated with the quick, easy, cheap, effective, robust, and safe (QuEChERS) method was evaluated to address variations in ionization efficiency in the LC–MS/MS determination of neonicotinoid pesticides in complex environmental samples. Limits of detection (1.4–3.4 ng/g) and limits of quantitation (4.6–11.3 ng/g) for various neonicotinoid analogs were comparable to previously reported QuEChERS extraction methods. Mean recovery of standard neonicotinoid samples spiked with 10 ng/g was found to be 78.0–100.5%, while samples spiked with 100 ng/g were found to be 55.1–99.9%. Recovery of analytes was matrix dependent; the highest recovery was from sediment (86.2–100.5%) followed by laboratory sand (70.9–81.7%) and agricultural soil (55.5–102.6%), respectively. Optimization of this methodology resulted in the reduction of procedure time and cost, and can aid in environmental monitoring efforts of common neonicotinoid pesticides in soils and sediments.

Unprecedented Selectivity and Rapid Uptake of CuS Nanostructures toward Hg(II) Ions.

Fast, selective, and effective enrichment is critical for onsite detection and online monitoring of extremely low-concentration toxic heavy metal ions in complex environmental samples. In the current work, varied CuS nanostructures (hollow nanospheres, nanoflowers, nanoparticles) were prepared and applied to the enrichment of Hg(II) ions. Surprisingly, the as-prepared CuS nanostructures exhibited unprecedented ultrahigh selectivity and rapid uptake toward Hg(II) ions in the presence of other seven metal ions, suggesting specificity of mercury enrichment by the CuS nanostructures. Upon treating a 100 mL aqueous sample containing 8 different metal ions with only 10 mg of CuS hollow nanospheres, over 99.5% of Hg(II) ions could be removed within just 1 min, achieving a final Hg(II) ion level down to 0.1 ppb. This excellent selectivity was well accounted for by the Hard Soft Acid Base theory and especially the solubility product constant, where the solubility product constant of CuS is higher than that of HgS but lower than that of sulfides of other interfering metal ions. The current results are striking and would open a new avenue to the search for highly selective and efficient absorptive nanomaterials toward varied heavy metal ions.

Dispersion of natural nanomaterials in surface waters for better characterization of their physicochemical properties by AF4-ICP-MS-TEM

Characterization and understanding of natural nanomaterials (NNMs) properties is essential to differentiate engineered nanomaterials (ENMs) from NNMs. However, NNMs in environmental samples typically occur as heteroaggregates with other particles, e.g., NNMs, ENMs, and larger particles. Therefore, there is a need to isolate NNMs into their primary particles to better characterize their physicochemical properties. Here, we evaluated the efficiency of sodium hydroxide, sodium oxalate, and sodium pyrophosphate to extract NNMs from surface waters. The extracted NNMs were characterized for total metal concentration by inductively coupled plasma-mass spectrometry (ICP-MS) following full digestion; size distribution, elemental composition and ratios by flow-field flow fractionation (AF4)-ICP-MS; and morphology by transmission electron microscopy (TEM). Sodium pyrophosphate extraction resulted in the highest NNM concentration and the smallest NNM size distribution. Sodium hydroxide and sodium oxalate extraction generated heteroaggregates with a broad size distribution. The NNM extraction efficiency increased with extractant (sodium oxalate and sodium pyrophosphate) concentration. The concentration of metals in the sodium pyrophosphate-extracted NNMs compared to the total metal concentration was element-dependent and varied from as high as >80% for Cu, Zn, and Sr to as low as <5% for Al, Ti, and Nb. This study provides a simple protocol for NNM extraction from complex environmental samples and provides a better understanding of NNM physicochemical properties. The presented NNM extraction protocol forms the basis for ENM extraction from natural waters.

Coupling High-Performance Thin-Layer Chromatography with Bacterial Genotoxicity Bioreporters.

We present an innovative technological platform for monitoring the direct genotoxicity of individual components in complex environmental samples, based on bioluminescent Escherichia coli genotoxicity bioreporters, sprayed onto the surface of a high-performance thin-layer chromatography (HPTLC) plate. These sensor strains harbor plasmid-borne fusions of selected gene promoters of the E. coli SOS DNA repair system to the Photorhabdus luminescens luxABCDE gene cassette, and mark by increased luminescence the presence of potentially DNA-damaging sample components separated on the plate. We demonstrate an "on plate" quantifiable dose-dependent response to several model genotoxicants (without metabolic activation). We further demonstrate the applicability of the system by identifying as genotoxic specific components of HPTLC-separated influent and effluent samples of wastewater treatment plants, thereby alleviating the need for a comprehensive chemical analysis of the sample.

Highly Sensitive Solid-Liquid Interfacing Triboelectric Nanosensor for Self-Powered Mercury Ion Detection

Till date, the potential of the solid-liquid triboelectric nanosensor for chemical sensing applications have remained unexplored. In this work, the first self-powered nanosensor based on solid-liquid triboelectric effect for the detection of mercury ions is substantiated. The triboelectric nanosensor was designed by using tellurium nanowires as the solid triboelectric layer and deionized water as the liquid triboelectric layer. Owing to the highly specific reaction between tellurium and mercury ions, the as-developed triboelectric nanosensor have proved to be highly selective and thereby have the capability to distinguish even small traces of mercury ions in complex environmental samples. The triboelectric nanosensor can offer a detection range of 10 nM-10 mM toward mercury ions. Moreover, hydrophilic and hydrophobic tellurium nanowires were synthesized to evaluate the effect of surface properties on the efficiency of triboelectric nanosensor. Based on the results, it is believed that solid-liquid triboelectric effect will be a new and efficient tool for the designing of rapid, portable and low-cost chemical nanosensors.

MON-030 Non-Target Assessment of Contributory Chemicals and In Vitro Assessment of Molecular Mechanisms of Indoor House Dust Extract-Induced Adipogenesis in 3T3-L1 Cells

Chemical exposures can promote triglyceride accumulation and/or increased adiposity in vitro and in various animal models, and numerous epidemiological studies have reported associations between exposure to putative “obesogens” and increased weight or adiposity in humans. We previously demonstrated that indoor house dust extracts could induce adipogenesis in vitro, and further demonstrated that the extent of triglyceride accumulation was associated with the body mass index and serum thyroid hormone concentrations of adult residents. Herein, we investigated the role of chemical mixtures isolated from house dust in child metabolic health. House dust samples (n=194) were collected from central NC households, solvent extracted, evaporated under nitrogen gas, and reconstituted in DMSO. 3T3-L1 cells were induced to differentiate, dosed with house dust extracts at 100 μg dust equivalence/well, and assayed for triglyceride accumulation and DNA content after ten days of exposure. One hundred and twenty-five dust extracts (64%) exhibited significant triglyceride accumulation at this concentration, while ninety seven (50%) of extracts exhibited significant proliferation. The fifty highest activity samples were further selected for molecular mechanism interrogation, assessing relative contributions of peroxisome proliferator activated receptor gamma activation and/or thyroid receptor inhibition to the observed activities. Preliminary statistical analyses assessed associations between the dust-induced adipogenic responses and the metabolic health of resident children. In children less than 4.5 years old, higher extract-induced proliferation tended to be associated with greater growth trajectories, and higher triglyceride accumulation with lower growth scores. In children older than 4.5, higher dust-induced triglycerides were associated with greater height and weight for age Z scores, and higher dust-induced proliferation with greater BMI Z scores. Dust extracts were also analyzed using a non-targeted analysis on an Orbitrap Fusion Lumos HRMS/MS. Preliminary differential analyses (using Compound Discoverer 3.0) between sample groups reveals three features that were significantly associated with greater extract-induced cell proliferation, respectively, seven features that were significantly associated with greater extract-induced triglyceride accumulation, and five features that were significantly higher in the homes of children who were categorized as overweight or obese. Further interrogation of these features is ongoing, though several nonionic surfactants and polyethylene glycols have been tentatively identified. Interestingly, several of these surfactants have been reported to promote adipogenesis in vitro. These results highlight the utility of non-target analysis for identifying active chemicals from complex environmental samples.

Lipopolysaccharides from Microcystis Cyanobacteria-Dominated Water Bloom and from Laboratory Cultures Trigger Human Immune Innate Response.

Massive toxic blooms of cyanobacteria represent a major threat to water supplies worldwide. Here, the biological activities of lipopolysaccharide (LPS) isolated from Microcystis aeruginosa, the most prominent cyanobacteria in water bloom, were studied. LPS was isolated from complex environmental water bloom samples dominated by M. aeruginosa, and from laboratory cultures of non-axenic as well as axenic M. aeruginosa strains PCC7806 and HAMBI/UHCC130. Employing human blood-based in vitro tests, the LPS isolated from complex water bloom revealed the priming of both major blood phagocyte population monocytes and polymorphonuclear leukocytes documented by the increased surface expression of CD11b and CD66b. This was accompanied by a water bloom LPS-mediated dose-dependent induction of tumor necrosis factor α, interleukin-1β, and interleukin-6 production. In accordance with its priming effects, water bloom LPS induced significant activation of p38 and ERK1/2 kinases, as well as NF-κB phosphorylation, in isolated polymorphonuclear leukocytes. Interestingly, the pro-inflammatory potential of LPS from the axenic strain of M. aeruginosa was not lower compared to that of LPS isolated from non-axenic strains. In contrast to the biological activity, water bloom LPS revealed almost twice higher pyrogenicity levels compared to Escherichia coli LPS, as analyzed by the PyroGene test. Moreover, LPS from the non-axenic culture exhibited higher endotoxin activity in comparison to LPS from axenic strains. Taking the above findings together, M. aeruginosa LPS can contribute to the health risks associated with contamination by complex water bloom mass.

Analysis of Selected Endocrine Disrupters Fraction Including Bisphenols Extracted from Daily Products, Food Packaging and Treated Wastewater Using Optimized Solid-Phase Extraction and Temperature-Dependent Inclusion Chromatography.

The aim of this research is to demonstrate the concept and ability for the fast and preliminary screening of complex food and environmental samples for the presence of endocrine disrupters fractions, consisting of low-molecular mass micropollutants, particularly various bisphenols (A, B, C, E, F, S, Z, AF, AP, BP and FL). The developed analytical protocol for this research requires two main steps: (i) optimized solid phase extraction (SPE) for selective isolation, purification and pre-concentration of target fraction, and (ii) selective temperature-dependent inclusion chromatography for samples analysis via a HPLC-UV-VisDAD system using isocratic elution and internal standard quantification approach. The chromatographic experiment revealed that both β-CD and its hydroxypropyl derivative strongly interact with selected bisphenols. This is in contrast to the steroids and PAHs molecules investigated previously, where a strong interaction with β-cyclodextrin was observed. Integrated areas derived from acquired chromatographic profiles for each individual sample were used as the simple classification variable enabling samples comparison. We demonstrated that the proposed analytical protocol allows for fast estimation of EDC fractions in various daily use products, food and environmental samples. The materials of interest were selected due to the presence in surface water ecosystems of their residues, and finally, in raw wastewater including rice bags, plastic bags, cloths, sanitary towels, fish baits and various plastic foils from food products. Treated sewage water released directly to the environment from a municipal treatment plant (Jamno, Koszalin) was also investigated. It has been demonstrated that a whole range of low-molecular mass compounds, which may be detected using UV-Vis detector, can easily be emitted from various in daily use products. The presence of micropollutants in treated wastewater, water ecosystems and plastic waste utilization via technological wastewater treatment processes must be addressed, especially in terms of microplastic-based pollutants acting as endocrine disrupters. It is hoped that the proposed simple analytical protocol will be useful for fast sample classification or selection prior to advanced targeted analysis involving the more accurate quantification of specific analytes using e.g., mass spectrometry detectors.

Separation and Analysis of Microplastics and Nanoplastics in Complex Environmental Samples.

The vast amount of plastic waste emitted into the environment and the increasing concern of potential harm to wildlife has made microplastic and nanoplastic pollution a growing environmental concern. Plastic pollution has the potential to cause both physical and chemical harm to wildlife directly or via sorption, concentration, and transfer of other environmental contaminants to the wildlife that ingest plastic. Small particles of plastic pollution, termed microplastics (>100 nm and <5 mm) or nanoplastics (<100 nm), can form through fragmentation of larger pieces of plastic. These small particles are especially concerning because of their high specific surface area for sorption of contaminants as well as their potential to translocate in the bodies of organisms. These same small particles are challenging to separate and identify in environmental samples because their size makes handling and observation difficult. As a result, our understanding of the environmental prevalence of nanoplastics and microplastics is limited. Generally, the smaller the size of the plastic particle, the more difficult it is to separate from environmental samples. Currently employed passive density and size separation techniques to isolate plastics from environmental samples are not well suited to separate microplastics and nanoplastics. Passive flotation is hindered by the low buoyancy of small particles as well as the difficulty of handling small particles on the surface of flotation media. Here we suggest exploring alternative techniques borrowed from other fields of research to improve separation of the smallest plastic particles. These techniques include adapting active density separation (centrifugation) from cell biology and taking advantage of surface-interaction-based separations from analytical chemistry. Furthermore, plastic pollution is often challenging to quantify in complex matrices such as biological tissues and wastewater. Biological and wastewater samples are important matrices that represent key points in the fate and sources of plastic pollution, respectively. In both kinds of samples, protocols need to be optimized to increase throughput, reduce contamination potential, and avoid destruction of plastics during sample processing. To this end, we recommend adapting digestion protocols to match the expected composition of the nonplastic material as well as taking measures to reduce and account for contamination. Once separated, plastics in an environmental sample should ideally be characterized both visually and chemically. With existing techniques, microplastics and nanoplastics are difficult to characterize or even detect. Their low mass and small size provide limited signal for visual, vibrational spectroscopic, and mass spectrometric analyses. Each of these techniques involves trade-offs in throughput, spatial resolution, and sensitivity. To accurately identify and completely quantify microplastics and nanoplastics in environmental samples, multiple analytical techniques applied in tandem are likely to be required.

Comprehensive Understandings of Rare Earth Element (REE) Speciation in Coal Fly Ashes and Implication for REE Extractability.

In recent years, recovery of rare earth elements (REEs) from coal fly ashes (CFAs) has been considered as a promising resource recovery option. Yet, quantitative information on REE speciation in CFAs and its correlation with REE extractability are not well established. This study systematically investigated the REE speciation-extractability relationship in four representative CFA samples by employing multiple analytical and spectroscopic techniques across the micro to bulk scale and in combination with thermodynamic calculations. A range of REE-bearing phases are identified, such as REE oxides, REE phosphates, apatite, zircon, and REE-bearing glass phase. REEs can occur as discrete particles, as particles encapsulated in the glass phase, or distribute throughout the glass phase. Although certain discrepancies exist on the REE speciation quantified by X-ray adsorption spectroscopy and acid leaching due to intrinsic limitations of each method, both approaches show significant fractions of REE oxides, REE phosphates, apatite, and REE-bearing Fe oxides. This study contributes to an in-depth understanding of the REE speciation-distribution-extractability relationship in CFAs and can help identify uncertainties associated with the quantification of REE speciation. It also provides a general methodology for future studies on REE speciation in complex environmental samples and a knowledge basis for the development of effective REE recovery techniques.

Differential amplicons for the evaluation of RNA integrity extracted from complex environmental samples

Reliability and reproducibility of transcriptomics-based studies are dependent on RNA integrity. Microfluidics-based techniques targeting rRNA are currently the only approaches to evaluate RNA integrity. However, the relationship between rRNA and mRNA integrity is unknown. Here we present a new integrity index, the Ratio amplicon, Ramp, to monitor mRNA integrity based on the differential amplification of RT-Q-PCR amplicons of the glutamine-synthetase A (glnA) transcript. We showed, in a suite of experimental degradations of RNA extracted from sediment, that while the RIN generally reflected the degradation status of RNA the Ramp mapped mRNA degradation better. Furthermore, we examined the effect of degradation on transcript community structure byamplicon sequencing of the 16S rRNA, amoA and glnA transcripts. We successful sequenced transcripts for all three targets even from highly-degraded RNA samples. While RNA degradation changed the community structure of the mRNA profiles, no changes were observed for the 16S rRNA transcripts profiles. Since both RT-Q-PCR and sequencing results were obtained, even from highly degraded samples, we strongly recommend evaluating RNA integrity prior to downstream processing to ensure meaningful results. For this both the RIN and Ramp are useful, with the Ramp better evaluating mRNA integrity in this study.

Colorimetric sensor based on 4-mercaptophenylboronic modified gold nanoparticles for rapid and selective detection of fluoride anion.

A highly selective and sensitive colorimetric sensor based on aggregation-induced color change of 4-mercaptophenylboronic modified gold nanoparticles was designed for the determination of fluoride anion. The 4-mercaptophenylboronic modified gold nanoparticles were synthesized by a simple one-pot reaction. The aggregation process occurred when interaction between fluoride anion and 4-mercaptophenylboronic on the surface of gold nanoparticles took place; as a result, fluoroborate anions were formed coupled with changes in the electronic properties of the AuNPs. The change can be measured by UV-Vis absorption spectra. The sensor shows good selectivity and sensitivity for fluoride anion. The linear range is 10.0-30.0 μM for fluoride and the detection limit of fluoride is 3.45 × 10-7 M according to IUPAC criteria (3σ rule). Furthermore, the sensor has been used for the detection of fluoride anion in tap water, ground water and human serum samples, the recovery can achieve 94.0%-103.3%, 94.7%-101.0% and 89.8-100.9%, respectively. The excellent performance of colorimetric sensor in the detection of the fluoride anion demonstrated the potential application in the detecting fluoride anion present in the complex environmental and biological samples.

Recent trends in analysis of nanoparticles in biological matrices.

The need to assess the human and environmental risks of nanoparticles (NPs) has prompted an adaptation of existing techniques and the development of new ones. Nanoparticle analysis poses a great challenge as the analytical information has to consider both physical (e.g. size and shape) and chemical (e.g. elemental composition) state of the analyte. Furthermore, one has to contemplate the transformation of NPs during the sample preparation and provide sufficient information about the new species derived from such alteration. Traditional techniques commonly used for NP analysis such as microscopy and light scattering are still frequently used for NPs in simple matrices; however, they have limitations in the analysis of complex environmental and biological samples. On the other hand, recent improvements in data acquisition frequencies and reduction of settling time of ICP-MS brought inorganic mass spectrometry into the forefront of NPs analysis. However, with the increasing demand of analytical information related to NPs, emerging techniques such as enhanced darkfield hyperspectral imaging, nano-SIMS and mass cytometry are in their way to fill the gaps. This trend review presents and discusses the state-of-the-art analytical techniques and sample preparation methods for NP analysis in biological matrices. Graphical abstract ᅟ.

Differential ratio amplicons (Ramp ) for the evaluation of RNA integrity extracted from complex environmental samples.

SummaryReliability and reproducibility of transcriptomics‐based studies are dependent on RNA integrity. In microbial ecology, microfluidics‐based techniques, such as the Ribosomal Integrity Number (RIN), targeting rRNA are currently the only approaches to evaluate RNA integrity. However, the relationship between rRNA and mRNA integrity is unknown. Here, we present an integrity index, the Ratio Amplicon, R amp, adapted from human clinical studies, to directly monitor mRNA integrity from complex environmental samples. We show, in a suite of experimental degradations of RNA extracted from sediment, that while the RIN generally reflected the degradation status of RNA the R amp mapped mRNA degradation better. Furthermore, we examined the effect of degradation on transcript community structure by amplicon sequencing of 16S rRNA, amoA and glnA transcripts. We successfully sequenced transcripts for all three targets even from highly‐degraded RNA samples. While RNA degradation changed the community structure of the mRNA profiles, no changes were observed for the 16S rRNA transcript profiles. Since both RT‐Q‐PCR and sequencing results were obtained, even from highly degraded samples, we strongly recommend evaluating RNA integrity prior to downstream processing to ensure meaningful results. For this, both the RIN and R amp are useful, with the R amp better evaluating mRNA integrity in this study.

Petroleomic depth profiling of Staten Island salt marsh soil: 2ω detection FTICR MS offers a new solution for the analysis of environmental contaminants

Staten Island is located in one of the most densely populated regions of the US: the New York/New Jersey Estuary. Marine and industrial oil spills are commonplace in the area, causing the waterways and adjacent marshes to become polluted with a range of petroleum-related contaminants. Using Rock-Eval pyrolysis, the hydrocarbon impact on a salt marsh was assessed at regular intervals down to 90 cm, with several key sampling depths of interest identified for further analysis. Ultrahigh resolution data are obtained by direct infusion (DI) atmospheric pressure photoionization (APPI) on a 12 T solariX Fourier transform ion cyclotron resonance mass spectrometer (FTICR MS) allowing trends in the compositional profile with depth to be observed, such as changes in the relative hydrocarbon intensity and the relative contributions from oxygen- and sulfur-containing groups. These trends may correlate with the timing of major oil spills and leaks of petroleum and other industrial chemicals into the waterways. The use of gas chromatography (GC) coupled to a 7 T solariX 2XR FTICR MS equipped with an atmospheric pressure chemical ionization (APCI) ion source offers retention time resolved and extensive compositional information for the complex environmental samples complementary to that obtained by DI-APPI. The compositional profile observed using GC-APCI FTICR MS includes contributions from phosphorous-containing groups, which may be indicative of contamination from other anthropogenic sources.

A new rapid detection method for ricin based on tunneling magnetoresistance biosensor

In this research, the magnetic immuno-chromatographic test strip and TMR magnetic sensitive sensor signal detection were combined effectively, which displayed the multiple advantages of magnetic nanoparticles (MNPs) label technique, immunochromatography (IC) and tunneling magnetoresistance (TMR) sensing technology. Through detecting magnetic field intensity generated by functionalized magnetic signal probe on immuno-chromatographic test strip, a new method for ricin detection was established based on TMR biosensor. Compared with traditional labeled biosensor based on optical signal detection, this method can overcome the interference of background color and light of complex environmental samples, and has advantages of easy operation, high sensitive, accurate quantification, good reproducibility, specificity and interference-resistance. With this method, the selective separation and rapid quantitative detection of complex samples can be achieved. The linear range of quantitative detection for ricin was 1 ng/mL–200 μg/mL, the regression equation was Y = 0.2125 X + 0.5675 (R = 0.9706, P < 0.0001, N = 12), the limit of detection (LOD) was 1 ng/mL. This method can overcome the influence of complex environmental interferents in the toxin detection, and can meet the analysis requirements for simulated samples such as water, soil, food, blood and so on. The method showed good recovery ratio and reproducibility, with the recovery ratio of 90.1%–94.2% and the RSD of 2.43%–3.35%.

Annotating Nontargeted LC-HRMS/MS Data with Two Complementary Tandem Mass Spectral Libraries.

Tandem mass spectral databases are indispensable for fast and reliable compound identification in nontargeted analysis with liquid chromatography–high resolution tandem mass spectrometry (LC-HRMS/MS), which is applied to a wide range of scientific fields. While many articles now review and compare spectral libraries, in this manuscript we investigate two high-quality and specialized collections from our respective institutes, recorded on different instruments (quadrupole time-of-flight or QqTOF vs. Orbitrap). The optimal range of collision energies for spectral comparison was evaluated using 233 overlapping compounds between the two libraries, revealing that spectra in the range of CE 20–50 eV on the QqTOF and 30–60 nominal collision energy units on the Orbitrap provided optimal matching results for these libraries. Applications to complex samples from the respective institutes revealed that the libraries, combined with a simple data mining approach to retrieve all spectra with precursor and fragment information, could confirm many validated target identifications and yield several new Level 2a (spectral match) identifications. While the results presented are not surprising in many ways, this article adds new results to the debate on the comparability of Orbitrap and QqTOF data and the application of spectral libraries to yield rapid and high-confidence tentative identifications in complex human and environmental samples.

Nanochannel-Confined Graphene Quantum Dots for Ultrasensitive Electrochemical Analysis of Complex Samples.

Herein, we present an electrochemical sensing platform based on nanochannel-confined graphene quantum dots (GQDs) that is able to detect a spectrum of small analytes in complex samples with high sensitivity. Vertically ordered mesoporous silica-nanochannel film (VMSF) is decorated on the supporting electrode, conferring the electrode with excellent antifouling and anti-interference properties through steric exclusion and electrostatic repulsion. The synthesized GQDs with different functionalities are confined in the nanochannels of VMSF through electrophoresis, serving as the recognition element and signal amplifier. Without the usual need of tedious pretreatment, ultrasensitive and fast detection of Hg2+, Cu2+, and Cd2+ (with limits of detection (LOD) of 9.8 pM, 8.3 pM, and 4.3 nM, respectively) and dopamine (LOD of 120 nM) in complex food (Hg2+-contaminated seafood), environmental (soil-leaching solution), and biological (serum) samples are realized as proof-of-concept demonstrations.

Antifungal-resistant Mucorales in different indoor environments

ABSTRACTThis paper sought to address the prevalence of Mucorales in different indoor environments in Portugal. Environmental samples (183 in total) were collected at dwellings (n = 79) and workplaces (bakeries, swine farms, taxis, waste-sorting plants) (n = 93) by passive sampling using electrostatic dust collector (EDC), air-conditioning filters, litter, and/or raw materials. Samples were inoculated onto non-selective MEA and DG18 media and were screened for antifungal drug-resistance in azole-supplemented agar Sabouraud media. A probe-based Mucorales-specific real-time PCR assay (Muc18S) was used to detect Mucorales in complement to conventional culture-based methods. Mucorales order was found as more prevalent in air-conditioning filters from waste-sorting fork lifters (35.7%). Amongst Mucorales isolates able to grow in azole-supplemented media, 16 isolates of Mucor sp., Rhizopus sp. or Rhizomucor sp. were not susceptible to 1 mg/L voriconazole, and four isolates of Mucor sp. or Rhizopus sp. were not susceptible to 4 mg/L itraconazole. In conclusion, combination of the culture-based and molecular methods proved to be reliable for Mucorales order identification in complex environmental samples.