Determination of polychlorinated biphenyl congeners in environmental samples

A modified separation method has been developed for determinating polychlorinated biphenyl congeners in environmental samples. Direct treatment of extract with concentrated HzSO4 was employed in the first step for removal of lipids and other interfering substances, then a joint column of alumina-silica gel(Ag+) was applied to separate PCBs fraction from HCH, DDT and its analogs. After this separation, the PCBs fraction was analyzed by capillary gas chromatography with ECD detector and confirmed by GC/MS. The recoveries of individual congeners in Aroclor 1254 through the separation are about 79%-84%. The method is very efficient and useful for determination of trace amount of PCB congeners in environmental samples.

Erratum to “Isolation, Characterization and Antimicrobial Resistance Patterns of Lactose-Fermenter Enterobacteriaceae Isolates from Clinical and Environmental Samples” [Open Journal of Medical Microbiology 5 (2015) 169-176]

The lactose-fermenter Enterobacteriaceae are the most frequent cause of clinical infection in our country. The objective of this study was to isolate and identify the most common lactose-fermenter Enterobacteriaceae from clinical samples, including urine, blood, wounds, and sputum, obtained from the local hospital and from environmental samples from a chicken farm, agriculture soil, and water from the Tigris River in Baghdad City. The study also aimed at establishing the antibiotic resistance patterns of the isolated bacteria. A total of 155 bacterial isolates were identified from 10 genera according to the Vitek 2 system. The most common bacterial isolates from the clinical and environmental samples were Escherichia coli and Klebsiella pneumoniae, respectively. The antibiotic resistance patterns showed that all clinical and environmental isolates were multidrug resistant to β-lactam (except carbapenems) drug and aminoglycosides and more sensitive to carbapenems.

Rapid HPLC Method for Monitoring Relevant Residues of Pharmaceuticals Products in Environmental Samples

This work presents a multi-residue analytical method based on solid phase extraction (SPE) followed by high-performance liquid chromatographic (HPLC) with diode array (DAD) detection for the simultaneous determination of a group of pharmaceutical products that include ten antidepressants and three anticanceri- genic in environmental samples (water and soil). Baseline separation of the studied compounds was obtained on an ultrabase C18 (4.6 mm i.d. × 150 mm, 5 μm particle) column using acetonitrile:phosphate buffer pH 2.5 (35:65 v/v) as mobile phase with a flow rate of 1.5 mL/min. Different aspects including linearity, accuracy, precision and detection and quantification limits were examined in order to validate the proposed method. Detection limits between 1 and 50 ng/mL were obtained for all the target compounds. This method was ap- plied to the analysis of environmental samples as waters and soils of different precedence. Prior, the HPLC determination the samples were purified and enriched using SPE or liquid-liquid extraction (LLE) of the tar- get compounds.

Application of closed-vessel microwave digestion method for the determination of multi-elements in environmental samples by sequential ICP-AES

A closed-vessel microwave digestion method is described for the rapid dissolution of environmental samples such as foods, soils and sediments. Depending on the sample type, 0.1-0.2 g sample was decomposed with HNO3/H2O2 or HNO3 / H2O2/HF acid mixture in a PTFE digestion vessel by using microwave heating for 2-3 min at 500W of microwave power. The solution, or to which 0.5 g of boric acid was added, was diluted to 25-50 ml and directly determined by sequential ICP-AES. The accuracy of the procedure was validated by the analysis of six standard reference materials for 10 elements. Ail results were in a good agreements with the certified values.

A Modified Qu EChERS-DART-MS/MS Technique for High-Throughput Detection of Organophosphate Nerve Agent Hydrolysis Products in Environmental Samples

Organophosphate nerve agents(OPNAs)are lethal chemical weapons(CWs)which hydrolyze rapidly to alkyl phosphate compounds in the environment.The identification of alkyl phosphate compounds in the environment is critical for the verification of OPNAs.Currently,due to the complex sample preparation and long detection process for organophosphate nerve agent hydrolysis products(OPNAHPs),their high-throughput determination is difficult.To simplify sample preparation and detection of OPNAHPs from environmental samples,a quick,easy,cheap,effective,rugged and safe(Qu ECh ERS)method for the simultaneous purification of the five OPNAHPs in environmental samples combined with detection through direct analysis in real-time ionization source coupled with tandem mass spectrometer(DART-MS/MS)was developed.An internal standard method was applied for the quantification.The method exhibited a good linearity(R^(2)>0.991)in the range of 1.00 ng/m L-4.00μg/m L.The limits of detection and limits of quantification were 1.00-7.00 ng/m L and 10.0-20.0 ng/m L,respectively.The recoveries of OPNAHPs in environmental samples were between 65.3%and 107%,with relative standard deviations ranged from 1.6%to 19%.In addition,the sample preparation and analysis process for OPNAHPs could be completed in less than 10 min.The results demonstrated that the modified Qu ECh ERS method could quickly and efficiently remove the matrix of environmental samples.Combined with DART-MS/MS,an accurate and high-throughput detection method of OPNAHPs in environmental samples was provided.The developed method has great potential in the fields of early warning,clinical treatment and environmental decontamination.

Development of a loop‑mediated isothermal amplification assay for detection of Austropeplea tomentosa from environmental water samples

Lymnaeid snails are key intermediate hosts for the development and survival of Fasciola spp.,the causative agent of Fascioliasis which are economically important parasites infecting humans and livestock globally.The current control method for treating Fascioliasis is heavily reliant on anthelmintic drugs,particularly Triclabendazole(TCBZ)which has resulted in drug-resistant parasites and poses significant risk as there are no long-term efficacious alternatives available.Sustainable control measures at the farm level could include both parasite and snail control will play an important role in Fasciola spp.control and reduce the reliance on anthelmintic drugs.Implementation of such sustainable control measures requires effective identification of snails on the property however Lymnaeid snails are small and difficult to physically locate.Snail identification using an environmental DNA approach is a recent approach in which physically locating snails are not required.Austropeplea tomentosa,is the primary intermediate snail host for F.hepatica transmission in South-East Australia and we present an in-field loop-mediated isothermal amplification and water filtering method for the detection of A.tomentosa eDNA from water samples to improve current surveillance methods.This methodology is highly sensitive with a detection limit of 5×10^(−6)ng/μL,detected in<20 minutes,with cumulative sample preparation and amplification time under 1 hour.This proposed workflow could assist in monitoring areas to determine the risk of Fascioliasis infection and implement strategies to manage snail populations to ultimately reduce the risk of infection for humans and livestock.

Free-Standing Membrane Liquid-State Platform for SERS-Based Determination of Norfloxacin in Environmental Samples

Surface-enhanced Raman scattering(SERS)has been widely used in various fields due to high sensitivity,but it is hindered by its low repeatability.Here,we explored a highly reproducible free-standing liquid-state platform(FSM)for monitoring norfloxacin(NOR)in the environmental field.After optimizing the types of nanoparticles(NPs)and pH value in NOR solution,the relative standard deviation(RSD)of FSM SERS analysis can be stabilized below 10%(n≥8),and the R^(2)of the calibration curve in the range of 20μg/L-100μg/L was 0.995.In addition,the results showed that the limit of detection(LOD)(3σ/k)of NOR was 1.3μg/L.Moreover,the NOR in the spiked samples was successfully quantified by FSM,and the recovery rate exceeded 95%.The proposed method has the potential for rapid analysis of drug residues in environmental samples.

Novel Screen-Printed All-Solid-State Copper(II)-Selective Electrode for Mobile Environmental Analysis

Based on poly(vinyl chloride) membranes, a novel miniaturized screen-printed all-solid-state copper(II)-selective electrode has been developed for applications in environmental monitoring. Performance and applicability of the ion-selective electrode (ISE) have been proved by potentiometric investigations. Conducting polymers were used as intermediate layers and as solid contacts between the ion-selective membrane and the graphite transducer. The ion-complexing reagent 2-mercapto-benzoxazole was incorporated into poly(vinyl chloride) membranes. In the concentration range 10-6 - 10-2 mol/L, the ISE exhibited a linear Nernstian potential response to copper(II) with an average slope value of 28 mV/decade. The detection limit was 3 × 10-7 mol/L. The electrode exhibits a short response time (<10 s) and can be used in the range of pH = 3 - 7. Selectivity coefficents against certain interfering ions are investigated. The life time of the electrode under laboratory conditions was approximately 12-month. The electrode was applied in the investigation of different aqueous environmental samples and the electrode characteristics were described. The copper(II) ASS electrode has also successfully been used in potentiometric, complexometric titrations with ethylenediaminetetraacetic acid.

同位素稀释-HRGC-LRMS法测定环境样品中二噁英类多氯联苯

多氯联苯(PCBs)是一类具有209种同类物的高毒性、难降解、强脂溶性和生物累积性的持久性有机污染物,自从1996年Jensen首次在鹰和鲱鱼中发现PCBs后[1,2],现在已在世界各地不同的环境介质中都发现有PCBs的存在[3].……

Immunoassay for Cadmium Detection and Quantification

Objective To detect cadmium in environmental and food samples by graphite furnace atomic absorption spectroscopy （GFAAS） and inductively coupled plasma atomic emission spectroscopy （ICPAES）. Methods An indirect competitive enzyme-linked immunosorbent assay （IC-ELISA） was developed based on a cadmium-specific monoclonal antibody. IC-ELISA for cadmium in environmental and food samples was evaluated. Results IC-ELISA showed an IC50 of 45.6 μg/L with a detection limit of 1.95 μg/L for cadmium, and showed a mean recovery ranging 97.67%-107.08%. The coefficient of variations for intra- and interassay was 3.41%-6.61% and 4.70%-9.21%, respectively. The correlation coefficient between IC-ELISA and GFAAS was 0.998. Conclusion IC-ELISA can detect and quantify cadmium residue in environmental or food samples.

Flow-Injection Flame Atomic Absorption Determination of Hexavalent Chromium with On-Line Preconcentration on an Anion Imprinted Polymer

A flow injection preconcentration system for the flame atomic absorption spectrometric determination of hexavalent chromium has been developed. The method employs on-line preconcentration of Cr(VI) on a minicolumn packed with Cr(VI)-imprinted poly(4-vinyl pyridineco-2-hydroxyethyl methacrylate) placed into a flow injection system. Hexava-lent chromium was eluted with a small volume of diluted hydrochloric acid into the nebulizer-burner system of a flame atomic absorption spectrometer. An enrichment factor of 550 and a 3σ detection limit of 0.04 μg·L-1 along a sampling frequency of 4 h-1 at a sample flow rate of 3.5 mL·min-1. The relative standard deviation is 2.9% for 1 μg·L-1 Cr(VI) (n = 11). The flow injection system proposed has the advantage of being simpler because the use of expensive and sophisticated instruments is avoided. Ease of use, continuous process and selectivity make this method suitable for Cr(VI) determination in different environmental samples such as sea and river waters, soils and sediments.

Methods for Detection of Viruses in Water and Wastewater

Viruses present in water might be harmful for human health and life. Nowadays over 100 pathogenic human virus species occur in water polluted with sewage. Chlorination, which is the most popular disinfection method is not able to remove easily viruses from treated water. Due to this, it’s necessary to detect viruses in water before treatment in order to determine disinfectant dose and to ensure the sanitary safety level of treated water. The aim of this article is to review viruses detection methods as well as the problems related to implementation of those methods in analysis of water and wastewater samples.

The Relations Among Various Markov Chains

Some basic equations and the relations among various Markov chains are established. These works are the bases in the investigation of the theory of Markov chain in random environment.

Determination of Triazine Herbicides in Environmental Water Samples by Acetonitrile Inorganic Salt Aqueous Two-Phase Microextraction System

Acetonitrile inorganic salt aqueous two-phase extraction method was established for the determination of triazine herbicides(simeton,cyanazine,desmetryn,terbumeton,terbuthylazine and dimethametryn)in environmental water samples by high-performance liquid chromatography(HPLC).The extraction solvents types and volume of acetonitrile,the inorganic salt types and amount of(NH_(4))_(2)SO_(4),extraction time and pH of sample solution were optimized by single-factor experiment and central composite design.Under the optimum extraction conditions,all linear ranges were obtained with coefficients of determination(r)≥0.9993.The limits of detection for this proposed method were in the range of 0.16-0.28μg/L for six triazine herbicides.The developed method has been successfully applied to the analysis of target triazine herbicides from lake,canal and moat in real-world water samples.The recoveries of target analytes were in the range from 87.0 to 110.9%and the relative standard deviation was lower than 7.3%.

Identifying the Risk of SARS-CoV-2 Infection and Environmental Monitoring in Airborne Infectious Isolation Rooms(AIIRs)

Healthcare workers(HCWs)are at high risk of occupational exposure to the new pandemic human coronavirus,SARSCoV-2,and are a source of nosocomial transmission in airborne infectious isolation rooms(AIIRs).Here,we performed comprehensive environmental contamination surveillance to evaluate the risk of viral transmission in AIIRs with 115 rooms in three buildings at the Shanghai Public Health Clinical Center,Shanghai,during the treatment of 334 patients infected with SARS-CoV-2.The results showed that the risk of airborne transmission of SARS-CoV-2 in AIIRs was low(1.62%,25/1544)due to the directional airflow and strong environmental hygiene procedures.However,we detected viral RNA on the surface of foot-operated openers and bathroom sinks in AIIRs(viral load:55.00–3154.50 copies/mL).This might be a source of contamination to connecting corridors and object surfaces through the footwear and gloves used by HCWs.The risk of infection was eliminated by the use of disposable footwear covers and the application of more effective environmental and personal hygiene measures.With the help of effective infection control procedures,none of 290 HCWs was infected when working in the AIIRs at this hospital.This study has provided information pertinent for infection control in AIIRs during the treatment of COVID-19 patients.

Environmental sampling of volatile organic compounds during the 2018 Camp Fire in Northern California

Trace analysis of volatile organic compounds(VOCs) during wildfires is imperative for environmental and health risk assessment. The use of gas sampling devices mounted on unmanned aerial vehicles(UAVs) to chemically sample air during wildfires is of great interest because these devices move freely about their environment, allowing for more representative air samples and the ability to sample areas dangerous or unreachable by humans. This work presents chemical data from air samples obtained in Davis, CA during the most destructive wildfire in California's history-the 2018 Camp Fire – as well as the deployment of our sampling device during a controlled experimental fire while fixed to a UAV. The sampling mechanism was an in-house manufactured micro-gas preconcentrator(μPC) embedded onto a compact battery-operated sampler that was returned to the laboratory for chemical analysis. Compounds commonly observed in wildfires were detected during the Camp Fire using gas chromatography mass spectrometry(GC–MS), including BTEX(benzene, toluene, ethylbenzene, m + p-xylene, and o-xylene), benzaldehyde, 1,4-dichlorobenzene, naphthalene, 1,2,3-trimethylbenzene and 1-ethyl-3-methylbenzene. Concentrations of BTEX were calculated and we observed that benzene and toluene were highest with average concentrations of 4.7 and 15.1 μg/m^(3), respectively. Numerous fire-related compounds including BTEX and aldehydes such as octanal and nonanal were detected upon experimental fire ignition, even at a much smaller sampling time compared to samples taken during the Camp Fire. Analysis of the air samples taken both stationary during the Camp Fire and mobile during an experimental fire show the successful operation of our sampler in a fire environment.

Standard method design considerations for semi-quantification of total naphthenic acids in oil sands process affected water by mass spectrometry： A review

Naphthenic acids are a complex class of thousands of naturally occurring aliphatic and alicyclic carboxylic acids found in oil sands bitumen and in the wastewater generated from bitumen processing. Dozens of analytical methods have been developed for the semiquantification of total naphthenic acids in water samples. However, different methods can give different results, prompting investigation into the comparability of the many methods. A review of important methodological features for analyzing total naphthenic acids is presented and informs the design of future standard methods for the semi- quantification of total naphthenic acids using mass spectrometry. The design considerations presented are a synthesis of discussions from an Environment and Climate Change Canada （ECCC） led taskforce of 10 laboratory experts from government, industry and academia during April 2016 and subsequent discussions between University of British Columbia and ECCC representatives. Matters considered are： extraction method, solvent, pH, and temperature; analysis instrumentation and resolution; choice of calibration standards; use of surrogate and internal standards; and use of online or offline separation prior to analysis. The design considerations are amenable to both time-of-flight and Orbitrap mass spectrometers.

A signal-amplified whole-cell biosensor for sensitive detection of Hg^2+ based on Hg^2+-enhanced reporter module

A signal-amplified mercury sensing biosensor with desired sensitivity was developed through firstly using the GFP mutant with fluorescence increasing response towards Hg^2+ as the reporter module.The developed biosensor showed response for Hg^2+ in a relatively wide range of 1–10,000 nmol/L,and the detection limit was improved one or two orders of magnitude in comparison with most metal-sensing biosensors in similar constructs.In addition,the biosensor could distinguish Hg^2+ easily from multiple metal ions and displayed strong adaptability to extensive p H conditions (pH 4.0–10.0).More importantly,the developed biosensor was able to provide an initial assessment of Hg^2+ spiked in the environmental water with the recoveries between 85.70%and 112.50%.The signal-amplified strategy performed by the modified reporter module will be widely applicable to many other wholecell biosensors,meeting the practical requirements with sufficient sensing performance.

Fast analysis method of strontium-90 after separation using crown ether resin

Objective:To explore the separation condition for 90Sr using crown ether resin,in order to establish a fast method for analysis of 90Sr in food and environmental samples.Methods:Stable strontium isotope(88Sr)was used to simulate the radioactive 90Sr,and the concentration of 88Sr in elution solution was detected using inductively coupled plasma mass spectrometry(ICP–MS).The separation conditions were investigated through batch experiment.Results:Under the optimized experimental conditions,the maximum adsorption capacity of crown ether resin was 22.28 mg/g.4.0–8.0 mol/L nitric acid made it easier for the Sr2þto load on the resin,and 20 mL ultrapure water was used to rinse the chromatographic column to achieve a good separation effect,by which the recoveries of Sr2þwere nearly close to 100%.The average recovery rates of 4 samples were 60.25%,69.26%,75.09%and 66.33%,respectively.Conclusions:Crown ether resin has very good selectivity and adsorption for 90Sr.The optimized conditions were high-efficiency and easy to operate.The separation method has great potential for the fast analysis of 90Sr in food and environmental samples.

Study on Preconcentration of Trace Copper Using Microcrystalline Triphenylmethane Loaded with Malachite Green

The paper describes a novel method for copper preconcentration using microcrystalline triphenylmethane loaded with malachite green prior to the determination by the flame atomic absorption spectrometry （FAAS）. Under the optimum conditions, Cu（Ⅱ） can be totally adsorbed on the surface of microcrystalline triphenylmethane, and completely separated from Pb（Ⅱ）, Cd（Ⅱ）, Co（Ⅱ）, Cr（Ⅲ）, Ni（Ⅱ）, Mn（Ⅱ）, Fe（Ⅲ） and Al（Ⅲ） by controlling acidity. The preconcentration factor of this proposed method is 200. The recovery is in a range of 97.5%-105%. The relative standard deviation （RSD） is not beyond 3.0%. The proposed method has been successfully applied to the determination of trace copper in various water samples with satisfactory results.