Application of PCR and probe hybridization techniques in detection of airborne fungal spores in environmental samples

Specific PCR amplification and probe hybridization techniques were applied to examine the compositions of airborne fungi in samples from three different environments. The results from microscopic and CFU counting were compared to those of the molecular-based detections. The detection sensitivity for PCR amplifications was 9 to 73 spores and 1.3 to 19.3 CFUs per PCR reaction. The hybridization detection limit was 2 to 4 spores and 0.2 to 1.2 CFU. The hybridization method was more sensitive than PCR amplification and showed less variation among samples. Using specific PCR primers and probes we identified the presence of several fungal groups and species in the air samples. Specific detections through probe hybridization to PCR products amplified with universal or group-specific fungal primers have promising applications in the examination of air samples for environmental monitoring.     

Recovery of Francisella tularensis from soil samples by filtration and detection by real-time PCR and cELISA

The aim of this study was to develop a specific and highly sensitive method able to detect very low concentrations of Francisella tularensis in soil samples by real-time PCR (qPCR) with SYBR Green I. tul4 gene, which encodes the 17-kDa protein (TUL4) in F. tularensis strains, was amplified using a LightCycler (LC) device. We achieved a detection limit of 0.69 fg of genomic DNA from F. tularensis subp. holarctica live vaccine strain (LVS), corresponding to a value less than 3.4 genome equivalents per reaction. The qPCR was shown to be specific, highly sensitive and reproducible. In addition, we evaluated 2 new methods for recovering bacteria from soil based on 1-step filtration using glass fiber filters and PVDF filters. These filtration methods enabled us to recover F. tularensis efficiently from soil samples. As few as 50 CFU per 0.5 g of soil were detected by qPCR. Capture enzyme-linked immunosorbent assay (cELISA) allowed us to detect and quantify the amount of bacteria recovered from soil by an immunological method. Although qPCR was more sensitive than cELISA, we did not observe substantial differences in the amount of bacteria quantified by both methods.     

锆涂覆石墨管-无火焰原子吸收测定环境水样中微量银

用锆盐对石墨炉进行涂覆处理,同时又将其作为基体改进剂,有效提高了测定环境水样中银的灵敏度和分析精度,方法快速简便,检出限为2 8×10-12g,相对标准偏差小于6 2%。     

磁性分散固相萃取气相色谱法测定地表水中有机磷化合物

应用磁性分散固相萃取技术对环境水体中有机磷化合物进行萃取测定,并对萃取剂的用量、萃取时间、解吸溶剂、盐度等实验影响因素进行了优化。在优化条件下,有机磷的回收率为80.1%~93.1%,相对标准偏差为4.6%~5.9%,检出限为0.000 2~0.000 4 mg/L。与传统的液液萃取及固相萃取相比,该磁性分散固相萃取方法操作更为简单、迅速,有机溶剂消耗量很少,方法环保。能很好的满足环境水体中有机磷化合物的测定。     

Monoclonal antibody-based broad-specificity immunoassay for monitoring organophosphorus pesticides in environmental water samples

The development of easy-to-use and rapid-monitoring immunoassay methods for organic environmental pollutants in a class-selective manner is a topic of considerable environmental interest. In this work, a heterologous competitive indirect enzyme-linked immunosorbent assay (ciELISA) based on a monoclonal antibody (MAb) with broad-specificity for organophosphorus pesticides (OPs) was applied to the detection of O,O-diethyl and O,O-dimethyl OPs in water samples. The ciELISA conditions were carefully optimized to obtain a three to five-fold improvement of sensitivity for most OPs, and thirteen OPs were determined at concentrations ranging from 0.017 to 30 ng mL(-1). The determination of spiked environmental water samples showed average recoveries from 81.5% to 115.1%, with the coefficient of variation (CV) ranging from 6.1% to 20.9%, which showed satisfactory reproducibility of the developed ciELISA. To overcome the negative aspect of broad-specificity immunoassays not providing qualitative and quantitative analysis of individual OPs in blind samples, we used "percent inhibition rate" to make the developed ciELISA a semi-quantitative method, which allows the monitoring of positive samples from hundreds of negative samples. The determination of OPs in blind water samples by the developed ELISA with confirmation by HPLC-MS/MS analysis demonstrated that the assay is ideally suited as a screening method for OP residues prior to chromatographic analysis.     

连续流动分析快速测定环境水样中的硫化物

用新型的连续流动分析对环境水样中的硫化物进行分析测定。与传统的分析方法相比,该方法具有快速、灵敏度高、检出限低的特点。该方法的分析频率可达60次/小时,检测下限为0.006mg/L,大大提高了实验室自动化程度。     

Voltammetric determination of platinum at a lead film electrode in environmental water samples

The paper presents the first report on the application of a lead film electrode for the determination of ultratrace concentrations of platinum. The procedure is based on preconcentration of the Pt(IV)-formaldehyde complexes at an in situ plated lead film electrode held at ?0.9 V (vs. Ag/AgCl), followed by a negatively sweeping differential pulse voltammetric scan. The composition of the supporting electrolyte, the influence of accumulation potential and time on the sensitivity of platinum responses are discussed. The detection limit of Pt(IV) with the accumulation time of 60 was equal to 9.2?×?10^?12 mol L^?1. The application of this method was tested by recovery of Pt(IV) from spiked environmental water samples.     

Estimation of environmental flow incorporating water quality and hypothetical climate change scenarios

Environmental flows (Eflow, hereafter) are the flows to be maintained in the river for its healthy functioning and the sustenance and protection of aquatic ecosystems. Estimation of Eflow in any river stretch demands consideration of various factors such as flow regime, ecosystem, and health of river. However, most of the Eflow estimation studies have neglected the water quality factor. This study urges the need to consider water quality criterion in the estimation of Eflow and proposes a framework for estimating Eflow incorporating water quality variations under present and hypothetical future scenarios of climate change and pollution load. The proposed framework is applied on the polluted stretch of Yamuna River passing through Delhi, India. Required Eflow at various locations along the stretch are determined by considering possible variations in future water quantity and quality. Eflow values satisfying minimum quality requirements for different river water usage classes (classes A, B, C, and D as specified by the Central Pollution Control Board, India) are found to be between 700 and 800 m³/s. The estimated Eflow values may aid policymakers to derive upstream storage-release policies or effluent restrictions. Generalized nature of this framework will help its implementation on any river systems.     

Application of flow cytometry and cell sorting to the bacterial analysis of environmental aerosol samples

Flow cytometry (FCM) combined with viability staining is a useful tool in discerning viable bacteria in environmental samples where traditional culture methods may fail. Contamination of aerosol samples with dust and other non-biological particles can interfere with accurate sample analysis and therefore there is a desire to exclude those particles from analysis. Particles were sorted according to their light scattering properties, cultured and isolates obtained. Isolates were cultured in suspension and reanalyzed by flow cytometry. The isolates were also analyzed and identified by DNA sequence analysis. Isolates with statistically similar light scattering properties shared common sequence identification. Isolates exhibited distinct light scattering profiles that roughly correlated with their originating gate, but often the peak of the profile was outside that gate.     

环境样品中 PCBs 的测定

通过碱解、酸洗、萃取、净化、浓缩、脱硫等步骤处理实际样品,利用毛细管柱GC/ECD进行PCBs的定性和定量.方法定性准确,定量良好,具有较高的回收率.各同系物的方法检出限,水样为0.01～0.08ng/L;土壤样为0.003～0.03μg/kg,可以应用于土壤、沉积物、水样、油样等环境样品中PCBs的测定     

The prevalence of bacterial resistance in clinical, food, water and some environmental samples in Southwest Nigeria

The resistance pattern and mechanisms of bacterial isolates obtained from clinical origin, soil, industrial effluent, orange juice products and drinking water were studied using commonly used antibiotics. The microbial load of the water samples, industrial effluent and orange juice products were 1.0 × 10¹–2.25 × 10⁶, 2.15 × 10⁵, and 3.5 × 10⁴–2.15 × 10⁵ cfu mL^–1, respectively. The faecal coliform test revealed that only two out of twenty orange juice products had MPN of 2 and 20, the MPN of water ranged from 1–1800, while the effluent had MPN of 1800. The bacterial isolates that were isolated include E. coli, S. aureus, P. vulgaris, S. marcescens, S. pyogenes, B. cereus, B. subtilis, Micrococcus sp., Klebsiella sp., P. aeruginosa, and Enterobacter sp. Also, clinical and soil isolates of P. aeruginosa were used in the study. Among the eight antibiotics tested for resistance on five strains of each bacterium, seven different resistance patterns were observed among the bacterial isolates obtained from water, effluent and orange juice products. Among the clinical and soil isolates of P. aeruginosa, four multiple-drug resistance patterns were obtained. Thirty strains of E. coli and S. aureus were tested for -lactamase production and fourteen strains, seven each of E. coli and S. aureus that had high Minimum Inhibitory Concentration values (MIC) for both Amoxycillin and Cloxacillin were positive.     

Magnetic microsphere confined ionic liquid as a novel sorbent for the determination of chlorophenols in environmental water samples by liquid chromatography

Magnetic microsphere confined ionic liquid was synthesized by covalently bonding N-methylimidazolium on magnetic microspheres. The functionalized magnetic microspheres were characterized by Fourier transform infrared (FT-IR) spectrometry, thermogravimetric analysis (TGA) and scanning electron microscopy (SEM). The prepared material was used for the preconcentration of three chlorophenols (CPs) in water combined with high-performance liquid chromatography (HPLC). Several conditions that probably affected the extraction efficiency such as standing time, eluent and its volume, sample pH and volume, were optimized. Under the optimal conditions, good recoveries (70.3-88.8%) were achieved with satisfactory relative standard deviations (RSDs) of less than 6.0%. The limits of detection for the three CPs were 0.20-0.35 μg L(-1). The results indicated that the ionic liquid-functionalized magnetic microspheres show significant promise for the analysis of CPs in environmental samples.     

膜、柱串联固相萃取-高效液相色谱法测定水中多环芳烃(PAHs)的研究

建立了用膜-柱串联固相萃取(SPE)技术,甲醇和水作为流动相进行梯度洗脱,紫外和荧光检测器串联的高效液相色谱法(HPLC)分析水中EPA优先监控的16种PAHs的方法.     

Stability and storage problems in organotin speciation in environmental samples

The stability of both tributyltin (TBT) and triphenyltin (TPT) in water, sediment, oysters and cockles was studied over a period of 18 months using several storage conditions. Butyltins were stable in unacidified sea-water stored in polycarbonate bottles in the dark at 4 degrees C for 7 months, but half of the TBT concentration was lost after 540 d. A comparable preservation time was achieved for butyltins stored on C18 cartridges at room temperature. However, phenyltins extracted from sea-water were stable for only 60 d stored on cartridges and even more pronounced losses (about 90% after 540 d) occurred when they were stored in either polycarbonate or Pyrex glass bottles. Losses of organotins were observed in sediments after air drying and pasteurization treatments using a freeze-dried sediment as a comparator, whereas both butyltin and phenyltin species remained stable in sediments stored at -20 degrees C for the 18 months tested, irrespective of the treatment used for stabilization. Air drying followed by pasteurization was shown to be superior to other treatments for the stabilization of organotin compounds in sediments stored at higher temperatures, but 30% of TBT was lost after 540 d at 25 degrees C. Finally, butyltins were stable in both frozen cockles and oysters in the dark over a 7 month period and in freeze-dried samples stored at 4 degrees C for 5 months, but TBT losses of about 70% were observed after 540 d.     

Study of heavy metals in some environmental samples

Fuels like coal and rubber are frequently used for brick burning. However, both coal and rubber contain heavy metals. These heavy metals may elutriate in the wake of fly ash or may adsorb or absorb in the product. The present work deals with the analysis of heavy metals in some samples collected from brick burning industries located in the vicinity of a metropolitan city, Peshawar, Pakistan. Samples from raw clay, product, chimney scale and fossil fuel & rubber were collected and leached with acid mixture. The leachates were concentrated and analyzed by atomic absorption spectrophotometer for the determination of chromium (Cr), lead (Pb), cadmium (Cd) and antimony (Sb). It was observed that heavy metals are present in clay, brick and chimney scale. However, significant amount of these metals was observed in chimney scale. It is inferred that such emanations laden with heavy metals are accompanying the stack gases which are being dumped in to the environment. In order to avoid environmental problems, strict environmental regulations shall be enforced and a constant check on these emanations to the environment must be made to ensure clean air act.     

Measurement of chemical oxygen demand (COD) in natural water samples by flow injection ozonation chemiluminescence (FI-CL) technique

COD determination based on ozone oxidation of alpha-naphthol combined with UV radiation (UV-O3) has been studied in the present work. Utilizing the phenomenon that luminol can be oxidized by the dissolved ozone to produce luminescence, we have established a new method of utilizing aqueous chemiluminescence to determine COD. The kinetics and mechanism of the ozonation reaction of alpha-naphthol have been investigated in order to gain a better understanding of the general applicability and limitation of the technique. Real world samples were analyzed and the results show that the relative error of COD(FI-CL) measurement for water samples was < 10%. Compared with the results of the conventional potassium permanganate method, the COD values of the FI-CL method are consistently higher (0-20% relative). The higher COD values suggest that the ozone-UV system is a more effective oxidation technique.     

Application of cryofocusing hydride generation and atomic fluorescence detection for dissolved mercury species determination in natural water samples

The concentration levels of mercury (Hg) species in natural water samples are usually low. Consequently, accurate analysis with low detection limits is still a major problem. In this work, a method was applied for the simultaneous direct determination of dissolved mercury species in water samples by on-line hydride generation (HG), cryogenic trapping (CT), gas chromatography (GC) and detection by atomic fluorescence spectrometry (AFS). The suitability of the method for real samples with different organic matter and chloride contents was evaluated by recovery experiments in synthetic and natural spiked water samples. The HG method was compared with other current available methods for mercury analysis with respect to the different fraction of mercury analysed, i.e. 'reactive', 'reducible' or total. HG derivatization and SnCl2 reduction (with and without previous oxidation with BrCl) were applied to synthetic and natural (spiked and non-spiked) water samples. The influence of chloride and dissolved organic matter concentrations was studied. The results suggest that the HG procedure is suitable for the simultaneous determination of Hg2+ and MeHg+ in surface water samples. Inorganic mercury analysed by HG (i.e. reducible) is close to the total inorganic mercury.     

WF-8型在线富集进样器应用于水中痕量CuPbCd测定的研究

用 WF 8型在线富集进样器与火焰原子吸收光度计联用 ,应用于水中痕量 Cu、Pb、Cd的测定 ,其富集倍数分别是 1 2 2、1 3 6和 94倍 ,测定的精密度分别是 3 7%、2 8%和 3 9% ,检出限分别是 0 4 7、1 3和 0 2 2μg L,在地表水样中的加标回收率分别为 94 2 %～ 1 0 0 %、98 8%～ 1 0 7%和 1 0 8%～ 1 2 0 % ,并对 WF 8型进样器与火焰原子吸收光度计的成功联用 ,提出了一种新操作程序。     

Methodologies for determination of antimony in terrestrial environmental samples

Methodologies for the environmental analysis of total antimony and aqueous chemical speciation are critically reviewed, including preparation techniques for aqueous and solid matrices and the determination of solid state partitioning and recommendations are given for future research directions. Concentrations of total antimony commonly present in aqueous and solid environmental samples are readily determined using present day analytical techniques. This has resulted primarily from technological advances in microwave digestion for solid matrices and the development of plasma based analyte detection systems. ICP-AES and ICP-MS techniques are both utilised for the environmental analysis of total antimony concentrations. However, ICP-MS is increasingly favoured as a result of reduced spectral interferences and the potential for analyte detection in the pg mL(-1) range. Determination of aqueous antimony speciation presents a number of complex analytical challenges and highly selective separation and identification techniques are required prior to detection. The majority of published techniques including common applications of hydride generation are insufficiently selective for the determination of intrinsic chemical speciation and often only oxidation state data are obtained. The recent in-line applications of HPLC-ICP-MS offer the potential for highly selective separations of aqueous antimony species and determination of detailed chemical speciation data. However, considerable development work is required to optimise chromatographic separations and identify uncharacterised species resident in environmental systems. Analytical techniques to aid the determination of antimony's associations with solid environmental matrices include the application of chemical extraction procedures and leaching experiments. To date, this area of analytical research has received little attention and further studies are required to elucidate this aspect of antimony's environmental chemistry.