Water Extracts Of Samples Research Articles

Direct aqueous supercritical fluid extraction coupled on-line with liquid chromatography–tandem mass spectrometry for the analysis of polyether ionophore antibiotics in water

A direct aqueous SFE system designed to extract water samples contained in vials has been coupled on-line with a reverse phase LC–MS–MS system using a single 10-port valve. An SFE trap system using C 1 stationary phase connected to a C 18 analytical HPLC column enabled the SFE–LC–MS–MS analysis of three polyether ionophore antibiotics in water using a step gradient. A quantitative SFE–LC–MS–MS method has been developed whereby the progress of SFE can be monitored directly on-line such that ionophore recovery profile data from a single water sample can be obtained. Using a continuous direct aqueous SFE period of 75 min, the SFE–LC–MS–MS recoveries of the ionophores were: monensin 76.2% with RSD 4.1%, lasalocid 84.6% with RSD 3.8% and narasin 91.2% with RSD 3.2%. With positive ion electrospray ionization, the SFE–LC–MS–MS system using a 4 mL water sample provided multiple reaction monitoring (MRM) limits of detection for monensin and lasalocid each equivalent to 90 ng/L whereas 30 ng/L for narasin. A two-way valve controlling carbon dioxide distribution to the SFE vessel has provided a means for the initial investigation of the recovery of ionophore sodium salts from water using static SFE.

A sensitive ligase-based ATP electrochemical assay using molecular beacon-like DNA

A sensitive and selective ligase-based signal-on electrochemical sensing method for adenosine-5′-triphosphate (ATP) detection had been developed using molecular beacon (MB)-like DNA. In this method, the biotin-tagged MB-like DNA was self-assembled onto a gold electrode to form a stem-loop structure by means of facile gold-thiol chemistry, which resulted in blockage of electronic transmission. It was eT OFF state. In the presence of ATP, two nucleotide fragments which were complementary to the loop of the MB-like DNA could be ligated by the ATP-dependent T4 DNA ligase. Hybridization of the ligated DNA with the MB-like DNA induced a significant conformational change in this surface-confined DNA structure, which in turn released the biotin from the surface allowing free exchange of electrons with the electrode generating a measurable electrochemical signal (eT ON). The resulting change in electron transfer efficiency was readily measured by differential pulse voltammetry at target ATP concentrations as low as 0.05 nM and with linear response range from 0.1 to 1000 nM. Moreover, it was also able to discriminate ATP from its analogues. The proposed method had been successfully applied to the determination of ATP in the Escherichia coli O157:H7 extracts of water samples, and the linear response was found between the concentrations of 10 3 and 10 7 cfu/mL.

Mutagenicity assessment in a river basin influenced by agricultural, urban and industrial sources

The genotoxic potential of samples from a river basin under impact of agricultural, urban and industrial activities was studied, to investigate the influence of climatic variations on the mutagenicity. Three sites were analyzed, a reference—SI121—and two with strong anthropic influence—SI028 and SI008. The Salmonella/microsome assay was performed in the presence/absence of hepatic metabolic system in samples of water and organic extracts. Different strains were used to identify frameshift mutagens, base-pair substitutions and oxidative damage. Indicative mutagens were detected especially with metabolization. The toxic response, which was quite frequent, may have interfered in the mutagenicity detection. The adverse impact of anthropic activities was detected through recurring cytotoxic and mutagenic responses at the site of greater urban and industrial concentration. The data suggest the influence of climatic conditions on mutagenic response, reinforcing the need to investigate mutagenicity for a prolonged period to a better risk assessment of exposure.

Genotoxicity of organic pollutants in source of drinking water on microalga Euglena gracilis

The potential toxicities of organic pollutants in the drinking water source at Meiliang Bay of Lake Taihu were investigated by comet assay and antioxidant enzyme approach on microalgae Euglena gracilis. The organic extracts of the water samples could induce DNA damage on microalgae cells. Statistically significant differences (P < 0.05) were observed at groups of 0.3x, 3x and 10x concentrations compared with the control and a solvent control (DMSO). The organic extracts also affected antioxidant enzyme activity and induced lipid peroxidation in the microalga. In the high dose group, there was an obvious increase in SOD content (P < 0.05). The results suggest that the concentrated organics from water sample extracts have adversary effects on E. gracilis and could possibly damage the ecosystem.

Method Development for the Analysis of 1,4-Dioxane in Drinking Water Using Solid-Phase Extraction and Gas Chromatography-Mass Spectrometry

1,4-Dioxane has been identified as a probable human carcinogen and an emerging contaminant in drinking water. The United States Environmental Protection Agency's (U.S. EPA) National Exposure Research Laboratory (NERL) has developed a method for the analysis of 1,4-dioxane in drinking water at ng/L concentrations. The method consists of an activated carbon solid-phase extraction of 500-mL or 100-mL water samples using dichloromethane as the elution solvent. The extracts are analyzed by gas chromatography-mass spectrometry (GC-MS) in selected ion monitoring (SIM) mode. In the NERL laboratory, recovery of 1,4-dioxane ranged from 94-110% in fortified laboratory reagent water and recoveries of 96-102% were demonstrated for fortified drinking water samples. The relative standard deviations for replicate analyses were less than 6% at concentrations exceeding the minimum reporting level.

Genotoxicity of water from the Songhua River, China, in 1994–1995 and 2002–2003: Potential risks for human health

A previous study showed that the cancer mortalities are higher for residents who lived nearby the Songhua River heavily polluted by organic contamination. It is important to determine its risk of carcinogenic potential. Short-term genotoxic bio-assays using Salmonella, Sister Chromatid Exchange (SCE), and Micronuclei (MN) assays were employed to examine the genotoxic activity of ether extracts of water samples taken from the Songhua River. The results of the Salmonella bioassay indicated that there were indirect frame-shift mutagens in the water samples. A dose–response relationship for the SCE and MN assays was obtained. These results showed that organic extracts of water samples have genotoxic activity and the risk of carcinogenic potential to human health. The mutagenesis of water samples had changed compared to the results in 1994–1995. An increasing trend of risk of carcinogenic potential in the Songhua River after ten years should be noted and needs to be studied further.

Changes in toxicity and Ah receptor agonist activity of suspended particulate matter during flood events at the rivers Neckar and Rhine — a mass balance approach using in vitro methods and chemical analysis

Background, aim, and scope As a consequence of flood events, runoff and remobilized sediments may cause an increase of ecotoxicologically relevant effects from contaminant reservoirs. Aquatic and terrestrial organisms as well as cattle and areas of settlement are exposed to dislocated contaminants during and after flood events. In this study, the impacts of two flood events triggered by intense rain at the rivers Neckar and Rhine (Southern Germany) were studied. Effects in correlation to flood flow were assessed at the river Neckar using samples collected at frequent intervals. River Rhine suspended particulate matter (SPM) was sampled over a longer period at normal flow and during a flood event. Three cell lines (H4L1.1c4, GPC.2D.Luc, RTL-W1) were used to compare Ah receptor agonist activity in different biotest systems. Multilayer fractionation was performed to identify causative compounds, focusing on persistent organic contaminants.

Detection of potential (anti)progestagenic endocrine disruptors using a recombinant human progesterone receptor binding and transactivation assay

The present work describes the identification of (anti)progestin endocrine disrupting chemicals (EDC) using a two step screening system. In the first step a competitive binding assay was developed using recombinant human progesterone receptor (hPR). The tested chemicals were of various classes like insecticides, their metabolites, industrial chemicals and waste water treatment plant (WWTP) effluents. All the tested chemicals demonstrated a high affinity binding for hPR. The average IC50 values of the test chemicals were within the range of 1-25microM. In the second step of screening, a mammalian cell-based hPR transactivation assay was developed where HEK 293 cells were co-transfected with hPR and luciferase reporter gene under the control of progesterone-response element. Stimulation of the cells with progesterone resulted in about 25-fold up regulation of luciferase activity, with EC50 value of 4nM. Potent anti-progesterone, RU486, significantly inhibited progesterone-induced transactivation and non-progestagenic steroids failed to transactivate hPR till 1microM concentrations. The chemicals showing high binding affinities in competitive binding assays were then tested in transactivation assay and all of them were found to be anti-progestative except WWTP effluents. Transactivation assays using extracted water samples from five different WWTP effluents showed that it was rich in progestative compounds. The levels of induction caused by these effluents were in the range of 15-25% of induction by progesterone and they represented about 6ng/l equivalent progesterone activities. In conclusion, we demonstrated that this two step assay provides an efficient screening tool for the detection of (anti)progestative EDC in various samples.

Screening of some anti-progestin endocrine disruptors using a recombinant yeast based in vitro bioassay

The present study was aimed to develop a sensitive, fast and user friendly progesterone receptor transactivation assay using recombinant yeast cells, Saccharomyces cerevisiae, modified to express human progesterone receptor (PR) and progesterone response element (PRE) driving the expression of green fluorescent protein. Stimulation of cells with increasing concentrations of progesterone resulted in significant elevation in fluorescence activity, with the minimum effective dose of progesterone being 0.1nM. RU486, significantly inhibited progesterone induced transactivation and non-progesterogenic steroids failed to transactivate PR till 10μM concentrations. About 7 different chemicals (mostly pesticides or their metabolites) like DDT and its metabolites, nonylphenol, endosulfan were screened in this assay system for their role in transactivation and they were all found to be anti-progestative and IC50 values within the range of 3–20μM. Further, the assay was used to analyze the endocrine disrupting activity of extracted water samples from leather industries known for their high content of various chemicals and it was found to be rich in anti-progestative compounds. It resulted in about 30% reduction in transactivation. In conclusion, we demonstrated that this yeast based bioassay provides a rapid and robust assay for high throughput screening of (anti)progestative compounds from various sources.

Development of an Analytical Protocol for Forensic Identification of Chemical Warfare Agent Surrogates

An analytical protocol for forensic identification of chemical warfare agent surrogates in various sample media is developed. This protocol can be implemented on site or in a mobile laboratory, based on a quick sample extraction procedure and a subsequent gas chromatography/mass spectrometry (GC/MS) analysis. The surrogates in this work include 2-chloroethyl ethyl sulfide (CEES), dimethyl methyl phosphonate (DMMP), 2-(butylamino) ethanethiol (BAET), pinacolyl methyl phosphonate (PMP), and diethyl phosphoramidate (DEPA) that are simulants of mustard gas, sarin, VX (O-Ethyl S-2-diisopropylaminoethyl methylphosphonothiolate), soman, and tabun, respectively. The target analytes in headspace or air sample are sampled by the solid phase microextraction (SPME) fibers and all surrogates are easily detected by GC/MS analysis. The neat vapor is also directly analyzed by a portable MS through a membrane inlet but only the more volatile CEES and DMMP are detectable and correctly identified. The stability of surrogates in acetone is monitored in the preparation of standard solution. All surrogates are relatively stable in acetone with the exception of BAET, which is found to degrade quickly in water and other organic solvents (e.g., acetone, methanol, ethanol, hexane). Extraction of water and soil samples is also investigated in this study. In analyzing water sample spiked with the surrogates, it is found that SPME does not offer any advantage over direct aqueous injection into the GC/MS. CEES readily hydrolyzes in water to form 2-(ethylthio)-ethanol. Soil samples are extracted by acetone and the raw extracts are analyzed without any concentration, and all surrogates are detectable at 5–10 ppm level for CEES, DMMP, and DEPA. An actual case study is carried out using SPME to detect the presence of surrogate vapor inside a laboratory refrigerator in which they are stored.

Subcritical water extraction of amino acids from Atacama Desert soils

Amino acids are considered organic molecular indicators in the search for extant and extinct life in the Solar System. Extraction of these molecules from a particulate solid matrix, such as Martian regolith, will be critical to their in situ detection and analysis. The goals of this study were to optimize a laboratory amino acid extraction protocol by quantitatively measuring the yields of extracted amino acids as a function of liquid water temperature and sample extraction time and to compare the results to the standard HCl vapor‐phase hydrolysis yields for the same soil samples. Soil samples from the Yungay region of the Atacama Desert (Martian regolith analog) were collected during a field study in the summer of 2005. The amino acids (alanine, aspartic acid, glutamic acid, glycine, serine, and valine) chosen for analysis were present in the samples at concentrations of 1–70 parts‐per‐billion. Subcritical water extraction efficiency was examined over the temperature range of 30–325 °C, at pressures of 17.2 or 20.0 MPa, and for water‐sample contact equilibration times of 0–30 min. None of the amino acids were extracted in detectable amounts at 30 °C (at 17.2 MPa), suggesting that amino acids are too strongly bound by the soil matrix to be extracted at such a low temperature. Between 150 °C and 250 °C (at 17.2 MPa), the extraction efficiencies of glycine, alanine, and valine were observed to increase with increasing water temperature, consistent with higher solubility at higher temperatures, perhaps due to the decreasing dielectric constant of water. Amino acids were not detected in extracts collected at 325 °C (at 20.0 MPa), probably due to amino acid decomposition at this temperature. The optimal subcritical water extraction conditions for these amino acids from Atacama Desert soils were achieved at 200 °C, 17.2 MPa, and a water‐sample contact equilibration time of 10 min.

Genotoxic activity of organic contamination of the Songhua River in the north-eastern region of the People's Republic of China

The Songhua River is one of the biggest rivers in China and is the major freshwater source for industry and agriculture, as well as the source of the drinking water for millions of residents living along it. Heavy contamination of the Songhua River is due to domestic sewage and industrial wastewater. Thus, we set out to determine the carcinogenic potential of water samples taken from drinking water source of Harbin city in the Songhua River. Short-term genotoxic bioassays using Ames, SCE, and cell transformation assays were employed to examine the genotoxic activity of the ether extracts of water samples taken from the Songhua River. The results of the Ames test indicated that there were frame shift mutagens in the water samples, which were both direct and indirect. A dose–response relationship for the SCE assay was obtained, and the SCE cumulative frequency moved obviously to the right with increasing doses of water samples. Typical transformed foci were formed in NIH3T3 cells induced by ether extracts of water samples and the transformation frequency showed a dose–response relationship. The transformed cells showed the characteristics of malignant cells. All of the results indicated that the ether extracts of water samples taken from the Songhua River showed genotoxic activity.

Determination of Cr(VI) in the Presence of Complexing Agents and Humic Substances by Catalytic Stripping Voltammetry

AbstractThe voltammetric method of Cr(VI) determination in a flow system is proposed. Determinations can be carried out in the simultaneous presence of an excess of Cr(III), complexing agents, humic substances and surfactants. The method is based on the combination of a selective accumulation of the product of Cr(VI) reduction to the metallic state and a very sensitive voltammetric method of chromium determination in the presence of DTPA and nitrates. The calibration graph is linear from 1×10−9 to 5×10−8 mol L−1 for accumulation time of 30 s. The relative standard deviation is 5.2% (n=5) for Cr(VI) concentration 1×10−8 mol L−1. The influence of humic and fulvic acids, complexing agents and surfactants on Cr(VI) and the interfering Cr(III) signal is presented. The method was applied to Cr(VI) determination in certified reference material, soil sample, natural water sample and EDTA extracts from soil certified reference material.

Mutagenicity analysis of water samples from Seydisuyu (Kırka, Turkey) stream under the influence of boron production complex

Kırka region in Turkey is naturally high in boron content. There is also a boron production complex in our study area. Although boron was found to be neither genotoxic nor carcinogenic, mutagenicity of boron can still be discussed. In this connection, the aim of the present study was to evaluate the potential mutagenicity of Seydisuyu stream water in Kırka due to high boron content. Salmonella/microsome test was performed with and without metabolic activation. Total boron contents were determined by inductively coupled plasma optical emission spectrometer (ICP-OES). IRA 743 extracts of water samples from four stations of Seydisuyu stream were tested for mutagenicity in Salmonella typhimurium strains TA 98 and TA 100, and environmental boron toxicity was discussed.

Removal of organic contaminants from water using nanosponge cyclodextrin polyurethanes

AbstractInsoluble nanoporous cyclodextrin (CD) polymers were synthesized using bifunctional isocyanate linkers. The ability of these polymers to remove selected organic pollutants from water at varying concentrations was studied. The investigated pollutants were selected high‐priority chlorinated disinfection by‐products (DBPs) and a common odour‐causing compound in water, 2‐methylisoborneol (2‐MIB). The unpleasant musty odour imparted by 2‐MIB and geosmin in water can be detected by the human nose even at ng L−1 (parts per trillion) levels. Pre‐concentration and extraction of water samples containing low levels of pollutants was performed using solid phase extraction (SPE) and subsequently quantified by gas chromatography‐mass spectrometry (GC/MS). Here we show that the CD polymers demonstrate excellent absorption efficiency (&gt;99%) with respect to the organic pollutants, considerably better than granular activated carbon (GAC). The recyclability efficiency of these CD polymers is also reported. Copyright © 2007 Society of Chemical Industry

A Mobile Field Extractor for Extracting Water Samples While Driving between Sampling Sites

A Mobile Field Extractor for Extracting Water Samples While Driving between Sampling Sites

Monitoring and assessment of oil pollution in the Danube River during the transnational Joint Danube Survey

An extensive river basin monitoring exercise of 2581 km of the river Danube was carried out in 2001 under of the aegis of the transnational Joint Danube Survey (JDS). Water, suspended and bottom sediment, and biota samples were collected from 76 cross-sections in the Danube main stream and 22 major tributaries during the 39-day cruise, and analysed for chemical and biological variables. During the JDS, oil pollution was characterised with GC-FID and fluorescence measurements. Fluorescence fingerprints of the cyclohexane extracts of water, suspended and bottom sediment samples allowed characterization and quantification of the type and level of oil pollution. The results revealed that the oil pollution in the water varied in the range 1-300 microg/l. Gasoline type contamination was found at the higher concentration levels and diesel oil type in the lower concentrations. Oil contamination was similar in the suspended and bottom sediment (the less than 63 microm grain-size fraction) and varied between 2-140 mg/kg. A higher contamination level was found along the middle Danube reach. The highest concentrations were observed in the suspended sediment upstream of the Danube delta. Weathered crude oil characteristics were observed in the upper Danube basin, whereas between crude and diesel oil characteristics were dominant along most of the middle and the lower Danube reaches.

호부추와 실부추 추출물의 생리활성 효과

호부추(Allium tuberosum)와 실부추(Allium senescens)를 열수, 50% 에탄올 및 100% 에탄올 등의 추출용매를 사용하여 건물 중량의 10배에 해당되는 부피(w/v)일 때, 추출물의 생리활성을 탐색하였다. 전자공여작용의 경우 호부추의 50% 에탄올추출물에서 41.68%의 높은 전자공여능을 나타내었으며, SOD 유사활성을 측정한 결과 호부추의 열수추출물이 36.33%로 다른 추출물에 비해 높은 활성을 보여주었다. Tyrosinase 저해활성의 경우 두 종류 모두 열수추출물에서 높은 저해활성을 보여주었으며, 호부추가 실부추보다 다소 높은 활성을 나타내었다. 특히 비교물질인 0.01% L-ascorbate와 유사한 활성을 보여주었다. 총 폴리페놀 함량의 경우 두 종류 모두 열수추출물보다 50%, 100% 에탄올추출물에서 높은 함량을 나타내었다. 아질산염 소거작용을 측정한 결과 pH 1.2일 때 호부추와 실부추 모두 소거능이 높게 나타났다. 이와 같은 결과는 부추의 생리활성을 밝혀 기능성 소재로써 이용도가 크게 증가할 것으로 판단된다.

Physiological Activities of Garlic Extracts as Affected by Habitat and Solvents

Physiological activities of Korean-grown garlic (GKG) and Chinese-grown garlic (GCG) were examined. Nitrite-scavenging activity (NSA), superoxide dismutase (SOD)-like activity, and electron-donating ability (EDA) of garlic extracted with water or with either 50% or 100% ethanol were measured. NSA was optimized at pH 1.2 and was highest in water and 50% ethanol extracts of both origins. SOD-like activities of water or 50% ethanol extracts from both Korea and China were 48.43-63.89% lower than those of 1% or 0.1% L-ascorbate solutions. SOD-like activities of GKG extracts were higher than those of GCG extracts, and those of water extracts of samples were highest. EDAs of GKG extracts were higher (32.51-43.74%) than those of GCG extracts, while those of both sample extracts were lower than 1% or 0.1% L-ascorbate solutions.

Development and validation of an analytical method for detection of estrogens in water

An analytical procedure enabling routine analysis of four environmental estrogens at concentrations below 1 ng L(-1) in estuarine water samples has been developed and validated. The method includes extraction of water samples using solid-phase extraction discs and detection by gas chromatography (GC) with tandem mass spectrometry (MS-MS) in electron-impact (EI) mode. The targeted estrogens included 17alpha- and 17beta-estradiol (aE2, bE2), estrone (E1), and 17alpha-ethinylestradiol (EE2), all known environmental endocrine disruptors. Method performance characteristics, for example trueness, recovery, calibration, precision, accuracy, limit of quantification (LOQ), and the stability of the compounds are presented for each of the selected estrogens. Application of the procedure to water samples from the Scheldt estuary (Belgium - The Netherlands), a polluted estuary with reported incidences of environmental endocrine disruption, revealed that E1 was detected most frequently at concentrations up to 7 ng L(-1). aE2 was detected once only and concentrations of bE2 and EE2 were below the LOQ.