Acid In Water Samples Research Articles

Determination of 4- tert-octylphenol, 4-nonylphenol and bisphenol A in surface waters from the Haihe River in Tianjin by gas chromatography–mass spectrometry with selected ion monitoring

The estrogenic pollutants 4- tert-octylphenol (OP), 4-nonylphenol (NP) and bisphenol A (BPA) were determined in surface water samples from the Haihe River, Tianjin, China. The analytes were extracted and concentrated from 300 ml acidified water samples by liquid–liquid extractions using dichloromethane, derivatized with trifluoroacetic anhydride, and quantified by gas chromatography–mass spectrometry (GC–MS) with selected ion monitoring (SIM). Among the samples collected from 14 sampling sites, only one sample was found to have a relatively high concentration of BPA (8.30 μg l −1) and NP (0.55 μg l −1). The concentrations of OP, NP and BPA in the other samples were in the range of 18.0–20.2, 106–296 and 19.1–106 ng l −1, respectively. Recoveries for OP, NP and BPA in the spiked water samples were all over 80%.

Environmental behaviour of metals from tailings in shallow rivers: Taxco, central Mexico

Mining in Mexico has produced important economic benefits since pre-Hispanic times. On the other hand, tailings and rock wastes constitute potential pollution sources in many zones of the country. Taxco, about 150 km south-west of Mexico City, is one of the historical mining zones of Mexico. The environmental behaviour of metals from tailings in a branch of the Taxco river was investigated. Several communities use the Taxco river water along its flow. Samples were taken from tailings, river-waters and sediments. Field determinations included conductivity, pH, Eh, temperature and alkalinity of the water. Mineralogical and chemical analyses were performed in tailings and sediments. Water analyses included main ions, and metals in acidified filtered and unfiltered samples. Quartz, jarosite, pyrite, chalcopyrite, Fe oxihydroxides, gypsum, clay and silica minerals were identified in the tailings. All samples had an acid pH (2·50–4·16) and high concentrations of Pb (up to 2750 mg/kg), Zn (up to 690 mg/kg) and As (up to 3530 mg/kg). Mineralogical and chemical characteristics of tailings indicated occurrence of sulphide oxidation. Higher metal concentrations were found in unfiltered, acidified water samples than in filtered water samples in the year 2000: Fe (up to 21·2 mg/l), Zn (up to 13·4 mg/l) Pb (up to 0·115 mg/l) and As (up to 0·035 mg/l). Zn, Fe and Pb reached much higher concentrations in the dry season than in the rainy season. The Taxco river water does not comply with Mexican drinking water standards. High concentrations of Pb (up to 5280 mg/kg) and Zn (up to 33,500 mg/kg) were measured in sediments. Pb and Zn in sediments accumulated downflow in the dry season. A more uniform distribution was found in the rainy season. Results showed that metals are released from tailings as a result of sulphide oxidation and rain-water erosion. Metals are then transported by the river-water mainly in particulate form and, after settling, increase the concentration of metals in the sediments.

Determination of gadolinium in river water by SPE preconcentration and ICP-MS

An analytical scheme was developed for the determination of Gd–diethylenetriaminepentaacetate (Gd–DTPA), Gd and the other rare earth elements (REE) in river water by inductively coupled plasma (quadrupole) mass spectrometry (ICP-Q-MS). The preconcentration step was essential, since the limits of detection of this multielemental analytical technique are higher than the trace concentrations of the interesting elements in river water.Solid phase extraction (SPE) with different commercially available complexing agents (Chelex 100, Toyopearl and ethylhexylphosphates) was employed for the preconcentration of REE. The investigations revealed that complex stability (varying in dependence of the pH value) has a strong influence on the degree of the enrichment of Gd–DTPA. Based on acidified water samples (pH<3) a procedure using ethylhexylphosphates was proposed for the preconcentration of Gd and REE from surface water samples. For this purpose C18-cartridges loaded with ethylhexylphosphates were used, resulting in an enrichment factor of 40.

Determination of fulvic acids in water samples of Hungarian caverns

Water samples from the region of Béke cavern of Aggtelek and above the Józsefhegyi and Pálvölgyi caverns of Buda, Hungary were analyzed by various chromatographic techniques and fluorescence spectrometry. According to size-exclusion chromatographic (SEC) measurements, the water samples contained only low-molecular-weight components, fulvic acids, which were concentrated and separated from inorganic and non-acidic organic compounds in the water samples at pH 2 using an XAD-8 resin column. Elution from the column was performed with 0.1 M NaOH solution. UV absorbance was monitored at 254 nm and fractions were collected and subsequently separated by applying a size-exclusion high-performance liquid chromatographic (SE-HPLC) method. The mobile phase was ammonium acetate at a concentration of 50 mmol/dm 3 and a flow rate of 0.5 cm 3/min. The SE-HPLC measurements confirmed the presence of low-molecular-weight compounds in the samples analyzed. Quantitative determination of the fulvic acid content of the concentrated samples was carried out by fluorescence spectrometry. The excitation and emission wavelengths were 325 and 440 nm, respectively. The fulvic acid concentrations of the water samples examined ranged between 2 and 112 μg/cm 3.

Determination of zinc levels in waters from southeastern Spain by electrothermal atomic absorption spectrometry: relationship with industrial activity

An efficient method for the determination of nanogram levels of zinc in waters (potable, irrigation, waste and sea waters) is described. Acidified water samples were analyzed by an accurately optimized time/temperature program for electrothermal atomic absorption spectrometry. The samples were previously treated with a matrix modifier consisting of 0.1% Mg(NO 3) 2 in 0.5 M HNO 3 and injected through a graphite tube with L’Vov platform. Sample recoveries, repeteability, and analyses of NIST reference material demonstrated the reliability and accuracy of this technique. Zinc concentrations ranged from 2.0 to 73.0 μg l −1. No significant differences among the mean zinc levels determined in the four types of water considered from southeastern Spain were found. Zinc concentrations in waters from the zone were not affected by human and industrial activity.

The occurrence of xenoestrogens in the Elbe river and the North Sea

The xenoestrogens Bisphenol A (BPA), p-alkylphenols and p-alkylphenol ethoxylates were determined in water samples of the North Sea, the Elbe river, and its tributaries Schwarze Elster, Mulde, Saale and the Weisse Elster. The sampling sites of the Elbe river reached from Schmilka at the German–Czech border to Cuxhaven at the estuary. Samples of the North Sea were taken in the German Bight. Additionally, freshly deposed sediments of the River Elbe and its tributaries were analyzed. Partitioning coefficients of these compounds for the distribution between suspended particulate matter (SPM) and the aqueous phase were calculated for samples of the River Elbe at sampling site Geesthacht. The analytical procedure consisted of liquid–liquid extractions of the acidified water samples using dichloromethane. Sediments and SPM samples were extracted by Accelerated Solvent Extraction with n-hexane/acetone. Following a clean-up by HPLC, the analytes were derivatized with heptafluorobutyric acid anhydride and quantified using GC–MSD. The concentration ranges of the compounds analyzed in water samples of the Elbe river were as follows (in ng l −1): BPA 9–776, alkylphenols 10–221 and alkylphenol ethoxylates 18–302. In sediment samples the concentrations were (in μg kg −1 dry mass): BPA 66–343, alkylphenols 17–1378 and alkylphenol ethoxylates 30–1797. In samples of the North Sea the concentrations were generally about 1 order of magnitude lower. As shown by the concentration profiles following the River Elbe into the North Sea, the Elbe river must be considered as a major pollution source for the North Sea concerning the compounds analyzed. The SPM/water-partitioning coefficients calculated (mean values) amounted to: BPA 4.50, alkylphenols 5.52–5.58 and alkylphenol ethoxylates 5.60–6.38. A comparison of the results with data from other surface waters showed that concentrations of these xenoestrogens in the River Elbe and its tributaries were relatively low. The evaluation of the data based on the lowest observable effect concentration (LOEC) for alkylphenols (endpoint: vitellogenin synthesis in male trout) indicated that the concentrations were well below the effectivity threshold.

GC analysis of trichloroacetic acid in water samples by large-volume injection and thermal decarboxylation in a programmed-temperature vaporizer

AGC method has been developed for the analysis of tricholoroacetic acid (TCA) in water samples. It entails large-volume injection (LVI) and programmed-temperature vaporization (PTV) of water samples, thermal decarboxylation of TCA to chloroform in the injector, and GC-ECD analysis of the decarboxylation product. Conditions such as final injector temperature, splitless time, and injection volume were optimized. The limit of detection is approximately 0.1 μg L−1 Several real samples were analyzed. The method presented is an easy means of determination of TCA and eliminates sample-preparation steps such as extraction and derivatization.

Determination of 1-aminopropan-2-one, a dissolved sewage component, in water samples

A new method for the determination of 1-aminopropan-2-one (APR) in water samples was developed. APR was synthesised as its hydrochloride and derivatized with 2,4-dinitrophenylhydrazine (DNPH) for determination by high-pressure liquid chromatography with ultraviolet detection (UV-HPLC). APR was determined in water samples at pH 12 using a gas-stripping chamber, connected to a cartridge containing DNPH. Acidified water samples were injected into the gas-stripping chamber and a solution of NaOH added to bring the solution to pH 12. APR was volatilised and stripped from solution and passed onto the cartridge under a constant stream of nitrogen gas. Gas flow rates were carefully controlled to allow maximum contact of APR with DNPH on the cartridge. When the reaction time had elapsed, the cartridge was disconnected and the derivative eluted with a fixed volume of acetonitrile and injected onto the HPLC, where the APR hydrazone was resolved isocratically with a mobile phase consisting of acetonitrile and water (60 : 40). The HPLC was calibrated using standard solutions of the APR hydrazone. Recoveries of APR from standard samples were 90–100% at the 10 μM level and the detection limit for the method was calculated as 18 nM. Detection of APR in urine and primary-treated sewage samples (41 nM and 1.225 μM, respectively) confirmed the applicability of the technique to analysis of environmental samples.

Ion-exchange extraction of organic acids in water samples. Study of the influential factors and interactions

The objective is to concentrate organic acid traces in water samples. The influence of several parameters and their interactions on the adsorption of organic acids on anion exchange resins was studied. A complete factorial design 2 4 was hence performed. The measured response corresponds to the maximal percolation volume and the studied parameters were the nature and the mass of the resin, the percolation flow-rate and the ionic strength of the analysed water. The results shown that the pe r- colation flow-rate is significant but not really important compared to the resin mass and to the nature of water. Indeed, the sa mple inorganic anions can compete with organic acids. This adsorption competition appears to be more important when a macropo- rous resin is used. A gel-type resin could be therefore better adapted to the extraction of organic acids in water samples.

Distribution, sources, and stability of haloacetic acids in Tokyo Bay, Japan

AbstractThe distribution and sources of haloacetic acids in seawater in the vicinity of Tokyo Bay, Japan, were investigated, in view of the potential toxicity of these compounds to aquatic organisms. Haloacetic acids were extracted from water samples collected at 66 sampling stations (n = 122). Concentrations of all nine haloacetic acids containing bromine and chlorine were determined by liquid chromatography–mass spectrometry. We found that concentrations of trichloroacetic acid (TCAA) were high (maximum: 20.3 μg/L) compared to those of the other haloacetic acids in coastal seawater. The distributions and relative concentrations of TCAA and other haloacetic acids (monochloroacetic acid, dichloroacetic acid, and bromochloroacetic acid) suggest that their sources are not identical; discharge of wastewaters containing TCAA in the bay area is probably one of the main sources of the observed high concentrations of TCAA in seawater there. The mean concentrations of haloacetic acids in water samples and the results of incubation experiments of haloacetic acids in river water and seawater suggest that TCAA is relatively stable in the aquatic environment.

Concentrations of Ames Mutagenic Chlorohydroxyfuranones and Related Compounds in Drinking Waters

The extremely potent Ames mutagen MX [3-chloro-4-(dichloromethyl)-5-hydroxy-2(5H)-furanone] has been found to account for a substantial part of the mutagenicity of drinking waters. Some compounds showing structural relationship with MX have been identified in drinking waters, but it has not been investigated whether they are commonly occurring. Therefore, the main purpose of this study was to make a comprehensive survey of the occurrence of such compounds in drinking waters and of their importance as mutagenicity contributors. Drinking water was collected from 35 localities in Finland and from St. Petersburg, Russia. The acidified water samples were processed through XAD-8 resin and eluted with ethyl acetate. The mutagenic activity was measured in the extracts using the Ames Salmonella typhimurium strain TA100 without metabolic activation. In addition, the concentrations of a total of 13 compounds were determined in the extracts using GC/MS in the selected ion monitoring mode. The study confirms that MX i...

Copper ligands isolated from estuarine water by immobilized metal affinity chromatography: temporal variability and partial characterization

Copper ligands were isolated from estuarine water using immobilized metal affinity chromatography (IMAC). Seasonal and diurnal variation of copper ligand concentrations as measured by IMAC peak areas were determined. Apparent molecular weight and UV-visible spectra of IMAC-isolated ligands were characterized. The effects of sample pH, flow rate, volume and storage (4 °C) on ligand recovery were determined. Removal of ligands of the L1 and L2 class from water samples by IMAC was measured using differential pulse anodic stripping voltammetry (DPASV). Removal of IMAC ligands from acidified water samples by XAD resin was evaluated in order to determine whether IMAC-isolated ligands are humic substances. Considerable variation was observed in IMAC peak areas over a 12-month period. Maximum peak areas of the high-affinity ligand (peak B) were observed in late summer corresponding to maxima in picoplankton abundances in the vicinity of the sample site. Diurnal variation was minimal. Molecular filtration indicated that IMAC-isolated ligands were primarily of low (< 10,000 Da) molecular weight. Spectral analysis of ligands contained in IMAC peaks showed significant heterogeneity on different sampling dates. Characteristic spectra exhibited absorbance peaks around 280 nm suggestive of the presence of proteins or peptides containing aromatic amino acids. No DNA was detected in IMAC fractions. Removal of humic substances from water samples using XAD prior to IMAC reduced IMAC peak areas ~ 50%, indicating that a significant portion of IMAC-isolated material was humic substances. The results show that copper ligands isolated and recovered by IMAC are a heterogeneous group of compounds that exhibit significant temporal variation, are primarily low molecular weight and contain humic substances. Temporal variation observed for the high-affinity ligand class suggests that the ligands may be a product of picoplankton in the water column. The data suggest that IMAC may be a useful method for preparative isolation of high-affinity copper ligands of the L1 and L2 class.

A reusable optical sensing layer for picric acid based on the luminescence quenching of the Eu—thenoyltrifluoroacetone complex

A new luminescene sensing layer for the determination of picric acid based on reversible luminescence quenching of the Eu-thenoyltrifluoroacetone (TTA) complex was proposed. The optosensor was based on the electrostatic immobilization of the Eu—TTA complex on the chelating resin of Chelex 100 packed in the flow cell, which can induce a room temperature luminescence behaviour in an aqueous phase. The quenching mechanism was also studied. The detection limit was 2 × 10 −6 M by using a response time of 1 min. The optosensor was easy to prepare and the lifetime of the optosensor was at least 1 month. The optosensor has been used for the direct determination of picric acid in water samples and the indirect measurement of some drugs such as quinine.

Quantitative Analysis of 2,4-Dichlorophenoxyacetic Acid in Water Samples by Two Immunosensing Methods

Two sensitive methods based on a monoclonal anti-2,4-dichlorophenoxyacetic acid (2,4-D) antibody, a flow injection immunoanalysis (FIIA), and a fiber optic immunosensor are described and evaluated for the quantitative determination of 2,4-D in water samples. Detection limits for 2,4-D of ∼0.03 μg/L with FIIA and 0.2 μg/L with the fiber optic immunosensor can be achieved, i.e. well below the maximum concentration permitted, in the case of FIIA, by the EC Drinking Water Directives of 0.1 μg/L. The midpoints of the 2,4-D test are found at concentrations of 0.3 μg/L with FIIA and 10 μg/L with the fiber optic immunosensor. Measurable concentrations range from 0.03 to 3 μg/L with FIIA and from 0.2 to 100 μg/L with the fiber optic immunosensor. The FIIA did not require concentration or cleanup steps for ground and surface water samples. In addition, validation experiments with GC/MS showed a good correlation of the data for the FIIA system. However, both tests can be applied as alarm systems for monitoring poten...

Selected applications of the use of supercritical fluids in coupled systems

The gas-like mass transfer and liquid-like solvating properties of supercritical fluids, together with considerations on automation, speed and cost, make supercritical fluids very attractive for application in coupled systems. A number of coupled systems in which supercritical fluids play a key role are described. Supercritical fluid extraction-capillary gas chromatography-mass spectrometry (SFE-cGC-MS) has been applied to the determination of pesticides in fruit juices. For the determination of polycyclic aromatic hydrocarbons, triazines, chlorophenols and phenoxy acids in water samples, the SFE-cGC-MS system was extended with a sample preparation station after SFE, allowing the addition of internal standards and derivation of the acidic solutes after SF extraction. The potential of on-line solid-phase extraction-supercritical fluid chromatography-diode array detection is illustrated with the determination of xanthines in iced tea and of traces of pesticides in water samples.

Examination of the different procedural steps in the determination of organotin compounds in water samples

The different steps in the proposed DIN (Deutsche Industrie Norm) procedure for the determination of organotin compounds in water samples were examined by means of a gas chromatography-mass spectrometry system. In the proposed DIN-procedure the organotin compounds RnSn(4−n)+ (with R = butyl (Bu), n=1–4; R = heptyl (He), n=1,2 (as internal standards), R = octyl (Oc), n=1, 2; R = phenyl (Ph), n=3; R = cyclohexyl (c-Hex), n=3) are extracted from acidified water samples by tropolone/hexane, derivatised with the Grignard reagent n-pentylmagnesium bromide, purified by solid phase extraction and determined after solvent evaporation. In this study the stability of the analytes in the samples, the extraction and the chromatographic purification step as well as a possible evaporation of the organotin compounds were examined.

Determination of halogenated acetic acids and 2,2-dichloropropionic acid in water samples

Summary. A new method is described for the determination of halogenated acetic acids and 2,2-dichloropropionic acid in slightly polluted water. The acids were extracted in a lightphase rotary perforator, derivatised with diazomethane and determined by GC-ECD and GC-MS. The standard deviations were in the range of 14.5-16.8%. Average recoveries were 82%, 92% and 79% for monochloro-, dichloro- and trichloroacetic acid, respectively. The extraction yields for the bromoacetic acids and dichloropropionic acid were in the range of 64-85%.

Determination of diacetoneketogulonic acid in water samples by high-performance thin-layer chromatography

A fast and efficient method for the determination of diacetoneketogulonic acid (DAG)—a substance relevant as contaminant in drinking water—is described. The method is characterized by enrichment of the analyte by solid-phase extraction using a innovative adsorbent and consecutive separation and quantitation by high-performance thin-layer chromatography. The method can be applied to the determination of diacetoneketogulonic acid in waste water, ground water and drinking water. The solid-phase extraction described may also be useful as sample preparation method for other separation techniques.

Extraction of low-level sulphide from groundwaters for sulphur isotope analysis

A method is described for the preparation of sulphide precipitates for sulphur isotope analysis from sub-ppm (< 1 mg 1 −1) levels of sulphide in natural waters. Hydrogen sulphide is degassed from acidified water samples into a nitrogen stream and subsequently re-precipitated in a silver nitrate trap. Control experiments on model waters of known sulphur isotope composition show that the average fractionation of sulphide is small (0.06‰) but an uncertainty of ±0.6‰ is appropriate for this method.

Extraction of low-level sulphide from groundwaters for sulphur isotope analysis

A method is described for the preparation of sulphide precipitates for sulphur isotope analysis from sub-ppm (< 1 mg 1 − levels of sulphide in natural waters. Hydrogen sulphide is degassed from acidified water samples into a nitrogen stream and subsequently re-precipitated in a silver nitrate trap. Control experiments on model waters of known sulphur isotope composition show that the average fractionation of sulphide is small (0.069‰) but an uncertainty of ±0.6‰ is appropriate for this method.