Validation interlaboratory trial for ISO 12010: Water quality—Determination of short-chain polychlorinated alkanes (SCCP) in water

A validation interlaboratory trial was carried out to prepare ISO 12010: Water quality??Determination of short-chain polychlorinated alkanes (SCCP) in water??Method using gas chromatography/mass spectrometry (GC-MS) and electron capture negative ionisation (ECNI). The task was to determine the sum of short-chain polychlorinated n-alkanes with carbon chain lengths of C₁₀?CC₁₃ and a chlorine content between 49% (g/100?g) and 67% (g/100?g) in water by GC-ECNI-MS. The quantification had to be performed by multiple linear regression as described in ISO/DIS 12010, the compulsory method. Samples distributed were real river samples, and waste water spiked with a target concentration of 0.4 and 0.6???g/L for the sum of SCCPs, i.e. a concentration around the environmental quality target level according to the European Water Framework Directive. The different types of water samples tested were surface water with <150?mg/L suspended matter, surface water with 0.5?g/L suspended matter, and filtered waste waster. The interlaboratory trial included the extraction of the water samples, a column chromatographic clean up, a concentration step, and integration of chromatographic unresolved complex mixtures as well as the calibration and quantification by multiple linear regression. The reproducibility standard deviation of the standard concentration was 11.9%. Reproducibility standard deviations of concentrations in the three different water samples between 27.8 and 34.2% were achieved by 10?C12 participating laboratories from six countries.     

Sorption–Atomic Absorption Determination of Trace Elements in Natural Waters Using Simultaneous Atomization of a Solid Concentrate and Suspended Matter

A sorption–atomic absorption technique with dynamic preconcentration on DETATA adsorbents in a microcolumn crucible followed by the direct atomization of a solid matrix (concentrate + suspended matter) was used to determine the total dissolved and suspended Cd, Pb, and Tl (El_dis+ El_susp) in natural waters. The detection limits were 1–3 ng/L for Cd and 5–30 ng/L for Pb and Tl. The results of the sorption–filtration atomic absorption determination of the total dissolved and suspended elements can provide extra information for the speciation analysis of waters.     

Anodic Stripping Potentiometric Determination of Cu,Pb, Cd and Zn In Natural Waters on a Novel Combined Electrode System

Abstract

A method is described for the reliable determination of copper, lead, cadmium and zinc in natural waters by anodic stripping potentiometry with the use of a novel combined electrode. The method involves two stripping cycles during which copper is initially determined on its own, followed by simultaneous determination of lead, cadmium and zinc after addition of gallium (III) ions. The optimum conditions include 0.01 M HCl as supporting electrolyte, 10 mg/L Hg (II) as chemical oxidant; E_dep(Cu) -700 mV vs Ag/AgCl; E_{dep(Pb,Cd,Zn)} -1200 mV vs Ag/AgCl; t_dep 10s; 150 μg/L Ga (III); sample rotation rate 5 and rest period 30s. Under these conditions, as low as 0.06 μg/L Cu (0.7% RSD); 0.2 μg/L Pb (13% RSD); 0.04 μg/L Cd (7.8% RSD) and 0.06 μg/L Zn (5.5% RSD) can be determined reliably. A linear concentration range of 0–110 μg/L was obtained for the four metals. The successful application of the method to reference fresh water, creek water and tap water is demonstrated.     

Determination of aliphatic aldehydes in waters by high-performance liquid chromatography

A method is described for the determination of linear aldehydes (C₁–C₈) in waters. Aldehydes are extracted into n-pentane after derivatization with 2,4-dinitrophenyhydrazine and quantified by reversed-phase high-performance liquid chromatography with detection at 365 nm. With a 250-ml sample, the limit of detection is 1 μg l^?1 for the C₁–C₈ aldehydes. The method is directly applicable to surface waters and drinking water. Analysis of different surface waters, treated water and a humic acid solution after ozonization showed that C₁–C₃ aldehydes predominated, their concentration increasing with increasing ozone dosage.     

Determination of volatile chlorinated hydrocarbons in water samples by static headspace gas chromatography with electron capture detection

A simple, efficient, solvent‐free, and commercial readily available approach for determination of five volatile chlorinated hydrocarbons in water samples using the static headspace sampling and gas chromatography with electron capture detection has been described. The proposed static headspace sampling method was initially optimized and the optimum experimental conditions found were 10 mL water sample containing 20% w/v sodium chloride placed in a 20 mL vial and stirred at 50ºC for 20 min. The linearity of the method was in the range of 1.2–240 μg/L for dichloromethane, 0.2–40 μg/L for trichloromethane, 0.005–1 μg/L for perchloromethane, 0.025–5 μg/L for trichloroethylene, and 0.01–2 μg/L for perchloroethylene, with coefficients of determination ranging between 0.9979 and 0.9990. The limits of detection were in the low μg/L level, ranging between 0.001 and 0.3 μg/L. The relative recoveries of spiked five volatile chlorinated hydrocarbons with external calibration method at different concentration levels in pure, tap, sea water of Jiaojiang Estuary, and sea water of waters of Xiaomendao were in the range of 91–116, 96–105, 86–112, and 80–111%, respectively, and with relative standard deviations of 1.9–3.6, 2.3–3.5, 1.5–2.7, and 2.3–3.7% (n = 5), respectively. The performance of the proposed method was compared with traditional liquid–liquid extraction on the real water samples (i.e., pure, tap, and sea water, etc.) and comparable efficiencies were obtained. It is concluded that this method can be successfully applied for the determination of volatile chlorinated hydrocarbons in different water samples.     

Seasonal Changes in Methylarsenic Distribution in Tosa Bay and Uranouchi Inlet

The distribution of arsenic species, including trivalent methylarsenicals, was observed in coastal seawater of Tosa Bay and Uranouchi Inlet Japan. In Tosa Bay, most arsenic was dissolved in the inorganic form throughout the year and the concentration of total dissolved arsenic was higher than that in Uranouchi Inlet. The sum of methylarsenicals found in surface waters comprised 2–25% and 10–82% of the total dissolved arsenic in Tosa Bay and Uranouchi Inlet, respectively. In Uranouchi Inlet, seasonal variations in the concentrations of arsenicals were observed both in the water column and in surface sediments. The maximum concentrations of methylarsenicals appeared during summer, and became comparable to those of inorganic arsenicals in surface water. The concentration of trivalent methylarsenicals was usually low, and their seasonal changes seemed to be independent of those of the pentavalent species. The variations in methylarsenic(V) concentration did not coincide with those of chlorophyll a in either Tosa Bay or Uranouchi Inlet. These results suggested that methylarsenic(V) in natural waters was produced not directly by the activity of phytoplankton but through decomposition of organic matter by bacteria.     

Metals in surface water of Ukraine: the migration forms,features of distribution between the abiotic components of aquatic ecosystems,and potential bioavailability

We have generalized the results of long-term studies of coexisting forms of a series of metals (Al, Fe, Mn, Zn, Cu, Cr, Pb, Mo, Cd, and V) in surface water bodies of Ukraine, differing in the hydrological regime and the water chemical composition (rivers, reservoirs, lakes, and ponds). The studied metals content has ranged widely, the concentrations of aluminum, iron, and manganese being typically the highest, and the concentration of molybdenum, vanadium, and cadmium being typically the lowest. The ratio between the suspended and the dissolved forms of the metals has been established. Iron and aluminum migrate mostly as part of the suspended matter, whereas the other metals mainly migrate in the dissolved state. The dissolved manganese form predominates in the water bodies under anaerobic conditions. Copper and molybdenum are present almost always in the dissolved state, regardless of the water body type. The data on the relative content of the labile metal fraction (potentially toxic to aquatic organisms) are reported. The relatively low content of this fraction has been found to be majorly owing to the metal ions complexing with natural organic ligands. The humic compounds, the most widespread group of natural organic compounds, play the primary role in the complexation. Even metals with variable oxidation state (Cr, Mo, and V) are found mainly in the form of anionic complexes with the humic substances. Carbohydrates are also involved in the metals binding in the highly bioproductive water bodies, thus increasing the mass fraction of the neutral complexes during the summer and autumn periods. The molecular weight distribution of anionic metal complexes has been discussed; the substantial part of the metals constitutes the compounds with the molecular weight of below 5.0 kDa.     

The discovery of hidden arsenic species in coastal waters

The analysis of ultraviolet (UV)-irradiated and untreated seawater samples has shown that the dissolved arsenic content of marine waters cannot be completely determined by hydride generation–atomic absorption spectrophotometry without sample pretreatment. Irradiation of water samples obtained during a survey of arsenic species in coastal waters during the summer of 1988 gave large increases in the measured speciation. Average increases in the measured speciation. Average increases in total arsenic, monomethylarsenic and dimethylarsenic were 0.29 μg As dm^?3 (25%), 0.03 μg As dm^?3 (47%) and 0.12 μg As dm^?3 (79%), respectively. Overall, an average 25% increase in the concentration of dissolved arsenic was observed following irradiation. This additional arsenic may be derived from compounds related to algal arsenosugars or to their breakdown products. These do not readily yield volatile hydrides when treated with borohydride and are not therefore detected by the normal hydride generation technique. This has important repercussions as for many years this procedure, and other analytical procedures which are equally unlikely to respond to such compounds, have been accepted as giving a true representation of the dissolved arsenic speciation in estuarine and coastal waters. A gross underestimate may therefore have been made of biological involvement in arsenic cycling in the aquatic environment.     

Steroids contents in waters of wastewater purification plants: determination with partial-filling micellar electrokinetic capillary chromatography and UV detection

Partial-filling micellar electrokinetic capillary chromatography (PF-MEKC) with UV detection was applied for determination of human-based steroids in water samples of Finnish wastewater treatment plants. The samples were purified with solid-phase extraction (SPE) on octadecyl substituted polymer sorbents obtaining analyte enrichment of 20,000-fold. The steroids studied were androgens, estrogens, and progesterone. Three of the steroids could be quantified with the PF-MEKC method. The detection and quantification limits were 0.05–1.06 μg/mL and 0.15–3.2 μg/mL, meaning in the SPE concentrates as 2.5–53 pg/L and 7.5–160 pg/L, respectively. In the influent waters, the total amount of testosterone glucuronide, androstenedione, and progesterone was up to 350 ng/L. In effluent water samples the total steroid quantity was maximum at 320 ng/L. Remarkably high quantity of androstenedione was quantified in both influent and effluent water samples. The cleanest effluent waters were produced in Western Finland. Correspondingly, the highest quantities were located near the largest lake and river areas in South-Eastern Finland. The concentration variation in effluent waters was explained with differences in the purification materials and processes at the plants and with steroid adsorption on soil and organic material suspended into water.     

Loss of Pendimethalin in Surface Runoff from Plots Untilled and Tilled with Tobacco

Abstract

The loss of pendimethalin (N-(ethylpropyl)-2,6-dinitro-3,4-xylidine), a selective herbicide in runoff water was determined on sandy-clay-loam soil plots cultivated with tobacco in relation with the use of ammonium nitrate limestone as fertelizer, for a period of two years, 1990 and 1991. The surface slope of plots was 11% and the use of fertilizer decreased the soil erosion from a value 617 g/m²to 320 g/m². The runoff of surface waters were between 16-24% of the rainfall amounts. Reduction in pendimethalin in waterways results from water loss by infiltration, sediment loss, and by attachment adsorption on vegetative and organic matter. Surface runoff levels were highest for the first runoff event after herbicide application, 1.5 g/10 m² and initial concentrations were related to the time lapse between herbicide application and the date of the first run-off event. Maximum concentrations were 5.95 and 8.54 μg/L in 1990 and 1991 respectively. Persistence studies showed that pendimethalin concentration in runoff of 0.5 cm soil layer decreased by 88.2%, from 2.46 to 0.29 μg/g within 233 days, in 1990 and by 87.6%, from 2.42 to 0.30 μg/g within 235 days in 1991. After 310 day the concentration of pendimethalin was only 0.1 μg/g.     

The determination of metals at ppb levels by thin-film x-ray fluorescence spectrometry after coprecipitation with a molybdenum carrier complex

A method is described for the determination of iron, cobalt, nickel, copper, zinc, cadmium and lead in water at μg 1^-1 levels, in which the metals are coprecipitated with a molybdenum—pyrrolidinedithiocarbamate carrier complex. The precipitate is collected as a thin film on a membrane filter (0.4-μm pore-size) and analysed directly by x-ray fluorescence spectrometry. Detection limits, for 100-ml water samples and counting times of 200 s per element, are 1 μg metal l^-1 or lower. Total dissolved metal concentrations are obtained without boiling or u.v. irradiation of the water sample. The method is applicable to river and estuarine waters and is not affected by dissolved organic matter.     

Simple field‐based automated dispersive liquid–liquid microextraction of trace level phthalate esters in natural waters with gas chromatography and mass spectrometric analysis

A small, simple, and field‐based automated dispersive liquid–liquid microextraction method followed by gas chromatography mass spectrometric analysis was developed for trace level phthalate esters analysis in natural waters. With a single syringe pump that is coupled with a multiposition valve, the whole extraction procedure including cleaning, sampling, mixing of extractant and disperser solvents, extraction, phase separation, and analytes collection was carried out in a totally automated way with a sample throughput of 21 h^?1. Key factors, such as type and ratio of the extractant and disperser solvent, aspiration flow rate, extraction time, and matrix effect, were thoroughly investigated. Under the optimum conditions, linearity was found in the range from 0.03 to 60 μg/L. Limits of detection ranged from 0.0015 to 0.003 μg/L. Enrichment factors were in a range of 106–141. Reproducibility and recoveries were assessed by testing a series of three natural water samples that were spiked with different concentration levels. Finally, the proposed method was successfully applied in analysis of real surface waters. The developed system is inexpensive, light (2.6 kg), simple to use, applicable in the field, with high sample throughput, and sensitive enough for trace level phthalate esters analysis in natural waters.     

Determination of organophosphorus insecticides in natural waters using SPE-disks and SPME followed by GC/FTD and GC/MS

Two methods for the analysis of ten organophosphorus insecticides in natural waters using solid phase extraction disks containing C₁₈ and SDB and solid phase microextraction fibers containing polyacrylate (PA) are developed. Bromophos ethyl, bromophos methyl, dichlofenthion, ethion, fenamiphos, fenitrothion, fenthion, malathion, parathion ethyl and parathion methyl were determined by GC/MS and GC/FTD. The SPE-disks require only 1000 mL of sample and provide a method limit of detection in the range of 0.01–0.07 μg/L and recovery rates from 60.7 to 104.1%. The solid phase microextraction (SPME) technique requires 2–5 mL of water sample and provides a method limit of detection in the range of 0.01 to 0.05 μg/L for all detectors and the recoveries compared to distilled water ranged from 86.2 to 119.7%. The proposed methods were applied to the trace level screening determination of insecticides in river water samples originating from different Greek regions.     

Crucible atomizer for determining dissolved and suspended forms of elements in natural waters

A model of a specialized microcolumn has been proposed and tested, namely, a crucible atomization microcolumn for electrothermal atomic absorption analysis of natural waters in which the zone of isolation of suspended matter and the zone of dynamic preconcentration of dissolved forms of elements are separated. A direct independent analysis of solid suspended matter and DETATA concentrate is possible upon completion of preconcentration. Such an approach is used to determine suspended and dissolved forms of cadmium and lead in river water and soil groundwater.     

Liquid chromatography/mass spectrometry stable isotope analysis of dissolved organic carbon in stream and soil waters

A commercial interface coupling liquid chromatography (LC) to a continuous‐flow isotope ratio mass spectrometry (CF‐IRMS) instrument was used to determine the δ¹³C of dissolved organic carbon (DOC) in natural waters. Stream and soil waters from a farmland plot in a hedgerow landscape were studied. Based on wet chemical oxidation of dissolved organics the LC/IRMS interface allows the on‐line injection of small volumes of water samples, an oxidation reaction to produce CO₂ and gas transfer to the isotope ratio mass spectrometer. In flow injection analysis (FIA) mode, bulk DOC δ¹³C analysis was performed on aqueous samples of up to 100 μL in volume in the range of DOC concentration in fresh waters (1–10 mg C.L^–1). Mapping the DOC δ¹³C spatial distribution at the plot scale was made possible by this fairly quick method (10 min for triplicate analyses) with little sample manipulation. The relative contributions of different plot sectors to the DOC pool in the stream draining the plot were tentatively inferred on the basis of δ¹³C differences between the hydrophilic and hydrophobic components. Copyright © 2011 John Wiley & Sons, Ltd.     

The spectrophotometric determination of antimony in water,effluents, marine plants and silicates

A spectrophotometric procedure is described for the determination of antimony in natural waters (including sea water and effluents), algae and silicates. After a preliminary oxidative digestion for waters, or acid attack for algae and silicates, the element is quantitatively coprecipitated at pH 5.0 with hydrous zirconium oxide. The precipitate is dissolved in acid, and, after reduction with titanium(III) chloride, antimony is oxidized to antimony(V) with sodium nitrite. The ion pair of the SbCl₆^- ion with crystal violet is extracted with benzene and its absorbance is measured at 610 nm (molar absorptivity 74,000 l mol^-1 cm^-1). Extraction with toluene causes some loss of sensitivity. The detection limit is 0.005 μg l^-1; relative standard deviations are 0.5% and 1.1% for spiked distilled water (0.5 μg l^-1) and sea water (0.26 μg l^-1), respectively. A wide range of anions and cations cause no interference at levels many times those in natural waters. The technique can be adapted for application to marine algae and silicates; relative standard deviations are 1.8% and 2% for samples of Pelvetia canaliculata (0.19 μg Sb g^-1) and a Pacific Ocean red clay (1.08 μg Sb g^-1), respectively. Results for the U.S. Geological Survey Standard rocks GSP1 (2.7 ppm) and DTS1 (0.53 ppm) are in good agreement with those of earlier workers.     

Organic solvent-soluble membrane filters for the preconcentration and spectrophotometric determination of iron(II) traces in water with Ferrozine

An organic solvent-soluble membrane filter (MF) is proposed for the simple and rapid reconcentration with subsequent spectrophotometric determination of trace levels of iron (II) in water. Iron (II) is collected on a nitrocellulose membrane filter as ion associate of an anionic complex, which is formed by iron (II) and Ferrozine and a cation-surfactant. The ion-pair compound and the MF can be dissolved in small volumes of 2-ethoxyethanol and the absorbance of the resulting solution is measured at 560 nm against a reagent blank with molar absorptivity of 4.01 × 10⁴ L mol^–1 cm^–1. Beer’s law is obeyed over the concentration range 0–10 μg L^–1 of iron (II) in water and the detection limit is 0.03 μg L^–1 with a 50-fold enrichment factor. The proposed method can satisfactorily be applied to the determination of iron (II) in natural water and sea water.     

Determination of trace organophosphorus pesticides in water samples with TiO2 nanotubes cartridge prior to GC‐flame photometric detection

This article described a new method for the sensitive determination of organophosphorus pesticides in water samples using SPE in combination with GC‐flame photometric detection. In the procedure of method development, TiO₂ nanotubes were used as SPE adsorbents for the enrichment of organophosphorus pesticides from water samples. Several factors, such as eluent and its volume, sample pH, sample volume, sample flow rate, and concentration of humic acid, were optimized. Under the optimal conditions, the proposed method had good linear ranges as 0.1–40 μg/L for each of them, LOD of 0.11, 0.014, and 0.0025 μg/L, and LOQs of 0.37, 0.047, and 0.0083 μg/L for chlorpyrifos, phorate, and methyl parathion, respectively. The proposed method was validated with real environmental water samples and the spiked recoveries were over the range of 86.5–115.1%. All these results indicated that TiO₂ nanotubes, as a new SPE adsorbent, would be used widespread for the preconcentraiton and determination of environmental pollutants in the future.     

Single-use optical sensor for the determination of iron in water and white wines

A new method, based on the use of a disposable sensor, for the determination of Fe(II) in waters and wines is proposed. The sensor is formed by an inert rectangular strip of polyester (Mylar) and a circular film (6 mm in diameter) adhered on its surface. This film, which contains the required reagents for the fixation of the analyte by means of a complexation reaction, forms the sensing zone of the sensor. When the sensor is introduced in an acidified (pH 2.5) sample solution containing between 4.0 and 300.0 μg/L of Fe(II), a violet-red colour develops in the initially colourless sensing zone. The linear range of the method depends of the equilibration time of the sensor with the sample solution. Thus, when the equilibration time was 5 min, the linear range was 41.0–300.0 μg/L, while for 60 min the range was 4.0– 50.0 μg/L. Detection and quantification limits were 12.0 and 41.0 μg/L, respectively, for an equilibration time of 5 min. The precision of the method, expressed as relative standard deviation of ten samples of 100.0 μg/L of Fe(II), was 4.9%. Interferences produced by other species usually present in waters or wines have been studied. Cu(II) and Co(II) interfered seriously at concentration levels higher than 100.0 and 150.0 μg/L, respectively. The method was applied to the determination of Fe(II) in different types of waters and wines, using atomic absorption spectrometry as a reference method.     

Study of Aqueous Chemical Forms of Silicon in Organic-rich Waters

The study of silicon species in organic-rich waters is a very significant problem. This type of waters is widely spread all over the world. It is characterized by a high content of humic substances, high color of water and low pH. In this regard, a certain determination of silicon concentration in this type of waters is impossible without a preliminary investigation of silicon species. The aim of this research is therefore an investigation of the ratio of silicon dissolved forms in organic-rich waters depending on the silicon concentration and the acidity of the water. The study of pH influence on silicic acids and a silicon–humic matter interaction was carried out using model solutions and natural bog waters (Tomsk region). It has been found that the degree of polymerization of silicic acids essentially depends on the acidity of a solution. Scanning of spectrophotometric measurements has shown that silicon does not form stable complexes with fulvic and humic acids in weak-acid media (рН 3-4). Studying the bog waters of Tomsk Region has shown that they (рН=3.66-3.80) contain only monomeric-dimeric and polymeric forms of silicic acids.