Occurrence and removal characteristics of phthalate esters from bottled drinking water using silver modified roasted date pits.

BACKGROUND: This paper aims to investigate the occurrence and removal characteristics of phthalate esters from bottled drinking water using silver modified roasted date pits. Three adsorbents, namely roasted date pits (RODP), silver-modified roasted date pits (S-RODP), and activated carbon (AC) were used to investigate their adsorption characterizations in removing dimethyl phthalate (DMP), diethyl phthalate (DEP), dibutyl phthalate (DBP), butyl benzyl phthalate (BBP), di-2-ethylhexyl phthalate (DEHP), and di-n-octyl phthalate (DNOP) from the collected bottle water samples. METHODS: The occurrences of the phthalate esters in the collected bottled water samples were carried out at different temperatures (30, 50, and 60 °C), and analyzed using gas chromatography-mass spectrometry analysis - selected ion monitoring. Batch adsorption isotherms were used to study and establish the efficiency of such adsorbents in removing phthalate esters, in which they describe the adsorbent-adsorbate interaction systems. Adsorption efficiency of the various adsorbents was investigated by using different adsorbent masses (0.05 g, 0.10 g, and 0.15 g) and temperature (30 °C, 50 °C, and 60 °C). Different physical and chemical characterizations were studied using scanning electron microscopy (SEM), Fourier transform infrared (FTIR), Brunauer-Emmett-Teller (BET) surface area, pore radius, and pore volume. RESULTS: The results indicated that the most abundant phthalate esters were DMP followed by DEP under 30 °C; however, DNOP was not detected in any of the tested water samples, except for one sample under 30 °C with a concentration of 0.031 µg/mL. The obtained results showed that phthalate esters leaching to the bottled drinking water were affected by storage temperature. The phthalate esters levels were increased with increasing the temperature to 60 °C. It was concluded that the ability of S-RODP for the adsorption of phthalate esters was better than the removal percentage obtained by AC and RODP. The removal percentage was increased from 90 to 99% by increasing the temperature from 30 to 50 °C and then decreased to 92.3% at 60 °C. CONCLUSION: RODP was successfully used as an effective adsorbent for phthalate esters removal from drinking water. However, S-RODP has the highest removal abilities than other adsorbents due to the newly formed functional groups on its surface.

Analytical strategy for the detection of ecdysterone and its metabolites in vivo in uPA(+/+)-SCID mice with humanized liver, human urine samples, and estimation of prevalence of its use in anti-doping samples.

Ecdysteroids are of interest as potential sport performance enhancers, due to their anabolic effects. The current study aimed to analyze levels of the most abundant ecdysteroid, ecdysterone (20-hydroxyecdysone, 20-OHE) in easily available dietary supplements, and, outline an analytical strategy for its detection, and that, of its metabolites, (1) following administration of pure 20-OHE to uPA(+/+)-SCID mice with humanized liver, (2) in a human volunteer after ingestion of two supplements, one with a relatively low, and the other a high, concentration of 20-OHE, and, (3) to estimate the prevalence of use of 20-OHE in elite athletes (n = 1000). Of the 16 supplements tested, only five showed detectable levels of 20-OHE, with concentrations ranging from undetectable up to 2.3 mg per capsule. Urine of uPA(+/+)-SCID urine showed the presence of 20-OHE and its metabolite, 14 deoxy ecdysterone, within 24 hours (hr) of ingestion. In humans, both the parent and the metabolite were detectable within 2 to 5 hr of ingestion, with the metabolite being detectable for longer than the parent. After ingestion of a low dose supplement, the parent and metabolite were detectable for 70 and 48 hr, while following the higher dose it was 96 and 48 hr, respectively. Analysis of urines from athletes (n = 1000) confirmed four positives for 20-OHE, suggesting a prevalence of use of 0.4%. Prevalence of its use by elite athletes was relatively low, however, this needs to be confirmed in other populations, and with other related ecdysteroids.

Indoor phthalates from household dust in Qatar: implications for non-dietary human exposure.

Phthalates are ubiquitous semi-volatile organic compounds in the indoor environment present in various consumer products such as cosmetics, polyvinylchloride (PVC) flooring, food packing, and many others. Indoor phthalate concentrations were investigated in 15 buildings including 11 homes, 3 laboratories, and 1 from a hospital in Qatar. Dust samples were collected from vacuum cleaning bags usually used for cleaning homes, labs, and hospitals. The main objectives of this study was to determine the occurrence and concentration of phthalates in dust in Qatar and consequently to estimate the non-dietary human exposure. Eleven phthalates was analyzed. The major identified phthalate compounds at homes in Qatar were bis(2-ethylhexyl) phthalate unlabeled (DEHP) and diisononyl phthalate (DINP) at a geometric mean of 288 µg/g (median 395 µg/g) and 106 µg/g (median 101 µg/g) accounting for 57% and 23% of the total measured phthalates, respectively. The major phthalate compounds found in the first lab building were DEHP and DINP with a median of 4861 µg/g and 943 µg/g, respectively, accounting for 82% and 16% of the total phthalates. For the second lab building, the major phthalates were DEHP with a median of 466 µg/g, accounting for 20% of the total phthalates measured, and DINP median of 1725 µg/g, accounting for 71% of the total measured phthalates. The dust sample tested from hospital building had DEHP as the major phthalate compound with a median of 793 µg/g, accounting for 4.0% of the total measured phthalates, and DINP with a median of 19,626 µg/g, accounting for 94%. The estimated human non-dietary exposure for children, adults, and toddlers was based on phthalate concentrations (median) and found to be 225 ng/kg bw/day for children, 2328 ng/kg bw/day for adults, and 2099 ng/kg bw/day for toddlers.

Occurrence and concentrations of polybrominated diphenyl ethers in sewage sludge from three wastewater treatment plants in Kuwait.

Polybrominated diphenyl ether (PBDE) concentrations were measured in sewage sludge samples collected from three wastewater treatment plants in Kuwait over a six month period. PBDEs were detected in all samples analyzed and there were significant differences between the three wastewater treatment plants. The mean (and range) of summation PBDEs concentrations measured are as follows: Jahra 52.5 ng g(-1) (5.7-169.5 ng g(-1)); Reqqa, 144 ng g(-1) (32-296 ng g(-1)); Umm Haylaman, 377 ng g(-1) (23-1599 ng g(-1)). The differences in concentrations of the sum of penta congeners were consistently different at the three treatment plants with values increasing in the order: Jahra

Development of QuEChERS Method for the Determination of Polycyclic Aromatic Hydrocarbons in Smoked Meat Products Using GC-MS from Qatar.

A simple and fast method for the determination of PAHs in smoked meat samples was described. The QuEChERS (Z-Sep) procedure was used for sample preparation. Gas chromatograph-mass spectrometer with electron ionization (EI) was used to separate and detect the PAHs. All 16 common PAHs were analyzed successfully. Matrix-matched calibration was applied. Spiked samples were performed at 1 ng/g (n=10) and 10 ng/g (n=10) for two days. Overall recoveries of PAHs were within 74 to 117%, with RSDs within 1.15 to 37.57% and 1 and 10 ng/g wet weight for first and second day, respectively. In most of the analyzed smoked meat samples, there were no exceeded levels compared to the maximum levels declared by Commission Regulation (EU) number 835/2011. The method can be recommended for routine analysis for laboratories having a large number of samples.

Association of polybrominated diphenyl ethers in two fat compartments with increased risk of insulin resistance in obese individuals.

BACKGROUND: Polybrominated diphenyl ethers (PBDEs), a widely utilized class of flame retardants in various commercial products, represent a prominent source of environmental contaminants. PBDEs tend to accumulate in adipose tissue, potentially altering the function of this endocrine organ and increasing risk of insulin resistance. The aim of this study was to compare levels of PBDEs in adipose tissues from two metabolically distinct obese groups; the insulin sensitive (IS) and the insulin resistant (IR). METHODS: Levels of 28 PBDE congeners were assessed in subcutaneous and omental adipose tissues from 34 obese Qatari individuals (11 IS and 23 IR) using gas chromatography (Trace GC Ultra) coupled to a TSQ Quantum triple Quadrupole mass spectrometer. Correlations of identified PBDEs and mediators of metabolic disease were established and effects of PBDEs treatment on insulin signaling in primary omental preadipocytes were determined. RESULTS: Out of 22 detectable PBDEs in subcutaneous and omental adipose tissues, PBDEs 28, 47, 99 and 153 were predominant in omental adipose tissues from obese Qatari subjects. PBDEs 99, 28, and 47 were significantly higher in IR individuals compared to their IS counterparts. Significant positive correlations were identified between PBDEs 28 and 99 in the omental tissues and with fasting insulin levels. When considering PBDEs congeners, penta congeners were also higher in IR compared to IS individuals, while no significant differences were detected in mono, tri, tertra, hexa, hepta and octa congeners between the two studied groups. Treatment of human omental preadipocytes from insulin sensitive individuals with PBDE28 caused inhibition of phosphorylation of GSK3 α/ß (Ser21/Ser9), mTOR (Ser2448), p70 S6 kinase (Thr389) and S6 ribosomal protein (Ser235/Ser236) and activation of PTEN (Ser380) phosphorylation, suggesting inhibition of insulin signaling. CONCLUSION: This pilot data suggests that accumulation of specific PBDEs in human adipose tissues is associated with insulin resistance in obese individuals. Further investigation of the functional role of PBDEs in the pathology of insulin resistance should help developing therapeutic strategies targeting obese individuals at higher risk.

Vacancy ion-exclusion chromatography of inorganic acids on a weakly acidic cation-exchange resin column.

Vacancy ion-exclusion chromatography (VIEC) for inorganic acids such as H(2)SO(4), HCl, H(3)PO(4), HNO(3), HI and HF is tested on a polymethacrylate-based weakly acidic cation-exchange resin column in the H(+)-form. That is, mixture of inorganic acids in the mobile phase is adsorbed to the resin phase passing through the separation column, and each vacant peak induced by injecting water is determined. Retention times are dependent on the degrees of retention for each analyte in the resin phase. In VIEC, well-shaped peaks of inorganic acids are produced, leading to efficient separations. However, retention behaviors of inorganic acids were strongly affected by the concentrations of the acids in the mobile phase. Sulfosalicylic acid was mixed with inorganic acids in the mobile phase prior to the introduction of a separation column in order to obtain the well-resolutions in the lower concentrations of the acids. By using this method, the separations of inorganic acids could be achieved in the range of 0.01-1 mM, and the linear ranges could be extended over two-orders of magnitude. This is considered since the protonated carboxylic groups fixed on the resin phase were increased with increasing the acid concentrations in the mobile phase, and the penetration effects for the acids to the resin phase were thus enhanced. The detection limits (S/N=3) were below 1.0 microM for all analyte acids. Precision values for retention times were below 0.32% and for peak area were below 0.91%.

Spatial distribution of polybrominated diphenyl ethers in coastal marine sediments receiving industrial and municipal effluents in Kuwait.

Polybrominated diphenyl ether (PBDE) concentrations were measured in surficial sediments from coastal sediments receiving industrial and municipal effluents in Kuwait. The summation PBDE concentrations varied by two orders of magnitude ranging from 80 to 3800 pg g(-1)dw. The congener distribution was dominated by BDE 183, with minor contributions from BDEs 154 and 153. The similarity between the congener profile to that of the technical octa formulation (Bromkal 79-8DE) suggests a source of this product in Kuwait. The observed gradient in concentration distribution, with high summation PBDE concentrations near the shore and an exponential decrease seaward, indicates that wastewater discharge from industrial activities in the study area is the primary source of these compounds in the sediments.

House dust as a source of human exposure to polybrominated diphenyl ethers in Kuwait.

This study reports concentrations of polybrominated diphenyl ethers (PBDEs) in dust samples collected from 17 homes in Kuwait. PBDEs were measured in all homes investigated with mean summation operatorPBDEs concentration ranging from 1 to 393 ng g(-1), with a geometric mean of 76 ng g(-1). The dominant congener in all samples was BDE 209 constituting ca. 85% of the summationPBDEs followed by BDE 99 (5%), BDE 47 (4.5%), and BDE 183 (2%). The congener mixture in dust is dominated by those in deca and penta formulations. Using the measured concentrations and estimates of dust ingestion rates for children and adults, estimated human non-dietary exposure based on mean PBDE levels were 14.8 and 1.5 ng day(-1) for children and adults, respectively. The 10-fold difference in exposure estimates between children and adults in this study supports previous reports that children are at greater risk from pollutants that accumulate indoors. The ubiquitous distribution of these chemicals as noted in this study highlights the fact that we are continuously exposed to low doses of chemicals in the indoor environment.

Passive sampler-derived air concentrations for polybrominated diphenyl ethers and polycyclic aromatic hydrocarbons in Kuwait.

The present study presents, to our knowledge, the first ambient air data for a range of polybrominated diphenyl ethers (PBDEs) and polycyclic aromatic hydrocarbons (PAHs) in Kuwait. This was achieved by concurrently deploying polyurethane foam-disk passive samplers at 14 sites over a six-week period. Calculated mean sigma5PBDE concentrations (sum of brominated diphenyl ethers [BDEs] 47, 99, 100, 153, and 154) ranged from 2.5 to 32 pg/m3 of air, with BDE 47 contributing between 39 and 65% of the sigmaPBDEs detected. Differences in relative concentrations were observed between sites, with higher concentrations measured close to suspected sources. Calculated sigmaPAH concentrations ranged from 5 to 13 ng/m3 (mean, 8.3 ng/m3). The compound distribution was dominated by three- and four-ring compounds, which constituted approximately 90% of the sigmaPAHs, with phenanthrene contributing approximately 35%. However, the proportion of five- and six-ring PAHs increased around the "oil lakes," which were formed by the torching of oil wells during the 1991 Gulf War. The oil lakes are a reservoir of PAHs that will continue feeding the atmosphere as long as they remain untreated.

Validation of various extraction techniques for the quantitative analysis of polycyclic aromatic hydrocarbons in sewage sludges using gas chromatography-ion trap mass spectrometry.

A new GC-ion trap MS method has been developed for the determination of polycyclic aromatic hydrocarbons (PAHs) in sewage sludge samples. The sludge samples were extracted with Soxhlet, Soxtec, and pressurized liquid extraction (PLE) using 1:1 (v/v) dichloromethane (DCM):n-hexane solvent mixture. A multi-layer clean-up (silica/Al2O3) column were used, followed by gel permeation chromatography (GPC) to eliminate the interfering organic compound as well as the lipids. The extracts were quantified with GC-EI-SIS and GC-EI-MS-MS. The method was successfully applied to determine the concentration of PAHs present in sewage sludge samples collected from four waste water treatment plants (WWTPs). The method recovery values varied from 61.5 to 90.5%, 65.0 to 91.8% and 60.0 to 93.4% for Soxtec extraction, Soxhlet extraction and PLE extraction, respectively. The total concentrations of the 16 PAHs in the sewage sludge samples were found to vary from 1.56 to 6.18 mg/kg. The concentration of PAHs in WWTPs did not significantly vary.

High-speed ion-exclusion chromatography of dissolved carbon dioxide on a small weakly acidic cation-exchange resin column with ion-exchange enhancement columns of conductivity detection.

The high-speed ion-exclusion chromatographic determination of dissolved carbon dioxide, i.e., carbonic acid, hydrogencarbonate or carbonate, with conductivity detection was obtained using a small column packed with a weakly acidic cation-exchange resin in the H+-form (40 mm long x 4.6 mm i.d., 3 microm-particle and 0.1 meq./ml-capacity). Two different ion-exchange resin columns, which were a strongly acidic cation-exchange resin in the K+-form and a strongly basic anion-exchange resin in the OH- -form, were connected after the separation column. The sequence of columns could convert dissolved carbon dioxide to KOH having high conductivity response. The enhancement effect for dissolved carbon dioxide could retain even on the vast chromatographic runs, by using the enhancement columns with high ion-exchange capacity above 1.0 meq./ml. The retention time was in 60 s at flow-rate of 1.2 ml/min. The calibration graph of dissolved carbon dioxide estimated as H2CO3- was linear in the range of 0.005-10 mM. The detection limit at signal to noise of 3 was 0.15 microM as H2CO3-. This method was applicable to several rainwater and tap water samples.

Monolithic octadecylsilyl-silica gel column for the high-speed ion chromatographic determination of acidity.

A monolithic ODS-silica gel column modified by saturating it with lithium dodecylsulfate (Li-DS) was used to demonstrate the high-speed separation of H+ from other mono- and divalent cations, such as Na+, NH4+, K+, Mg2+ and Ca2+ using ion chromatography (IC). Using a 5 mM EDTA-2K solution containing 0.10 mM Li-DS (pH 4.80) as eluent, H+ was eluted with a sharp and symmetrical peak within 1.0 min before other cations at a flow-rate of 1.5 ml min(-1). The rapid elution of H+ and its conductimetric detection could be attributed to the presence of EDTA (HY2-), which can convert H+ ions as anions. i.e. H(+) + H2Y(2-) --> H3Y(-). The acidity of rainwater and deionized water samples was determined using this IC system with satisfactory results.

Vacancy ion-exclusion/adsorption chromatography of aliphatic amines on a polymethacrylate-based weakly basic anion-exchange column.

Vacancy ion-exclusion/adsorption chromatography has been applied to investigate the separation behavior of five aliphatic amines (ethylamine, propylamine, butylamine, pentylamine and hexylamine) on a polymethacrylate-based weakly basic anion-exchange column (Tosoh TSKgel DEAE-5PW). This system is consisted of analytes as a mobile phase and water as an injected sample. In the vacancy ion-exclusion/adsorption chromatography, the elution order was as follows: ethylamine < propylamine < butylamine < pentylamine < hexylamine, depending on their hydrophobicity. The retention times of the amines were decreased with decreasing their concentrations in the mobile phase. The retention times and resolutions of the amines were increased by adding a basic compound (e.g., lithium hydroxide or heptylamine) and by increasing the pH of mobile phase (pH > 11). This was because the dissociations of amine samples in the mobile phase were suppressed and thus the hydrophobic adsorption effects were enhanced. The linearity of calibration graphs could be obtained from the peak areas of the amine samples injected to the 0.05, 0.5 and 5 mM of amine mobile phase at pH 11 by heptylamine. The detection limits of aliphatic amines as injected samples were around 1 microM for five aliphatic amines at three different amine mobile phases. From these results, the retention behaviors of aliphatic amines on vacancy ion-exclusion/adsorption chromatography were concluded to be governed by the hydrophobic adsorption effect.

Vacancy ion-exclusion chromatography of carboxylic acids on a weakly acidic cation-exchange resin.

In this preliminary study, a new approach to ion-exclusion chromatography is proposed to overcome the relatively poor conductivity detection response which occurs in ion-exclusion chromatography when acids are added to the eluent in order to improve peak shape. This approach, termed vacancy ion-exclusion chromatography, requires the sample to be used as eluent and a sample of water to be injected onto a weakly acidic cation-exchange column (TSKgel OApak-A). Vacancy peaks for each of the analytes appear at the retention times of these analytes. Highly sensitive conductivity detection is possible and sharp, well-shaped peaks are produced, leading to efficient separations. Retention times were found to be affected by the concentration of the analytes in the eluent, and also by the presence of an organic modifier such as methanol in the eluent. Detection limits for oxalic, formic, acetic, propionic, butyric and valeric acids were 0.1, 0.2, 0.3, 0.3, 0.4 and 0.5 microM, respectively, and linear ranges for some acids extended over two orders of magnitude. Precision values for retention times were 0.21% and for peak areas were <1.90%. The vacancy ion-exclusion chromatography method was found to give detection responses four to 10 times higher than conventional ion-exclusion chromatography using sulfuric acid eluent and two to five times higher than conventional ion-exclusion chromatography using benzoic acid eluent.

Ion-exclusion chromatography with conductimetric detection of aliphatic carboxylic acids on a weakly acidic cation-exchange resin by elution with benzoic acid-beta-cyclodextrin.

In this study, an aqueous solution consisting of benzoic acid with low background conductivity and beta-cyclodextrin (beta-CD) of hydrophilic nature and the inclusion effect to benzoic acid were used as eluent for the ion-exclusion chromatographic separation of aliphatic carboxylic acids with different pKa values and hydrophobicity on a polymethacrylate-based weakly acidic cation-exchange resin in the H+ form. With increasing concentration of beta-cyclodextrin in the eluent, the retention times of the carboxylic acids decreased due to the increased hydrophilicity of the polymethacrylate-based cation-exchange resin surface from the adsorption of OH groups of beta-cyclodextrin. Moreover, the eluent background conductivity decreased with increasing concentration of beta-cyclodextrin in 1 mM benzoic acid, which could result in higher sensitivity for conductimetric detection. The ion-exclusion chromatographic separation of carboxylic acids with high resolution and sensitivity was accomplished successfully by elution with a 1 mM benzoic acid-10 mM cyclodextrin solution without chemical suppression.

Vacancy ion-exclusion chromatography of haloacetic acids on a weakly acidic cation-exchange resin.

A new and simple approach is described for the determination of the haloacetic acids (such as mono-, di- and trichloroacetic acids) usually found in drinking water as chlorination by-products after disinfection processes and acetic acid. The new approach, termed vacancy ion-exclusion chromatography, is based on an ion-exclusion mechanism but using the sample solution as the mobile phase, pure water as the injected sample, and a weakly acidic cation-exchange resin column (TSKgel OApak-A) as the stationary phase. The addition of sulfuric acid to the mobile phase results in highly sensitive conductivity detection with sharp and well-shaped peaks, leading to excellent and efficient separations. The elution order was sulfuric acid, dichloroacetic acid, monochloroacetic acid, trichloroacetic acid, and acetic acid. The separation of these acids depends on their pKa values. Acids with lower pKa values were eluted earlier than those with higher pKa, except for trichloroacetic acid due to a hydrophobic-adsorption effect occurring as a side-effect of vacancy ion-exclusion chromatography. The detection limits of these acids in the present study with conductivity detection were 3.4 microM for monochloroacetic acid, 0.86 microM for dichloroacetic acid and 0.15 microM for trichloroacetic acid.

Vacancy ion-exclusion chromatography of aromatic carboxylic acids on a weakly acidic cation-exchange resin.

Determination of aromatic carboxylic acids by conventional ion-exclusion chromatography is relatively difficult and methods generally rely on hydrophobic interaction between the solute and the resin. To overcome the difficulties in determining aromatic carboxylic acids a new approach is presented, termed vacancy ion-exclusion chromatography, which is based on use of the sample as mobile phase and an injection of aqueous 10% methanol onto a weakly acidic cation-exchange column (TSKgel OApak-A). Highly sensitive conductivity detection occurred with sharp and well-shaped peaks, leading to very efficient separations. The effects of sulfuric acid concentration added to the mobile phase, flow-rate, and column temperature on the retention volume of tested aromatic carboxylic acids was investigated. Retention times were found to be affected by the concentration of the analytes in the mobile phase and to some extent also by the addition of an organic modifier such as methanol to the injected water sample. Separation of sulfuric acid (SA), naphthalenetetracarboxylic acid (NTCA), phthalic acid (PA) and benzoic acid (BA) was satisfactory using this new approach. Detection limits were 0.66, 0.67, 0.42 and 0.86 microM and detector responses were linear in the range 1-100, 1-80, 2.5-100 and 10-40 microM, for SA, NTCA, PA and BA, respectively. Precision for retention times was 0.36% and for peak areas was 1.5%.

Selective determination of ammonium ions by high-speed ion-exclusion chromatography on a weakly basic anion-exchange resin column.

This paper describes an ion-exclusion chromatographic system for the rapid and selective determination of ammonium ion. The optimized ion-exclusion chromatographic system was established with a polymethacrylate-based weakly basic anion-exchange resin column (TSKgel DEAE-5PW) as the separation column, an aqueous solution containing 0.05 mM tetramethylammonium hydroxide (pH 9.10) as eluent with conductimetric detection for the analyte determination. Under the optimum chromatographic conditions, ammonium ion was determined within 2.3 min with a detection limit (S/N=3) better than 0.125 microM. Ammonium ion in rain and river waters was precisely determined using this ion-exclusion chromatographic system.

High-speed simultaneous ion-exclusion/cation-exchange chromatography of anions and cations on a weakly acidic cation-exchange resin column.

The simultaneous ion-exclusion/cation-exchange separation column packed with a polymethacrylate-based weakly acidic cation-exchange resin of 3 microm particle size was used to achieve the simultaneous high-speed separation of anions and cations (Cl(-), NO3(-), SO4(2-), Na(+), K(+), NH4(+), Ca(2+) and Mg(2+)) commonly found in environmental samples. The high-speed simultaneous separation is based on a combination of the ion-exclusion mechanism for the anions and the cation-exchange mechanism for cations. The complete separation of the anions and cations was achieved in 5 min by elution with 15 mM tartaric acid-2.5 mM 18-crown-6 at a flow-rate of 1.5 ml/min. Detection limits at S/N=3 ranged from 0.36 to 0.68 microM for anions and 0.63-0.99 microM for cations. This method has been applied to the simultaneous determination of anions and cations in several environmental waters with satisfactory results.