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.

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.

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.

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.

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).

Simultaneous analysis of organochlorinated pesticides (OCPs) and polychlorinated biphenyls (PCBs) from marine samples using automated pressurized liquid extraction (PLE) and Power Prep™ clean-up.

An automated pressurized liquid extraction (PLE) method followed by Power Prep™ clean-up was developed for organochlorinated pesticide (OCP) and polychlorinated biphenyl (PCB) analysis in environmental marine samples of fish, squid, bivalves, shells, octopus and shrimp. OCPs and PCBs were simultaneously determined in a single chromatographic run using gas chromatography-mass spectrometry-negative chemical ionization (GC-MS-NCI). About 5 g of each biological marine sample was mixed with anhydrous sodium sulphate and placed in the extraction cell of the PLE system.

Determination of the levels of polycyclic aromatic hydrocarbons in toasted bread using gas chromatography mass spectrometry.

Concentration of 16 polycyclic aromatic hydrocarbons (PAHs) in eighteen baked bread samples using gas oven toasting were evaluated in this study. Samples were classified into the following categories: (1) bread baked from white wheat flour, (2) bread baked from brown wheat flour, and (3) sandwich bread baked from white wheat flour. Analysis was performed by GC-MS after Soxhlet extraction of the sample and clean up of the extract.

Development of passive sampler technique for ozone monitoring. Estimation of indoor and outdoor ozone concentration.

A passive sampler method has been developed for ozone monitoring. The method involves a badge type passive sampler and is applied to the analysis of ozone exposure as an indoor and outdoor air pollutants. The passive sampler used in this experiment consists of glass fiber filter coated with NaNO(2), Na(2)CO(3) and ethylene glycol, and diffusion filter to remove the wind effects and several spacer effects.

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.

Polycyclic aromatic hydrocarbons in indoor air and dust in Kuwait: implications for sources and nondietary human exposure.

This study reports concentration of polycyclic aromatic hydrocarbons (PAHs) in indoor air and dust samples collected from 24 homes in Kuwait. Mean SigmaPAHs in indoor air ranged from 1.3 to 16 ng/m(3) with a geometric mean of 5.

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.

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.

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.

Spatial distribution of polychlorinated biphenyls in coastal marine sediments receiving industrial effluents in Kuwait.

The concentrations of polychlorinated biphenyls (PCBs) were measured in surficial sediments receiving industrial and municipal effluents in Kuwait. The SigmaPCB concentrations varied by two orders of magnitude ranging from 0.4 to 84 microg kg(-1) dw.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.