Determination Of Organic Contaminants Research Articles

Determination of organic contaminants in L'Albufera Natural Park using microporous polyethylene tube passive samplers: An environmental risk assessment

L'Albufera Natural Park (Valencia, Spain) is a protected wetland of international significance that provides critical habitats to endemic and threatened bird and plant species. This study aims to use multiple cross-validation techniques to generate an accurate estimation of the environmental risk of organic contaminants (OCs) in an internationally important coastal wetland, to identify compounds of concern and their potential sources and risk factors. Microporous polyethylene tube (MPT) passive samplers were deployed at 12 locations across L'Albufera Natural Park with concurrent grab samples collected. A subset of MPT samplers were also analysed by an additional laboratory in Australia to widen the range of contaminants and assess interlaboratory reproducibility of results. Forty-three pesticides, 20 pharmaceuticals and personal care products (PPCPs), 20 per-and polyfluoroalkyl substances (PFAS) and 4 organophosphorus flame retardants (OPFRs) were detected in the MPT samplers. The fungicides tebuconazole and difenoconazole were detected at the highest concentrations in passive samplers (maximum concentrations, 153 ng sampler−1 and 106 ng sampler−1, respectively). Several other pesticides were detected in all locations (mean concentrations >1 ng sampler−1). The compounds fenamiphos, propyzamide, difenoconazole, propiconazole, metsulfuron methyl, sodium bis (perfluorohexyl) phosphinate (6:6 PFPiA), 6:2 fluorotelomer sulfonamide alkylbetaine (6:2 FTAB), 6:2 fluorotelomersulfonate (6:2 FTS), citalopram desmethyl and citalopram were reported in the wetland for the first time. Spatial distribution analysis revealed higher pesticide concentrations in the North of L'Albufera. A risk quotient (RQ) analysis showed that ibuprofen is of concern in the area. Overall, the MPT sampling approach is promising as a risk assessment tool for better understanding the transport and fate of OCs in protected areas.

Determination and elimination of hazardous pollutants by exploitation of a Prussian blue nanoparticles-graphene oxide composite

The exploitation of desired materials with specific properties for water remediation has become an irresistible trend. Generally, materials favorable to the elimination of hazardous contaminants are always beneficial to the detection of these compounds. Nevertheless, few researches combined these two procedures into a treating line. Therefore, a Prussian blue nanoparticles-doped graphene oxide (PBGO) composite was successfully synthesized and prepared as a solid-phase microextraction (SPME) coating for pollutant detection and a three-dimensional (3D) aerogel for contaminant removal in this study. Owing to its highly conjugated structure, abundant oxygen sites and periodical cyano groups, the composite achieved satisfactory enrichment capacity towards specific pollutants. The combination of elimination and determination of organic contaminants by using the PBGO composite not only possessed satisfactory performance but also avoided the separation process and secondary pollution. Finally, the PBGO SPME coating was utilized for the sensitive detection of several hazardous contaminants in environmental water samples with satisfactory recoveries. We think the combination of a PBGO composite with the green sample pretreatment technique (SPME) and pollutant elimination will not only help to facilitate the improvement in analytical fields, but also provide a secondary pollution-free way to explore the adsorption properties of adsorptive materials for environmental contaminants.

Photo enhanced methanol electrooxidation: Further insights into Pt and TiO2 nanoparticle contributions

Pt nanoparticles (PtNPs) were deposited on two different supports: Vulcan® XC-72R carbon (PV) and TiO2/G-PV, a TiO2/carbon composite support prepared using glucose-doped Vulcan® XC-72R carbon (G-PV). The presence of TiO2 has been shown to maximize the PtNPs specific surface area and improves the catalytic performance through Pt-metal oxide interaction. The catalytic activity of Pt/TiO2/G-PV and Pt/PV toward the methanol oxidation reaction (MOR) was investigated with and without ultraviolet-visible (UV–vis) light irradiation using different electrochemical techniques. The results show the enhancement in catalytic activity in Pt/PV under illumination (Ipeakillumination-Ipeakdark)*100/Ipeakdark∼100%) can be attributed to a significant reduction in the charge transfer resistance (Rct) when the electrode is illuminated (635Ω (dark) vs 84Ω (illumination)) as determined by electrochemical impedance spectroscopy (EIS). The observed photo enhancement is relatively modest when compared to the Pt/TiO2/G-PV catalyst (Ipeakillumination-Ipeakdark)*100/Ipeakdark∼171%), even though the change in the Rct (185Ω vs. 99Ω) is not as pronounced as in the Pt/PV samples. The carbon monoxide (CO) stripping results indicate that illumination aids the removal of adsorbed CO from the PtNPs surface. The remarkable enhancement on the oxidation of methanol under UV–vis illumination in the case of the Pt/TiO2/G-PV catalyst materials show the potential of these materials for applications such as disposable and portable electrochemical sensors for water analysis, mainly the determination of organic contaminants in water. Moreover, it can be a breakthrough in the development of novel photoelectrochemical ethanol sensors and a new generation of energy conversion devices.

Determination of selected organic contaminants in soil by pressurized liquid extraction and gas chromatography tandem mass spectrometry with in situ derivatization

The determination of organic contaminants in soil is a real challenge due to the large number of these compounds with quite different physico-chemical properties. In the present work, an analytical method was developed for the simultaneous determination in soil of 40 organic contaminants belonging to different chemical classes: polycyclic aromatic hydrocarbons, polychlorinated biphenyls, polybrominated diphenyl ethers, UV filters, parabens, bisphenols and triclosan. Soil was extracted by pressurized liquid extraction and the extracts, without the need of a clean-up step, were analyzed by gas chromatography–tandem mass spectrometry after in situ derivatization in the gas chromatographic system. In the pressurized liquid extraction step, two extraction cycles were performed with a mixture of ethyl acetate–methanol (90:10, v/v) at 80°C. Recovery of these contaminants from soil samples spiked at levels ranging from 30 to 120ngg−1 was satisfactory for most of the compounds. The developed procedure provided detection method limits from 0.1 to 2.5ngg−1. The analysis of soil samples collected in different agricultural fields confirmed the presence of some of the studied contaminants. Polycyclic aromatic hydrocarbons were the main contaminants detected, parabens and polychlorinated biphenyls were also found but at relatively low concentration levels, 2-ethylhexyl salicylate was the UV filter that appeared most frequently at levels ranging from 17.2 to 43.4ngg−1 and triclosan was found in eight out of fourteen samples, at relatively low concentration levels (0.8–28.6ngg−1).

New Developments in Standard Reference Materials (SRMs) for Environmental Forensics

For nearly three decades the National Institute of Standards and Technology (Gaithersburg, MD) has been involved in the development of Standard Reference Materials (SRMs) for the determination of organic contaminants in environmental matrices. Classes of organic contaminants characterized in these materials include polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs), chlorinated pesticides, and most recently, brominated flame retardants (polybrominated diphenyl ethers [PBDEs]). Environmental matrices include fossil fuels, air and diesel particulate matter, house dust, coal tar, sediment, mussel and fish tissue, fish oil, and whale blubber. Recent SRM developments and activities have led to a number of environmental SRMs that are useful for assuring quality of analytical measurements in environmental forensics where source profiling of organic contaminants is often conducted in a range of environmental or biological matrices. Particle-related SRM developments include the issue of a new house dust material (SRM 2585 Organic Contaminants in House Dust), and the recertification of two SRMs: a diesel particulate matter material (SRM 1650b Diesel Particulate Matter) for certified and reference values for 97 PAHs and nitro-PAHs and a river sediment (SRM 1939b PCBs in River Sediment A) for a greater number of PCB congener concentrations relative to its former certification in 1998 as well as for total PCBs. A coal tar SRM (SRM 1597a Complex Mixture of PAHs from Coal Tar) has also been reissued with an expanded range of values for PAHs (including methyl- and dimethyl-substituted PAHs, PAH isomers of molecular mass 302, and polycyclic aromatic sulfur heterocycles [PASH]). The latest biological SRM developments include the issue of a new fish tissue SRM (SRM 1947 Lake Michigan Fish Tissue) and the recertification of a cod liver oil (SRM 1588b Organics in Cod Liver Oil) and a human serum (SRM 1589b PCBs, Pesticides, PBDEs, and Dioxins/Furans in Human Serum). SRM 1588b has values assigned for 124 constituents, and SRM 1589b has values assigned for 88 constituents. An overview of these recent SRM activities is provided in this paper, and selected organic contaminant values in newly developed particulate-related and biological SRMs are presented. The usefulness of these materials for assuring quality in environmental forensic measurements is also discussed.

Determination of organic contaminants in food by capillary electrophoresis

This review addresses recent advances in the analysis of organic contaminants, such as antibiotics, pesticides, biological toxins, and food-borne pathogens, in foods by capillary electrophoresis (CE). Special attention is paid to those aspects that increase sensitivity and/or selectivity, such as sample extraction and concentration, on-line preconcentration techniques (stacking), affinity capillaries or/and specific detectors (laser induced fluorescence (LIF), mass spectrometry (MS)). The various CE modes used to separate the compounds and the quantification strategies are also examined. As a result, this work presents an updated overview on the principal applications of CE, together with a discussion of their main advantages and drawbacks, and an outline of future trends in the analysis of organic contaminants in food.

Determination of organochlorinated compounds and petroleum hydrocarbons in fish-homogenate sample IAEA-406: results from a worldwide interlaboratory study

Fish-homogenate IAEA-406 was used as an intercomparison sample for the analyses of organochlorinated pesticides, polychlorinated biphenyls (PCBs) and petroleum hydrocarbons. The sample material was analysed by 59 laboratories from 36 countries. The results reported by the laboratories shows that there are still some difficulties with the accurate determination of organic contaminants, notably pesticides and polycyclic aromatic hydrocarbons (PAHs). More consistent interlaboratory results were obtained for PCB congeners. Many laboratories reported results in close agreement and, after statistical screening of the data, consensus values were obtained for the concentration of several analytes in this sample. These results allowed several values for the concentrations of the analytes to be assigned, and the sample IAEA-406 can be used as a reference material (RM) for quality control of data in the determination of chlorinated compounds and petroleum hydrocarbons in biological samples. Furthermore, considering the matrix type and the number of contaminants certified, this sample is unique in the collection of RMs available at present.

Interlaboratory comparisons - demonstrating degree of equivalence

The role of matrix reference materials in the process of demonstrating the degree of equivalence of measurement results obtained from intercomparisons is outlined, reviewing exemplary selected experience gained at BAM regarding the determination of organic contaminants in environmental matrices. The specific characteristics of reference materials employed in the process of demonstrating equivalence between laboratories in the course of proficiency testing as well as the development, comparison and validation of methods are elaborated. The demand is for series of appropriately characterised samples which are fit for the purpose and it is seen from representative examples that the utilisation of such tailor-made RM designed to tackle the specific need of an analytical problem dominates over certified matrix reference materials in this context. Concluding, the role of certified matrix reference materials in quality assurance is briefly looked at both from the user’s and providers’ points of view.

Isolation and Determination of Volatile Organic Compounds from Water by Dynamic Purge-and-Trap Technique Coupled with Capillary Gas Chromatography

The preconcentration technique of purge-and-trap has been investigated in the present work for quantitative adsorption of volatile organic pollutants purged from water samples. A dynamic purging device with variable volume size has been constructed and tested to purge different concentrations of organic compounds. With Tenax GR as the adsorbent, a dynamic purge-and-trap technique was developed combining on-column preconcentration procedures using ambient trapping/thermal desorption/cryogenic focusing/back-flash injection prior to separation and determination using capillary gas chromatography. Various aromatic compounds in water were determined, giving linear working ranges over five orders of magnitude from 0.02 to 5000 µg/L. The analytical procedures were optimized under the assistance of ultrasonication with results validated for the determination of organic contaminants in underground water and tap water, giving over 93% recoveries and a detection limit of 0.01 µg/L, two orders of magnitude lower than those obtained using commercial available instruments with on-line configuration to minimize cross-contamination. The technique provides a potential automated method for in situ monitoring of volatile organic compounds in water.

Determination of Organic Contaminants in Aqueous Samples by Near-Infrared Spectroscopy

The feasibility of determining low levels of organic solvents in water by near-infrared (near-IR) spectroscopy is investigated. Mixture samples of tributyl phosphate (TBP) and methyl iso-butyl ketone (MIBK) are determined in aqueous solutions over the concentration range of 1–160 ppm. Through the use of C–H combination bands in the region of 5000–4000 cm−1, sufficient selectivity is obtained to determine each compound in the presence of the other. Separate multivariate calibration models are computed for each compound by use of a combination of bandpass Fourier digital filtering and partial least-squares (PLS) regression with both analysis of absorbance and single-beam spectra. A genetic algorithm is used to implement a joint optimization of the parameters governing the filtering and PLS calculations. Through the use of this procedure, a calibration model based on absorbance spectra is computed for MIBK with a standard error of prediction (SEP) of 3.82 ppm over the 1–160 ppm range. This five-term model utilizes the spectral range of 4495–4335 cm−1. A similar nine-term model based on absorbance spectra is computed for TBP over the 4620–4320 cm−1 range. For the range of 1–100 ppm, an SEP of 4.84 ppm is achieved. The results obtained from the analysis of single-beam spectra are comparable with those obtained in the analysis of absorbance data. Calibration models computed with samples prepared in natural water are also found to have a similar level of performance. These results establish the feasibility of using near-IR spectroscopy to screen water samples for solvent contamination.

98/03350 Determination of organic contaminants in soil from coking plant: Kubica, K. et al. Chemical Anal., 1998, 43, (1), 57–67

98/03350 Determination of organic contaminants in soil from coking plant: Kubica, K. et al. Chemical Anal., 1998, 43, (1), 57–67

Organochlorines and Polycyclic Aromatic Hydrocarbons in the Sediments of Ganges River (India)

Organochlorine(OC) insecticides have been extensively used in India since 1954 in agriculture as well as public health sector. The use of OCs which are banned or restricted in most developed countries are still being used in this country. The major factors responsible for detrimental effects on the environment from use of these chemicals are that they are very persistent, extremely toxic to fish, used more as preventive measures rather than cure in controlling insects and some of them were found to biomagnify in organisms. Their accumulation about 26 mg DDT in their body through food items. Polycyclic aromatic hydrocarbons (PAHs) are formed as a result of incomplete combustion of organic compounds but may also be synthesized by some bacteria, algae and plants. PAHs are on the USEPA and EC priority pollutants list since some PAHs are known or suspected carcinogens/mutagens. In surface waters, they are known to be strongly adsorbed on sediment clays and other particles while their degradation in sediment also occur. Therefore, during low stream flow, fluvial materials settle down and may contain concentrations of OCs and PAHs. Hence, it is necessary to include sediment in the determination of organic contaminants in surface waters. This paper refers to more » a monitoring programme for screening the OCs and PAHs concentrations in the Ganges river sediments. 29 refs., 3 figs., 1 tab. « less

On-line versus off-line solid-phase extraction in the determination of organic contaminants in water : Advantages and limitations

Solid-phase extraction (SPE) has become and important and frequently employed method for the preconcentration of organic pollutants from water samples. From the methodological standpoint, two basic approaches can be recognized, on-line and off-line, each of which has its advantages and limitations. The original off-line modification is simple and highly flexible. Therefore, it is often used in analytical research and in quick testing methods. On the other hand, the possibility of automation and the high sample throughput of on-line SPE are the major reasons for its growing use in routine target analyses and in analytical methods for continuous monitoring of water quality. While the growing interest in automation in laboratory practice leads to promising perspectives for on-line techniques, the relatively unlimited flexibility of the classical off-line SPE makes it always a suitable procedure to be used for trace enrichment purposes in diverse analytical applications. This paper gives an overview of the basic principles and possibilities of both off-line and on-line SPE approaches and provides a brief survey of their benefits and limitations.

Determination of Organic Contaminants in Residential Indoor Air Using an Adsorption-thermal Desorption Technique

This field study evaluated the ability of a multi-sorbent sampling tube/thermal desorption technique to identify and to provide quantitative data on volatile organic contaminants in indoor air. Air samples, from 12 Canadian homes, were collected on multilayer sorbent cartridges and analyzed using Adsorption/Thermal Desorption coupled with Gas Chromatography/Mass Spectrometry. The study included the identification and quantitation of 23 target compounds. Analysis of sorbent tubes fortified with these target compounds indicated that recoveries were greater than 70 percent and the precision was usually better than 15 percent. These organic compounds were found to be stable on the sorbent tubes for at least seven days. With some exceptions, the target compounds were usually detected at 1 to 10 micrograms/m3 in indoor air samples; other organics identified qualitatively were saturated hydrocarbons, unsaturated hydrocarbons, cyclic hydrocarbons, substituted aromatics, oxygenates, some halogenates and cyclic species such as camphenes/pinenes and carenes.

Determination of organic contaminants in ultra-pure water by reversed-phase high-performance liquid chromatography with ultraviolet detection

High-performance liquid chromatography on reversed-phase columns with ultraviolet detection is a useful tool for the determination of the amount of organic impurities present in water. A sufficiently sensitive analysis of different types of ultra-pure water requires sample volumes of several hundred millilitres combined with a very low detection wavelength. In the work described here, sample volumes of 480 ml were analysed at a detection wave-length of 210 nm. Using these experimental conditions it was possible to detect and eliminate several contamination sources interfering in the preparation and handling procedures of ultra-pure water.

Determination of organic contaminants by the Grob closed‐loop‐stripping technique

A modified Grob closed‐loop‐stripping device is currently being used to concentrate organic contaminants from drinking water. The identification and quantification of organic contaminants at the nanogran per litre (part‐per‐trillion) level are accomplished by a computerized glass capillary gas chromatography–mass spectrometry system. Applications of closed‐loop‐stripping analysis (CLSA) for monitoring water by water utilities, for studying the use and effects of alternative disinfectants in drinking water, and for providing data on the removal of organic contaminants from water by granular activated carbon (GAC) treatment are discussed. An attempt to validate the method using statistical computations is also included.