Comparative Enrichment Capabilities of Some Carbonaceous and Macroreticular Resins Using Selected Radioactive Model Compounds in Fortified Aqueous Samples

Abstract

The concentration efficiency of synthetic macroreticular resins, XAD-2 and XAD-7 and carbonaceous resins, XE-340, XE-347 and XE-348 was evaluated and compared using trace levels of eight radioactive model environmental contaminants present in aqueous medium. Influences of chemical functionalities of the solvents, physical characteristics of the sorbents, and pH of the aqueous medium on sorption of the model compounds were investigated under frontal dynamic chromatographic conditions. The elution behavior of these sorbates and desorption properties of the polymer adsorbents with respect to solvents of different polarities were studied.     

GC/MS Identification of Organic Pollutants in the Caroni River,Trinidad

Abstract

Water samples from the Caroni River, Trinidad and other rivers which flow into the Caroni River were qualitatively analyzed for trace organic contaminants by procedures based on XAD extraction followed by GC/MS analysis. Pesticides, polyaromatic hydrocarbons, aliphatic hydrocarbons, phenols and phthalate esters were the main groups of compounds found. Many of the contaminants present in these water samples are known industrial pollutants, and several have been found in waste waters examined by other workers, which suggests that the factories of an industrial complex located upstream of the Caroni/Arena Water Treatment Plant may be the major source of the pollutants. Some compounds identified in the water samples have not been previously reported.     

An Investigation on the Concentration Efficiencies of Some Macroreticular and Ambersorb Resins Using Radio-Labelled Organic Contaminants Commonly Encountered in Water

Abstract

The extraction efficiencies of the three commercially available Ambersorb®, carbonaceous, polymeric resins, XE-340, XE-347 and XE-348 were evaluated for their use as sorbents for environmental pollutants using four model, radio-labelled water-borne organic contaminants. Their accumulation behaviour was compared with that of the thoroughly-studied Amberlite®, macroreticular XAD-2 (hydrophobic) and XAD-7 (hydrophilic) resins. These model compounds were desorbed from the resins using known volumes of commonly-used solvents to select the solvent for a particular resin(s). In this preliminary study, at <4 μg/L concentrations of the labelled compounds in aqueous solution (pH 5.78), the order of extraction efficiency of the resins was found to be XAD-2 > XAD-7 > XE-340?-347?-348 for organics. Several inherent impurities originally present in the carbonaceous resins were desorbed by solvents during elution. These resins therefore required exhaustive soxhlet purification prior to use. Most of the impurities were identified by gas chromatography/mass spectrometry.     

Environmental Determination of Alkylphenol Polyethoxylate Refractory Residues Using Mass Spectrometric Techniques

Abstract

The use of methane chemical ionisation GC/MS gave satisfactory results when applied to environmental analysis of halogenated octylphenol polyethoxylates residues. In addition the selected ion monitoring GC/MS technique has been successfully applied for simulataneous qualitative and quantitative determination of some refractory metabolites of nonylphenol polyethoxylates in secondary sewage effluent and surface waters.     

Identification of Organic Compounds Solvent Extracted from Paper and Glass Soxhlet Thimbles

Abstract

Organic compounds leached from paper and glass soxhlet thimbles have been identified by computerized high resolution gas chromatography /mass spectrometry. Nineteen specific organics have been tentatively identified from paper thimbles. The analysis of glass thimbles have not demonstrated these contaminants. The use of glass thimbles as a substitute for paper is advantageous in preparation of samples for trace organic analysis. This is an improvement but not a panacea as cross-contamination must still be evaluated by the analytical chemist.     

Overview of Analytical Methodologies for Dioxin Analysis

Abstract

Poly(chlorinated) dibenzo‐p‐dioxins and dibenzofurans (PCDDs/PCDFs) are persistent organic pollutants which are globally distributed in practically all environmental compartments and which exert a broad spectrum of toxic and biochemical effects. Humans are exposed to these compounds mainly through the diet with food of animal origin usually being the predominant source.

Multiple step isolation and clean up procedures are necessary to determine trace levels of these analytes in complex environmental and biological samples. This article reviews some of the recent developments in the extraction procedures, such as SFE, PLE, HS‐SPME, MAE, SCWE, ASE; clean‐up areas and instrumental analysis of dioxins in biological/environmental samples. Due to its specificity and sensitivity gas chromatography coupled with high resolution mass spectrometry (GC–HRMS), high‐resolution gas chromatography high‐resolution mass spectrometry (HRGC‐HRMS), or GC‐MS/GC techniques have been extensively applied to environmental, medicinal, and biological studies.     

Determination of N-Nitrosonornicotine in Tobacco by Gas Chromatography/Mass Spectroscopy

Abstract

N-Nitrosonornicotine has been determined in tobacco products. Quantitation was accomplished by GC/MS operated in the chemical ionization mode with selected-ion recording of N-nitrosonornicotine and the deuterated internal standard, N-nitrosonornicotine-d₄. Levels ranging from 0.7 to 26 mcg/gm were found.     

Metabolism of Pyrene and Chrysene in Epithelial Human Bronchial and Hamster Lung Cells

Abstract

The metabolism of pyrene and chrysene in epithelial human bronchial and in hamster lung cells has been studied and found to be very similar in both systems, although it differs from that observed in rat lung microsomes. Metabolite profiles have been analyzed by means of capillary GC and by GC/MS.     

The Usefulness of Amino Acid Ester Isothiocyanate Derivatives in GLC Analysis,Pyrolysis Products of Carboalkoxydithiocarbamates

Abstract

Amino acid isothiocyanate derivatives have been used in GC/MS analysis. The best method providing these derivatives is decomposition of carboalkoxydithiocarbamates. Analysis by gas chromatography and mass spectrometry has shown that carbon oxysulfide, methanol, ethanol, amino acid ester isothiocyanate and trace carbon disulfide are pyrolysis products of amino acid ester carboalkoxydithiocarbamates. However, isothermal pyrolysis at 200° and direct MS analysis, FI and EI ionization modes, give rise to a few more by-products with m/z 145 and 177. This suggests a stepwise mechanism of thermal decomposition of the compounds studied. The number of by-products was seen to decrease when the R and R moieties were identical.     

Toxaphene (Polychlorinated Camphenes) Analysis in Human Blood

Abstract

A method for the determination of toxaphene in whole blood using gas chromatography (GC)-electron capture negative ion ECNI/MS and pure polychlorobornane congerners has been evaluated. Blood samples were extracted with hexane/acetone (9:1), extracts defatted with sulfuric acid, analytes fractionated on Carbopack-C/ Florisil (or silica gel) SPE columns then concentrated to final volumes for GC-ECNI/MS analysis. For confirmation, interference from PCBs and other organochlorine pesticides were removed by nitration.     

Description of a Method for Automated Determination of Organic Pollutants in Water

Abstract

A method for automated determination of 73 organic pollutants in water is described. The compounds, which are key representatives for different types of pollutants are determined in two chromatographic runs. 11 halogenated aliphatic hydrocarbons are determined using capillary GC equipped with electron capture detector. The remaining pollutants, representing both basic/neutral and acidic compounds are determined by using GC/MS combined with an automated search computer program. The majority of the compounds have a limit of quantitation at 1 ig/1 or lower. The precision of the GC method is in the range of 1.8% to 4.3%, with an average of 3.2%. The precision for compounds determined by GC/MS is in the range of 1% to 38%, with an average of 14%.

So far 30 water samples representing both polluted fjord areas as well as effluents from municipal treatment plants, refineries, petrochemical industries and metallurgic industries have been analysed. The method has been found to be an interesting alternative to traditional methods for monitoring water quality, and has demonstrated its potential both as a screening method for detecting “hot spots” as well as for routine monitoring of specific hazardous compounds.     

Preparation of Creatinine Standard Stock Solution

Abstract

The liquid chromatography isotope dilution mass spectrometry (LC/ID‐MS) has recently been used for the certification of organic reference materials. We are developing a new definitive method of LC‐ID/MS as to determination creatinine in serum. We prepared a stock standard solution of creatinine in 10 mmol/l of acetic acid at a concentration of 8.84 mmol/l. With this acetic acid concentration, creatinine dissolved completely in a few minutes. This stock standard solution was stable at least for 1 year and has widely applications (such as GC‐MS, LC‐MS, LC, colorimetric method, etc).     

Artifacts Observed When Using Tenax-GC for Gas Sampling

Abstract

Artifact peaks have been observed when samples of the detonation products of a number of U.S. Navy explosives were collected on Tenax-GC, desorbed with pentane, and analyzed by gas chromatography/mass spectrometry (GC/MS). We have shown that the formation of these spurious peaks takes place slowly when Tenax-GC is stored in the dark, but the formation is greatly accelerated when air flows over this polymeric absorbent.     

N-Alkanes in Air Particulates of the Eastern Province of Saudi Arabia

Abstract

Oil hydrocarbons represent a great proportion of organic compounds in the atmosphere. Information about these compounds in the atmosphere of the Eastern Province of Saudi Arabia is lacking. In this study, n-alkanes and polynuclear aromatic hydrocarbons in air particulates were determined. The highest median concentration levels of n-alkanes in three urban areas and three areas near oil production centers were 121 ng/m³ and 42.9 ng/m³, respectively. Polynuclear aromatic hydrocarbons were also detected, although they are present in too low concentration for reliable quantitative measurement by GC and GC/MS techniques. A positive correlation was found between the concentration levels of n-alkanes in air particulates and the total suspended particulates measured at most locations. The carbon preference index (CPI) and the presence of the unresolved complex envelope suggested an anthropogenic origin for the n-alkanes.     

Mass spectrometric techniques for characterizing low-molecular-weight resins used as paint varnishes

The molecular structure of three low-molecular-weight resins used as paint varnishes has been characterized by use of an approach based on three different mass spectrometric techniques. We investigated the ketone resin MS2A, the aldehyde resin Laropal A81, and the hydrocarbon resin Regalrez 1094, now commonly used in restoration. To date, the molecular structures of these resins have not been completely elucidated. To improve current knowledge of the chemical composition of these materials, information obtained by gas chromatography–mass spectrometry (GC/MS), pyrolysis–gas chromatography–mass spectrometry (Py/GC/MS), and electrospray ionization mass spectrometry (ESI–Q–ToF) was combined. Analysis, in solution, of the whole polymeric fraction of the resins by flow-injection ESI–Q–ToF, and of the non-polymeric fraction by GC–MS, enabled us to identify previously unreported features of the polymer structures. In addition, the Py–GC/MS profiles that we obtained will help to enhance the databases currently available in the literature. The proposed approach can be extended to other low-molecular-weight resins used as varnishes in conservation.     

Monitoring of Polychlorinated Biphenyls in Surface Water Using Liquid Extraction,GC/MS,and GC/ECD

Abstract

A rapid and reliable analytical method, at trace level concentration was developed and validated for monitoring polychlorinated biphenyls (PCBs) in Jordanian surface water. The method combines the advantage of liquid extraction together with gas chromatography‐mass spectrometry (GC/MS) and gas chromatography‐electron capture detector (GC/ECD). The performance of the method was evaluated by analyzing certified reference material (CRM) of the analytes and applied on real water samples collected from different sites in Jordan. A mixture of 60∶40 dichloromethan‐petroleum ether was chosen as a convenient binary solvent for liquid–liquid extraction. The GC conditions for GC/MS were optimized using He as a carrier gas, temperature programming, and chlorpropham as an internal standard (IS).

The conditions for GC/ECD were performed using N₂ gas and a temperature program from 160 to 280°C with different increasing rates. The method of GC/MS in the selective ion mode (SIM) gave linear relationships for all PCBs tested between 0.60–6.0 µg/l with R ²=0.9934 (n=7×18). Recoveries from spiked water samples ranged between 87.6 and 91.4%. The mean accuracy and precision obtained were 4.9% and 2.16%, respectively. The mean of detection limit was 0.14±0.04 µg/l. In GC/ECD, linear relationships for all PCBs examined over the range of 0.3–2.4 µg/l was verified as characterized by a linear regression equation and correlation coefficient, R ²=0.9915 (n=12). The average precision and accuracy were 4.86% and 5.21%, respectively. Analyses results clarified that none of the examined Jordanian water samples contained any of the searched for PCBs within the detection limit achieved.     

Quantitation Of The Local Anesthetic Dibucaine With Gas Chromatography / Mass Spectrometry

Abstract

A chemical ionization and an electron impact GC/MS assaying approach is presented for determining dibucaine concentrations in biological fluids. Both use deuterium-labeled drug as the internal standard and rely on the same sample extraction and sample preparation procedure. Under chemical ionization conditions (CH₄), the assaying limits are in the range of 1–80 ng/ml of serum. Under electron impact conditions, the analytical range is 20–800 ng/ml. The chemical ionization procedure has been found suitable for monitoring drug levels in man. One volunteer, who received a single 5-mg oral dose, showed peak serum drug concentrations of 23 ng/ml attained 2 hr after drug administration. The biologic half-life (ß phase) was 11 hr.     

Hair Analysis as Method for Determination of Level of Drugs and Pharmaceutical in Human Body: Review of Chromatographic Procedures

Abstract

Interest in hair analysis as an alternativ or complementary approach to urinalysis for drug abuse detection has grown in recent years. Hair analysis can be particularly advantageous for drugs and their enantiomers.

More than hundred pharmaceuticals, drugs of abuse agents are reported to be detectable in human and animal hair. This article reviews the aalysis of drugs and drug metabolites by chromatographic procedures, incuding the pretreatment steps, and the xtraction methods. Tihe eneral tendency in the last years, to highly sophisticated techiques gas chromatography–mass spectrometry (GC–MS–NCI), high pressure liquid chromatography–mass spectrometry (HPLC–MS), gas chromatography–mass spectrometry–mass spectrometry (GC–MS–MS) well illustrates this constant fight for sensitivity.     

Analysis Of Contaminants On The Inner Surfaces Of Copper Tubing

Abstract

Polycyclic aromatic hydrocarbons (PAHs) have been determined by GC/MS to be present on the inner surfaces of copper tubing as supplied by the manufactures. The PAHs presumably exist as byproducts of the manufacturing process. Concentrations of PAHs found ranged from 0.00021 to 0.17 mg/m of tubing.     

Analysis of Organic Matter in Water of Low TO C (Total Organic Carbon) Content by Chromatographic Techniques

Abstract

The problems encountered when analyzing organic pollutants in drinking water stem from the large number of unknown compounds at very low concentration.

The concentration of the organics is carried out on n-alkyl silica, after a rigorous cleaning, or by liquid-liquid extraction. The complexity of these extracts renders a direct analysis by gas chromatography coupled with mass spectrometry impossible; hence, a pre-separation step is required.

Reversed and normal phase chromatography have been investigated with these extracts. The former leads to informative fingerprints but subsequent identification is difficult.

Normal phase liquid chromatography is more suitable and a separation by chemical classes of increasing polarity is applied to water extracts. The eluent is fractionated, each fraction is then gently evaporated and subsequently analyzed by GC. Identification is then possible by coupling with mass spectrometry.

These procedures are used to follow the change in organic matter during the two last steps of the drinking water treatment: ozonation and filtration on active charcoal. Another application is the analysis of humic extracts.