Određivanje benzena u urinu plinskokromatografskom tehnikom analize para iznad otopine

This paper describes the application of static headspace gas chromatography in determining benzene in urine. The method was analytically validated for sensitivity (DL=42 ng/l), repeatability (RSD=3% and 4%), and accuracy (71%), and was applied in measuring urine benzene in nonsmokers (N=14) and smokers (N=18). All urine samples had measurable benzene concentrations. The method proved sensitive enough to establish a significant statistical difference (P<0.000614) in urine benzene concentrations between smokers (mean=760; range =181–1869 ng/l) and nonsmokers (mean=214; range=61–515 ng/l).Opisana je metoda za određivanje benzena u urinu plinskokromatografskom tehnikom analize para iznad otopine (“headspace”). Metoda je analitički vrednovana s obzirom na osjetljivost (granica detekcije = 42 ng/l), ponovljivost (RSD = 3 i 4%) i točnost (71%). Primijenjena je u analizi benzena u urinu nepušača (N=14) i pušača (N=18). Benzen je bio mjerljiv u svim uzorcima urina. Dobivena je statistički značajna razlika (p<0.000614) između koncentracija benzena u urinu pušača (x=760; raspon=181–1869 ng/l) i nepušača (x=214; raspon=61–515 ng/l). Benzen ne dolazi u urin normalnim fiziološkim procesima; u nepušača uglavnom potječe iz ispušnih plinova automobila i izgaranja benzina, a u pušača je glavni izvor izloženosti benzenu dim cigarete

Rapid qualitative and quantitative analysis of novel drug analogues via Desorption Electrospray Ionisation - Mass Spectrometry (DESI-MS)

University of Technology, Sydney. Faculty of Science.Desorption electrospray ionisation - mass spectrometry (DESI-MS) is an ambient ionisation technique that can be applied to the analysis of illicit drugs and novel drug analogues in seized drug material. Currently used preliminary identification techniques lack sensitivity and selectivity and are prone to false positive and false negative results. Therefore, it was important to investigate the use of DESI-MS as a novel preliminary identification technique in the analysis of a range of compounds with the potential for future automated library matching aiding in the rapid identification of unknowns. In this research, 4-methylmethcathinone (mephedrone or 4-MMC), cocaine, 1-benzylpiperazine (BZP), 3-trifuoromethylphenylpiperazine (TFMPP), 3-chlorophenylpiperazine (mCPP), 4-methoxyphenylpiperazine (MeOPP) and other amphetamine-type substances (ATS) such as amphetamine (AP), methylamphetamine (MA), 3,4-methylenedioxymethylamphetamine (MDMA), N,N-dimethylamphetamine (DMA), 4-methoxyamphetamine (PMA), and 4-methoxymethylamphetamine (PMMA) were the drugs of interest since they are increasingly prevalent drugs of abuse globally. The optimisation of the technique and the application of DESI-MS to the analysis of these compounds were demonstrated. A particularly suitable surface, semi-porous polytetra fluoroethylene (PTFE, Teflon) was utilised, as it gave superior signal stability and reproducibility as compared to other surfaces (polymethyl methacrylate (pMMA) and polyvinyl chloride (PVC)). The limits of detection (LOD) of 4-MMC and the piperazine analogues were determined to range between 0.0023 - 2.30 μg/mm². The LOD of the ATS was determined to be in the range 0.02 - 2.80 μg/mm². DESI-MS was also utilised in the preliminary analysis of illicit cocaine samples. The LOD of cocaine was determined to be 3.47 μg/mm². The chemical profiles obtained using DESI-MS were also compared to two current confirmatory analysis techniques, gas chromatography – mass spectrometry (GC-MS) and liquid chromatography – mass spectrometry (LC-MS). The by-products and impurities detected were used to link samples to their synthetic route of manufacture and to the precursors used. The detection of truxillines in the seized cocaine samples aided in determining their geographical origin. Selectivity and matrix effects were evaluated for the compounds of interest in each study. The effect of adulterants including caffeine, procaine, levamisole, lignocaine, paracetamol, and atropine on the detectability of cocaine were investigated. The detectability of ATS were evaluated by adding caffeine, paracetamol, magnesium stearate, and dimethyl sulfone. Piperazine compounds were adulterated using caffeine and a mixture of piperazines (TFMPP and BZP) was also evaluated since these are commonly found in combination. 4-MMC was adulterated with caffeine, paracetamol, MA, phentermine, AP, MDMA, 4-hydroxyamphetamine, 4-fluoroamphetamine, nordiazepam, diazepam, oxazepam, cocaine, heroin, methadone, cathine, cathinone, 4-diethylaminobenzaldehyde, 1-benzyl-3-pyrrolidinol, and methylone. In most cases, despite the presence of ion enhancement or suppression due to the addition of adulterant, the analytes remained detectable. Quantitative experiments for 2 μL spotted solutions of 4-MMC, using codeine-D₆ as an internal standard, introduced in the desorption spray solvent, showed a linear correlation (R² > 0.9840) over the range 50 – 800 μg/mL. The precision for triplicates analysed on five different days (n = 15) was <38 % RSD. The accuracy, expressed as relative error, was <13 %. Identification based on accurate mass and MS/MS spectra aided in discriminating compounds with the same molecular formula. The results obtained using DESI-MS demonstrate its applicability in the rapid qualitative analysis (and preliminary quantitative analysis of 4-MMC) of cocaine, 4-MMC, BZP, TFMPP, mCPP, MeOPP and ATS

Mass spectral characterisation of a polar, esterified fraction of an organic extract of an oil sands process water.

RATIONALE: Characterising complex mixtures of organic compounds in polar fractions of heavy petroleum is challenging, but is important for pollution studies and for exploration and production geochemistry. Oil sands process-affected water (OSPW) stored in large tailings ponds by Canadian oil sands industries contains such mixtures. METHODS: A polar OSPW fraction was obtained by silver ion solid-phase extraction with methanol elution. This was examined by numerous methods, including electrospray ionisation (ESI) Fourier transform ion cyclotron resonance mass spectrometry (FTICRMS) and ultra-high-pressure liquid chromatography (uHPLC)/Orbitrap MS, in multiple ionisation and MS/MS modes. Compounds were also synthesised for comparison. RESULTS: The major ESI ionisable compounds detected (+ion mode) were C15-28 SO3 species with 3-7 double bond equivalents (DBE) and C27-28 SO5 species with 5 DBE. ESI-MS/MS collision-induced losses were due to water, methanol, water plus methanol and water plus methyl formate, typical of methyl esters of hydroxy acids. Once the fraction was re-saponified, species originally detected by positive ion MS, could be detected only by negative ion MS, consistent with their assignment as sulphur-containing hydroxy carboxylic acids. The free acid of a keto dibenzothiophene alkanoic acid was added to an unesterified acid extract of OSPW in known concentrations as a putative internal standard, but attempted quantification in this way proved unreliable. CONCLUSIONS: The results suggest the more polar acidic organic SO3 constituents of OSPW include C15-28  S-containing, alicyclic and aromatic hydroxy carboxylic acids. SO5 species are possibly sulphone analogues of these. The origin of such compounds is probably via further biotransformation (hydroxylation) of the related S-containing carboxylic acids identified previously in a less polar OSPW fraction. The environmental risks, corrosivity and oil flow assurance effects should be easier to assess, given that partial structures are now known, although further identification is still needed

Characterisation and determination of fullerenes: a critical review

A prominent sector of nanotechnology is occupied by a class of carbon-based nanoparticles known as fullerenes. Fullerene particle size and shape impact in how easily these particles are transported into and throughout the environment and living tissues. Currently, there is a lack of adequate methodology for their size and shape characterisation, identification and quantitative detection in environmental and biological samples. The most commonly used methods for their size measurements (aggregation, size distribution, shape, etc.), the effect of sampling and sample treatment on these characteristics and the analytical methods proposed for their determination in complex matrices are discussed in this review. For the characterisation and analysis of fullerenes in real samples, different analytical techniques including microscopy, spectroscopy, flow field-flow fractionation, electrophoresis, light scattering, liquid chromatography and mass spectrometry have been reported. The existing limitations and knowledge gaps in the use of these techniques are discussed and the necessity to hyphenate complementary ones for the accurate characterisation, identification and quantitation of these nanoparticles is highlighted

Hand-disinfectant alcoholic vapors in incubators

La désinfection des mains avant d'effectuer des soins est un acte indispensable en médecine clinique pour limiter le risque de transmission de germes. Après utilisation des produits désinfectants mis à disposition dans les services de soins, il se dégage une odeur alcoolique forte et désagréable, liée directement aux alcools antimicrobiens des solutions. Une étude a montré qu'une exposition aiguë et brève aux vapeurs d'éthanol et isopropanol chez des enfants prématurés pouvait être mise en relation avec des changements hémodynamiques au niveau de la zone olfactive orbito-frontale [1]. Aucune norme réglementant les concentrations de vapeurs d'éthanol ou isopropanol auxquelles les nouveau-nés peuvent être exposés n'existe. Cette thèse avait pour but d'étudier l'exposition des nouveaux nés soignés dans des incubateurs à des vapeurs d'alcool (éthanol et isopropanol). Elle était composée de 2 parties qui ont été publiées dans 2 articles différents et qui représentent le travail de doctorat [2-3]. La 1ère partie était une étude observationnelle d'une série de cas [2], Des mesures des concentrations des vapeurs d'alcool ont été effectuées auprès de 9 nouveau-nés soignés dans des incubateurs de même modèle au sein de l'unité de néonatologie du Centre Hospitalier Universitaire Vaudois à Lausanne. Sur 4 heures, les concentrations instantanées et moyennes ont été mesurées par deux techniques (photoionisation et respectivement chromatographic après absorption sur charbon actif). Onze analyses ont été effectuées en 2004-2005. Elles ont révélé des taux très variables d'éthanol et d'isopropanol dans les incubateurs (avec des valeurs maximales de 1982 ppm pour l'isopropanol et 906 ppm pour l'éthanol) correspondant aux introduction de mains fraîchement désinfectées dans les isolettes. Les concentrations moyennes variaient entre 9.8 ppm et plus de 61 ppm pour l'éthanol et &lt; 0.01 ppm et 119 ppm pour l'isopropanol. La 2e partie a été réalisée en collaboration avec le PD Dr D. Vernez de l'Institut Universitaire Romand de Santé au Travail [3], Un modèle théorique prédictif des concentrations alcooliques dans des incubateurs pour nouveau-nés a été développé. Des séries de mesures standardisées des variations des concentrations alcooliques dans un incubateur sans patient ont été effectuées en changeant trois variables: 1) le renouvellement de l'air dans l'incubateur en variant le nombre de portes ouvertes, 2) la quantité de solution alcoolique versée sur les mains avant de les introduire dans l'incubateur 3) le temps de séchage des mains après désinfection et avant de les introduire dans l'incubateur. La modélisation a permis de décrire la cinétique des concentrations d'alcool dans les incubateurs et d'évaluer les pistes potentielles pour diminuer les risques d'exposition des nouveau-nés à ces vapeurs dans leurs incubateurs. En conclusion, la 1 ère partie a mis en évidence, pour la première fois, que des nouveau- nés soignés en incubateurs peuvent être exposés à des vapeurs d'alcool. Comme il η y a aucune norme d'exposition pour cette population et que les seules limites d'exposition existantes sont destinées à des travailleurs adultes, aucune conclusion précise ne peut être avancée sur les risques toxicologiques. L'exposition à des vapeurs polluantes d'un nouveau-né à terme ou prématuré, en plein développement neuro-sensoriel, devrait toutefois, à priori, être évitée. La 2ème partie permet de proposer des pistes pratiques pour diminuer les concentrations des vapeurs d'alcool dans les incubateurs: respecter le temps de séchage des mains après leur désinfection et avant de les introduire dans les isolettes et/ou préférer un désinfectant alcoolique à faible temps d'évaporation

A Gas Sensor for the Selective Detection of Volatile Organic Compounds

Volatile Organic Compounds (VOCs) are an important class of air pollutant because many of them are harmful to human health. VOCs are typically present at very low concentrations – parts-per-billion (ppb) and lower – which makes their detection a significant challenge. Standard measurement techniques, such as Gas Chromatography (GC), are typically sensitive and selective, but are limited by their large size, high cost and complexity to operate. Such factors restrict deployment for practical applications, including measurement across air quality networks. In contrast, gas sensors are typically small, inexpensive and easily deployed, but are limited by poor selectivity. This work aims to establish the extent to which gas sensors can be used to achieve sensitive and selective detection of VOCs. Based on the processes of adsorption and desorption, it examines how temperature control of functionalised silica adsorbents can be used to produce discriminable signals of VOCs. In this context, the VOCs of interest were benzene, toluene, ethyl benzene, para-xylene (BTEX), due to their proven toxicity and prevalence in human environments. With the aim of producing a potentially deployable device, a novel sensing platform was designed and constructed. The main features of this Adsorption Device were an aluminium channel, a peltier module heating unit, flow path control and photoionisation detector (PID). In addition to unmodified silica, this thesis presents six modified silica adsorbents with amino, chloro, (n8) alkyl, fluoroalkyl, phenyl and chlorophenyl functionality. Analysis of BTEX vapours with the seven silica adsorbents indicated adsorption was physical (physisorption) and desorption was readily reversible between 25 and 100 °C. Adsorption was influenced by the strength of adsorbent-vapour interaction, which could be increased by introducing delocalised electron density (phenyl and chlorophenyl silica), but modification could not compensate for any significant loss of surface area and pore volume that occurred. PID responses during adsorption and desorption were found to be discriminable from each other. Vapour desorption was examined with different heating profiles, which were found to initiate distinct response patterns. Principle Component Analysis (PCA) of Adsorption Device data indicated that the responses were sufficiently discriminable that they could be offer a means of vapour selectivity. Tests of the Adsorption Device indicate that selective detection of individual and dual component BTEX vapours is achievable in the ppb concentration range and with a cycle time of 10 minutes. Classification algorithms based on the Adsorption Device output were found to be at least as accurate as previously published research. This work presents significant progress towards to the development of a selective and practical sensor for air quality applications

Rapid continuous chemical analysis of meat chicken shed emissions by SIFT–MS

Assessing and addressing odour impacts from poultry production is extremely difficult and subjective because the odorants involved and their dynamics over time and space are poorly understood. This knowledge gap is due, in part, to the lack of suitable analytical tools for measuring and monitoring odorants in the field. The emergence of Selected Ion Flow Tube – Mass Spectrometry (SIFT–MS) and similar instruments is changing that. These tools can rapidly quantify targeted odorants in ambient air in real time, even at very low concentrations. Such data is essential for developing better odour abatement strategies, assessment methods and odour dispersion models. This project trialled a SIFT–MS to determine its suitability for assessing the odorants in meat chicken shed emissions over time and space. This report details evaluations in New Zealand and Australia to determine the potential of SIFT–MS as a tool for the chicken meat industry, including odour measurement (as a proxy for dynamic olfactometry). The report is specifically targeted at those funding and conducting poultry odour research. It will be of interest to those involved with environmental odour monitoring and assessment in general. The high upfront cost of SIFT–MS will lead to potential users wanting compelling evidence that SIFT–MS will meet their needs before they invest in one

Chloride-attachment atmospheric pressure photoionisation for the determination of short-chain chlorinated paraffins by gas chromatography-high-resolution mass spectrometry

In this work, a new gas chromatography-high-resolution mass spectrometry (GC-HRMS) method based on atmospheric pressure photoionisation (APPI) has been developed for the accurate determination of short-chain chlorinated paraffins (SCCPs) as a reliable alternative to the established methods. To the best of our knowledge, this is the first time these compounds has been analysed by GC-MS using atmospheric pressure photoionisation (APPI). Efficient ionisation of SCCPs was achieved using the new GC-APPI source by the formation of [MþCl]e adduct ions in negative ion mode using dopant-assisted APPI with a mixture of acetone/CCl4 (3:1, v/v). Operating at a resolution of 70,000 FWHM (full width at half maximum) and monitoring the [MþCl]e adduct ions for each congener group, a selective determination of the SCCPs was achieved, avoiding isobaric interferences between homologue groups with different carbon chain length and chlorination degree. Moreover, the GC-APPI-HRMS response of each congener group was mainly influenced by its concentration and did not depend on the number of chlorine atoms in the molecule as occurs with the GC-MS methods based on the electron-capture negative ionisation (ECNI). Thus, the contribution of the different carbon and chlorine homologue groups in the SCCP mixtures was determined by the internal normalization method, and the quantification was performed independently of the chlorine content of the SCCP standard mixture employed. The developed GC-APPI-HRMS method offers some interesting advantages over the existing methods, particularly the possibility to quantify individual SCCP congener groups, the use of a simple calibration method for quantification, and an important timesaving in the data processing, especially over ECNI-based traditional methods. The GC-APPI-HRMS method allowed the determination of SCCPs at low concentration levels in fish samples with lowmethod limits of detection (17e34 pg g1 wet weight for total SCCPs), good precision (RSD < 7%) and trueness (relative error < 8%) and can be proposed as a reliable alternative of the established methods for the determination of these pollutants in environmental sample