Multidimensional gas chromatographic determination of cotinine as a marker compound for particulate-phase environmental tobacco smoke

Multidimensional gas chromatographic analysis of air particles for the tobacco alkaloid cotinine is described. The analytical procedure requires little sample preparation. Unambiguous identification of cotinine and nicotine in cigarette smoke and indoor air samples was achieved by precise, reproducible retention times observed with two parallel analytical columns of different polarities and a nitrogen-specific detector. Further investigation of smoking and environmental variables is needed to validate the use of cotinine as a marker compound for environmental tobacco smoke particulate matter.     

Kinetic and product yield study of the heterogeneous gas-surface reaction of anthracene and ozone

Little quantitative information exists regarding the products of the heterogeneous reaction of polycyclic aromatic hydrocarbons (PAHs) and ozone. We have, therefore, performed the first quantitative study investigating the kinetics and products of the heterogeneous gas-surface reaction of anthracene and ozone as a function of ozone concentration and relative humidity (RH). The reaction exhibited pseudo-first-order kinetics for anthracene loss under dry conditions (RH < 1%) and the pseudo-first-order rate coefficients displayed a Langmuir-Hinshelwood dependence on the gas-phase ozone concentration, which yielded the following fitting parameters: the equilibrium constant for ozone adsorption, K(O3) = (2.8 +/- 0.9) x 10(-15) cm3 and the maximum pseudo-first-order rate coefficient, k(I)max = (6.4 +/- 1.8) x 10(-3) s(-1). The kinetics were unchanged when experiments were performed at approximately 50% and 60% RH. In the product study, a nonlinear dependence, similar to a Langmuir adsorption plot, of the anthraquinone product yield as a function of ozone concentration was observed and resulted in the following fitting parameters: K(O3) = (3.4 +/- 1.5) x 10(-15) cm3 and the maximum anthraquinone yield, ANQmax % = 30 +/- 18%. Experiments performed under higher relative humidity conditions ( approximately 50% and 60% RH) revealed that the anthraquinone yield was unaffected by the presence of gas-phase water. It is noteworthy that both the anthracene loss kinetics and the anthraquinone yields have a similar dependence on the degree of ozone partitioning to the surface. This can be understood in terms of a mechanism whereby the rate-determining steps for anthracene loss and anthraquinone formation are both driven by the amounts of ozone adsorbed on the surface. Our results suggest that at atmospherically relevant ozone concentrations (100 ppb) the anthraquinone yield from the ozonolysis of anthracene under dry and high relative humidity conditions would be less than 1%.     

Simultaneous determination of nicotine and 3-vinylpyridine in single cigarette tobacco smoke and in indoor air using direct extraction to solid phase

The aim of the present study was to develop a new analytical method of chromatographic determination of two important markers of ETS exposure: nicotine and 3-vinylpyridine (3-ethenylpyridine, 3-EP) in mainstream (MS) and sidestream (SS) smoke of one single cigarette and in indoor air using direct solid phase extraction combined with gas chromatography. The method can be utilised for both nicotine and 3-EP determination in SS and MS of one single cigarette as well as it allows for a precise determination of compound distribution in indoor air. The application of the same analytical method for both kinds of samples allows anticipating indoor air distribution of both analysed compounds in a very precise way. The precision of the method (calculated as a relative standard deviation) was 9.78% for nicotine and 2.67% for 3-EP; whereas the accuracy (evaluated by a recovery study conducted at three different levels) was 70.1 and 87.3%, respectively. The limit of detection was 0.06 µg per cigarette for both nicotine and 3-EP. The method was evaluated by determining the compounds of interest in two commercially available brands of cigarettes as well as in the reference cigarettes 3R4F and also in indoor air polluted with tobacco smoke. Determined levels of compounds of interest in MS varied from 586 to 772 (nicotine) µg per cigarette and from 3.5 to 10.7 (3-EP) µg per cigarette. In SS smoke the level varied from 14,370 to 22,590 (nicotine) µg per cigarette and from 185 to 550 (3-EP) µg per cigarette, whereas levels in indoor air polluted with tobacco smoke varied from 50.1 to 157.3 (nicotine) µg m^?3and from 7.7 to 20.8 (3-EP) µg m^?3.     

Optimization of HPLC-APCI-MS conditions for the qualitative and quantitative determination of total solanesol in tobacco leaves

HPLC coupled online with atmospheric pressure chemical ionization MS (APCI-MS) technique was evaluated for the qualitative and quantitative determination of solanesol in extracts of tobacco leaves. The solanesol and other compounds in the extract were separated on an Alltima C(8) (4.6 mm x 250 mm) column with methanol and water (98:2 v/v) as mobile phase, with flow rate of 0.8 mL/min and UV detection wavelength of 211 nm. In the APCI(+) mode, abundant stable [M-H(2)O + H](+) ion (m/z at 613.5) was observed, with low abundance of other fragmentation ions. A comparison of APCI-MS and ESI-MS techniques showed that APCI mode is more sensitive than ESI mode, and thus better suited for solanesol analysis. When comparing UV 211 nm and APCI-MS in SIM for solanesol quantification, the former offered better precision and reproducibility, but the latter was more than 200 times sensitive in detection. The developed method has been successfully applied to the analysis and comparison of solanesol concentration in different tobacco leaf samples.     

Evaluation of indoor exposition to benzene, toluene, ethylbenzene, xylene, and styrene by passive sampling with a solid-phase microextraction device

A solid-phase microextraction (SPME) sampling method is developed to evaluate indoor exposure to benzene, toluene, ethylbenzene, xylene, and styrene with gas chromatography and flame ionization detection for quantitative analysis. An SPME holder with a 100-pm polydimethylsiloxane (PDMS) and 65-pm PDMS-divinylbenzene fiber coating is tested in different air relative humidity conditions. The method gives good resolution, shows a linear response, is repeatable, and presents high sensitivity. This method is compared with National Institute of Occupational Safety and Health (NIOSH) active sampling.     

Measurements Of Biogenic Hydrocarbons And Their Atmospheric Degradation In Forests

Abstract

An analytical procedure for the sampling and quantitative determination of biogenic hydrocarbons in the atmosphere is presented. The method is based on the adsorptive preconcentration of the hydrocarbons using Tenax TA/Carbopack B filled sampling tubes followed by thermodesorption of the trapped compounds and gas chromatographic analysis. To avoid losses of the biogenic alkenes as a consequence of their reaction with ozone on the adsorbents during the sampling step, an ozone scrubber is used in front of the adsorption tubes. Diurnal variations of the monoterpene- and ozone-concentrations are determined at different heights in and above a forest stand (coniferous and deciduous trees) in the Vosges (Col du Donon, 760 m a.s.l.) in order to elucidate the importance of terpene-oxidation reactions on the formation of peroxidic products in forest air.     

Microwave-assisted extraction of solanesol from tobacco leaves

Solanesol is the starting material for many high-value biochemicals, including co-enzyme Q10 and Vitamin K analogues. In the present study, a microwave-assisted extraction (MAE) technique has been developed for the fast extraction of solanesol from tobacco leaves. Compared to heat-reflux extraction, MAE reduced extraction time and obtained higher percentage extracted of solanesol. The effect of microwave on cell destruction of plant material was observed by scanning electron microscopy (SEM). The microwave-assisted extraction efficiency was further improved by adding NaOH into the extraction solvent, and the maximum percentage extracted of solanesol reached 0.91% (weight solanesol/weight tobacco) in 40 min at an optimum NaOH concentration of 0.05 M. The developed MAE integrated with saponification process provided an efficient method for solanesol recovery from tobacco leaf materials, and it also alleviated emulsification in the following separation and purification procedure as well.     

Determination of particle-associated hydroxynitropyrenes with correction for chemical degradation on a quartz fibre filter during high volume air sampling

A correction method for the determination of atmospheric monohydroxylated derivatives of 1-nitropyrene (hydroxy-1-nitropyrenes, OHNPs) based on their degradation rates during high volume air sampling was established. OHNPs adsorbed directly on a quartz fibre filter (QFF) or on airborne particles collected on a QFF were exposed to ambient air passively or actively in a high volume air sampling system. The influence of ozone flux and exposure time on the degree of degradation of OHNPs was investigated. Up to 50% of OHNPs degraded over 1 h of exposure to ambient air containing ～60 ppbv of ozone in the active system. The degradation rate constants of OHNPs were found to correlate with the number of ozone molecules passing through the QFF in a unit time (N_O3) during high volume air sampling. The chemical loss of OHNPs under high volume air sampling conditions was successfully evaluated by the exposure time and the pseudo-first-order rate constant for OHNP degradation estimated from the correlation with N_O3. Concentrations of 3-, 6-, and 8-hydroxy-1-nitropyrenes in airborne particles collected in Osaka, Japan were determined using the established correction method.     

Measurements of ambient ozone using indigo blue-coated filters

Ozone monitoring techniques utilize expensive instruments that are often large and heavy. These instruments are not easy to handle in the field, and their size also limits some sampling schemes, principally for indoor ozone determination. We have developed a lightweight, inexpensive, and sensitive method that offers flexibility to undertake measurements of ambient ozone in many environments, both indoor and outdoor. The method is based on the reaction of ozone with indigo blue dye. The indigo molecule contains 1 carbon double bond (C = C) that reacts with ozone and results in nearly colorless reaction products. During sample collection, 2 cellulose filters coated with 40 micro of 1.0 x 10(-3) M indigo blue were used. The determinations were done spectrophotometrically at 250 and 600 nm. The analytical parameters studied were sampling time and flow rate. Analytical curves were constructed with concentrations ranging from 37 to 123 parts per billion by volume (ppbv) of standard ozone, at 0.4 L/min and 15 min sampling time. The detection limits achieved were 6 and 9 ppbv, respectively, at 250 and 600 nm. Considering interferences, measurements made at 250 nm gave more reliable and specific values for ozone.     

SPME sampling of BTEX before GC/MS analysis: examples of outdoor and indoor air quality measurements in public and private sites

This article presents the results of an exploratory application of the Solid Phase MicroExtraction (SPME) technique to the analysis of BTEX (benzene, toluene, ethylbenzene and xylenes) at the microg/m3 level in outdoor and indoor air. The salient features of the method validation are reported. As shown by the various examples of field sampling described, SPME technique appears as a method of choice for fast qualitative analysis and quantitative determination of Volatile Organic Compounds (VOC). The small dimensions of the SPME sampling system and the short sampling time let envisage its utilisation for the rapid diagnostic of outdoor and indoor air quality.     

Determination of low carboxyhemoglobin blood levels by gas chromatography

Carbon monoxide (CO) is one of the anthropogenic environmental pollutant. An essential source of this compound, especially in indoor air, is tobacco smoke, which itself contains high amount of the compound. CO from tobacco smoke states the risk not only for active smokers but also for passive ones. Carboxyhemoglobin HbCO blood level is a biomarker of exposure to CO. The aim of the study was to develop method of HbCO analysis by gas chromatography based on quantitative determination of released CO from analyzed HbCO. Before developing of the method the authors stated that the method should require only small amount of the blood for analysis and be enough sensitive to determined HbCO level in persons exposed to low concentrations of CO including passive smokers. A specific reactor for quantitative release of CO from blood sample was developed. The process of CO release was caused by internal mixing of the blood sample with releasing agent K₃[Fe(CN)₆] and stimulated by internal mixing of the blood sample with external rotating magnetic field. The method for preparing calibration solutions was developed. The method was calibrated for two ranges of HbCO concentrations (0-2.5% and 0-15%). The HbCO levels were determined in 0.15 ml blood samples taken from the finger tips of passive smokers exposed to environmental tobacco smoke with different intensities. The determined HbCO levels varied from 0.31% to 2.19% of total hemoglobin.     

Solid Phase Extraction of Solanesol

The method of solid-phase extraction (SPE) for the concentration and clean-up of tobacco extract samples during solanesol analysis was proposed in this work. A column (200 mm × 4 mm i.d.) packed with 0.10 g silica gel (with particle size of 70 μm, porosity of 0.5 and surface area of 400 m² g⁻¹) was used as SPE cartridge. Several extraction parameters, such as sample loading flow (0.3–7 mL min⁻¹), sample volume (5–50 mL), the column adsorption capacity and elution were evaluated to provide a fast, quantitative and reproducible SPE method. A mean solanesol recovery was 97.5 ± 1.6% (mean ± sd) and mean intra- and inter-day reproducibility was higher than 97%. It can be used in the analysis of solanesol in tobacco extracts.     

Fast determination of nicotine and 3-ethenylpyridine in indoor environments

Summary Different sampling and analysis techniques for the determination of gas-phase nicotine and 3-ethenylpyridine in environmental tobacco smoke are reported. Graphitized carbon traps, annular diffusion denuders, and nebulizer collectors have been used as sampling devices in combination with either thermal desorption or with water extraction. Capillary gas chromatography and ion-pair reversed-phase chromatography were applied to desorbed and liquid samples obtained in an intercomparison indoor study. The methods developed here show some advantages over existing methods in terms of analysis time, sensitivity and loading capacity.     

Potential Mitigation of Smoke Taint in Wines by Post-Harvest Ozone Treatment of Grapes

When bushfires occur near grape growing regions, vineyards can be exposed to smoke, and depending on the timing and duration of grapevine smoke exposure, fruit can become tainted. Smoke-derived volatile compounds, including volatile phenols, can impart unpleasant smoky, ashy characters to wines made from smoke-affected grapes, leading to substantial revenue losses where wines are perceivably tainted. This study investigated the potential for post-harvest ozone treatment of smoke-affected grapes to mitigate the intensity of smoke taint in wine. Merlot grapevines were exposed to smoke at ~7 days post-veraison and at harvest grapes were treated with 1 or 3 ppm of gaseous ozone (for 24 or 12 h, respectively), prior to winemaking. The concentrations of smoke taint marker compounds (i.e., free and glycosylated volatile phenols) were measured in grapes and wines to determine to what extent ozonation could mitigate the effects of grapevine exposure to smoke. The 24 h 1 ppm ozone treatment not only gave significantly lower volatile phenol and volatile phenol glycoside concentrations but also diminished the sensory perception of smoke taint in wine. Post-harvest smoke and ozone treatment of grapes suggests that ozone works more effectively when smoke-derived volatile phenols are in their free (aglycone) form, rather than glycosylated forms. Nevertheless, the collective results demonstrate the efficacy of post-harvest ozone treatment as a strategy for mitigation of smoke taint in wine.     

The spectrophotometric determination of polycyclic aromatic hydrocarbons

The determination of polycyclic aromatic hydrocarbons by elution chromatography from alumina columns followed by ultra-violet spectrophotometry has been elaborated for a more extended range of substances than has been published previously. The methods have been standardised and tables of absorption peaks are provided for easy identification of a number of compounds commonly found as traces in combustion products. Recommendations are given for the preparation of samples for determinations by this method, which has been successfully employed for the analysis of carbon blacks, soots, urban air solids, condensible smokes such as tobacco smoke, wood smoke and coal tar. thermal decomposition or pyrolysis products and other substances, such as urban vegetation, soil, tobacco, snuff, smoked food, and surface drainage water, which have been subjected to the action of smokes or other combustion products.     

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. The principle component of coating is nitrite ion, which in the presence of ozone is oxidized to nitrate ion on the filter medium and then analyzed by ion chromatography. The results from laboratory and field tests show excellent correlation between the passive method and standard ozone monitoring system, integrated over the same time period. The wind tunnel parameters that were examined show that determination of relative humidity (ranging from 30 to 80%), temperature (ranging from 10 to 20 degrees C) and wind velocity ( ranging from 0.5 to 1.5 m s(-1)) at typical ozone levels (1-40 ppb) do not influence sampler performance. The detection limit attained 0.1 ppb is adequate for the determination of ozone in indoor and outdoor areas. A statistical comparison with a reference method was done in order to demonstrate the validation of the developed method. The accuracy of the proposed method, expressed as a percent relative error, when compared with a standard reference method, is found to be better than about +/-3.5%. The standard errors of the difference was measured in terms of relative standard deviation (R.S.D.) and it was found that the R.S.D. of the passive sampler for O(3) sampler ranged from 2.0 to 6.0%.     

Disturbance of the determination of aldehydes and ketones: Structural elucidation of degradation products derived from the reaction of 2,4-dinitrophenylhydrazine (DNPH) with ozone

None of the reaction products of ozone and DNPH immobilized on solid phase support have been identified yet. However, they can interfere with the determination of carbonyl compounds in ozone containing air when analysis is performed by sampling and derivatization with DNPH coated silica cartridges. To elucidate the structure of these compounds, DNPH silica cartridges were treated with synthetic air containing defined concentrations of ozone and eluted with acetonitrile. The products were characterized by HPLC-UV/Vis and nuclear magnetic resonance (NMR) spectroscopy. Three of the degradation products were identified as 2,4-dinitrophenol, 2,4-dinitroaniline and 1,3-dinitrobenzene. The identification was confirmed by comparison with commercially available standard compounds. The other elutable products were characterized as substituted aromatic compounds. The formation of all characterized products is consistent with a radical mechanism which has been previously discussed in the literature. Received: 9 September 1998 / Revised: 9 February 1999 / Accepted: 11 February 1999     

System for the generation of standard gas mixtures of volatile and semi-volatile organic compounds for calibrations of solid-phase microextraction and other sampling devices

Standard gases are used for quality control and quality assurance, development of analysis methods and novel air sampling devices. The use of solid-phase microextraction (SPME) and other novel technologies for research in the area of air sampling and analysis requires systems/devices for reliable standard gas generation and sampling. In this paper we describe a new gas standard generating system for volatile organic compounds (VOCs) and semi-VOCs that was designed, built, and tested to facilitate fundamental and applications research with SPME. The system provided for the generation of a wide range of VOC/semi-VOC concentrations and mixing various standard gases, estimation of detection limits, testing the effects of sampling time, air temperature and relative humidity, testing the effects of air velocity and ozone on sampling/extractions. The system can be also used for calibrations of analytical instrumentation, quality control and quality assurance checks, and cross-validations of SPME with/and other sampling techniques.     

Separation of solanesol in tobacco leaves extract by slow rotary counter-current chromatography using a novel non-aqueous two-phase solvent system

Non-aqueous solvent system composed of sunflower oil-ethanol was found to be suitable for the separation of lower polarity components. Employing this solvent system, 3 g of tobacco leaves extract containing 15% solanesol was separated using a slow rotary counter-current chromatograph equipped with an 1100 mL column made of 5.7 mm I.D. convoluted PTFE tube. The separation yielded 1.5 g of yellow oily product in which solanesol occupied 26.8% determined by HPLC. The tobacco tar and other main impurities in the tobacco leaves extract were removed after slow rotary counter-current chromatographic separation. The separation processing may be developed as a technique for producing a solanesol product with food grade.     

Air sampling of aromatic hydrocarbons in the presence of ozone by solid-phase microextraction

Effects of ozone on air sampling of standard gas mixtures of aromatic hydrocarbons were tested using solid-phase microextraction (SPME). Standard concentrations of ozone ranging from 10 ppb (v/v) to 6400 ppm (v/v) were generated using an in-house built ozone generator based on corona discharge. Effects of temperature, discharge voltage, and oxygen flow on the ozone generation were tested. The working dc voltage had the greatest effect on generated ozone concentration and was proportional to the ozone concentration. Generation temperature and oxygen flow rate were inversely proportional to ozone concentrations. Produced ozone was mixed with standard benzene, toluene, ethylbenzene, and xylenes (BTEX) gas at less than 100 ppb (v/v). Air samples were collected with poly(dimethylsiloxane) (PDMS) 100 microm SPME fibers and analyzed by gas chromatography (GC)-flame ionization detection (FID) and GC-MS. Significant reductions of BTEX concentrations were observed. In addition, some products of BTEX-ozone-oxygen reactions were identified. SPME worked well as a rapid sampler for BTEX and BTEX-ozone-oxygen reaction products. No significant deterioration of the PDMS coating and no significant reduction of absorption capacity were observed after repeated exposure to ozone.