Occurrence and toxicity of disinfection byproducts in European drinking waters in relation with the HIWATE epidemiology study.

The HIWATE (Health Impacts of long-term exposure to disinfection byproducts in drinking WATEr) project was a systematic analysis that combined the epidemiology on adverse pregnancy outcomes and other health effects with long-term exposure to low levels of drinking water disinfection byproducts (DBPs) in the European Union. The present study focused on the relationship of the occurrence and concentration of DBPs with in vitro mammalian cell toxicity. Eleven drinking water samples were collected from five European countries. Each sampling location corresponded with an epidemiological study for the HIWATE program. Over 90 DBPs were identified; the range in the number of DBPs and their levels reflected the diverse collection sites, different disinfection processes, and the different characteristics of the source waters. For each sampling site, chronic mammalian cell cytotoxicity correlated highly with the numbers of DBPs identified and the levels of DBP chemical classes. Although there was a clear difference in the genotoxic responses among the drinking waters, these data did not correlate as well with the chemical analyses. Thus, the agents responsible for the genomic DNA damage observed in the HIWATE samples may be due to unresolved associations of combinations of identified DBPs, unknown emerging DBPs that were not identified, or other toxic water contaminants. This study represents the first to integrate quantitative in vitro toxicological data with analytical chemistry and human epidemiologic outcomes for drinking water DBPs.

The stereoisomers of menthol in selected tobacco products. A brief report.

INTRODUCTION: Menthol has long been an important flavorant in tobacco products, and both its historical and present uses are topics of increasing debate. Menthol can exist in eight different stereoisomeric forms (as four enantiomeric pairs) that possess different sensory properties. As regards use in tobacco products, the open scientific literature and available industry documents focus on the D-menthol and l-menthol enantiomeric pair, and in particular on l-menthol, but are ambiguous about the actual importance of D-menthol in tobacco products. This study provides the first openly available measurements regarding the stereoisomeric forms of menthol as found in selected United States sub-brands of smokeless tobacco (SLT), cigarettes, and cigarette smoke. METHODS: Gas chromatography/mass spectrometry (GC/MS) was applied using a "chiral" GC column to separate and determine the forms of menthol present in headspace air above various samples of United States sub-brands of SLT, cigarette filler material, and cigarette smoke particulate matter. Additional GC × GC/Time-of-flight mass spectrometry measurements were also made. RESULTS: The dominant form of menthol by far in any of the samples was l-menthol. CONCLUSIONS: For the selected cigarettes and SLT products tested from the U.S. market, the only form of menthol found was l-menthol. Other forms may be present in products that were not tested. No evidence was found of thermal racemization upon smoking of l-menthol to a d+l mixture.

Determination of cortisol production rates with contemporary liquid chromatography-mass spectrometry to measure cortisol-d(3) dilution after infusion of deuterated tracer.

OBJECTIVES: Measurement of 24-h cortisol production rate (CPR) using steady-state infusion of deuterated cortisol and analysis of stable-isotope dilution by MS is a valuable tool to examine hypothalamic-pituitary-adrenal axis activity in humans. We have developed and validated an improved method for measuring cortisol dilution with contemporary LC-MS technology. DESIGN AND METHODS: Plasma samples and calibrators were extracted with ethylacetate. LC-MS was performed with a Surveyor HPLC and TSQ Quantum triple-quadrupole mass spectrometer equipped with an atmospheric pressure chemical ionization (APCI) source. RESULTS: Selectivity was improved over previous methods via elimination of an interferent identified as 20ß-dihydrocortisol. The LLOQ for cortisol-d(3) was 2.73nmol/L and LOD 1.37nmol/L. Plasma calibrators were linear over the concentration range 1.5-10% cortisol-d(3), with correlation coefficients >0.995. CONCLUSIONS: This APCI LC-MS method offers simplified sample work-up and analysis and enables selective detection of the low concentration of cortisol-d(3) infused for determination of 24-h CPR.

Tobacco smoke particulate matter chemistry by NMR.

The submicron liquid droplets constituting the particulate matter of mainstream tobacco smoke (PMMTS) are viscous and of a composition that is complex and poorly understood. PMMTS is often approximately 80% w/w 'tar' where 'tar'=total PMMTS- (nicotine+water). Many of the chemical agents in MTS responsible for smoking-related cancers are found at least partially in the PMMTS portion of MTS. The properties of PMMTS vary with brand and with puffing patterns. The chemical forms and total levels of nicotine, the identities/levels of other compositionally dominant compounds, and the identities/levels of carcinogens are of interest. Most studies of the composition of PMMTS have involved extraction then chromatography. Such methods allow the determination of low-level constituents, but alter the samples such that direct information regarding chemical conditions within the PMMTS cannot be obtained. Here, we utilize nuclear magnetic resonance spectroscopy (NMR) to examine native PMMTS in conventional cigarettes, including measurements of the brand-dependent fraction of PMMTS nicotine that is in the free-base form (increasing this fraction in inhaled tobacco smoke affects the rates of the processes governing nicotine deposition in the respiratory tract, and so has implications for smoking behavior and addiction). We also demonstrate the use of NMR for characterizing the composition of PMMTS (including the levels of selected cigarette additives) when the cosolvent DMSO-d6 is added to improve spectral resolution. The native and solvent-assisted results open the door to a range of future studies.

Delivery levels and behavior of 1,3-butadiene, acrylonitrile, benzene, and other toxic volatile organic compounds in mainstream tobacco smoke from two brands of commercial cigarettes.

Mainstream tobacco smoke (MTS) was collected from Camel and Marlboro cigarettes for the determination of the delivery levels and equilibrium gas/particle partitioning constants K(p) (m(3) microg(-)(1)) of 26 volatile organic compounds (VOCs) of toxicological interest. K(p) values are important for understanding the fractional distribution of each compound of interest between the gas and the particle phases of MTS. The experimental method involved (i) drawing a smoke sample into a Teflon sampling bag at 20 degrees C, (ii) allowing the smoke particulate matter (PM) to collect on the walls of the bag, (iii) sampling the bag to determine the initial gas phase concentration of each VOC, (iv) removing the gas phase from the bag, (v) refilling the bag with humidified nitrogen gas, (vi) reestablishing the gas/PM equilibrium, and (vii) redetermining the gas phase concentrations. For each smoke sample, a comparison of the initial and redetermined gas phase concentrations allowed calculation of the total (i.e., gas + particle) delivery level (= m(tot), ng cig(-)(1)) and K(p) value (= c(p)/c(g)) at 20 degrees C for each compound, where c(p) (ng microg(-)(1)) = concentration in the PM phase and c(g) (ng m(-)(3)) = concentration in the gas phase. Significant deliveries were observed for a number of carcinogenic VOCs. For the Camel cigarettes tested, the average m(tot) values for 1,3-butadiene, acrylonitrile, and benzene were 10(4.6), 10(4.4), and 10(4.8) ng cig(-)(1), respectively; for Marlboro, the m(tot) values were 10(5.0), 10(4.6), and 10(4.7) ng cig(-)(1), respectively. For each of the 26 VOCs, the smoke PM from the two brands yielded very similar K(p) values at 20 degrees C. In addition, the vapor pressure-dependent K(p) values of the 26 VOCs were in close agreement with predictions made by the Pankow theory of absorptive gas/particle partitioning [Pankow, J. F. (1994) Atmos. Environ. 28, 185-188]. These results can be used in general predictions of chemical behavior in tobacco smoke, including deposition mechanisms and rates in the respiratory tract from inhaled MTS. Example calculations are provided to illustrate how the gas phase fraction at equilibrium (f(g,e)) increases strongly with increasing compound vapor pressure and temperature and with dilution of the inhaled tobacco smoke total PM concentration (microg m(-)(3)).

Association of 24-hour cortisol production rates, cortisol-binding globulin, and plasma-free cortisol levels with body composition, leptin levels, and aging in adult men and women.

The present study was designed to examine the hypothesis that hypothalamic-pituitary-adrenal axis activity as measured by 24-h cortisol production rate (CPR) and plasma levels of free cortisol is linked to increased body fat in adults, and that increased cortisol levels with aging results from increased CPR. Fifty-four healthy men and women volunteers with a wide range of body mass indexes and ages underwent measurement of CPR by isotope dilution measured by gas chromatography-mass spectroscopy, cortisol-binding globulin, and free cortisol in pooled 24-h plasma, body composition, and leptin. Cortisol clearance rates were determined from the 10-h disappearance curves of hydrocortisone after steady-state infusion in a separate group of lean and obese subjects with adrenal insufficiency. Although CPR significantly increased with increasing body mass index and percentage body fat, free cortisol levels remained independent of body composition and leptin levels due to increased cortisol clearance rates. CPR and free cortisol levels were, however, significantly higher in men than women. In addition, 24-h plasma free cortisol levels were increased with age in association with increased CPR, independent of body size. This increase in hypothalamic-pituitary-adrenal axis activity may play a role in the alterations in body composition and central fat distribution in men vs. women and with aging.

Percent free base nicotine in the tobacco smoke particulate matter of selected commercial and reference cigarettes.

The available evidence suggests that most of the nicotine in mainstream tobacco smoke is in the smoke particle matter (PM) phase. Nicotine can exist in protonated and free base forms in the smoke PM, and alpha(fb) is the fraction of the PM nicotine that is in the free base form. Because only the free base form can volatilize from the smoke PM phase to the gas phase of an inhaled aerosol and because gaseous nicotine deposits rapidly in the respiratory tract (RT), the magnitude and rate of nicotine deposition in the RT will depend on alpha(fb). The types of values that alpha(fb) can assume in the PM of cigarette smoke aerosols have not been well-known. The conventional view has been that mainstream cigarette smoke PM contains relatively little free base nicotine so that the cigarette smoker must absorb nicotine mostly from deposited particles. A prior study concluded that because cigarette smoke is at "pH 5.3", there is very little free base nicotine in such smoke. A 1994 internal tobacco company document discusses the view that "smoke pH" values for cigarette smoke are "approximately 6.0". This work uses volatility-based measurements to provide determinations of equilibrium nicotine alpha(fb) values for mainstream smoke PM from selected cigarettes. The effective pH (i.e., pH(eff)) of the smoke PM from selected brands of commercial cigarettes was found to span a range of 6.0-7.8 (nicotine alpha(fb) = 0.01-0.36), with all pH(eff) values much larger than 5.3 and most larger than 6.0.