Todd Pagano

Determination of Nicotine Content and Delivery in Disposable Electronic Cigarettes Available in the United States by Gas Chromatography-Mass Spectrometry

INTRODUCTION Electronic cigarettes (E-Cigs) are popular alternatives to conventional tobacco cigarettes. Disposable E-Cigs are single-use devices that emit aerosols from a nicotine-containing solution (e-liquid) by activating a heating coil during puffing. However, due to lack of regulations and standards, it is unclear how product claims are aligning with actual content and performance. Some analytical methods for characterizing E-Cigs are still in an exploratory phase. METHODS Five products of disposable E-Cigs (purchased March-April, 2014 from a local smoke shop and an on-line US distributor) were studied for nicotine content, number of puffs obtained before depletion, portion of nicotine delivered via aerosolization, and e-liquid pH. Protocols were developed to consistently extract e-liquid from puffed and unpuffed E-Cigs. An in-house mechanical puffing machine was used to consistently puff E-Cig aerosols onto filter pads. A gas chromatography-mass spectrometry method was developed that produced sensitive and repeatable nicotine determinations. RESULTS Under our experimental parameters, results showed a disparity between nicotine content and number of puffs achieved relative to what was claimed on product packaging. The portion of nicotine delivered to filter pads was often less than half that which was available, indicating much of the nicotine may be left in the E-Cig upon depletion. CONCLUSIONS Analyses of unpuffed E-Cigs by gas chromatography-mass spectrometry indicate the nicotine content of these products can be considerably different from manufactures labeling. Furthermore, a large portion of the nicotine in E-Cigs may not be transferred to the user, and that which is transferred, may often be in the less bioavailable form.

The Value of Native and Invasive Fruit-Bearing Shrubs for Migrating Songbirds

Abstract The success of annual migrations for songbirds is greatly affected by habitat quality at stopover sites, particularly in relation to food needed for rapid refueling. The abundance and nutritional quality of important food resources may be linked to the presence of deciduous shrub species that provide seasonal fruits in the fall and support insects in the spring. The objective of this study was to determine whether migrating songbirds benefit from resources provided by native or invasive fruit-bearing shrubs found at 2 bird-banding stations in Rochester, NY. We conducted nutritional analyses (energy density, fat content, total soluble solids) on the fruits of common shrub species at the study sites, monitored removal of the fall fruits of focal native and invasive shrub species in the field, and measured the abundance of midges—a common insect resource for migrating songbirds— supported by the focal shrub species in the spring. The highest fat content and energy densities were found in fruits of native shrubs, ranging from 6.57 to 48.72% fat and 18.83 to 28.68 kJ/g of energy. All invasive fruits had ≤0.99% fat and ≤17.17 kJ/g of energy. We also found a significant positive correlation between fat and energy content of the fruits. Native dogwood fruits were consumed by migrating songbirds at higher rates than invasive fruits over the fall migration period. However, there was no clear pattern of midge abundance between native and invasive shrub species during the spring migration period. Our results suggest that fruits of native shrubs are of greater nutritional value to migrating songbirds than the fruits of invasive shrubs during fall migration, which is supported by the higher removal rates by songbirds of native dogwood fruits than fruits of the 4 other invasive fruit species. This finding suggests that removal of invasive fruit-bearing shrubs or plants will not negatively impact migrating birds when high-quality native fruit-bearing shrubs are available. However, additional study on the relative value of these shrubs in the spring and over multiple seasons is needed to provide insight into their overall value for birds during annual migrations.

Multidimensional fluorescence studies of the phenolic content of dissolved organic carbon in humic substances

Indicators suggest that the amount of dissolved organic carbon (DOC) in natural waters may be increasing. Climate change has been proposed as a potential contributor to the trend, and under such a mechanism, the phenolic content of DOC may also be increasing. This study explores the assessment of the phenolic character of DOC using multidimensional fluorescence spectroscopy as a more convenient alternative to traditional wet chemistry methods. Parallel factor analysis (PARAFAC) is applied to fluorescence excitation emission matrices (EEMs) of humic samples to analyze inherent phenolic content. The PARAFAC results are correlated with phenol concentrations derived from the Folin-Ciocalteau reagent-based method. The reagent-based method reveals that the phenolic content of five International Humic Substance Society (IHSS) samples varies from approximately 5.2 to 22 ppm Tannic Acid Equivalents (TAE). A four-component PARAFAC fit is applied to the EEMs of the IHSS sample dataset and it is determined by PARAFAC score correlations with phenol concentrations from the reagent-based method that components C2, C3, and C4 have the highest probability of containing phenolic groups. The results show the potential for PARAFAC analysis of multidimensional fluorescence data for monitoring the phenolic content of DOC.

Nitrogen Gas Purging for the Deoxygenation of Polyaromatic Hydrocarbon Solutions in Cyclohexane for Routine Fluorescence Analysis

During routine fluorescence analysis, the presence of dissolved oxygen in solutions can result in the dynamic quenching of a fluorophores emission through collisional deexcitation of the fluorophores excited state. In order to avoid this type of fluorescence quenching, dissolved oxygen is often removed from solutions by an inert gas purging procedure. However, the details and quantification of this purging process are often limited in fluorescence studies. In this work, standard 10 mm × 10 mm fluorescence cuvettes are filled with polyaromatic hydrocarbon (PAH) solutions in cyclohexane and purged using nitrogen gas, and the experimental purging parameters (nitrogen flow rate, amount of volatile solvent loss, and rate of oxygen removal) are measured and analyzed. For experimental conditions similar to those used in this study, we are able to provide useful guidelines for the deoxygenation of solutions, specifically the purge times required for solutions of fluorophores with various fluorescence lifetimes. Enhancement factors, or F0/F values (the ratio of fluorescence intensity of a completely deoxygenated solution to the fluorescence intensity of an aerated solution), for chrysene, phenanthrene, naphthalene, and pyrene solutions in cyclohexane were found to be 3.61 ± 0.02, 4.17 ± 0.02, 7.63 ± 0.07, and 21.81 ± 0.35, respectively.

Qualitative Analysis of E-Liquid Emissions as a Function of Flavor Additives Using Two Aerosol Capture Methods

This work investigates emissions sampling methods employed for qualitative identification of compounds in e-liquids and their resultant aerosols to assess what capture methods may be sufficient to identify harmful and potentially harmful constituents present. Three popular e-liquid flavors (cinnamon, mango, vanilla) were analyzed using qualitative gas chromatography-mass spectrometry (GC-MS) in the un-puffed state. Each liquid was also machine-puffed under realistic-use flow rate conditions and emissions were captured using two techniques: filter pads and methanol impingers. GC-MS analysis was conducted on the emissions captured using both techniques from all three e-liquids. The e-liquid GC-MS analysis resulted in positive identification of 13 compounds from the cinnamon flavor e-liquid, 31 from mango, and 19 from vanilla, including a number of compounds observed in all e-liquid experiments. Nineteen compounds were observed in emissions which were not present in the un-puffed e-liquid. Qualitative GC-MS analysis of the emissions samples identify compounds observed in all three samples: e-liquid, impinge, and filter pads, and each subset thereof. A limited number of compounds were observed in emissions captured with impingers, but were not observed in emissions captured using filter pads; a larger number of compounds were observed on emissions collected from the filter pads, but not those captured with impingers. It is demonstrated that sampling methods have different sampling efficiencies and some compounds might be missed using only one method. It is recommended to investigate filter pads, impingers, thermal desorption tubes, and solvent extraction resins to establish robust sampling methods for emissions testing of e-cigarette emissions.

Essential oil compounds from the leaf of Eugenia samanensis Alain (Myrtaceae), a species endemic to the Samaná Peninsula, Dominican Republic

ABSTRACT Eugenia samanensis Alain is an endangered species of Myrtaceae unique to the Samaná Peninsula, Dominican Republic. We investigated its foliar essential oil (EO) composition from dried leaves, extracted via hydrodistillation, by gas chromatography-mass spectrometry (GC-MS) for identification and gas chromatography-flame ionization detection (GC-FID) for quantification. E. samanensis leaves produced an average of 1.6 ± 0.1% (w/w) EO and 23 compounds were identified, representing 98.4% of the EO composition. The EO composition consisted of 84.4% phenylpropenes, 8.9% oxygenated monoterpenes, 4.0% oxygenated sesquiterpenes, 0.4 % monoterpenes, 0.4% sesquiterpenes, and 0.25% other. The EO was richest in the phenylpropene, methyleugenol. The abundance of phenylpropenes in the EO of E. samanensis may be unique to Eugenia, suggesting the need for further research to elucidate the biological function of these compounds, to review the taxonomic status of this species, and to perform further studies to explain the high phenylpropene content of this species.

Comparative validation of amperometric and optical analyzers of dissolved oxygen: a case study

A comprehensive comparative validation for two different types of dissolved oxygen (DO) analyzers, amperometric and optical, is presented on two representative commercial DO analyzers. A number of performance characteristics were evaluated including drift, intermediate precision, accuracy of temperature compensation, accuracy of reading (under different measurement conditions), linearity, flow dependence of the reading, repeatability (reading stability), and matrix effects of dissolved salts. The matrix effects on readings in real samples were evaluated by analyzing the dependence of the reading on salt concentration (at saturation concentration of DO). The analyzers were also assessed in DO measurements of a number of natural waters. The uncertainty contributions of the main influencing parameters were estimated under different experimental conditions. It was found that the uncertainties of results for both analyzers are quite similar but the contributions of the uncertainty sources are different. Our results imply that the optical analyzer might not be as robust as is commonly assumed; however, it has better reading stability, lower stirring speed dependence, and typically requires less maintenance. On the other hand, the amperometric analyzer has a faster response and wider linear range. Both analyzers seem to have issues with the accuracy of temperature compensation. The approach described in this work will be useful to practitioners carrying out DO measurements for ensuring reliability of their measurements.