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Planar Chromatography Applications in Veterinary Toxicology
Published in Bernard Fried, Joseph Sherma, Practical Thin-Layer Chromatography, 2017
The bait, stomach contents, or liver can be extracted by solubilizing the analyte in acetonitrile and acid (dilute).1 The extract can be defatted with solvent (when acidic) without loss of alkaloid. Then the extract is made basic and the free base is extracted into organic solvent. Care must be taken not to lose Avitrol® or nicotine-volatile alkaloids and to cause decomposition of strychnine and other more complex alkaloids. Urine and blood samples may be used also to determine exposure in acute toxicity.
Effects of propylene glycol, vegetable glycerin, and nicotine on emissions and dynamics of electronic cigarette aerosols
Published in Aerosol Science and Technology, 2020
Liqiao Li, Eon S. Lee, Charlene Nguyen, Yifang Zhu
PG and VG could undergo thermal degradation when in contact with the heating coil of the e-cig atomizer to form a significant amount of volatile carbonyl compounds, such as formaldehyde, acetaldehyde, acrolein and acetone (Geiss, Bianchi, and Barrero-Moreno 2016; Kosmider et al. 2018; Ogunwale et al. 2017; Sleiman et al. 2016). PG is more susceptible to thermal decomposition than VG, leading to more volatile carbonyls generated from PG-based e-liquids (Kosmider et al. 2014). With greater nicotine content in the e-liquid, however, lower levels of these carbonyls are generated potentially reducing the volatility of e-cig aerosols (Kosmider et al. 2018). On the other hand, under certain temperature and oxidative conditions and in the presence of metals, these carbonyls might further degrade to acidic products that can protonate the nitrogen on the pyrrolidine ring in nicotine when the e-liquid is aerosolized (Liang and Pankow 1996; Rossiter et al. 1985). Compared to VG-based e-liquids, PG-based e-liquids with lower pH could facilitate the formation of the protonated nicotine with lower volatility than the free-base nicotine in the e-cig aerosol (El-Hellani et al. 2015; Son et al. 2018). Consequently, depending on the chemistry and rate at which these possible acidic degradation compounds can form in the aerosol, nicotine may interact more strongly with these acidic products causing the particle volatility to decrease (Jensen, Strongin, and Peyton 2017).
Spectroscopic studies of water-soluble superstructured iron(III) porphyrin. Interaction with the bovine serum albumin protein
Published in Journal of Coordination Chemistry, 2018
Hermas R. Jiménez, María Arbona
The “one-face” hindered sulfonated porphyrin, e-HSP(C12), was prepared as reported [45]. Anaerobic insertion of iron into the free base porphyrins was accomplished using iron(II) sulfate in water under reflux in the presence of sodium bicarbonate [45]. Bovine serum albumin (fraction V powder minimum 97% pure) was purchased from Sigma. All other reagents were analytical grade chemicals, purchased from Aldrich and Merck. Water was bidistilled before use. The concentrations of metalloporphyrin were measured spectrophotometrically using the extinction coefficient described previously (ε = 70.0 mM−1 cm−1 at 397 nm, pH 3, 25 °C) [45]. All the measurements were carried out with 0.1 M KNO3 as the background electrolyte under the same conditions in which the molar extinction coefficients of the metalloporphyrin has been determined. D2O (99.9%) was obtained from SDS Chemical. Sample concentrations for 1-D and 2-D 1H NMR were 3 to 6 mM of the metalloporphyrin dissolved in D2O or in 90% H2O/10% D2O.
Volatilization and partitioning of residual electronic cigarette emissions to particulate matter
Published in Aerosol Science and Technology, 2023
Henry J. Colby, Erin F. Katz, Peter F. DeCarlo
Experiments with both the JUUL and tank-based e-cigs demonstrated re-volatilization and partitioning to AS aerosol particles in all tests performed, indicating the importance of this mechanism for secondary exposure to e-cigarette effluent in the indoor environment. This is true despite the low fraction of free-base nicotine in JUUL vape. For JUUL experiments, both the primary vape signature and that of the partitioned aerosol showed similar chemical distributions, although the relative magnitude of several m/z differ (Figure 2). The two species clearly absent in the partitioned spectra are BA and cadmium. It was expected that BA would deposit to and remain on surfaces because of its negligible vapor pressure in the ionic benzoate form and thus would not be detected in the evaporated residue. Metals species are difficult to measure due to the use of thermal vaporization at 600 °C and many metal species will not have sufficient vapor pressure at that temperature to be measured in the gas phase. Cadmium, on the other hand, has relatively low melting and boiling points (321 and 767 °C, respectively) and is the likely reason it can be detected. Attempts to identify other metal species were inconclusive due to either mass spectral interferences or the refractory nature of the metal species. Other studies focused on metal detection have found varying concentrations of metals in e-cig (including JUUL) vape (Gaur and Agnihotri 2019; Zhao et al. 2019; Neu et al. 2020). The absence of cadmium from the evaporated residue is also expected since it is solid at room temperature and will remain on surfaces to which the primary particles deposit.