Last data update: May 06, 2024. (Total: 46732 publications since 2009)
Records 1-3 (of 3 Records) |
Query Trace: Cowan EA[original query] |
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The quantitation of squalene and squalane in bronchoalveolar lavage fluid using gas chromatography mass spectrometry
Cowan EA , Tran H , Watson CH , Blount BC , Valentín-Blasini L . Front Chem 2022 10 874373 Chemicals of unknown inhalational toxicity are present in electronic cigarette and vaping products. E-cigarettes typically contain nicotine and other relatively hydrophilic chemicals while vaping products typically contain cannabinoids and other hydrophobic chemicals. For example, vaping products can include hydrophobic terpenes such as squalane (SQA) and squalene (SQE). However, little is known about the SQA and SQE transmission from liquid to aerosol. SQA and SQE are used in commercial products that are applied dermally and ingested orally, but limited information is available on their inhalational exposure and toxicity. We developed and validated a quantitative method to measure SQE and SQA in bronchoalveolar lavage fluid to assess if these chemicals accumulate in lung epithelial lining fluid after inhalation. Calibration curves spanned a range of 0.50-30.0 µg analyte per mL bronchoalveolar lavage fluid. Recoveries were found to be 97-105% for SQE and 81-106% for SQA. Limits of detection were 0.50 μg/ml for both SQE and SQA. The method was applied to bronchoalveolar lavage fluid samples of patients from the 2019 outbreak of e-cigarette, or vaping, product use-associated lung injury (EVALI) and a comparison group. Neither SQA nor SQE was detected above the method LOD for any samples analyzed; conversely, SQA or SQE were reproducibly measured in spiked quality control BAL fluids (relative standards deviations <15% for both analytes). Further applications of this method may help to evaluate the potential toxicity of SQA and SQE chronically inhaled from EVPs. |
A gas chromatography-mass spectrometry method for quantifying squalane and squalene in aerosol emissions of electronic cigarette, or vaping, products
Cowan EA , Tran H , Gray N , Perez JJ , Watson C , Blount BC , Valentín-Blasini L . Talanta 2022 238 122985 Numerous chemicals of unknown inhalational toxicity have been measured in electronic cigarette, or vaping, products (EVPs). In addition, little is known about the liquid-to-aerosol transmission and deliveries of these chemicals, including oil-like terpenes such as squalene (SQE) and squalane (SQA). To provide information on the aerosol deliveries of these compounds from EVPs, we developed and validated a quantitative method to measure squalene and squalane in EVP aerosol emissions. Validation parameters include measurement repeatability (SQA and SQE %RSD <6%), intermediate precision (SQA: %RSD 11%, SQE: %RSD 17%), accuracy (SQA: 86-107%, SQE: 104-113%), matrix effects, method robustness, and analyte stability. Limits of detection were 6.06 ng/mL puffed air volume for both squalene and squalane. The method was used to measure squalene and squalane in aerosol emissions of 153 EVPs associated with case patients from a recent outbreak of e-cigarette, or vaping, product use associated lung injury (EVALI). The EVPs analyzed were organized into nicotine, cannabidiol, and tetrahydrocannabinol products by the percentage of nicotine, cannabidiol, and tetrahydrocannabinol in total particulate matter after vaping. In case-associated tetrahydrocannabinol products the detection rates and mean concentrations were 82.4% and 33.0 ng/mL puffed air for squalene and 4.41% and 7.80 ng/mL puffed air for squalane. |
Quantitation of urinary volatile nitrosamines from exposure to tobacco smoke
Seyler TH , Kim JG , Hodgson JA , Cowan EA , Blount BC , Wang L . J Anal Toxicol 2013 37 (4) 195-202 A sensitive and selective method was developed and validated to detect six volatile nitrosamines (N-nitrosodimethylamine, N-nitrosomethylethylamine, N-nitrosodiethylamine, N-nitrosopiperidine, N-nitrosopyrrolidine and N-nitrosomorpholine) in human urine. This method uses a liquid-liquid extraction cartridge followed by analysis with gas chromatography-tandem mass spectrometry (GC-MS-MS) and quantification based on isotopic dilution. This is the first GC-MS-MS method reported for measuring volatile nitrosamines in human urine. This method reduces the sample volume required in other methods from 5-25 to 2 mL. The limits of detection (2.62, 1.99, 2.73, 0.65, 0.25, 3.66 pg/mL, respectively) were better than existing methods, largely because of improved positive chemical ionization achieved by using ammonia gas and reducing background noise. Using nitrogen as the collision gas allowed the confirmation transition in the low mass region to be monitored. The analysis of human urine using this validated method is accurate (relative bias of 0-19%) and precise (relative standard deviation of 0.2-18% over two months of analyses). The validated method was applied to 100 urine samples and the levels of all six volatile nitrosamines were reported for the first time in urine specimens collected from smokers and nonsmokers, with smoking status determined by urinary cotinine measurement. Among 100 smokers and nonsmokers, the levels of three analytes (N-nitrosodimethylamine, N-nitrosomethylethylamine and N-nitrosopiperidine) were significantly higher in smokers than nonsmokers (p < 0.05). |
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