Identification of Volatiles by Headspace Gas Chromatography with Simultaneous Flame Ionization and Mass Spectrometric Detection

Journal of Analytical Toxicology 2013;37:573 –579 doi:10.1093/jat/bkt072 Advance Access publication September 4, 2013 Special Issue Identification of Volatiles by Headspace Gas Chromatography with Simultaneous Flame Ionization and Mass Spectrometric Detection Nicholas B. Tiscione1*, Dustin Tate Yeatman1, Xiaoqin Shan1 and Joseph H. Kahl2 1 Palm Beach County Sheriff’s Office, 3228 Gun Club Road, West Palm Beach, FL 33406, USA, and 2Miami-Dade Medical Examiner Department, 1851 NW 10th Ave., Miami, FL 33136, USA *Author to whom correspondence should be addressed. Email: Volatiles are frequently abused as inhalants. The methods used for identification are generally nonspecific if analyzed concurrently with ethanol or require an additional analytical procedure that employs mass spectrometry. A previously published technique utilizing a capillary flow technology splitter to simultaneously quantitate and confirm ethyl alcohol by flame ionization and mass spectrometric detection after headspace sampling and gas chromatographic separation was evaluated for the detection of inhalants. Methanol, isopropanol, acetone, acetaldehyde, toluene, methyl ethyl ketone, isoamyl alcohol, isobutyl alcohol, n-butyl alcohol, 1,1-difluoroethane, 1,1,1-trifluoroethane, 1,1,1,2-tetrafluoroethane (Norflurane, HFC134a), chloroethane, trichlorofluoromethane (Freonw-11), dichlorodifluoromethane (Freonw-12), dichlorofluoromethane (Freonw-21), chlorodifluoromethane (Freonw-22) and 1,2-dichlorotetrafluoroethane (Freonw-114) were validated for qualitative identification by this method. The validation for qualitative identification included evaluation of matrix effects, sensitivity, carryover, specificity, repeatability and ruggedness/robustness. Introduction Volatile organic compounds (VOCs) are commonly used as propellants in compressed air duster products and as solvents in other household and commercial products such as varnish, nail polish, glue, paint stripper and degreaser. These VOCs are hydrocarbons, ketones, alcohols and halogenated alkanes, with low to moderate molecular weights and low boiling points, allowing them to be inhaled in their gaseous state. As a result of being easy to obtain, they are frequently seen as a cheap and legal alternative to abusing other drugs by adolescents and young adults (1, 2). Administration can be achieved through numerous methods, such as direct inhalation of compressed air duster products or breathing through solvent-soaked rags, and may be referred to by different terms such as huffing, sniffing, snorting, bagging, or spraying depending on the method of administration (3). The abuse of inhalants produces euphoric and psychoactive effects occasionally resulting in severe toxicity or death, and is routinely encountered in forensic toxicology casework (4 –11). Some inhalants, such as the fluorinated alkanes and Freonsw are cardio-toxic and may cause fatal cardiac arrhythmias (7, 11). Propellants used in air duster products are among the most frequently abused and can include 1,1-difluoroethane (DFE), 1,1,1-trifluoroethane (TFE) or 1,1,1,2-tetrafluoroethane (Norflurane, HFC-134a); however, there have been no reports of TFE or Norflurane in forensic toxicology literature. The abuse of nitrites results in the presence of the corresponding alcohol (isoamyl, isobutyl and n-butyl alcohols) in biological specimens and detection of the alcohol may be evidence of nitrite abuse (12). Other commonly abused VOCs include toluene and methyl ethyl ketone (MEK), compounds found in paint strippers, industrial adhesives and solvents. As a result of the increasing number of inhalant-related impairment cases and deaths over the past 5 years in the State of Florida (13–17), the authors found it necessary to validate a method to qualitatively identify an extensive list of VOCs, including methanol, isopropanol, acetone, acetaldehyde, toluene, MEK, isoamyl alcohol, isobutyl alcohol, n-butyl alcohol, DFE, TFE, Norflurane, chloroethane, trichlorofluoromethane (Freonw-11), dichlorodifluoromethane (Freonw-12), dichlorofluoromethane (Freonw-21), chlorodifluoromethane (Freonw-22) and 1,2-dichlorotetrafluoroethane (Freonw-114). Current methods used for the identification of VOCs are generally nonspecific if analyzed concurrently with ethyl alcohol, or require an additional analytical procedure employing mass spectrometry for identification. A previously published technique utilizing a capillary flow technology (CFT) splitter to simultaneously quantitate and confirm ethyl alcohol by flame ionization detector (FID) and mass spectrometric (MS) detection after headspace (HS) sampling and gas chromatographic (GC) separation was evaluated for the detection of VOCs (18). The validation for qualitative identification included evaluation of matrix effects, sensitivity, carryover, specificity, repeatability and ruggedness/robustness. Materials and methods Chemicals, reagents and supplies Human whole-blood and urine (catalog no., respectively, 44600WB(F), 88121-CDF(F)) were from UTAK (Valencia, CA, USA) and verified to be negative for all target compounds. Methanol, acetone, acetaldehyde, toluene and isoamyl alcohol (catalog no., respectively, MX0484-1, AX0115-1, AX0025-4, TX0737-1, AX1440-3) were from EMD Chemicals (Gibbstown, NJ, USA); isopropanol and n-butyl alcohol (catalog nos., respectively, AH323-4, 024-1L) were from Burdick and Jackson (Muskegon, MI, USA); MEK (catalog no. M1260) was from Spectrum Chemical (Gardena, CA, USA); isobutyl alcohol (catalog no. 9044-01) was from JT Baker (Phillipsburg, NJ, USA); TFE (catalog no. 1100-3-07) was from Synquest Labs (Alachua, FL, USA). A Freonw mix (catalog no. 48420-U) containing trichlorofluoromethane (Freonw-11), dichlorodifluoromethane (Freonw-12), dichlorofluoromethane (Freonw-21), chlorodifluoromethane (Freonw-22) and 1,2-dichlorotetrafluoroethane (Freonw-114) in ethyl acetate; DFE (catalog no. 295264-100G); Norflurane (catalog no. 374334-100G) and chloroethane (catalog no. 295310-100G) were from Sigma-Aldrich (St. Louis, MO, USA). Normal propanol (catalog no. 41842) was from Alfa Aesar (Ward Hill, MA, USA); deionized (DI) water (catalog no. W2-4) was from # The Author [2013]. Published by Oxford University Press. All rights reserved. For Permissions, please email: Fisher Scientific (Pittsburgh, PA, USA); 20 mL glass round-bottom HS vials and 20 mm crimp top seals (catalog nos., respectively, C4020-2, C4020-3A) were from National Scientific (Rockwood, TN, USA); 20 mm grey butyl stoppers (catalog no. 73827-21) were from Kimble Chase (Vineland, NJ, USA). Equipment included Referencew pipettes with disposable tips from Eppendorf (Westbury, NY, USA). Normal propanol internal standard was prepared at a concentration of 0.01% by volume (% v/v) in DI water. Stock standards of all compounds were prepared in DI water to eliminate the appearance of an additional solvent peak unless the compound did not have sufficient solubility in water. Toluene and MEK were prepared in meth (...truncated)