Disease relevance of isobutane

• Sudden death after isobutane sniffing: a report of two forensic cases [1].
• The efficacy of triamcinolone in the treatment of these dermatoses was not altered by the isobutane [2].
• We present a case of a patient who survived ventricular fibrillation after inhalation of Glade Air Freshener, which contains short chain aliphatic hydrocarbons (butane and isobutane) [3].

High impact information on isobutane

• The measured activation energy for isobutane H/D exchange is 57 kJ/mol [4].
• The hydroxylation step involves a concerted but nonsynchronous transfer of a hydrogen atom from this newly formed, bound, water molecule to the ferryl oxygen with a concomitant rebound of the incipient *OH radical to the carbon radical of isobutane to produce the C-O bond of the final product, tert-butyl alcohol [5].
• In situ 13C MAS NMR and complementary ex situ GC-MS data provided evidence for a monomolecular mechanism of the 13C-label scrambling, whereas both isobutane and propane are formed through intermolecular pathways [6].
• Advantages of ammonia ionization over the previously studied isobutane ionization include a 130-270% enhancement in the sensitivity of base peak monitoring, and direct determination of molecular weight from the base peak (M + NH4+) in the mass spectrum of any of the derivatives [7].
• Negative chemical ionization mass spectrometry with a mixture of isobutane, methylene chloride, and oxygen as the reagent gas has been used to explore contamination of environmental substrates with xenobiotic chemicals [8].

Chemical compound and disease context of isobutane

• Triamcinolone acetonide spray was reformulated, incorporating isobutane as the propellant and used on 50 patients with a wide variety of corticosteroid responsive dermatosis [2].

Biological context of isobutane

• Eight adult volunteers of both sexes were exposed to isobutane in a controlled-environment chamber for the purpose of monitoring their physiological responses to a series of gas concentrations ranging from 250 to 1,000 ppm [9].
• The alkylation of butene with isobutane on WO(3)/ZrO(2) was carried out in a fixed-bed reactor [10].
• Reaction kinetics data were collected for isobutane conversion over a series of ultra stable Y (USY) zeolite catalysts with and without rare earth cations and subjected to various extents of dealumination by steaming [11].

Anatomical context of isobutane

• Ultrasonographic appearance of exogenous isobutane gas in the mammary glands of dairy cows [12].
• OBJECTIVE: To determine whether exogenous isobutane gas infused into the udders of dairy cattle could be detected ultrasonographically, and if so, what effects volume of gas infused and infusion pressure had on how long after infusion exogenous isobutane gas could be detected [12].

Associations of isobutane with other chemical compounds

• Neopentane as a possible replacement for isobutane in chemical ionization mass spectrometry [13].
• The combination of gas chromatography and mass spectrometry using a polar capillary column and isobutane chemical ionization made it possible to determine mevalonic acid (MVA) as the lactone at subnanogram levels using 1 mL of plasma [14].
• Sialic acids were analyzed as per-O-trimethylsilylated compounds by gas-liquid chromatography/mass spectrometry either on electron or chemical ionization by isobutane [15].
• The structures of the new compounds 6-DMC-dGuo, 6-DEC-dGuo, 4-DMA-dThd and 6-DMA-dGuo were deduced from chemical analyses and syntheses, UV and nuclear magnetic resonance (NMR) spectra and electron impact, isobutane chemical ionization and source insertion isobutane chemical ionization mass spectra [16].
• The four components were identified as farnesene, bisabolene, anastrephin, and epianastrepin based on their relative retention indexes from capillary gas chromatography analysis, using both apolar and polar phase columns and their chemical ionization (isobutane) mass spectra [17].

Gene context of isobutane

• This bond energy is the strongest tertiary C-H bond to be measured, is much larger than the corresponding bond in isobutane (96.5 +/- 0.4 kcal/mol), and is more typical of an alkene or aromatic compound [18].
• Their heptafluoropropionic (PFP) derivatives are ionized under electron impact and isobutane-chemical ionization [19].
• Structural elucidation has been carried out by isobutane-chemical ionization mass spectrometry of the fatty acyl biosynthetic precursor-derived methyl ester [20].
• For this reason, the authors have adapted gas chromatography/negative ion chemical ionization mass spectrometry (GC/NICI-MS) (developed by Ramesha and Pickett in 1985) by employing an SPB-1 column and isobutane as the reagent gas [21].
• Urine was enzymatically hydrolyzed, cleaned up on a C18 micro-column and the metabolites were identified by GC-MS using electron impact (70 eV) and chemical ionization with ammonia or isobutane as the reagent gas [22].

Analytical, diagnostic and therapeutic context of isobutane

• Isobutane was used as both gas chromatography (GC) carrier gas and chemical ionization (CI) reagent gas [23].
• Broadband attenuation measurements are described for two different types of microbubble suspension (albumin encapsulated octofluropropane and copolymer encapsulated isobutane) to ascertain whether or not multiple scattering may be observed experimentally [24].
• CONCLUSIONS AND CLINICAL RELEVANCE: Results suggest that exogenous isobutane gas infused into the mammary glands to enhance the appearance of the udder of show dairy cattle can be readily detected by ultrasonography [12].
• In prospect, isobutane chemical ionization mass spectrometry seems to be a useful technique for peptide sequence determination, and may have advantages in some cases [25].

References