Identification and determination of 16-carbon 2,5-dialkyloxolanes in autoxidized n-hexadecane samples by capillary gas chromatography and mass spectrometry

Methods for determining the efficacy of radical-trapping antioxidants

“…Alternatively, high-performance liquid chromatography (HPLC) with UV detection has been used when the product is a hydroperoxide that has a reasonable chromophore, such as the diene moiety of the linoleyl hydroperoxides, or the phenyl rings of cumene hydroperoxide or tetralin hydroperoxide. GC/FID and/or GC/MS analyses are also possible, but must be preceded by reduction of the hydroperoxide to the corresponding alcohol using, e.g., sodium borohydride or triphenylphosphine, 39,40 and sometimes bolstered by silylation of the alcohols for better chromatographic separation. 41 Unfortunately, these methods are generally time-consuming.…”

Antioxidants in Chemistry and Biology

“…75,76 The primary products of polyunsaturated fatty acid (PUFA) autoxidation are conjugated diene hydroperoxides, which exhibit UV absorbance around 234 nm. 77 To avoid interference by other UV-absorbing species, the progress of the reaction can be monitored at regular time intervals by HPLC-UV analysis of the reaction mixture.…”

“…An important example of this in a biological context involves the interplay between α-TOH and ascorbate in the inhibition of LDL oxidation. In the absence of ascorbate, α-TOH reacts with a chain-carrying lipid peroxyl radical (75); but in competition with the expected second chain-breaking reaction (76), the α-tocopheroxyl radical can react with a lipid in a chain transfer reaction, thereby mediating the chain reaction in lieu of inhibiting it. This has been referred to as tocopherol-mediated peroxidation (TMP).…”

2,5-DialkyItetrahydrofurans, Common Components of the Cuticular Lipids of Lepidoptera

“…The lipids were extracted as described and the extracts submitted to GC-MS. Long chain un branched 2,5-dialkyltetrahydrofurans and related alcohols were identified in addition to the usual alkanes and other compounds. They exhibited dis tinct mass spectra, permitting easy location of the ring in the chain (Brandt and Djerassi, 1968;Zinbo and Jensen, 1985;Takabayashi and Takahashi, 1986a). The mass spectrum of 2-nonyl-5-octadecyltetrahydrofuran (9/18-THF*) is depicted in Fig.…”