title: A method of calculating the second dimension retention index in comprehensive two-dimensional gas chromatography time-of-flight mass spectrometry.
abstract: A method was developed to calculate the second dimension retention index of comprehensive two-dimensional gas chromatography time-of-flight mass spectrometry (GC×GC/TOF-MS) data using n-alkanes as reference compounds. The retention times of the C(7)-C(31) alkanes acquired during 24 isothermal experiments cover the 0-6s retention time area in the second dimension retention time space, which makes it possible to calculate the retention indices of target compounds from the corresponding retention time values without the extension of the retention space of the reference compounds. An empirical function was proposed to show the relationship among the second dimension retention time, the temperature of the second dimension column, and the carbon number of the n-alkanes. The proposed function is able to extend the second dimension retention time beyond the reference n-alkanes by increasing the carbon number. The extension of carbon numbers in reference n-alkanes up to two more carbon atoms introduces <10 retention index units (iu) of deviation. The effectiveness of using the proposed method was demonstrated by analyzing a mixture of compound standards in temperature programmed experiments using 6 different initial column temperatures. The standard deviation of the calculated retention index values of the compound standards fluctuated from 1 to 12 iu with a mean standard deviation of 5 iu.
authors.affiliation: Department of Chemistry, University of Louisville, Louisville, KY 40292, USA.
authors.forename: Yaping
authors.initials: Y
authors.lastname: Zhao
authors.forename: Jun
authors.initials: J
authors.lastname: Zhang
authors.forename: Bing
authors.initials: B
authors.lastname: Wang
authors.forename: Seong Ho
authors.initials: SH
authors.lastname: Kim
authors.forename: Aiqin
authors.initials: A
authors.lastname: Fang
authors.forename: Bogdan
authors.initials: B
authors.lastname: Bogdanov
authors.forename: Zhanxiang
authors.initials: Z
authors.lastname: Zhou
authors.forename: Craig
authors.initials: C
authors.lastname: McClain
authors.forename: Xiang
authors.initials: X
authors.lastname: Zhang
mesh_terms: D000473:Alkanes / Q000737:chemistry; D002244:Carbon / Q000737:chemistry; D008401:Gas Chromatography-Mass Spectrometry / Q000379:methods*; D006358:Hot Temperature; D008956:Models, Chemical; D015394:Molecular Structure
chemical_list: D000473:Alkanes; D002244:Carbon