Evaluation of sources of irreproducibility of retention indices under programmed temperature gas chromatography conditions.
Retention index under the programmed temperature gas chromatography (PTGC) conditions (IT) is widely accepted despite of its unsatisfactory reproducibility. Effects of heating rate (rT), stationary liquid film thickness (df), inlet pressure (pi), initial temperature (To) and polarity of stationary phase (sp) on ITreproducibility were studied in the present work. We found that excellent reproducibility and regularity of ITvalues are obtainable at conditions of relatively low Toand relatively high rTand pi, as well as use of quality thick-film column under an operation in a single-retention behavior region (i.e., cubic equation model region). Most solutes were eluted in the dual-retention behavior region under the commonly used conditions described in the literature (i.e., relatively high Toand relatively low rTfor thin-film columns). The ITreproducibility under the optimum condition was approximately 37 times better than that under the commonly used conditions. The present work further validated the concept about dual- and single-retention behaviors of solutes in PTGC and proposed a principle to improve ITreproducibility.
Department of Molecular Biosciences and Bioengineering, University of Hawaii at Manoa, Honolulu, HI 96822, USA.
Liejun
L
Wu
Department of Molecular Biosciences and Bioengineering, University of Hawaii at Manoa, Honolulu, HI 96822, USA.
Ii Kyu
IK
Cho
Department of Molecular Biosciences and Bioengineering, University of Hawaii at Manoa, Honolulu, HI 96822, USA.
Yanjie
Y
Li
Biostatistics and Data Management Core, John A. Burns School of Medicine, University of Hawaii at Manoa, Honolulu, HI 96813, USA.
Guangxiang
G
Zhang
Department of Molecular Biosciences and Bioengineering, University of Hawaii at Manoa, Honolulu, HI 96822, USA. Electronic address: qingl@hawaii.edu.
Qing X
QX
Li
D002849:Chromatography, Gas / Q000379:methods*; D008962:Models, Theoretical; D011312:Pressure; D015203:Reproducibility of Results; D013696:Temperature
GC column; Programmed temperature gas chromatography; Retention index; Retention model