Wu Liejun, Cho Ii Kyu, Li Yanjie, Zhang Guangxiang, Li Qing X
Department of Molecular Biosciences and Bioengineering, University of Hawaii at Manoa, Honolulu, HI 96822, USA.
Biostatistics and Data Management Core, John A. Burns School of Medicine, University of Hawaii at Manoa, Honolulu, HI 96813, USA.
J Chromatogr A. 2017 Apr 28;1495:57-63. doi: 10.1016/j.chroma.2017.03.009. Epub 2017 Mar 8.
Retention index under the programmed temperature gas chromatography (PTGC) conditions (I) is widely accepted despite of its unsatisfactory reproducibility. Effects of heating rate (r), stationary liquid film thickness (d), inlet pressure (p), initial temperature (T) and polarity of stationary phase (s) on I reproducibility were studied in the present work. We found that excellent reproducibility and regularity of I values are obtainable at conditions of relatively low T and relatively high r and p, 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 T and relatively low r for thin-film columns). The I reproducibility 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 I reproducibility.
程序升温气相色谱法（PTGC）条件下的保留指数（I）尽管重现性不尽人意，但仍被广泛接受。本研究考察了升温速率（r）、固定液膜厚度（d）、进样口压力（p）、初始温度（T）以及固定相极性（s）对保留指数I重现性的影响。我们发现，在相对较低的温度T、相对较高的升温速率r和进样口压力p的条件下，以及在单保留行为区域（即三次方程模型区域）操作时使用优质厚膜柱，可获得出色的保留指数I值重现性和规律性。在文献所述的常用条件下（即薄膜柱相对较高的温度T和相对较低的升温速率r），大多数溶质在双保留行为区域被洗脱。最佳条件下的保留指数I重现性比常用条件下约好37倍。本研究进一步验证了溶质在程序升温气相色谱法中的双保留和单保留行为概念，并提出了提高保留指数I重现性的原则。
