Research Progress of Analysis of Mineral Oil Hydrocarbons using On-line High Performance Liquid Chromatography Coupled with Gas Chromatography
Abstract In the past decades, the application of on-line high performance liquid chromatography coupled with gas chromatography (HPLC-GC) has been rapidly developed for the quantitative analysis of mineral oil hydrocarbons (MOH). MOH are derived from petroleum and synthetic fuels, and cover a large range of boiling points, mainly consisting of mineral oil saturated hydrocarbons (MOSH) and aromatic hydrocarbons (MOAH). MOH can migrate into food and environment through a variety of pathways, consequently impose an adverse impact on human health. However, the analysis of MOH is challenging due to the limited selectivity and sensitivity of hydrogen flame ionization detector (FID). On-line HPLC-GC combines the high separation efficiency of HPLC with the equal-carbon-response detection of GC-FID, which solves the problems associated with selectivity and sensitivity of MOH analysis. The innovation of the retention gap, Y-piece interface, and solvent vapor exit (SVE) with which the HPLC-GC is equipped enables large-volume injection into GC-FID. By allowing the elution fractions from HPLC to be completely transferred into the GC, the analytical sensitivity of the MOH is enhanced by more than two orders of magnitude, and the contaminants introduced are minimized during the analytical procedure, ensuring the reproducibility and accuracy of the MOH analysis. In this paper, the research history of the interfaces used in on-line HPLC-GC and the matching conditions between HPLC and GC were described in detail, and the sample preparation methods for the removal of interferences and the enrichment of MOH based on HPLC-GC were reviewed. In addition, the limitations of HPLC-GC were summarized, and the future applications of this technology and the trends in the development of MOH analysis were prospected.