Recent advances in modulator technology for comprehensive two dimensional gas chromatography

One of the greatest advancements in the field of gas chromatography (GC) has been the development of comprehensive two-dimensional gas chromatography (GC x GC). As the field of GC evolved from one-dimensional gas chromatography (1D-GC) to heart cutting (GC-GC), followed by the advent of GC x GC, the critical component at the center of this evolution has been the interface between the separation columns. The interface, referred to as the modulator for GC x GC, links the primary and secondary columns. This review covers the evolution of modulator systems from the founding of GC x GC in 1991 by Liu and Phillips, while focusing on the last six years. Since its inception, modulators have evolved into two distinct categories: thermal, and valve-based. The advantages and shortcomings of each category will be covered. Recent developments in the research, development, and commercialization of these various modulators is provided, with a glimpse into future modulator designs. (C) 2018 Elsevier B.V. All rights reserved.