Capillary-based microfluidic interface enables multidimensional gas phase separations of complex organic mixtures
Thermal desorption modulation for comprehensive two-dimensional gas chromatography using a simple and inexpensive segmented-loop fluidic interface
Vanessa Mucédola,a,b Luis C. S. Vieira,a Danilo Pierone,c Angelo L. Gobbi,a Ronei J. Poppi,a,b Leandro W. Hantaoa,b,*
a Laboratório Nacional de Nanotecnologia, Centro Nacional de Pesquisa em Energia e Materiais, Campinas, SP 13083-100, Brazil
b Instituto de Química, Universidade Estadual de Campinas, Campinas, SP 13083-970, Brazil
c Nova Analítica Importação Exportação LTDA, São Paulo, SP 04131-000, Brazil
In this study, we introduce a modulation strategy for comprehensive two-dimensional gas chromatography (GC×GC) by using a simple and consumable-free modulator. This “Do-It-Yourself” interface comprised a 1.0 m × 0.25 mm segment of MTX-5 metallic column and a low-cost DC power supply. Thermal desorption modulation (TDM) was attained using a dual-stage heater-based modulator in a novel segmented-loop configuration. TDM was achieved by alternating analyte trapping and thermal desorption. Former process relied on analyte partition to sorbent phase, while latter explored direct resistive heating. Introduction of an intermediate delay segment between the two stages mitigated analyte breakthrough, improving peak symmetry and chromatographic efficiency. This feature was critical to acquire reliable GC×GC modulation using such simple heater-based device. The effects of important modulation variables on 2D separations were investigated, including TDM stage length, dimension of delay loop, and outlet pressure. Significant advances and limitations of proposed TDM strategy were carefully determined. Proposed GC×GC prototype by using an in-oven TDM modulator was successfully applied to a series of challenging matrices, including petroleum distillates, biodiesel, and essential oil. This open-hardware, cost-effective modulator was easy to install and operate, as it circumvented the need for sophisticated components (e.g. moving parts and cooling systems). Therefore, our modulator is a compelling alternative to existing GC×GC solutions to operate in resource-limited laboratories.
This research was recently published in Talanta (Elsevier, DOI: 10.1016/j.talanta.2016.12.005). Funding for this research was provided by the São Paulo Research Foundation (AP.R 2015/05059-9) and Petrobras (2014/00228-4). Stefano Galli (MEGA snc) is thanked for providing GC columns. The authors also acknowledge Prof. Fabio Augusto (IQ-Unicamp) for providing GC Image software. Prof. Emanuel Carrilho and Stanislau Bogusz Junior (IQSC-USP) are thanked for supplying GC-MS system.