Alexandrino Guilherme L, de Sousa Gustavo R, de A M Reis Francisco, Augusto Fabio
Institute of Chemistry, State University of Campinas, Cidade Universitária Zeferino Vaz, 13083-970 Campinas, SP, Brazil.
Institute of Chemistry, State University of Campinas, Cidade Universitária Zeferino Vaz, 13083-970 Campinas, SP, Brazil.
J Chromatogr A. 2018 Feb 9;1536:82-87. doi: 10.1016/j.chroma.2017.10.054. Epub 2017 Oct 25.
The enhanced chromatographic capability of the comprehensive two-dimensional gas chromatography (GC×GC) has already found several applications in analytical chemistry comprising complex samples. However, setting the appropriate chromatographic conditions that maximize sensitivity and separation efficiency in GC×GC may be more difficult than in conventional one-dimension gas chromatography, mainly due to the additional parameters strictly related to the modulation. Loop-type cryogenic modulators have been currently used for crude oil analysis using GC×GC, requiring sometimes a laborious try-and-error procedure to properly tune the dual-jets elapsed times on modulation. In this work, the advantages of choosing a time-variable combination of cold and hot jets pulses in a loop-type cryogenic modulator is presented when performing the fingerprinting analysis of crude oils using GC×GC-QMS, contrary to the conventional procedure based on a single combination for the dual-stage jets. A design of experiments approach is proposed to most effectively optimize the time-variable combination of the dual-jets elapsed times while modulating the wide hydrocarbons range along the GC×GC analysis. The most abundant classes of hydrocarbons contained in the maltenes fraction of a crude oil sample, such as paraffins, aromatics, steranes and hopanes were successfully resolved.
全二维气相色谱（GC×GC）增强的色谱能力已在分析包含复杂样品的分析化学中得到了多种应用。然而，要在GC×GC中设置能使灵敏度和分离效率最大化的合适色谱条件可能比传统一维气相色谱更困难，主要是因为有一些与调制严格相关的额外参数。环形低温调制器目前已用于使用GC×GC的原油分析，有时需要经过费力的反复试验过程来恰当地调整调制时双喷口的流逝时间。在这项工作中，与基于双级喷口单一组合的传统方法相反，展示了在使用GC×GC - QMS对原油进行指纹分析时，在环形低温调制器中选择冷喷口和热喷口脉冲的时变组合的优势。提出了一种实验设计方法，以在沿着GC×GC分析调制宽范围烃类时最有效地优化双喷口流逝时间的时变组合。原油样品的软沥青质馏分中所含的最丰富的烃类类别，如链烷烃、芳烃、甾烷和藿烷，都成功地得到了分离。
