Stacked injection with low thermal mass gas chromatography for PPB level detection of oxygenated compounds in hydrocarbons

The presence of oxygenated compounds in light hydrocarbons can have a negative impact in manufacturing processes and on the quality of products produced. The development of an analytical technique termed "stacked injection" has been reported earlier. With this technique, sensitivity in the parts-per-billion (ppb) range for oxygenated compounds can be achieved, even with a flame ionization detector; however, there are drawbacks for this approach that limit its overall effectiveness. A new, improved analytical technique has been developed that not only addresses the shortcomings encountered, but offers markedly higher analytical performance. The new concept employs multidimensional gas chromatography (GC) with low thermal mass GC. With this new approach, throughput improvements of up to 5 times, range extension of solutes amenable for this analysis of up to nC16 alcohol, and ppb levels of detection for oxygenated compounds are achieved. Apart from alcohols, this technique is successfully employed for the ppb level analysis of other classes of oxygenated compounds, such as ethers, aldehydes, and aromatics.