Evaluating stationary phase selectivity for retention index determination and resolution of n-hexadecene isomers

Higher olefins, specifically n -hexadecene (C 16 H 32 ), are essential raw materials in the cosmetic industry, particularly for the synthesis of biodegradable surfactants. However, resolving the complex landscape of positional and geometric ( cis/trans ) isomers remains a significant analytical challenge. This study presents a comprehensive evaluation of gas chromatography (GC) stationary phase selectivity for the separation of n -hexadecene isomers and stereoisomers. By comparing non-polar (Rxi-5Sil MS), polar (ZB-WAX plus ) and highly polar (SP-2560) columns against historical stationary phases, we identified a distinct ‘crossover’ elution trend on non-polar phases. Conversely, the highly polar SP-2560 demonstrated superior selectivity, consistently eluting trans -isomers before their cis -counterparts across all positional n -hexadecene isomers. Notably, this research is the first to utilize synthesized and NMR-characterized analytical standards to establish Retention Indices (RI) for these specific isomers. By eliminating the ambiguity associated with historical isomer mixtures, this work provides a rigorous benchmark for future analysis of complex C 16 olefins-based raw materials.