New on-column GC sample injection techniques: Making holes in separation capillaries

Varejão, Jorge M. T. B.; Costa, M. Conceição Cruz

Palavras-chave: on-column GC injection, capillary hole.

Resumo: Cold on-column capillary injection is a precise and convenient way of sample insertion in capillary gas chromatography analysis especially when samples contain thermally labile analites or mixtures with components showing very different volatilization properties, yielding injector analite discrimination for the high boiling substances. On-column injection avoids these problems but the method requires dedicated injector hardware is not accessible to all GC equipment. It would be advantageous and convenient having adequate methods for the reversible conversion of the common split/splitless injectors in the on-column mode. We have successfully implemented two solutions to such a problem, one of them by building a liner with a funnel and the other involving the making of a hole in a 0.53mm quartz capillary guard column. Both methods allow the easy cold on-column injection with a modified capillary needle syringe on common split/splitless injectors.

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