Concurrent Solvent Recondensation

The recondensation of the solvent inside of the capillary column is causing a volume contraction and hence a pressure drop at the beginning of the column. 

Sample volumes of up to 10 pL can be injected in liquid band mode by using the regular 0.25 mm capillary columns, while sample volumes of up to 50 pL require the wider diameter of an empty retention gap with 0.32 or 0.53 mm ID to accept the complete amount of liquid injected, and some sUanized glass wool in the insert liner (focus liner). 

The practical benefit of CSR is the flexibility for the injection of a wider range of diluted sample volumes reducing significantly the time for extract preconcentration. As the CSR injection is performed with the regular SSL injector hardware without any modifications, only the autosampler injection volume. 

Injection with hquid band formation The collection of the liquid on the glass wool allows a slow evaporation from a single droplet. 

Auto-pressure surge due to the large amount of solvent A temporary increase of the inlet pressure rapidly drives the vapours into the column where the recondensation process starts. The concurrent solvent recondenzation in the pre-column is generating a strong suction effect. 

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Figure 2.59 Principle of concurrent solvent recondensation in splitless injection (Magni and...

LV-on-column with solvent vapour exit LVI-PTV with solvent split LV-split/splitless with concurrent solvent recondensation... 

Magni, P. and Porzano, T. (2003) Concurrent solvent recondensation large sample volume splidess injection. J. Sep. Sci., 26, 1491-1498. 

Large volume splitless injection, using the concurrent solvent recondensation effect (CSR). 

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