This technique is useful for large volumes (10-50 |L, even 1 mL), especially if solvent vapours are vented to atmosphere before the remaining sample is directed on to the column. This is especially useful for analysis of high boiling solutes (sometimes called split-split-less injection or solvent - split injection), but results in loss of volatile compounds (possibly up to C20). The vapour cloud from the solvent injected must not be so great that it flows back from the injector insert. To some extent this can be achieved by careful injector heating. Needle-in-plunger syringes can be used for small injections (injector not hot).

The PTV injector is useful for both split and split-less injection. Solvent trapping can be achieved with the latter but can often be avoided by adjusting the timing. Heating should be fast so that volatilization occurs quickly, especially if chromatographic migration starts immediately (i.e. no cold trapping or solvent trapping), but this might cause thermal degradation.

The narrow liner means high carrier gas flow, so transfer to column is fast; retention by packing can be tolerated as carrier flow partially compensates (less likelihood of problematical matrix effects with dirty samples). Shorter transfer periods can be used for splitless injection; the use of lower column flow rates than for conventional split or splitless injection can still result in good transfer. The technique gives good precision because there is no aerosol formation and diffusion of quickly flowing carrier gas with sample means little recondensation of solvent in the column in split or solvent-splitless injection. There is no pressure wave, and less chance of matrix effects with dirty samples. Finally, there are no unwanted solvent effects with split or solvent-split injection.

Solar Panel Basics

Solar Panel Basics

Global warming is a huge problem which will significantly affect every country in the world. Many people all over the world are trying to do whatever they can to help combat the effects of global warming. One of the ways that people can fight global warming is to reduce their dependence on non-renewable energy sources like oil and petroleum based products.

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