What should I consider when choosing between split and splitless injection modes?

Split injections are the simplest to implement and are suitable for most samples. However if analytes are present at trace levels, splitless injection may be considered to increase the transfer of analyte onto the column, resulting in higher sensitivity. It should be noted that in splitless mode analytes spend a long time in the hot injection port (relative to split injections where gas flow through the injection port is much higher) and this can be detrimental if active or thermally labile compounds are being analysed.