Sample evaporation in conventional split/splitless GC injectors: Part 2: Use of perylene for visual observation of three different scenarios in empty injector inserts

Abstract

Abstract Perylene is strongly fluorescent as long as it is in solution. This has enabled visual observation of non‐evaporated sample material in a “transparent injector”, i.e. in a heated glass device imitating a conventional vaporizing injector. Three scenarios of sample evaporation are described. Some samples (solvents) are nebulized and “flash evaporated” in the gas phase between the needle exit and the column entrance (Scenario 1). With most solvents, the liquid leaves the syringe needle as a thin jet which rushes through both the empty vaporizing chamber and the split outlet at high velocity, often without substantial evaporation. It does not touch the surfaces of the insert and passes round the bend at the bottom of the device without any problem (Scenario 2). Some samples are splashed on to the insert wall, wet it, and evaporate rather slowly from this surface (Scenario 3).