Area Percent Calculation on TCD and inlet question

[LabProARW]

Recently in the course of troubleshooting I ran a sample using split ratio 10:1 in an inlet of 180C and starting column temp. of 50C using a methylene chloride solvent for the sample. I also ran splitless injecting 1-uL and splitless injecting 2-uL. The chromatography looked OK to me and the integration was correct - but my main peak area percent changed between all three runs progressively lower from my split ratio run of 97.29%, my splitless 1-uL injection 96.38%, and finally my splitless 2-uL injection was 93.04%! *The integration was correct on all scans.... so what explains what I have found!? NOTE: The product peak elutes ~ 23 minutes of a 32 minute run and is not especially high molecular weight.

[freddiespedalo]

Might this discrepancy be due to the combination of additional material in the inlet combined with the lower total flow leading to a slower exit of the sample from the inlet? Some may be lost to the septum purge line if the sample and solvent hang around too long in the inlet. ??