Chromatography Forum

Using a 30m x 320µm x 1.8 µm Agilent DB-624 UI column, what would be a typical split ratio with a 1µl injection volume? A little background. I'm trying to make a GC separation and prepared a stock std which I inject at 20:1. For this std I achieve adequate separation of all peaks. I prepared a 10X dilution of this stock std in order to make sure I could detect peaks at my sample concentration which is going to be 100 mg/ml. FYI the stock standard was made at USP467 limits and this is the reason I made the 10X dilution. The split is 10X for this and now I see distortions in the later eluting pyridine, why? Thanks.

What are the concentrations of the standards - stock and diluted ?. 100 mg/ml is 100 ug/ul, which is about 100 times what you need to get a very large peak at a split of 10:1, so you are probable seeing concentration overloading.

Peter

My thoughts exactly, Peter. 10%? That is a HUGE concentration. I'd be running 50:1 or 100:1 splits for that much analyte.

It would help to know the detector type. You could help out a lot by giving us conditions.