Erratic recoveries in manual injections

[wrb10dana]

Can anyone suggest a reason for variations seen in manual injections of standard directly into a GC injection port? I am working with an Agilent 6890N GC/5973 Inert GC. Inj port temp = 180 C; split 30:1; 1 uL inj vol. There are no leaks anywhere in the system. Thanks.

[Peter Apps]

Poor syringe handling is by far the most likely.

Peter

[rb6banjo]

What is the solvent for your samples?

[James_Ball]

Poor syringe handling is by far the most likely.

Peter

The time the needle is in the injection port can make a difference in your analyte response. Also the needle depth at time of injection or the speed you inject. It takes a lot of practice to be reproducible with manual injection techniques, but it can be done.