Chromatography Forum

Hello people,

I run PCBs on a HP 5890 ECD GC. For the past month or so I have had to run an initial calibration on my instrument almost every other day.

It can't be contamination from my samples because I am only running MDLs on that instrument.

I completely cleaned out my injection port, put in a new liner, septum, gold seal, syringe and replaced the weldman and gas lines but still had the same problem.

Next I changed the split ratio from 5:1 to 12:1 and changed my injection volume from 1ml to 2ml, but now I can't my initial calibration to pass.

I am almost out of ideas .... how should I proceed ?

Somebody help me !!!!

Thanks..

Hi!
First,why do you have change or clean injector, liner, ect....?what was your problem for change this item?

I changed the liner and cleaned out the instrument to rule out the possibility of contamination from the instrument.

Hi!
Your initial calibration don't pass.....why?...give your symptoms...area count, sensitivity, tailing,no or lost of peak??

How old/used are your detectors? Have you considered the possibility that they may need cleaning? That is a common problem with a local
laboratory I work with. Their 5890 ECD's will show slightly elevated standing currents and not be able to hold calibration.