TCD not detecting anything
Posted: Thu Oct 15, 2009 6:47 pm
Hi,
I am looking for help on a mystery. I have a Shimadzu GC-17A, single injection port with TCD detector. It is used mainly for in process material, our feed material contains salts so I use inj liners with wool to trap some of the gunk and swap them out frequently. I noticed the peaks were starting to come out later so I replaced the liner, trimmed the column on the injection side and replaced the septum. But now the TCD is not detecting ANY peaks. I unhooked the column from the detector to check for flow through the column and that appears normal, trimmed that end of the column while it was unhooked just in case. But there was no change, still no peaks. I only do manual injections so I can see the syringe is working normally. I do get some noise and the baseline increases normally with the temp program then gets wavy on cooldown (which is a little unusual for our GC). I did the zero adjustment and slope test which seemed normal (200). The unit is not detecting any leaks and the flow / pressure are staying on program. The column is only a month old, the one we replaced (same type and length - RTX-5 wide bore 15m) worked well for nearly a year. Not sure what I can try next.
I am looking for help on a mystery. I have a Shimadzu GC-17A, single injection port with TCD detector. It is used mainly for in process material, our feed material contains salts so I use inj liners with wool to trap some of the gunk and swap them out frequently. I noticed the peaks were starting to come out later so I replaced the liner, trimmed the column on the injection side and replaced the septum. But now the TCD is not detecting ANY peaks. I unhooked the column from the detector to check for flow through the column and that appears normal, trimmed that end of the column while it was unhooked just in case. But there was no change, still no peaks. I only do manual injections so I can see the syringe is working normally. I do get some noise and the baseline increases normally with the temp program then gets wavy on cooldown (which is a little unusual for our GC). I did the zero adjustment and slope test which seemed normal (200). The unit is not detecting any leaks and the flow / pressure are staying on program. The column is only a month old, the one we replaced (same type and length - RTX-5 wide bore 15m) worked well for nearly a year. Not sure what I can try next.