Chromatography Forum

Limited knowledge.
Using HP II 5890 for alcohol fuel testing. Having trouble with 'lazy' peaks, no crisp, sharp peak upwards or downwards to taper off.
Before this happened, I was getting no peaks at all, just high static print-out. Cut short lengths from both ends of column, re-inserted and cautiously tightened. That is when my 'lazy' peaks began.
Cut column again with same peaks.
All other functions of GC and programs running within parameters.
All information given will be greatly appreciated.

WillieBill

Could you post a chromatogram i wonder how these peaks look like.

FID detection?

Yes, FID. Hope this print works.[img]"C:\Users\Psycho\Documents\Track%20GC%202017\Track%20GC.jpg"[/img]

Yes, FID. the beginning upward stroke remains constant size no matter how much sample I inject. At the 2/3's point of up peak the path begins to falter to the right then rounds off the peak top point. The downwards fall seems 'lazy' in that it is not more of a straighter angle.
At bottom of image there is a column "Area counts". I normally get a result of how pure test sample is. Now nothing.


Hope this print works.[img]"C:\Users\Psycho\Documents\Track%20GC%202017\Track%20GC.jpg"[/img]

Looks to me like that link is pointing to someplace on your C: drive on your computer. You'll need to upload that to site that will allow image sharing. Here's one of mine from my "photobucket" account:

http://i1285.photobucket.com/albums/a59 ... ab8b6a.jpg

More information would be helpful.
Usually "lazy" peaks are a function of events in the injection port.
Is your column cut properly?
Is the column inserted into the injection port the proper distance?
Clean, de activated liner?

[img][IMG]http://i1378.photobucket.com/albums/ah120/WillieBill66/Track%20GC_zpswgngw3eg.jpg[/img][/img]

Column was cut cleanly with ceramic blade. I'll check my clearance of the column inserts, I may have inserted too much. I'll check this week before this weekends races.

What alcohol are you looking for? Are you using direct injection or head space?
The peak in the chromatogram, is it the solvent peak?
If it's your compound, you may be either running a to high column flow, or your initial temp is to high.

I'll be at the track Saturday afternoon before racers show up. I'll have laptop at site and check what great posts have been asking me to do.