Chromatography Forum

Hello

We recently acquired a AlphaMOS heracles, with MXT-5 and MXT1701 column. Unfortunately, the baseline for the MXT-1701 column is already drifting downward to about -2000 intensity. Our Alpha MOS contact has suggested that this drift is insignificant, and maybe it is, but it still annoys me.

Do you have any suggestions what might be causing it, and how we could fix it? The drift started after we sent it in for reparation for a different problem at AlphaMOS ...

I'm hopelessly new at gaschromatography btw.

Cheers in advance.

Does your baseline autozero at the beginning of each run A?

and this drop in signal happens during the run B?

If answer to A? is yes, then something is bleeding off less and less during (between) the runs.

If A? is no, then the drop is probably due to the normal amount of conditioning of the column.

If B? is yes, is the run isothermal, or programmed?

I assume your metal column is not touching anything it is not supposed to touch in the detector.

Some additional information as if the signal is smooth or jagged, the film thickness and ID of the column might be helpful in giving a diagnosis to your problem.

Either your bleed is from the column phase/something injected upon the column, or some contamination from the gases, lines, traps, connections, detector parts, that have been touched and contaminated by a dirty hand.

Trouble shooting is a valuable skill. To what degree do you possess it? Are you able to tell us what you have done so far?

best wishes,

Rod