decreasing the Peak area in sample For Agilent 1200 series

[ranjithmuthoju]

How can i know the possible reasons for decreasing the Peak area in the sample , i have tried all the possibilities ,Pl help

[tom jupille]

Obviously you have not tried *all* the possibilities, since the problem is still there. So, why don't you tell us what you *have* tried and we can go from there.

[Consumer Products Guy]

How can i know the possible reasons for decreasing the Peak area in the sample , i have tried all the possibilities ,Pl help

I can't even understand if you WANT to decrease the peak area (like using a different wavelength not at peak apex), or if you're observing peak area decrease over time.

Everyone needs to provide details. And most stuff is not nearly as "proprietary or secret" as one thinks.

[ranjithmuthoju]

Hi ,
i have tried
1.replacing the standards with new standards
2.washed the column
3.clean & sonicated the needle seat
4.checked the Lamp health

[Uros]

What is the sampler, manual or automatic, which model? Is there pressure drop when the area decrease?

[mattmullaney]

Hi ranjithmuthoju,

Here's a list of some possibilities (not an exhaustive list)...really, though, more information about what you are trying to separate (that is, for what type of compound is the peak area decreasing...what type of detection and the like) would be helpful. Please, see what you think...some I list are somewhat obvious, perhaps.

1. Decrease in injection volume, or perhaps, a leak in the system between the injector and column.

2. Increase in eluent flow rate, or perhaps a leak that occurred between the column and detector somehow "got fixed".

3. If UV-type detection, a change in wavelength.

4. A change in pH value of the eluent (either with or without the sample dissolved in it).

5. Adsorption of the analyte somewhere within the chromatograph.

6. Solvent mismatch between the sample and the eluent...in particular with early-eluting analytes.