Noise increase between Empower and Chemstation with 1100 LC

[raza bal]

Hi all!
For those that have switch from Chemstation to Empower with their Agilent 1100 LC, do you noticed increase of baseline noise value on Empower compared to Chemstation (with exactly same detector parameters on both programs)?
Our Empower "average peak-to-peak" noise is 5-10 times higher than the "ASTM noise" measured with Chemstation on same apparatus and with same detector parameters. Empower Average peak-to-peak noise should be equivalent to ASTM noise.

Any feedback about it?

Best Regards

Raza

[DR]

Are you sending an analog signal to an eSATIN or are you using a jet-direct card?

[unmgvar]

peak to peak noise from waters is in accordance to the ASTM requirement for calculating noise with compensation of drift, but it is not the same as the ASTM noise mode calculation from chemstation

you can see in the link from agilent for chemstation that the 2 ways are not equivalent
http://jbbeach.com/files/Chemstation/Un ... n_7_08.pdf

[raza bal]

Hi all!

@DR: HPLC and Pc's are connected via Ethernet... So I think it correspond to jet-direct card... So, what is your idea?

@unmgvar: We use average peak-to-peak noise... That mean that noise is calculated on several segments included in an interval of time and averaged (segments and intervals are defined the same for our methods in Empower and Chemstation). ASTM short time noise used in Chemstation( corresponding to definition ASTM E685-93) shall be equivalent to average peak-to-peak noise on Empower (corresponding to definition ASTM E685-79). After reading both ASTM versions, I have not seen any difference. So, have you any other idea?

Thanks all

Raza

[DR]

If you are using an analog signal output from the detector, you should probably expect it to be a little noisier than a digital signal. If you're connected via ethernet, all you can do is make sure that sampling rates and AU/V settings are comparable.

[unmgvar]

you will need also to see that the noise is being "collected" in the same manner over the same time regions, and with the same segment width.
defaults settings are never the same in the softwares, and many times users change it to suit the specific application
and if we go over the empower manual we see that the amount of data points needed for each software is different in concept, yet both try to at least cover a range of 1 minute for the noise calculation.
but it is still kind of different, and in chemstation there is also a 10% overlapping.

also very important, is that the S/N of chemstation is not done using ASTM noise, but using the 6 sigma version, so if you are right now looking at the noise because you got worst S/N results, then be careful because then you are not looking at the same noises if this is your base of evaluation.