peak naming and no calibration

[Brockboy02]

Hi all,

Our lab is still undergoing our transformation from Chemstation to Empower 2. I have figured out a lot of ways to get what I need from Chemstation. I am sure Empower2 can do the same things even better (although some would argue this point!), so I figure I would ask the group a couple questions.

The majority of our HPLC assays do not require a calibration curve to be generated. It is a lot of cation exchange and SEC of biologics (large molecule) and we simply run a system suitability and our samples, and calculate area%. We group peaks together, too. So in SEC we would group all the aggregates (higher molecular weight) together, and the fragments together (lower molecular weight). In Chemstation, I was able to name multiple peaks with the same name. How do I do this in Empower2? I thought there was an easy way to do this using groups. I have no desire to name each peak as Peak 1, Peak 2, etc.
In addition, because there is no calibration needed, are there some steps i can just simply skip over to get right into processing my run? I was hoping some one could guide me to the most elegant way of processing data using multiple processing methods (not all samples will integrate similarly as some are stressed stability samples)?
Also, if anyone out there has experiencing integrating biological samples (not the cool, sharp, small-molecule peaks!), I would love some tips. These peaks are broad and have subtle shoulders sometimes.

Thanks!!

[Karen01]

I was able to name multiple peaks with the same name. How do I do this in Empower2? I thought there was an easy way to do this using groups.

YEs you can do it using groups... If I was in front of Empower I could tell you how to do it (last time I did it was about 6 years ago. You might need to name the peaks and then make the group by the named peaks... In nay case you can set the report only to report peak groups.

I remember to , I'll take a look at the software and tell you tomorrow.

In addition, because there is no calibration needed, are there some steps i can just simply skip over to get right into processing my run? I was hoping some one could guide me to the most elegant way of processing data using multiple processing methods (not all samples will integrate similarly as some are stressed stability samples)?

Assuming you know which types of samples needs which type of processing,
you can assign the same instrument method to multiple method sets with different processing and report/export methods, then when setting up teh sample set just use the correct method set with each sample type.

You can then either have it have it process automatically by injection while running, or process the data by sample set as batch or select individual samples to process with any processing method you like.


- Karen

[benW]

Hi Brockboy02,

As Karen01 has advised, you can use named groups to group together peaks and have them considered as the same object.

Named groups are created in the Named groups tab of the processing method. Simply click on a line in the table and give the group a name and add your parameters. To add peaks to the group you will need to have filled in details for each peak in the Components tab of the processing method so the software can identify them. Any components you have filled in the components tab of the processing method will also be available in the tree on the left of the Named groups tab of the processing method; to add them to the group, simply drag them up to the group in that tree view on the left.

Once created, the named group will be automatically added to the table in the components tab of the processing method where you can set further processing parameters. To have Empower 2 not create any calibration curves, set the Y value to “None” for each component or group in the table of the components tab of the processing method.

Timed groups can be used to group peaks when you do not want to or cannot identify each specific peak. Under the timed groups tab of the processing method, a group can be created for a time region of the chromatograph. Then any peaks within this region will be grouped and treated as one in a similar way to a named group. This may be just what you are after for fragments and aggregates.

For multiple processing methods, as we suggested, you can use different method sets in your sample set or multiple processing methods in your method sets… take a quick look at your other post regarding multiple processing methods and update if anything isn’t as clear as it should be… : ).


To improve you processing, it is difficult to give such concise answers here. But as a start I would recommend the following (apologies if they are a bit obvious…):

1) Work on the chromatography first to optimise separation and make as robust as possible
2) Look to reuse Empower methods to improve robustness etc.
3) For processing methods, recommend using ApexTrack.
4) Start with the auto calculated values, then tweak PW and threshold as best as you can, - in small increments (remember that PW is a smoothing function in the integration algorithm).
5) Then use timed events where specific areas are troublesome – these will work best if you have reliable chromatography, hence starting with point 1).


Hope this helps.
Ben

[Brockboy02]

thanks!! So far, so great!!