Exporting chemstation data collected at 200hz to Excel

[JasonNJ]

I am running a chemstation method which lasts 40 minutes, collecting data at 200hz. The peaks I am specifically interested in (desorption following a valve switch) occur starting at 28 minutes into the method.

My problem is that when I try to export the datafile into Excel as a .csv, I only capture the first 5 minutes of the run, which is of no real use. This is due to the .csv file being completely filled to the ~64000 row mark at this data collection rate. Is it possible to configure the exportation of the data or the method itself to be concerned with (or only collect) data from the 28 to 33 minute mark?

Best regards,

Jason

[tom jupille]

A .csv file is simply text. You should be able to open the exported file with any text editor and then copy the first line (which is the header) and any other portion you're interested in. Paste those into a new file, save it, and rename the extension to .csv.

For example, I created a small file in Excel with two columns (the value of the second is twice that of the first). I saved it as "demo.csv" and then opened it in NotePad. Here's what it looks like:

Column 1,Column 2
1,1
2,4
3,6
4,8

[macgyver]

Try and use a later version of Excel. Older versions of Excel had a row limit of 65,536 rows. Excel 2007 and later increased the maximum number of rows to 1,048,576. You should be able import up to 87 mins of 200Hz data. It might be slow trying to create a plot of this data in Excel though.

I don't know whether there is a way to export a certain time range in Chemstation. Someone on the forum may be able to write a macro for you to do this if it can't easily be done from Chemstation.

[lmh]

what's your peak width? Do you really need to collect data at 200Hz?

[AICMM]

JasonNJ,

Instrument, Edit parameters, signals, partial, start and stop time. Have not done it myself but I just looked at my Chemstation software. Unless you are doing multi-dimensional chromatography, the question about 200 Hz being too fast is certainly one you might wish to think about. Typically people say 10 - 20 points describes a peak so unless you peak width at that time is 1/2 second or less wide, you may be acquiring too much data.

Best regards,

AICMM

[Peter Apps]

Number crunching on this scale is not Excel's strong point (I have tried some plotting of 5 min subsections of MS data, with 20 m/z values at each scan) and it goes very slowly.

At the cost of a bit of user friendliness, you would do better with one of the more "mathematical" packages like MATLAB or R. If you have one of the statistics packages it might also work.

Peter