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How to decrease file size with Waters 2996 PDA?

Posted: Wed Jan 11, 2017 9:30 pm
by Dr Zoidberg
Maybe a bizarre problem, but here goes. We got a PDA detector over the summer and now our computer's hard drive is full. I'm currently doing a 15 min run with a gradient of 5-95% ACN over that period. Each run takes up 700 MB! I could get away with just a UV detector, but now we have the PDA so I've got to figure out how to make this work. I've been looking for a way to decrease the raw data file size, but increasing the resolution (1.2 to either 2.4 or 3.6 nm) and decreasing the sampling rate (1 to 0.5 sample/sec) haven't helped. I'm trying to find something online or in the user manual but am coming up empty. Any suggestions?

Re: How to decrease file size with Waters 2996 PDA?

Posted: Thu Jan 12, 2017 8:35 am
by etaxene
Dr Zoidberg wrote:
Maybe a bizarre problem, but here goes. We got a PDA detector over the summer and now our computer's hard drive is full. I'm currently doing a 15 min run with a gradient of 5-95% ACN over that period. Each run takes up 700 MB! I could get away with just a UV detector, but now we have the PDA so I've got to figure out how to make this work. I've been looking for a way to decrease the raw data file size, but increasing the resolution (1.2 to either 2.4 or 3.6 nm) and decreasing the sampling rate (1 to 0.5 sample/sec) haven't helped. I'm trying to find something online or in the user manual but am coming up empty. Any suggestions?


Change Method Instrument. Uncheck "spectra".

Re: How to decrease file size with Waters 2996 PDA?

Posted: Thu Jan 12, 2017 5:00 pm
by ScottHorn
You could also try compression software, if you decide you do want the spectral data. Zip is generally the most common, but I find .RAR (Winrar, the free download says it's a trial, but it really never stops working) to be superior in some situations. If you have a fast processor, select "Best" under compression method. I imagine your chromatography software probably doesn't apply any compression to the collected data, so you should be able to get some decent compression ratios.
On another note, hard drives are dirt cheap nowadays, with the increasing popularity of SSD's. A 2 terabyte internal hard drive can be had for around $50 before shipping. You'd be able to fit a few thousand chromatograms on one before compression.

Re: How to decrease file size with Waters 2996 PDA?

Posted: Sun Jan 15, 2017 2:58 am
by DR
Higher sampling rates, max resolution, huge wavelength range all lead to huge files for spectral data. Waters' defaults all tend to be too big/fast/narrow vs what's actually needed. You probably don't need 3d for your entire run either.