PeakWright / Guides
Opening ChemStation data without ChemStation
Six short guides for the situation almost everyone here is in: you have the files, the instrument PC is somewhere else, and nobody is going to buy you a licence to look at your own run.
These pages describe the whole field, not just this tool. Where something else is the better answer for what you are doing, they say so, because a page that pretends otherwise is not worth reading twice.
Start here
Almost everyone arriving at these pages is in one of four situations, and they need different things.
- You left the lab. You ran the samples on an instrument you no longer have access to, and the files came with you. Start with opening a .ch file.
-
Someone sent you data. A collaborator emailed a folder and nothing on your
machine will open it. Start with
what is inside a .D folder, because a
.Dis a folder and that alone stops most people. - You need the numbers. The plot is not enough and you want retention time against signal in something you can work with. Start with getting the data into CSV.
- Something already failed. You tried and got an error, or worse, a chromatogram that looks wrong. Start with when a file will not open.
None of these files are encrypted or licence locked. The reason they were hard to open for so long is that Agilent never published the layout, so every reader that exists was written by someone reading bytes. That work is largely done now, and the format reference writes down what is known.
The guides
-
How to open a .ch file without ChemStation
The main question, answered directly. What a
.chfile actually is, which versions can be read outside Agilent software, and the four routes that work. -
What is inside a .D folder
A
.Dis a folder, not a file, which is where most confusion starts. What each file in it holds, which one has your chromatogram, and which ones you can ignore. -
Reading .uv DAD data without a licence
The hardest one. A
.uvholds a full spectrum at every time point, most free tools treat it as experimental, and that is why so many DAD threads go unanswered. - Getting ChemStation data into CSV Once you can read the file, you usually want the numbers somewhere else. Retention time against signal, at full resolution, in something Excel, Python or R will open.
-
When a ChemStation file will not open
The specific failures: an unsupported file type number, a
.Dcopied without its contents, a zero byte file, an archive rather than a run, and a file that opens but looks wrong. - The tools compared: OpenChrom, rainbow, chromConverter and this What each one is, what it costs, what it installs, and which to pick. Written to be useful even if you decide against us.
The format reference
If you are writing your own reader rather than looking for one, the binary format reference documents the header layout, the string offsets, the delta encoding and the four offsets that no published document covers.
Or just open the file
Drop a .ch or .uv into the viewer and read the chromatogram. It
runs in your browser, the file is never uploaded, and there is nothing to install or sign up
for.
PeakWright is not affiliated with or endorsed by Agilent Technologies. "ChemStation" and "OpenLab" are their trademarks.