Chromatography Forum

Hi guys,

I want to just run a test-run on a UHPLC with mobile phase 100% H2O. I only have NaH2PO4 dihydrate and 0.1 M HCl in the lab, with no pH meter...with this, I am hesitant about making a buffer, so I want to run the caffeine w/out buffer. Since its a test run I don't care about the quality of my peak/or peaks. Just wanted to know if this would hurt the machine. I will start with making probably a 10 to 50 mM solution. Thanks a lot guys.

You will need 40-60% methanol to get a reasonable elution time for caffeine on a C-18 column. You can just add 1% acetic acid to the mixture instead of messing with a buffer.

Do you want to run with or without column? What are you trying to accomplish by this test run?

You will need 40-60% methanol to get a reasonable elution time for caffeine on a C-18 column. You can just add 1% acetic acid to the mixture instead of messing with a buffer.

We run our caffeine method on plain water-methanol, without buffer, so no worries about messing around with buffers/acetic acid/....

thanks guys. I just want to get a hang on using the HPLC... My background is in theoretical chem. but unfortunately I only have a Master's degree and most jobs for computational chem require Ph.D. But they say if you are theoretical then you can do analytical, but not the other way around.

they say if you are theoretical then you can do analytical, but not the other way around.

That's interesting. I'm an analytical chemist but many of my experiments begin with the comment "Theoretically, this should work."