Chromatography Forum

We were about to order a few reagents as modifiers/buffers for our lab. Looking through the catalog, we noticed only a few were sold as HPLC reagents and that most were only available as ACS or in 99 or 99.5 % purity.

Do you *need* the HPLC-grade stuff? Have you had problems with UV absorbance using ACS-grade reagents? Being a university, there is also a cost-issue here...

Mostly, we were looking at DEA, TEA, TFA, NH4OAc, AcOH, NaOAc, phosphoric acid, dibasic and monobasic sodium phosphates.

Thank you!

Roxanne.

one thing I know: if you develop a gradient method the buffer impuirty will cause much more troubles than an isocratic method. If you can stick to isocratic methods you do not have to worry about the impurity unless the impurity irreversibly sticks to the column so that destroys the column.

HPLC grade solvent is not much more expensive than ACS, some times even cheaper. I guess the only difference is that some particulate is remvoed in HPLC grade. I am not sure but it may be true for all chemicals.

Good TFA is worth the extra expense. One wasted day, even at grad student wages, will pay for the difference. In general, the quantities of modifiers and buffers you need are small, a few grams at a time, so you can buy a small bottle, and reserve it for HPLC use. You won't run out before the project is finished.