Urea analysis HPLC/ C18 column

[ap.floriano]

Does anyone know a method to determine urea in aqueous solution with a C18 column?

[tom jupille]

4,250,000 of them according to Google: +urea +HPLC +C18".

[ph/Amr Tarek]

Urea cannot be retained by C18 columns ( reversed columns )
This is an official method to analyze urea by HPLC :
1) column : Zorbax RX SIL 4.6 × 150 mm
2) mobile phase : (acetonitrile : 0.02M K2HPO4 pH 7.2) (90 : 10)
3) detector : UV 210 nm
4) flow rate : 1 ml/min
Urea retention time is about ( 3 - 4 ) min
Note : Zorbax RX SIL column should be flushed with THF befor equilibrating by the mobile phase .

ph/Amr Tarek
Instrumental Unit Head at Otsuka Pharmaceutical Company

[Vlad Orlovsky]

here are two methods:
http://www.sielc.com/Compound-Urea.html

[dap]

Hello!
Ion pair agent buffered solution may increase retention time. Sodium hexanesulfonate seems to be a good choice. Columns with polar stationary phase such as NH2 or Silica usually show wavy baseline imho.

[Vlad Orlovsky]

Urea is a neutral compound, ion-pairing reagent is going to do nothing

[dap]

Sorry if so.