Saturday, July 8, 2017
When selecting standards for use in testing an HPLC column OR for evaluation of an HPLC system’s performance (e.g. System Suitability, Performance Verification, Retention), in addition to selecting special high purity chemical compounds, consider using the actual sample which is specific to the method or application. Characterize the sample’s retention, peak shape and spectra (if applicable) and use the data to measure, compare and detect changes in performance over time.
Running Sugars on an Amino Column? Use simple and complex sugars as standards. Example: D-Fructose; D-Glucose; Lactose; Maltose; Sucrose.
NP (prepare the test solution in a mixture of Hexane/Ethanol, as appropriate)
Diethyl phthalate; Dimethyl phthalate; Toluene; Benzene.
RP (prepare a test solution in ACN/Water or Methanol/Water, as applicable)
Select 4 or 5 of these compounds for use in a mix. Uracil; Benzene, Acetophenone; Toluene; Naphthalene; N,N-Diethyl-m-toluamide; Phenol; diethyl phthalate; diamyl phthalate; di-n-hexyl phthalate; dioctyl phthalate.
Include a Void Marker in your Test Solution:
Always measure the actual void volume of your specific HPLC column with a compound which is un-retained by your column. For RP applications which utilize at least 20% organic, Uracil or Thiourea are often used, but some inorganic salts (e.g. sodium nitrite and sodium nitrate) have also been shown to work as well.