Difference between UV-spectra assay results and HPLC-UV

[ajaykashetti]

Dear all,
I am facing one issue, assay values by Normal UV-Spectra were less than HPLC-UV specra for one formulation.
What are the possibilities for getting this type of issue.

[tom jupille]

Lots of possible reasons, but we would have to get much more detail about each assay. For starters, did you run calibration curves with known standards in both cases, or did you rely on literature values for extinction coefficient in the UV assay?