Bioequivalence and Bioavailability Forum • variation in response of the analyte and internal standard

variation in response of the analyte and internal standard [Bioanalytics]

posted by haydonat – Turkey, 2011-01-13 11:27 (5644 d 08:46 ago) – Posting: # 6410
Views: 6,748

Dear all;

I have response variation problem. When injections made from same vial responses of the analyte and IS changes but not with same proportionation.

extraction procedure: liquid-liquid sample preparation
column: x-terra c18
mobile phase: Acetonitrile: 10mM ammonium acetate:formic acid (50:50:0.530, v:v:v) pH: 4.6
reconstitue solution: water+25mM ammonia+ACN (50:50), pH: 9.9
injection volume: 15 µl
flow rate: 0.25 ml/min

Also after every six injections in a batch mobile phase is injected four times
and results get better with this procedure. But, I can not provide reproducibility between batches.Results of one batch could be good with MP cleaning,but the other ones results could be bad. :crying:

I have written my conditions above, without any changes in my conditions, what can you suggest me solve response difference problem? :ponder:

Hale Aydonat

Complete thread:

variation in response of the analyte and internal standardhaydonat 2011-01-13 10:27
- variation in response of the analyte and internal standard Helmut 2011-01-13 17:08
  - variation in response of the analyte and internal standard haydonat 2011-01-15 15:16
    - variation in response of the analyte and internal standard Ohlbe 2011-01-15 23:09
- variation in response of the analyte and internal standard Ohlbe 2011-01-13 19:14
  - variation in response of the analyte and internal standard haydonat 2011-01-15 15:22
- variation in response of the analyte and internal standard NewInPK 2011-02-01 18:32
  - variation in response of the analyte and internal standard Ohlbe 2011-02-02 10:22