Rachel Sun, Gary Overdorf
Bioanalytical Systems, Inc., 2701 Kent Avenue, West Lafayette, IN 47906
|Column:||Gemini C18, 50 x 2.0, 3Î¼, #408886-5|
|Mobile Phase A:||0.1% formic acid in water|
|Mobile Phase B:||100% Acetonitrile|
|Run time:||7.5 minutes|
|Retention time:||2.5 minutes for HCD; 4.2 minutes for MPA|
|Mass spectrometer:||API 4000|
|Ion Monitored:||0 to 3.2 minutes|
|HCD and HCD-d6, +300.1/199, +306.2/202,|
|3.2 to 6.0 minutes|
|MPA and MPA-d3, -319/191, -322/191,|
Low calibration standard
0.200 ng/mL for HCD and 50.0 ng/mL for MPA
The recovery for liquid-liquid extraction is variable with different extraction conditions.
The presence of drugs, their metabolites and co-administered drugs often require quantitation of a set of chemicals with different chemical properties, such as pKa. One solvent or pH extraction condition could prove difficult in achieving adequate recovery for all the interested compounds in a single extraction. Double liquid-liquid extraction gives the flexibility to change extraction pH, as demonstrated above, or extraction solvents to greatly enhance analyte recovery.
This novel methodology enlarges the scope of a liquid-liquid extraction sample preparation method. The method could be adjusted according to analytes' pKa. Acidic, basic or neutral conditions could be combined to extract compounds with different chemical identities, such drug and metabolites.