one analyte - two peaks

[ToxicLy]

hi,

im working with LC/MS (Shimadzu/API2000) using a HILIC column. when I spike my matrix (saliva) with the analytes (drugs), one analyte gives me two peaks. the second peak is baseline-seperated and symmetric. has anyone an idea why this phenomenon occurs?

[Noser222]

Does it give you two peaks only when you spike in the matrix?
Please give more info about your method...

(my 100th post )

[chromatographer1]

You have not said anything about if you do not spike this analyte in the matrix. Does it give one peak in solution and two peaks in the matrix?

Assuming it gives one peak in solution and two peaks in the matrix (saliva) then perhaps saliva causes a reaction and has enough reactant to partially react with the analyte added to it, giving you two products which separate on your chromatography system.

Another situation: The saliva causes a splitting of the pure analyte's plug into two peaks initially on the column but separates sharply enough and quickly enough to maintain the split plug as it elutes from the column. Do you still get two peaks if you dilute the saliva matrix with water?

A lot of speculation could be offered without knowing the nature of the analyte and the chromatography conditions but I would just be typing myself to death. Please offer additional and complete information that may help the forum answer your question.

best wishes,

Rod