Matrix response higher than analyte!

[koko]

Hi!
I need help!

I´m develope a method for drug analisys, in the specificity test, matrix show a peak at 1.3 min. The drug show a peak at 7.3 min. different retention time but the response of matrix is higher. Can I use the matrix? I have to change it?

Thank you!

[tom jupille]

So long as the matrix has no peak which overlaps your analyte, there is no problem.

[koko]

Thank you Tom.

[koko]

That means that I have to consider like noise?[/b]

[tom jupille]

No, it's entirely independent of noise.

Your matrix will almost always show some peaks. One of the reasons for demonstrating specificity is to show that none of those peaks interferes (overlaps) with your analyte. That's why you run a matrix blank and then a spiked matrix and you overlay the chromatograms. Here's an old (but good) example (an insect growth regulator in bovine manure):

[koko]

Than you for your help!