Question

8. Why does the extract have to be concentrated prior to analysis for low concentration samples?

9. Why is sample clean-up necessary?

Answer 1

8.The development of new LC-MS/MS methods for small molecules in biological fluids is becoming increasingly more challenging, because of the need to continuously achieve higher sensitivity and better assay robustness in complex biofluids such as serum, plasma, urine, oral fluid or cerebrospinal fluid (CSF). In addition, because of the very low concentration levels of( pharmaceutical) targets, samples often need to be pre-concentrated before analysis. Unfortunately, this does not only increase the concentration of the desired compound in the sample extract but also often raises the levels of interfering components. As a result, very specific and effective sample clean-up procedures are required for sensitive and selective LC-MS/MS assays.

9.The primary goal of sample preparation is to isolate one or several target analytes from the other components of the sample mixture (matrix). Depending on their nature and concentration levels, co-components of the sample matrix can influence the quantitation of target analyte(s) during subsequent liquid chromatography-mass spectrometry (LC-MS) or tandem mass spectrometry (LC-MS/MS) experiments if not removed prior to analysis.