Self-test 5.4A – Validation of liquid chromatography mass spectrometry (LC-MS) methods

1. If blank matrix is not available for the analyst matrix effect can be estimated with:

Comparing peak areas for post-extraction spiked samples and standards with the same concentration.

Comparing calibration graph slopes for post-extraction spiked samples and standards.

Comparing calibration graph slopes for pre-extraction spiked samples and standards.

2. You are using a LC-MS (LC is reversed phase) and you observe severe matrix effect. How to remove or reduce matrix effect?

Add solid phase exctraction (C18) procedure for sample concentration to your sample preparation.

Dilute the sample.

Inject smaller sample amount.

3. Process efficiency expresses the efficiency of the sample preparation step.

True

False

4. Process efficiency refers to the joint effect of possible losses during sample preparation and ionization suppression/enhancement in the ion source.

True

False

5. Please rate the options for counting the matrix effect:

Structurally similar internal standard
Standard addition
Matrix matched calibration
Isotope dilution