Validation of liquid chromatography mass spectrometry (LC-MS) methods

Self test 10.1

1. Look at the list of compounds. Please indicate the compounds with increasing retention time in reversed phase stationary phase (C18) when the mobile phase pH is changed one unit from pH 10 to 11.
CompoundpKa

Bases

Pyrrolidine11.27
Piperidine11.12
2-methylpyridine5.97

Acids

2-nitrophenol7.17
2,5-dinitrophenol5.15
3-nitroaniline17.9

2. Indicate correct statements concerning  influence of the changes in liquid chromatography.

 

3. Indicate correct statements concerning  influence of the changes in sample preparation.

4. Indicate correct statements concerning  influence of the changes in mass spectrometry.

5. Indicate the correct influence (Low, Medium, High) of the parameter to the method performance:

1. Liquid chromatography

Parameter Change in the parameter Influence
pH - 1 unit
Organic solvent + 10%
Column temperature +15 °C
Eluent flow rate + 20%

 

2. Mass spectrometry

Parameter Change in the parameter Influence
Drying gas temp + 10 °C
Nebulizer gas pressure/flow rate + 5 psi / + 1 L/min
Ion source configuration (Nebulizer position) Variations in the configuration during the last usage


 

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