WorksheetsRound 2: Finals
Total questions: 10
Worksheet time: 3mins
To evaluate the matrix effects, which of the following would be used as
the reference sample
QC prepared in calf plasma
QC prepared in human plasma
QC prepared in solvent
QC prepared in extracted plasma
Compounds with high Log D are all EXCEPT
Mitotane
Voriconazole
Colistin
Mycophenolic Acid
What is the instrument used for
To remove particulate matter from guard column
Degas the solvents
Remove air bubbles from lines
Both A and B
All statements regarding buffers are true except
Buffering increases the ruggedness of the assay since retention of the functional group and peak shape are pH dependent
If 2 compounds co-elute, and if one compound is basic, when the pH of the mobile phase is made more acidic, the retention time of the basic compound will decrease
Buffer capacity is 0% when used at the pKa value
A buffer is a solution that resists pH changes when acids or bases are added to the solution
If Pka of drug is 4 and Mobile phase pH is 4, which among the following represents the state of drug in the solution
Fully ionized
Fully unionized
50% ionized and 50 %unionized
75% ionized and 25 %unionized
If an analyte peak area decreases due to injection variability, but the internal standard peak area decreases proportionally, the calculated concentration will:
Be overestimated
Be underestimated
Remain accurate
Not be detected
The matrix used for calibration spiked with the IS but not containing the analyte is known as
LLOQ
ULOQ
Blank sample
Zero sample
Drug X is a weak acid with a pKa of 5.6. When the mobile phase is a 20 mM phosphate buffer at pH 3.5, the retention time for Drug X is 6 minutes. If the pH of the buffer is increased to 7.0, while keeping the molarity the same, what will happen to the retention time of Drug X?
Retention time remains unaffected
Retention time increases
Retention time decreases
Drug peak will not be detected
Reason for no peaks in chromatogram?
Problem with oven temperature
problem with the Lamp
Not maintaining pump pressure
Changes in pH of buffer
The westguard rule violated in the given diagram is
R4s
41s
2of32s
31s
