Quantutative And Quslitiate Abslysys

Question 1

What features of a chromatogram peak would you use to identify the analyte?

Answer 1

Retention time

Question 2

What features of a chromatogram peak would you use to
determine its concentration

Answer 2

Area under the peak area

Question 3

In a chromatogram, what numerical feature is determined from the time of maximum peak height?

Answer 3

Retention time

Question 4

How is retention time measured?

Answer 4

Go to top of the peak and drop a line down to the axis

Question 5

In a HPLC separation, peak 9 elutes after 4.6 minutes. A standard sample of the amino acid lysine also elutes after 4.6 minutes. When you change the solvent composition, the lysine retention time changes to 6.3 minutes. If peak 9 is lysine, what would happen to its retention time in the new solvent?

Answer 5

If peak 9 is lysine it’s retention time will be 6.3 minutes

If peak nine is not lysine you’ll get an additional peak at another time

Question 6

Normalisation formula

Answer 6

% area of A = area of A x 100/ total area

Question 7

All standard curves in chromatography have what on their axis

Answer 7

y = peak area
x = concentration

Question 8

30 mg / l diluted 2 to 3
30 mg / l diluted 1 to 3

Answer 8

2:3 is 20 mg / l
1:3 is 10 mg / l

Question 9

External standard

Answer 9

Peak area A vs concentration of A

Concentration units eg mg / l

Question 10

Internal standard

Answer 10

Involves calculating the peak area ratio

Y = Divide test sample peak area by internal standard peak area eg ethanol pa / propanol pa

X = test sample concentration v ethanol concentration