HPLC

Analytical Science 2 Practical 2: High Pressure Liquid Chromatography

Results
Retention times should be quoted to two decimal places and standard deviations to three significant figures.
Retention times (mins):
Anthracene 8.67
Benzene 4.37
Naphthalene 5.98

Anthracene standards

Peak Area
Ratio
Sample
Concentration
Anthracene
Benzene
A/B
4
2.25 mg/100mL
355003
496920
0.714406746
3
4.5 mg/100mL
583453
467385
1.248334885
2
6.75 mg/100mL
888620
513249
1.73136236
1
9 mg/100mL
1097279
518713
2.115387507

Naphthalene standards

Peak Area
Ratio
Sample
Concentration
Naphthalene
Benzene
N/B
4
1.5 mg/100mL
667589
496920
1.343453675
3
3 mg/100mL
1208716
467385
2.586124929
2
4.5 mg/100mL
1978578
513249
3.85500605
1
6 mg/100mL
2566562
518713
4.947942311

Use these data to plot calibration curves of peak area ratio vs. concentration for each analyte. Determine the regression equations. Attach the graphs to your report.

Unknown
Peak Areas
Ratios

Anthracene
Naphthalene
Benzene
A/B
N/B
Injection 1
726795
1593385
470989
1.54312521
3.38306203
Injection 2
739198
1633910
474939
1.55640619
3.44025233
Injection 3
710447
1557105
444770
1.59733570
3.50092183
Average
725480
1594800
463566
1.56499830
3.44028682
SD
14400
38400
16400
0.0283
0.0589

Calculate the concentrations of anthracene and naphthalene in the unknown sample. Include a calculation of the errors associated with the values. Show your calculations below then enter the values into the table.

Anthracene

The average for the peak areas = (726795 + 739198 +710447)/3

= 725480

The standard deviation, s is the square root of the squares of the sum of differences between the mean and the other variables as shown below:

725480 – 726795 = -1315 725480 – 739198 = -13718 725480 – 710447 = 15033

The standard deviation = √(15033^2 +(– 13718^2 )+(–