Question

Experiment #4 Data Name of Energy Drink: Red but Mass of Caffeine in Stock Solution: 1293 Mass of Pyridoxine Hydrochloride (Vitamin B6) in stock solution: 0.05189 HPLC data: Caffeine Data: Stock Solution Added 0 mL Peak Area 107648 0.5 mL 127414 1.0 mL 1.5 mL 130320 136455 14५५०१ 2.0 mL Vitamin B6 Data: Sample 0 mL Peak Area 51785 0.5 mL 62596 Sot 1819 1.0 mL 1.5 mL 88529 7933) 89862 2.0 mL

Answer 1

a) concentration of caffeine = mass of caffeine /Volume added = 0.1293 g/ 0.5mL = 0.2586 g/mL

Concentration of Vitamin B6 = mass of Vitamin B6 /Volume added = 0.0518g/ 0.5 mL = 0.1036 g/mL

This can be repeated for all the volumes.

Caffeine stock volume (mL)	Peak area	Concentration caffeine (g/mL)	B6 stock volume (mL)	peak area	Concentration B6 (g/mL)
0	107648	0.0000	0	51785	0.0000
0.5	127414	0.2586	0.5	62596	0.1036
1	130320	0.1293	1	88509	0.0518
1.5	136455	0.0862	1.5	79331	0.0345
2	144429	0.0647	2	89862	0.0259

b)

Standard Addition curve Caffeine 160000 140000 120000 100000 80000 60000 40000 20000 y = -142377x + 144636 peak area 0.0000 0.0500 0.1000 0.3000 0.1500 0.2000 0.2500 concentration of caffein (g/mL) Standard Addition curve. Linear (Standard Addition curve)

c)

Standard Addition curve B6 100000 80000 60000 y=-315406x + 97093 Peak Area 40000 20000 0.0000 0.0200 0.1000 0.1200 0.0400 0.0600 0.0800 Concentration B6 (g/mL) Standard Addition curve B6.***** Linear (Standard Addition curve B6)

d)

Concentrations of caffeine and Vitamin B6 can be found out once we know the peak area for them. Using the equations of the graph we can calculate for x.

Caffeine: y =-142377x + 144636

y = 107648 when no stock solution is added.

x = -(107648-144636)/142377 = 0.259 g/mL

Vitamin B6: y = -315406x + 97093

y= 51785 when no stock is added

x = -(51785-97093)/ 315406 = 0.144 g/mL