Hi guys,
could you please help me out
I made 1000 ppm standard solution of caffeine by dissolving 198,2mg caffeine in 200 ml of purified water.
Than mixture was pipetted to different 50 ml volumetric flask as follows 25 ml, 12.5 ml, 10 ml, 7.5 ml, 5 ml and 2.5 ml and than diluted to volume with purified water.
QUESTIONS IS How to calculate these samples caffeine concentration (ppm)?
It shows on my lab protocol that 25 ml is 100 ppm, 12.5 ml is 50ppm, 10 ml is 40 ppm.
Can not get my head right to answer and tried everything. I really need your help people PRETTY PLEASE!