High Perform Liquid Chromatography 2e: 33 (Analytical Chemistry by Open Learning)

A super book will explain gas chromatography too.Need to think about the maths do not just learn formula, more than one way to think about it, use triangles of 180 and 90 to work out dilutions, that is 180/3 is 60 and 90 is near 100 so 90 divided by 3 is 30 and 30 divided by 3 is 10 so 60 +40 is 100%, so weigh your tablet and crush then dissolve in 100mls. A 100 x 10 is a 1000 so muliply percent by 10 to get Milligrams, so 1.2% becomes 12ppm of caffeine. 12x5=60 which is close to std.