HPLC determination of caffeine and theophylline by direct serum injection.
Helmsing
P J
PJ
Huisman
R
R
van der Weele
A
A
D002110:Caffeine / Q000097:blood*; D002851:Chromatography, High Pressure Liquid / Q000379:methods* / Q000706:statistics & numerical data; D006801:Humans; D013806:Theophylline / Q000097:blood*
D002110:Caffeine; D013806:Theophylline