Optimization of extraction procedure for determination of caffeine residue in water

Extraction procedure for determination of caffeine in water with aided experimental design was successfully optimized. three variables,namely ph sample,flow rate and elution volume were tested during this study using 23 full factorial of central composite design. an optimum working condition was suggested at ph sample (6.4),flow rate (1.2 ml/min) and elution volume of caffeine from sorbent is 9.5 ml of methanol. detection and quantification limits were obtained at 0.02 and 0.25 ng/ml respectively. good recovery was calculated within the range of 80.9 - 93.7 % at three levels of concentration. repeatability and reproducibility value show this method to be reliable for routine analysis with low rsd < 10 %. concentration levels of caffeine in real samples were recorded in the range of 0.64 - 59.01 ng/ml. hierarchical cluster analysis grouped all stations into three clusters at dlink/dmax x 100 < 15. wastewater discharge from cafeteria or residential area was a solid reason linked to the presence of high caffeine during this study.