Table 1.

The influence of pH adjustment and buffering on the observed concentration of caffeine at t = 0. The actual quantity was 5.0 mg L⁻¹.

C0 (mg L−1)
pH=4.0	pH=7.0		pH=9.0
	no buffer	with buffer
4.85±0.15	4.30±0.29	4.49±0.59	3.98±0.50