Fig. 2. (a) The absorbance spectra of guava leaf extract–iron complex in
water, measured against water. (b) The absorbance spectra of guava leaf
extract–iron complex in acetate buffer solution, measured against acetate
buffer: ( ) guava leaf extract; ( ) guava leaf extract with Fe (III) 100 ppm;
( ) guava leaf extract with Fe (III) 10 ppm; () guava leaf extract with Fe
(II) 100 ppm and (× ) guava leaf extract with Fe (II) 10 ppm