The FIC was determined according to the method of Wang
et al.[17]. The sample consisted of 1 mL of algal extracts at
different concentrations (7.81–1000mg/L), 1.35 mL distilled
water, 50mL ferrous chloride (2 mM) and 100mL ferrozine
(5 mM). In the blank sample, 100 mL distilled water replaced
ferrozine, while in the control, 1 mL water was used instead
of the algal extract. Sample, blank sample and control were
incubated at room temperature for 10 min, and the absorbance
was read at 562 nm in a microplate reader (Biochrom Asys
UVM 340). The ethylenediaminetetraacetic acid was used as a
positive control at the same concentrations of algal extracts.
The percentage of ferrous ion chelating ability was calculated
according to the Eq.(2)