Spectrophotometric Determination of Iron(II) after Solid Phase Extraction of Its 2,2′ Bipyridine Complex on Silica Gel-Polyethylene Glycol

Table 3

Determination of iron(II) in different samples.

Sample	Added (ng mL^−1)	Found^a (ng mL^−1)	Recovery (%)
Tap water	—	ND	—
	4	3.9±0.5	97.5
	8	7.8±1.0	97.5
Multivitamin^b	—	7.6±1.0	—
	10	17.6±1.0	100.0
	20	27.5±1.2	99.5
Spinach^c	—	39.0±0.8	—
	10	48.2±1.3	97.9

^a𝑥±𝑡𝑠/√𝑛 at 95 % confidence (𝑛=5).
^bAmount of iron per tablet was 9.7 mg.
^cAmount of iron was 40.6 μg g⁻¹ of spinach.
ND: not detected.