Development of a Cloud-Point Extraction Method for Cobalt Determination in Natural Water Samples

Table 4

Determination of Co(II) in tap, mineral, river, and sea water samples and relative recoveries of spiked samples.

Sample	Co(II) ± S.D.^a (μg L^−1)	Added Co(II) (μg L^−1)	Found Co(II) ± S.D.^a (μg L^−1)	Recovery (%)
Tap water^b		—	—	—
	n.d.^f	50.0	51.6±1.8	103.2
		100.0	102.1±3.9	102.1
Mineral water^c		—	—	—
	n.d.	50.0	49.0±1.7	98.0
		100.0	98.7±3.2	98.7
River water^d		—	—	—
	8.5±0.3	50.0	56.2±1.9	95.4
		100.0	105.6±3.7	97.1
Sea water^e		—	—	—
	9.4±0.5	50.0	56.5±1.6	94.2
		100.0	106.2±3.5	96.8

^aStandard deviation (𝑛=5).
^bBehshahr drinking water system, Iran.
^cDamavand mineral water, Iran.
^dTajan river water, north of Iran.
^eCaspian sea water, Iran.
^fNot detected.