Cloud Point Extraction for the Determination of Trace Amounts of Cobalt in Water and Food Samples by Flame Atomic Absorption Spectrometry

Table 2

Characteristics performance of the presented CPE method.

Parameter	Optimum value
Equation for the calibration curve, 𝐶/(μg mL^−1)	𝐴=0.0767𝐶Co+0.0095
Correlation coefficient (𝑅)	0.9984
Linear range (μg mL^−1)	0.002–1.2
RSD (%, 𝑛=6)	2.78
Limit of detection (ng mL^−1) (3𝑆𝑏/𝑚, 𝑛=11)	0.47
Enrichment factor	19
Extraction coefficient	~1
Phase volume ratio	0.02

Enrichment factor: ratio between Co concentration in the surfactant-rich phase and in the original solution.
Extraction coefficient: ratio between Co  quantity in the surfactant-rich phase after the cloud point and in the original solution.
Phase volume ratio: ratio between the final volume of the surfactant-rich phase and the aqueous phase.