Surfactant Sensitized Calix[4]arenes Fluorescence Quenching Method for Speciation of Cr(VI)/Cr(III) in Water Samples

Table 4

Determination of Cr(III) and Cr(VI) in real water samples (mean ± S.D., 𝑛=3).

Sample	Added (µg mL^−1)		Found (µg mL^−1)			Recovery (%)
	Cr(VI)	Cr(III)	Cr(VI)	Cr(III)^a	Total Cr	Cr(VI)	Cr(III)	Total Cr
Tap water	0	0	ND	ND	ND	—	—	—
	0.25	0.25	0.24±0.01	0.26±0.01	0.51±0.01	96.0	104.0	102.0
	0.50	0.50	0.52±0.01	0.51±0.01	1.03±0.01	104.0	102.0	103.0

ND: Not detected; ^aThe concentration of Cr(III) was calculated by subtracting of Cr(VI ) from the total chromium.