Determination of Chromium in Natural Water by Adsorptive Stripping Voltammetry Using In Situ Bismuth Film Electrode

Table 4

Accuracy of the SqW-AdSV/in situ BiFE for the determination of chromium in surface water.

Information		[Cr(VI)](ppb)	CCr (ppb)
Experiment	1	0.38	1.90
	2	0.40	2.00
	3	0.40	2.00
Average ± S (ppb)		1.97 ± 0.08
Cr content in the CRM sample (ppb)		2.00 ± 0.02 (CCr = 1.98 ÷ 2.02 ppb)
RSD (%), n = 3		4

^(a)[Cr(VI)] is the concentration of Cr(VI) in the electrolyte minus the blank. White sample has [Cr(VI)] = 0.034 ppb; C_Cr is the Cr content in the sample (calculated by the formula: C_Cr = [Cr(VI)] .V₂/V₁). V₁: volume of solution taken into the electrolyser (V₁ = 2 ml), V₂: volume of solution in the electrolyser (V₂ = 10 mL), S is the standard deviation. Experimental conditions are as shown in Table 3.