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

Table 2

Influence of Zn(II), Co(II), and Ni(II) concentrations on peak current.

Cation	Zn(II)			Co (II)			Ni (II)
No.	CZn(II)(nM)	Ip(Cr)(μA)	RE Ip(Cr)(%)	CCo(II)(nM)	Ip(Cr)(μA)	REIp(Cr)(%)	CNi(II)(nM)	Ip(Cr)(μA)	RE Ip(Cr)(%)
1	0	96.4	0	0	76.5	0	0	49.7	0
2	770	96.3	0.1	84	82.4	7.6	84	53.2	3.9
3	1540	94.6	1.9	168	82.5	7.9	168	58.3	10.4
4	2310	87.9	8.7	252	81.7	6.8	252	61.5	14.6
5	3080	80.9	16.0	336	77.8	1.7	336	62.4	19.4

Conditions: C_Cr(VI) = 3.8.10⁻⁹ M = 0.2 ppb; C_Bi(III) = 28.8.10⁻⁵ M; t_ad = 120 s; E_clean = 400 mV; t_clean = 100 s; U_step = 6 mV;  = 210 mV/s; ∆E = 30 mV; f = 35 Hz.;  = 2000 rpm; C_DTPA = 0.4 mM; C_Ac = 0.4 M; C_NaNO3 = 0.4 M; E_ad = −800 mV.