Evaluating the Performance of a Diffusive Gradient in Thin Film Embedded with Montmorillonite for the Determination of Labile Cd, Pb, Mn, and Zn in Natural River Water

Table 2

Average labile concentrations, standard deviations of the measurements, and recovery values for metals uptake by DGT-MMT and DGT-Chelex-100 (n = 7).

DGT device	DGT-MMT				DGT-Chelex-100
	Cd^2+	Pb^2+	Zn^2+	Mn^2+	Cd^2+	Pb^2+	Zn^2+	Mn^2+
Average labile metal concentration (Cavg), μg L^−1	19.2	19.6	18.1	18.0	19.0	19.4	18.0	18.1
Standard deviation (SD), μg L^−1	0.40	0.26	0.60	0.46	0.36	0.17	0.75	0.84
Relative standard deviation (RSD), %	2.10	1.31	3.30	2.53	1.88	0.86	4.15	4.65
Recovery (H), %	95.8	97.8	90.3	90.2	95.1	96.9	90.0	90.4
Relative error (X), %	4.2	2.2	9.7	9.8	4.9	3.1	10	9.6