A silver enhanced and sensitive strip sensor for Cadmium detection

Figures & data

Figure 1. The scheme of antibody-based Cd(II) immunochromatographic strip (a), the negative and positive results (b) and silver enhancement before and after (c).

Figure 2. Immunochromatographic detection of Cd(II). A series of dilutions (2–20 µg/L) of Cd(II) was prepared in HBS.

Figure 3. Immunochromatographic detection of Cd(II) with silver enhancement (b) and without (a). A series of dilutions (0.5–5µg/L) of Cd(II) was prepared in HBS.

Figure 4. The calibration curve for detection of Cd (II) with silver enhancement. The optical responses of red bands on the strip were recorded with a strip reader. Each sample was analysed for three replicates.

Figure 5. Cross-reactivity of other metal ions by the immunochromatographic strip. The optical responses of red bands on the strip were recorded with a strip reader. Each sample was analysed for three replicates.

Figure S1. TEM image of the synthesized gold nanoparticles.

Figure S2. Standard curve for detection of Cd(II) using ELISA. Each sample was analyzed for three replicates.

Table S1. The intra- and inter-assay of the visual sensor for Cd(II).

Concentration Cd(II) (µg/L)	Intra-assay CV (%)	Inter-assay CV (%)
0	2.2	2.9
0.5	3.4	2.3
1	3.8	4.6
2	4.2	3.4
5	3.2	4.3

Table S2. Recovery test of Cd(II) in drinking water samples.

Drinking water samples	Original concentrations^a (µg/L)	Spiked concentration (µg/L)	Detected concentrations (mean±SD, n = 3) (µg/L)	Recovery (%) (mean±SD, n = 3)
1	0.65	1	1.78±0.06	108±3.7
2	0.65	2	2.59±0.13	98±4.9
3	0.65	5	5.64±0.19	99.0±3.5

^a Original concentrations were detected by ICP-MS.