Figure 2

Performances of the single-indicator-based sensing platform to multiple metal ions.
(a) Color images of the dithizone-CTAB mixture before and after exposure to ten heavy metal ions at their standard concentrations of wastewater discharge of China and the color difference map. For purposes of visualization, the color range of the difference map was expanded from 4 to 8 bits per color (RGB range of 4–19 expanded to 0–255). (b,c) Recognition patterns (b) and HCA (c) for the ten heavy metal ions at their wastewater discharge standard concentrations of China and a control based on their corresponding ΔRGB values obtained from the “before” and “after” images. No confusions or errors in classification were observed in 66 trials. Error bars in (b) represent standard deviations of six parallel measurements.