Fig. 12
From: Validation and calibration of a novel GEM biosensor for specific detection of Cd2+, Zn2+, and Pb2+
Calibration plot of heavy metal combination treatments between fluorescent intensities in CTCF and heavy metal concentrations in ppb. The fluorescent intensities have been obtained for samples containing metal ion concentrations in between 1 to 6 ppb of total heavy metal concentrations. The treatments with [Cd2+  + Pb2+], [Pb2+ + Zn2+], [Cd2+  + Zn2+], and [Cd2+  + Zn2+  + Pb2+] are shown in black colour bars, orange colour bars, blue colour bars and red colour bars in order. The R2 values for [Cd2+  + Pb2+], [Pb2+ + Zn2+], [Cd2+  + Zn2+], and [Cd2+  + Zn2+  + Pb2+] combination treatment trends are as 0.9427, 0.9719, 0.9803 and 0.9820. The error bars represent standard mean differences of three independent biological treatments. A single asterisk (*) represents a P value less than 0.05 (P < 0.05), indicating statistical significance at the 0.05 level. Double asterisks (**) represent a P value less than 0.01 (P < 0.01), indicating statistical significance at the 0.01 level. Triple asterisks (***) represent a P value less than 0.001 (P < 0.001), indicating statistical significance at the 0.001 level. Quadruple asterisks (****) represent a P value less than 0.001 (P < 0.0001), indicating statistical significance at the 0.0001 level