File Name : figure s1.tif Caption : thermogravimetric analysis (tga) curve of agnps synthesized using averrhoa bilimbi fruit extract at 60 °c and ph =10 for 30 min (conditions: n2 and 10 °c/min). File Name : figure s2.tif Caption : edx spectrum of agnps synthesized using averrhoa bilimbi fruit extract at 60 °c and ph =10 for 30 min File Name : figure s3a.tif Caption : sr-xps c1s core level spectra File Name : figure s3b.tif Caption : sr-xps o1s core level spectra File Name : figure s4.tif Caption : colorimetric image of agnps with different metal ions File Name : figure s5.tif Caption : uv-vis absorption of agnps solutions incubated with hg2+ and other 14 metal ions. inside: colorimetric images of agnps with equimolar hg2+ and other metal ions. File Name : figure s6.tif Caption : uv-vis spectra of agnps, agnps incubate with 14 other metal ions and agnps incubated with hg2+ along 14 other metal ions File Name : figure s7 .tif Caption : colorimetric image of agnps with different concentration of hg2+ ions.