Concentration Peak (nm) Absorbance Band width (nm) 1mM Au & 40 mM citrate 527 0.51 140 1mM Au & 100 mM citrate 523 0.6 110 1mM Au & 150 mM citrate 523 0.27 100 4mM Au & 100 mM citrate 256,530,772 0.43,0.28,0.29 50,65,190

Table 1: UV–VIS spectrum for different Au and citrate concentrations.