Trisodium citrate (Na3C6H5O7.2H2O) was used as reducing agent. Gold salt was mixed and boiled to the boiling point (97.5°C) at prepared concentration to start the synthesis reaction. Gold salt was yellow at that time. After adding the prepared sodium citrate to the solution, sodium citrate turned to citric acid. At that stage yellow coloured solution suddenly became transparent and colourless. It changed to black and after than slowly to wine red [15]