o AAS (Seawater) o GF-AAS (Chinese tea) o AAS (Chinese tablets) o AAS (Chinese taponintablet recipe) o XRFS (Soil, coastal sea water, soil sample, fish tissues) o Amperometric method (Single carbon fibre electrode) The current method uses a biosensor that detects changes in temperature and colour changes unlike the previous methods which used various spectroscopy techniques and amperometric methods.