o GF-AAS (Muscle samples of fish) o AFS (Water) o XRFS (Wastewater sample) o Potentiometry (Thiourea-functionalized nanoporous silica-modified carbon paste electrode) o Screen-printed electrode (Zirconium antimonateionophore) o Amperometric method (Pt/CeO2/urease-modified electrode) The current method uses a biosensor that detects changes in temperature and color, unlike the previous methods which used various spectroscopy techniques, potentiometry, and amperometric methods.