State of the art in fiber optics sensors for heavy metals detection

• An exhaustive study of various optical methods for heavy metal detection, i.e. , fiber grating method, modal interference method, fluorescence method, optical absorbance method, and surface plasmon method. • Practical demonstration of the various fiber optics sensor and sensing setup for heavy metal detection. • Detail information about several antigens and antibodies, chelators, chemicals to detect heavy metal ions along with their chemical and structural formula. Several pollutants are getting added to the water content in today's world, sometimes intentionally and sometimes unintentionally. These pollutants, chemicals, and heavy metals can severely affect people's health, causing cancer, tuberculosis, and even death. An optical sensor has tremendous potential to detect heavy metals ion. These sensors possess several properties like minute size, remote sensing monitoring, real-time investigation, chemical inertness, non-reactiveness, etc. , which are considered ideal for heavy metal detection. This work has presented an exhaustive study of different optical methods like fiber grating method, modal interference method, fluorescence method, optical absorbance method, surface plasmon method, and surface-enhanced Raman scattering method to detect heavy metals ions. Various advantages and shortcomings of these methods are analyzed, along with details of the chemicals, structural formulas, and multiple setups developed to detect heavy metal ions. Finally, the advancement in fiber optics sensors from future perspectives is also discussed.