Heavy metal ions are basic elements of earth crust. These metal ions are
non-biodegradable in nature and tend to accumulate in our ecosystem in due course of
time. Some of the most toxic heavy metal ions include arsenic, mercury, cadmium,
lead, nickel etc. The toxicity level depends on density for any biological system. Due to
increasing applications of heavy metal ion compounds in industrial, agricultural and
medical fields, water pollution induced by excess levels of heavy metal ion becomes a
big crisis for us. As such, detection of heavy metal ions in water is an important issue
for us. Mass spectroscopy methods are the most conventionally applied methods for the
detection of heavy metal ions in water. Some of the mass spectroscopic methods are
atomic absorption spectroscopy, inductively coupled plasma mass spectroscopy,
graphite furnace atomic absorption spectroscopy etc. These methods have well
detection capability of heavy metal ions in water with good selectivity and sensitivity.
Along with mass spectroscopic methods, the use of optical fiber technology for heavy
metal ions detection is remarkable. Optical fiber based sensors system for the detection
of heavy metal ions basically works by changing the effective refractive index of its
surroundings. For selective binding of heavy metal ions, sensitive layers are coated on
optical fiber probe. Laser or light emitting diode is used as a light source in an optical
fiber sensor for signal purpose. Accordingly, output response for various heavy metal
ions is recorded on an optical spectrometer. From their output response, we can
determine the concentration of metal ions present in water. It is noticed that optical
fiber sensor can also have good sensitivity and selectivity towards the detection of
heavy metal ions as mass spectroscopy methods.
Keywords: Arsenic, Cadmium, Colorimetric, Detection, Electrochemical, Heavy metal ion, Lead, Mass spectrometry, Mercury, Optical fiber sensor, Sources of heavy metal ions.
