been applied for the determination of cyanide. In the presence of oxygen, generally,
cyanide can transform gold atom into water soluble Au(CN)
2– ion and results in the
gold nanoparticles fluorescence quenching. Keeping this principle in mind, Liu
et al. (2010) developed BSA-Au nanoparticles for the determination of cyanide. In a
study conducted by Faghiri and Ghorbani [32], a new composite nanosensor of
sodium alginate-silver nanoparticles was synthesized in order to solve the issue of
low sustainability of sensors by solvent casting technique and was applied in naked
eye and colorimetric detection of ultra-low concentration of Hg
2+ ions in aqueous
environmental samples.
The developed nanosensor was characterized for the determination of structural
features by using instrumental techniques. The synthesis of silver nanoparticles was
confirmed with the help of obtained results showing an average size of 13.34 nm.
Under specific environments, the colorimetric sensing of Hg
2+ was carried out (6pH
and reaction time of 7 min) with a linear correlation obtained between the absorbance at 402 nm and different Hg
2+ ion concentrations within the 0.025 lM–
60 lM range. For the detection of Hg
2+ ions in the aqueous environmental samples,
the developed sensor was successfully employed for the detection of Hg
2+ ions with
recoveries ranging between 81.58 and 114.73%. The developed nanosensor
exhibited good selectivity toward Hg
2+ ions in the presence of several competing
ions. Maleki et al. [54, 55] studied the synthesis of second-generation polyamidoamine dendrimer functionalized with magnetic nanoparticles (Fe 3 O 4 /G2-PAD)
and its application in the determination of Pb
2+ and Cd
2+ ions in aqueous environment. The performance of the modified magnetic electrode by recording the
impact of changing experimental variables was determined and optimized. Under
optimized environment, the developed sensor showed a linear response to lead and
cadmium ions over a concentration range from 0.5 to 80 ng mL
−1 . The developed
sensor was successfully employed for the determination of Pb
2+ and Cd
2+ in the
presence of some potentially interfering ions.
Some accomplishments are also there in using carbon nanoparticles to characterize the biological variable of the environmental sample. The work by Mandal and
Parvin [56] has verified the application of carbon nanoparticles for rapid determination and enumeration of bacterial cell from a water sample collected from the
contaminated environment. For the sensing/detection of bacterial cells gold
nanorods can be applied as optical sensor. The presence of Escherichia coli in the
drinking water as well as in aqueous environmental is an ongoing serious, worldwide health concern. Singh et al. (2009) demonstrated a sensitive assay for E. coli
using a gold nanorod-based antibody-conjugated two-photon scattering system,
with lower detection limit up to 50 colonies forming unit (cfu)/mL.
Materials in Emerging Water Pollutants Detection
263
cyanide can transform gold atom into water soluble Au(CN)
2– ion and results in the
gold nanoparticles fluorescence quenching. Keeping this principle in mind, Liu
et al. (2010) developed BSA-Au nanoparticles for the determination of cyanide. In a
study conducted by Faghiri and Ghorbani [32], a new composite nanosensor of
sodium alginate-silver nanoparticles was synthesized in order to solve the issue of
low sustainability of sensors by solvent casting technique and was applied in naked
eye and colorimetric detection of ultra-low concentration of Hg
2+ ions in aqueous
environmental samples.
The developed nanosensor was characterized for the determination of structural
features by using instrumental techniques. The synthesis of silver nanoparticles was
confirmed with the help of obtained results showing an average size of 13.34 nm.
Under specific environments, the colorimetric sensing of Hg
2+ was carried out (6pH
and reaction time of 7 min) with a linear correlation obtained between the absorbance at 402 nm and different Hg
2+ ion concentrations within the 0.025 lM–
60 lM range. For the detection of Hg
2+ ions in the aqueous environmental samples,
the developed sensor was successfully employed for the detection of Hg
2+ ions with
recoveries ranging between 81.58 and 114.73%. The developed nanosensor
exhibited good selectivity toward Hg
2+ ions in the presence of several competing
ions. Maleki et al. [54, 55] studied the synthesis of second-generation polyamidoamine dendrimer functionalized with magnetic nanoparticles (Fe 3 O 4 /G2-PAD)
and its application in the determination of Pb
2+ and Cd
2+ ions in aqueous environment. The performance of the modified magnetic electrode by recording the
impact of changing experimental variables was determined and optimized. Under
optimized environment, the developed sensor showed a linear response to lead and
cadmium ions over a concentration range from 0.5 to 80 ng mL
−1 . The developed
sensor was successfully employed for the determination of Pb
2+ and Cd
2+ in the
presence of some potentially interfering ions.
Some accomplishments are also there in using carbon nanoparticles to characterize the biological variable of the environmental sample. The work by Mandal and
Parvin [56] has verified the application of carbon nanoparticles for rapid determination and enumeration of bacterial cell from a water sample collected from the
contaminated environment. For the sensing/detection of bacterial cells gold
nanorods can be applied as optical sensor. The presence of Escherichia coli in the
drinking water as well as in aqueous environmental is an ongoing serious, worldwide health concern. Singh et al. (2009) demonstrated a sensitive assay for E. coli
using a gold nanorod-based antibody-conjugated two-photon scattering system,
with lower detection limit up to 50 colonies forming unit (cfu)/mL.
Materials in Emerging Water Pollutants Detection
263