electrodes. The device is quite robust and demonstrates up to 10 repetitive measurements stably. The detection limits achieved were as low as 1.2 µg L
−1 and
1.8 µg L
−1 for Cd
2+ and Pb
2+ ions, respectively.
3.5 Detection of Arsenic
Measuring arsenic in the aquatic and drinking water is imperative for protecting
human health. Drinking water and wastewater treatment facilities are already
subject to arsenic regulations to protect human exposure and environmental contamination. There are different methods of determining the arsenic mostly common
with the above mentioned heavy metal ions like Colorimetry, Fluorescent spectroscopy etc. [38, 75–78] Some notable ones wherein nanofibers were used are
detailed below.
Nellaiappan et al. [79] fabricated AuNPs decorated carbon nanofiber-chitosan
modified electrodes for flow injection analysis of As(III) species. The electrochemical detector showed excellent stability, reproducibility and workability with a
limit of detection value of 38.3 33 µg L
−1 . Saikia et al. [80] have reported the use of
PANI nanofiber with carbon dot derived from green synthesis route for fluorimetric
detection of As
3+ in water with a detection limit of up to 0.001 ppb.
Kempahanumakkagari et al. [81] have provided a review of nanomaterials based
electrochemical sensors for arsenic.
3.6 Detection of Chromium
Chromium is another element which can be very harmful for human and aquatic
health. It is considered a carcinogen and causes genotoxic effects. It can cause
maturity onset, cardiovascular disease and inhibit DNA replication [82]. Its infection in water is mainly due to anthropogenic activities and industrial effluents [83].
It occurs most stably in trivalent and hexavalent states. Many researchers have
detected its presence using variety of techniques, most of which has already been
detailed above.
Electrospun PVA nanofiber membranes modified with spirolactum-rhodaminene
derivatives exhibited high selectivity and sensitivity towards Cr
3+ ions as demonstrated by Wei et al. [84]. The membrane showed a detection limit of 1 µM for Cr
3+ in
aqueous solutions with excellent adsorption capacity. Wang et al. [85] have utilized a
fluorophore, 1,4-Dihydroxyanthraquinone doped cellulose nanofiber film fabricated
by electrospinning and deacetylating for Cu
2+ and Cr
3+ detection. Interestingly, once
utilized for Cu
2+ sensing the Chromium ion reverses the phenolate-Cu
2+ reaction thus
leading to recovered fluorescence which is proportional to Cr
3+ ion concentration. The
detection range for Cr
3+ ion reported is 2.5 Â 10
−9 to 2.5 Â 10
−8 M in aqueous
solution.
310
A. K. Srivastava et al.
−1 and
1.8 µg L
−1 for Cd
2+ and Pb
2+ ions, respectively.
3.5 Detection of Arsenic
Measuring arsenic in the aquatic and drinking water is imperative for protecting
human health. Drinking water and wastewater treatment facilities are already
subject to arsenic regulations to protect human exposure and environmental contamination. There are different methods of determining the arsenic mostly common
with the above mentioned heavy metal ions like Colorimetry, Fluorescent spectroscopy etc. [38, 75–78] Some notable ones wherein nanofibers were used are
detailed below.
Nellaiappan et al. [79] fabricated AuNPs decorated carbon nanofiber-chitosan
modified electrodes for flow injection analysis of As(III) species. The electrochemical detector showed excellent stability, reproducibility and workability with a
limit of detection value of 38.3 33 µg L
−1 . Saikia et al. [80] have reported the use of
PANI nanofiber with carbon dot derived from green synthesis route for fluorimetric
detection of As
3+ in water with a detection limit of up to 0.001 ppb.
Kempahanumakkagari et al. [81] have provided a review of nanomaterials based
electrochemical sensors for arsenic.
3.6 Detection of Chromium
Chromium is another element which can be very harmful for human and aquatic
health. It is considered a carcinogen and causes genotoxic effects. It can cause
maturity onset, cardiovascular disease and inhibit DNA replication [82]. Its infection in water is mainly due to anthropogenic activities and industrial effluents [83].
It occurs most stably in trivalent and hexavalent states. Many researchers have
detected its presence using variety of techniques, most of which has already been
detailed above.
Electrospun PVA nanofiber membranes modified with spirolactum-rhodaminene
derivatives exhibited high selectivity and sensitivity towards Cr
3+ ions as demonstrated by Wei et al. [84]. The membrane showed a detection limit of 1 µM for Cr
3+ in
aqueous solutions with excellent adsorption capacity. Wang et al. [85] have utilized a
fluorophore, 1,4-Dihydroxyanthraquinone doped cellulose nanofiber film fabricated
by electrospinning and deacetylating for Cu
2+ and Cr
3+ detection. Interestingly, once
utilized for Cu
2+ sensing the Chromium ion reverses the phenolate-Cu
2+ reaction thus
leading to recovered fluorescence which is proportional to Cr
3+ ion concentration. The
detection range for Cr
3+ ion reported is 2.5 Â 10
−9 to 2.5 Â 10
−8 M in aqueous
solution.
310
A. K. Srivastava et al.