Phenolic and Nitro-Aromatic Compounds
Phenols are extensively use organic chemicals. Many different synthetic organic
compounds used as agricultural and industrial chemicals contain the phenolic group
as their basic structural units. Mainly, paper, petroleum, plastic pesticides and
pharmaceutical manufacturing industries use and release these phenolic compounds
into the environment (Naghibi et al. 2003). Among the organic contaminants
discharged into the aquatic environment, a large percentage consists of phenolic
compounds. The potential of free radical formation and hydrophobicity of such
compounds is the major reason for their toxicity (Hansch et al. 2000). Due to their
highly toxic nature, many phenolic compounds have been listed as high priority
pollutants by the United States environmental protection agency (USEPA) (Laine
and Jorgense 1996). The maximum of individual and total permitted phenol levels in
water suitable for human consumption has been set as 0.1 and 0.5 mg/L by the
European Union (Daskalaki et al. 2011). These compounds possess serious threat to
the environment and human health. Conventional methods for detection of these
compounds include gas chromatography (GC), mass spectrometry, high performance liquid chromatography (HPLC) etc. But as mentioned above, these
techniques have their own limitations for practical applications. Hence, methods
for effective and convenient detection of such compounds in a serious issue, and the
advancement of nanosensors technology can be used potentially to overcome this
challenge. Nanosensors based detection of some phenolic compounds which are
major environmental pollutants and matter of current concern has been
discussed here.
Recently, Mazhari et al. (2017) have reported the development of a paper-based
nanobiosensor for the efficient and cost-effective detection of phenol from effluents
of plastic, paper and wine industries. The sensor was prepared using Whatman
no. 2 filter paper modified with Tyr-AuNPs bioconjugates. Streptomyces tuirus
DBZ39 was used for bioconjugate formation of tyrosinase and Au NPs. The sensor
displayed high efficiency for the detection of phenol from the effluents due to the
SPR exhibited by AuNPs and substrate specific catalytic behaviour of tyrosinase.
Thus, the sensor provides potential for cost-effective detection of phenol from the
environmental samples.
Bisphenol A (BPA) is a phenolic compound. This compound is extensively used
in products like plastics, thermal papers and epoxy resins. BPA can leach out from
product linings, and cause contamination of soil and water sources. It is a harmful
endocrine disruptor (EDC) and can result in health issues like physiological
abnormalities and reproductive dysfunction in humans. Elderly people, pregnant
women and children are most vulnerable to BPA exposure. Although, nowadays,
BPA-free products are being developed, but its detection is still important. Recently,
various nanosensor based BPA detection methods have been developed and
reported. Lee et al. (2019) reported optical nanosensor for sensitive detection of
BPA using modified aptamer/AuNP conjugated with fluorescing single-stranded
DNA aptamer. The sensor detected BPA with LOD as low as 9 pg mL
À1 .
An efficient, cheap and rapid electrochemical method for BPA detection was
reported by Bolat et al. (2018) using poly(CTAB)-MWCNTs based nanosensor.
130
U. Chakraborty et al.
Phenols are extensively use organic chemicals. Many different synthetic organic
compounds used as agricultural and industrial chemicals contain the phenolic group
as their basic structural units. Mainly, paper, petroleum, plastic pesticides and
pharmaceutical manufacturing industries use and release these phenolic compounds
into the environment (Naghibi et al. 2003). Among the organic contaminants
discharged into the aquatic environment, a large percentage consists of phenolic
compounds. The potential of free radical formation and hydrophobicity of such
compounds is the major reason for their toxicity (Hansch et al. 2000). Due to their
highly toxic nature, many phenolic compounds have been listed as high priority
pollutants by the United States environmental protection agency (USEPA) (Laine
and Jorgense 1996). The maximum of individual and total permitted phenol levels in
water suitable for human consumption has been set as 0.1 and 0.5 mg/L by the
European Union (Daskalaki et al. 2011). These compounds possess serious threat to
the environment and human health. Conventional methods for detection of these
compounds include gas chromatography (GC), mass spectrometry, high performance liquid chromatography (HPLC) etc. But as mentioned above, these
techniques have their own limitations for practical applications. Hence, methods
for effective and convenient detection of such compounds in a serious issue, and the
advancement of nanosensors technology can be used potentially to overcome this
challenge. Nanosensors based detection of some phenolic compounds which are
major environmental pollutants and matter of current concern has been
discussed here.
Recently, Mazhari et al. (2017) have reported the development of a paper-based
nanobiosensor for the efficient and cost-effective detection of phenol from effluents
of plastic, paper and wine industries. The sensor was prepared using Whatman
no. 2 filter paper modified with Tyr-AuNPs bioconjugates. Streptomyces tuirus
DBZ39 was used for bioconjugate formation of tyrosinase and Au NPs. The sensor
displayed high efficiency for the detection of phenol from the effluents due to the
SPR exhibited by AuNPs and substrate specific catalytic behaviour of tyrosinase.
Thus, the sensor provides potential for cost-effective detection of phenol from the
environmental samples.
Bisphenol A (BPA) is a phenolic compound. This compound is extensively used
in products like plastics, thermal papers and epoxy resins. BPA can leach out from
product linings, and cause contamination of soil and water sources. It is a harmful
endocrine disruptor (EDC) and can result in health issues like physiological
abnormalities and reproductive dysfunction in humans. Elderly people, pregnant
women and children are most vulnerable to BPA exposure. Although, nowadays,
BPA-free products are being developed, but its detection is still important. Recently,
various nanosensor based BPA detection methods have been developed and
reported. Lee et al. (2019) reported optical nanosensor for sensitive detection of
BPA using modified aptamer/AuNP conjugated with fluorescing single-stranded
DNA aptamer. The sensor detected BPA with LOD as low as 9 pg mL
À1 .
An efficient, cheap and rapid electrochemical method for BPA detection was
reported by Bolat et al. (2018) using poly(CTAB)-MWCNTs based nanosensor.
130
U. Chakraborty et al.