2 Affinity-Based Methods for the Analysis of Emerging …
51
et al. 2004; Tarley and Kubota 2005; Watabe et al. 2006; Liu et al. 2006; Ou et al.
2006; Beltran et al. 2007; Sambe et al. 2007; Sanchez-Barragan et al. 2007; Gros
et al. 2008; Cacho et al. 2009; Gonzalez-Marino et al. 2009; Luo et al. 2011; Qin et al.
2012; Madikizela et al. 2018; Hudson et al. 2019). As noted previously, the extraction
of analytes by combining MIPs with SPE makes use of forces such as electrostatic
interactions, hydrophobic interactions, and hydrogen bonding between the analyte
and binding pockets within the MIP (Sun and Qiao 2008; Huang et al.2015). The use
of these forces for retention can be challenging in the direct presence of an aqueous
sample, as water will tend to compete for many of these interactions and weaken
binding between the polymer and target (Ou et al. 2006).
Another possible issue with MIPs is the presence of any remaining template in
the polymer may result in leakage of this template during an extraction and loss of
sensitivity for detecting the same compound in samples (Anderson et al. 1997). To
overcome this problem, MIPs can instead be prepared by using a dummy template
that is related to but different from the analyte (Huang et al. 2015).
This type of MIP has been prepared with silica microparticles for the extraction
of bisphenol A from water samples (Zhao et al. 2010). These MIPs were made by
using templates that were analogs of bisphenol A, such as 4,4-dihydroxybiphenyl
and 3,3,5,5-tetrabromobisphenol A. These MIPs avoided contamination of samples
by the MIP while also providing a high binding capacity and good recognition for
bisphenol A (Zhao et al. 2010). A similar strategy has been employed for the analysis
of bisphenol A when using SMPE (Liu et al. 2019).
Magnetic MIPs, or MMIPs have also been utilized for the extraction and analysis
of emerging contaminants in aqueous samples (Ansell and Mosbach 1998; Lu et al.
2005, 2006). An advantage of using MMIPs for SPE is they can easily be collected
from a solution by applying an external magnetic field. This type of material has been
employed as an adsorbent for the selective extraction and detection of bisphenol A in
a variety of water samples, including tap water, drinking water, and river water (Lin
et al. 2012). In this approach, bisphenol F was employed as a dummy template and
used in surface molecular imprinting on supramagnetic core-shell nanoparticles. The
use of this material for SPE resulted in a detection limit of 2.50 pg mL
−1 for bisphenol
A in spiked water samples examined by HPLC and a recovery for bisphenol A of
84.7–93.8% (Lin et al. 2012). Other emerging contaminants that have been analyzed
by using MMIPs are 4-nitrophenol and sulfonamides (Kong et al. 2012; Li-Li et al.
2013; Mehdinia et al. 2013).
2.3.3 Online Use of MIPs
Most applications of MIPs for extraction have used these materials in off-line protocols for sample pretreatment. MIPs in packed cartridges have recently been coupled
online with LC for the separation and measurement of sulfathiazole in wastewater (Zazouli et al. 2017). The MIP in this example was synthesized by employing
methacrylic acid as a functional monomer, sulfathiazole as the template, and ethylene
51
et al. 2004; Tarley and Kubota 2005; Watabe et al. 2006; Liu et al. 2006; Ou et al.
2006; Beltran et al. 2007; Sambe et al. 2007; Sanchez-Barragan et al. 2007; Gros
et al. 2008; Cacho et al. 2009; Gonzalez-Marino et al. 2009; Luo et al. 2011; Qin et al.
2012; Madikizela et al. 2018; Hudson et al. 2019). As noted previously, the extraction
of analytes by combining MIPs with SPE makes use of forces such as electrostatic
interactions, hydrophobic interactions, and hydrogen bonding between the analyte
and binding pockets within the MIP (Sun and Qiao 2008; Huang et al.2015). The use
of these forces for retention can be challenging in the direct presence of an aqueous
sample, as water will tend to compete for many of these interactions and weaken
binding between the polymer and target (Ou et al. 2006).
Another possible issue with MIPs is the presence of any remaining template in
the polymer may result in leakage of this template during an extraction and loss of
sensitivity for detecting the same compound in samples (Anderson et al. 1997). To
overcome this problem, MIPs can instead be prepared by using a dummy template
that is related to but different from the analyte (Huang et al. 2015).
This type of MIP has been prepared with silica microparticles for the extraction
of bisphenol A from water samples (Zhao et al. 2010). These MIPs were made by
using templates that were analogs of bisphenol A, such as 4,4-dihydroxybiphenyl
and 3,3,5,5-tetrabromobisphenol A. These MIPs avoided contamination of samples
by the MIP while also providing a high binding capacity and good recognition for
bisphenol A (Zhao et al. 2010). A similar strategy has been employed for the analysis
of bisphenol A when using SMPE (Liu et al. 2019).
Magnetic MIPs, or MMIPs have also been utilized for the extraction and analysis
of emerging contaminants in aqueous samples (Ansell and Mosbach 1998; Lu et al.
2005, 2006). An advantage of using MMIPs for SPE is they can easily be collected
from a solution by applying an external magnetic field. This type of material has been
employed as an adsorbent for the selective extraction and detection of bisphenol A in
a variety of water samples, including tap water, drinking water, and river water (Lin
et al. 2012). In this approach, bisphenol F was employed as a dummy template and
used in surface molecular imprinting on supramagnetic core-shell nanoparticles. The
use of this material for SPE resulted in a detection limit of 2.50 pg mL
−1 for bisphenol
A in spiked water samples examined by HPLC and a recovery for bisphenol A of
84.7–93.8% (Lin et al. 2012). Other emerging contaminants that have been analyzed
by using MMIPs are 4-nitrophenol and sulfonamides (Kong et al. 2012; Li-Li et al.
2013; Mehdinia et al. 2013).
2.3.3 Online Use of MIPs
Most applications of MIPs for extraction have used these materials in off-line protocols for sample pretreatment. MIPs in packed cartridges have recently been coupled
online with LC for the separation and measurement of sulfathiazole in wastewater (Zazouli et al. 2017). The MIP in this example was synthesized by employing
methacrylic acid as a functional monomer, sulfathiazole as the template, and ethylene