52
S. Iftekhar et al.
glycol dimethacrylate as the cross-linking agent (Zazouli et al. 2017). A sequential
injection technique was then employed. A sample-containing sulfathiazole was first
loaded onto the MIP column for extraction. The isolated analyte was then passed
onto a C18 RPLC column by gradient elution and monitored by absorbance detection. A recovery of 90% for sulfathiazole and a detection limit of 0.05 ng mL
−1 was
obtained (Zazouli et al. 2017). MIPs have also been coupled online with LC and
absorbance detection to measure trace levels of estrones and bisphenol A in river
water, lake water, and well water (Ou et al. 2006; Xu et al. 2009).
2.4 Affinity Methods Using Chiral Stationary Phases
Several other affinity ligands have been used for the separation and analysis of emerging contaminants in water samples (Nelson and Hage 2006). Many of these ligands
are chiral stationary phases (CSPs) that possess the ability to interact differently with
some enantiomeric compounds. Examples of chiral binding agents that have been
used as stationary phases for emerging contaminants include polysaccharides, serum
transport proteins, enzymes, and macrocyclic antibiotics (Teixeira et al. 2019).
2.4.1 Polysaccharide-Based Methods
Polysaccharide derivatives of amylose and cellulose can be utilized to obtain CSPs
because of their chiral structures and good enantioselectivity (Ali et al. 2009). The
properties of these agents that result in chiral recognition include the types of sugars
and linkages that are present between the sugars, as well as the three-dimensional
arrangement and structures of the sugar chains (Chen et al. 2007; Lämmerhofer
2010). Phenylcarbamates and benzoate derivatives are the most common types of
polysaccharide CSPs (Chen et al. 2007; Chankvetadze 2012). For instance, 3,5dimethylphenyl tris-phenylcarbamate derivatives of cellulose and amylose are often
used as CSPs (Franco et al. 2001; Teixeira et al. 2019). These polysaccharide derivates
can be coated by adsorption onto silica supports (Okamoto et al. 1984; Park et al.
2003) and used for separations in either normal-phase or reversed-phase modes
(Lämmerhofer 2010). Alternatively, polysaccharide CSPs can be produced by covalently immobilizing a polysaccharide derivative directly onto a support (Ali and
Aboul-Enein 2006, 2007).
Several types of emerging contaminants in water have been analyzed by using
polysaccharide CSPs. In one study, lansoprazole, omeprazole, pantoprazole, and
rabeprazole were examined in wastewater and river water by using such a phase (Zhao
et al. 2016). These samples were first extracted by SPE and liquid–liquid microextraction. The contents of the extracts were then separated and analyzed by LCMS/MS using a column that contained a 3,5-dimethylphenyl tris-phenylcarbamate
S. Iftekhar et al.
glycol dimethacrylate as the cross-linking agent (Zazouli et al. 2017). A sequential
injection technique was then employed. A sample-containing sulfathiazole was first
loaded onto the MIP column for extraction. The isolated analyte was then passed
onto a C18 RPLC column by gradient elution and monitored by absorbance detection. A recovery of 90% for sulfathiazole and a detection limit of 0.05 ng mL
−1 was
obtained (Zazouli et al. 2017). MIPs have also been coupled online with LC and
absorbance detection to measure trace levels of estrones and bisphenol A in river
water, lake water, and well water (Ou et al. 2006; Xu et al. 2009).
2.4 Affinity Methods Using Chiral Stationary Phases
Several other affinity ligands have been used for the separation and analysis of emerging contaminants in water samples (Nelson and Hage 2006). Many of these ligands
are chiral stationary phases (CSPs) that possess the ability to interact differently with
some enantiomeric compounds. Examples of chiral binding agents that have been
used as stationary phases for emerging contaminants include polysaccharides, serum
transport proteins, enzymes, and macrocyclic antibiotics (Teixeira et al. 2019).
2.4.1 Polysaccharide-Based Methods
Polysaccharide derivatives of amylose and cellulose can be utilized to obtain CSPs
because of their chiral structures and good enantioselectivity (Ali et al. 2009). The
properties of these agents that result in chiral recognition include the types of sugars
and linkages that are present between the sugars, as well as the three-dimensional
arrangement and structures of the sugar chains (Chen et al. 2007; Lämmerhofer
2010). Phenylcarbamates and benzoate derivatives are the most common types of
polysaccharide CSPs (Chen et al. 2007; Chankvetadze 2012). For instance, 3,5dimethylphenyl tris-phenylcarbamate derivatives of cellulose and amylose are often
used as CSPs (Franco et al. 2001; Teixeira et al. 2019). These polysaccharide derivates
can be coated by adsorption onto silica supports (Okamoto et al. 1984; Park et al.
2003) and used for separations in either normal-phase or reversed-phase modes
(Lämmerhofer 2010). Alternatively, polysaccharide CSPs can be produced by covalently immobilizing a polysaccharide derivative directly onto a support (Ali and
Aboul-Enein 2006, 2007).
Several types of emerging contaminants in water have been analyzed by using
polysaccharide CSPs. In one study, lansoprazole, omeprazole, pantoprazole, and
rabeprazole were examined in wastewater and river water by using such a phase (Zhao
et al. 2016). These samples were first extracted by SPE and liquid–liquid microextraction. The contents of the extracts were then separated and analyzed by LCMS/MS using a column that contained a 3,5-dimethylphenyl tris-phenylcarbamate