allow an effective starting point for the selectivity challenges of the new tasks of
modern environmental chemistry (Fischer et al. 2012; Kalachova et al. 2013).
However, also today, methods that are specially optimised for the needs of chiral
trace analysis have to be developed, keeping in mind that the separation of two
enantiomers by chromatography leads to a considerable reduction in sensitivity
(Trivedi et al. 2007; Samuelsson et al. 2009; Camacho-Munoz and KasprzykHordern 2015; Adhikari et al. 2016; Kazsoki et al. 2016; Naile et al. 2016;
Sanganyado et al. 2017). Therefore, only highly sensitive, but very selective detection methods can be used for the ultra-trace analysis of chiral environmental pollutants. In addition, today all commercially available stationary phases used for
separation purposes in high-resolution liquid and gas and liquid chromatography
are highly selective (Bidleman et al. 2002; Qi et al. 2016). Thus, these methods are
only able to separate a very limited number of compounds simultaneously. In order
to increase in the effectivity of these stationary phases, different technical
approaches have been investigated for all types of chromatographic separation
methods. A detailed and updated discussion of these different methods will be
given in the next sections of this chapter.
For new emerging environmental contaminants as well as for conventional
environmental pollutants, two important physical parameters have to be considered
when choosing a suitable chromatographic separation and a subsequent detection
method.
2.1 Polarity Expressed as Octanol–Water Partitioning
Coefficient (K OW )
One of the most comprehensively applied parameters for the characterisation of
chromatographic separation as well as for the assessment of environmental behaviour of chemicals during the past four decades is the log K OW (¼ the logarithm of the
octanol–water partition coefficient). According to the general partition theory, the
distribution of a substance, S, between two immiscible solvents (such as aqueous and
organic phases) is based on the substance-specific equilibrium condition that is
described by the following equation:
S aq , S org
where S aq is the amount of substance “S” in the aqueous phase and S org is the amount
of substance “S” in the organic phase.
Thus, the equilibrium constant “K” for this equilibrium condition represents the
quotient of the respective concentrations:
20
2 Criteria for the Selection of a Proper Enantiomer-Selective Analytical Method
modern environmental chemistry (Fischer et al. 2012; Kalachova et al. 2013).
However, also today, methods that are specially optimised for the needs of chiral
trace analysis have to be developed, keeping in mind that the separation of two
enantiomers by chromatography leads to a considerable reduction in sensitivity
(Trivedi et al. 2007; Samuelsson et al. 2009; Camacho-Munoz and KasprzykHordern 2015; Adhikari et al. 2016; Kazsoki et al. 2016; Naile et al. 2016;
Sanganyado et al. 2017). Therefore, only highly sensitive, but very selective detection methods can be used for the ultra-trace analysis of chiral environmental pollutants. In addition, today all commercially available stationary phases used for
separation purposes in high-resolution liquid and gas and liquid chromatography
are highly selective (Bidleman et al. 2002; Qi et al. 2016). Thus, these methods are
only able to separate a very limited number of compounds simultaneously. In order
to increase in the effectivity of these stationary phases, different technical
approaches have been investigated for all types of chromatographic separation
methods. A detailed and updated discussion of these different methods will be
given in the next sections of this chapter.
For new emerging environmental contaminants as well as for conventional
environmental pollutants, two important physical parameters have to be considered
when choosing a suitable chromatographic separation and a subsequent detection
method.
2.1 Polarity Expressed as Octanol–Water Partitioning
Coefficient (K OW )
One of the most comprehensively applied parameters for the characterisation of
chromatographic separation as well as for the assessment of environmental behaviour of chemicals during the past four decades is the log K OW (¼ the logarithm of the
octanol–water partition coefficient). According to the general partition theory, the
distribution of a substance, S, between two immiscible solvents (such as aqueous and
organic phases) is based on the substance-specific equilibrium condition that is
described by the following equation:
S aq , S org
where S aq is the amount of substance “S” in the aqueous phase and S org is the amount
of substance “S” in the organic phase.
Thus, the equilibrium constant “K” for this equilibrium condition represents the
quotient of the respective concentrations:
20
2 Criteria for the Selection of a Proper Enantiomer-Selective Analytical Method