(Garrison et al. 2011a, b). For more information on enantiomer-selective transformation pathways for relevant pesticides, we also refer to recent reviews and updated
scientific monographs (Müller and Kohler 2004; Garrison 2006; Garrison et al.
2008, 2011a, b; Li et al. 2010; Nillos et al. 2010; Perez-Fernandez et al. 2010;
Ulrich et al. 2012; Leon-Gonzalez et al. 2014; Tuzimski and Sherma 2015; Gamiz
et al. 2016a; Asad et al. 2017; Yang et al. 2017).
8.2.5 Artificial Fragrances and Personal Care Products
Second-generation synthetic musk compounds like Galaxolide
® (HHTB) and
Tonalide
® (HHCB) belong to the group of polycyclic musks and are in the focus
of environmental chemistry for the past two decades (Rimkus 2004; Taylor et al.
2014; Homem et al. 2015).
In the case of HHCB, the early attempts for the separation of the diastereomers on
capillary columns for enantiomer-selective gas chromatographic separation, which
were commonly applied in pesticide and PCB residue analysis, turned out to be a
challenge. Only in two studies the diastereomers were separated, that is, in extracts
of human adipose tissue and in fish extracts using a methylpolysiloxane phase with
12–15% phenyl groups and a polyethylene glycol phase, respectively (Rimkus
1999). The successful enantioselective cGC separations of four of the polycyclic
musks shown in Fig. 8.30, including the diastereomeric pairs of enantiomers, are
reported in follow-up studies (Franke et al. 1999; Hühnerfuss et al. 1999; Kallenborn
et al. 1999a, b, c).
In the investigation carried out by Gatermann and co-workers (Kallenborn et al.
1999a, b, c; Gatermann et al. 2002a, b) two different cyclodextrin-type chiral
stationary phases were tested. Using a column coated with a 1:4 mixture of OV
1701/octakis(2,3,6-tri-O-ethyl)-γ-cyclodextrin, only a baseline separation of the
HHCB diastereomers was achieved, where cis-HHCB was the first eluting isomer.
The enantiomers of ATII were partly separated, whereas no separation of the AHTN
enantiomers was obtained (Fig. 8.31). Accordingly, this column can only be used for
a determination of the cis/trans ratio of HHCB diastereomers.
A satisfactory enantiomer separation of all chiral polycyclic musks was achieved
with a column coated with a 1:1 mixture of OV 1701/heptakis(6-Otertbutyldimethylsilyl-2,3-di-O-methyl)-β-cyclodextrin (TBDMS-CD). Selected
ion monitoring (SIM) fragmentograms (m/z ¼ 187, m/z ¼ 213, m/z ¼ 215, m/
z ¼ 229, m/z ¼ 243 and m/z ¼ 258) of a standard mixture containing HHCB,
AHTN, ATTn and AHDI (1 ng/μL each) are shown in Fig. 8.32. As the technical
formulation of HHCB used in fragrance formulations contains different chiral
by-products with the same fragmentation ions m/z ¼ 258 and m/z ¼ 243 (Kallenborn
et al. 1999a, b, c, 2001), possible co-elution of these by-products and the polycyclic
musks themselves cannot be basically excluded. However, injection of the authentic
mixture confirmed that no co-elution between HHCB and the by-products takes
place on this column (Fig. 8.32).
216
8 Enantiomer-Specific Fate and Behaviour of Chiral Contaminants
scientific monographs (Müller and Kohler 2004; Garrison 2006; Garrison et al.
2008, 2011a, b; Li et al. 2010; Nillos et al. 2010; Perez-Fernandez et al. 2010;
Ulrich et al. 2012; Leon-Gonzalez et al. 2014; Tuzimski and Sherma 2015; Gamiz
et al. 2016a; Asad et al. 2017; Yang et al. 2017).
8.2.5 Artificial Fragrances and Personal Care Products
Second-generation synthetic musk compounds like Galaxolide
® (HHTB) and
Tonalide
® (HHCB) belong to the group of polycyclic musks and are in the focus
of environmental chemistry for the past two decades (Rimkus 2004; Taylor et al.
2014; Homem et al. 2015).
In the case of HHCB, the early attempts for the separation of the diastereomers on
capillary columns for enantiomer-selective gas chromatographic separation, which
were commonly applied in pesticide and PCB residue analysis, turned out to be a
challenge. Only in two studies the diastereomers were separated, that is, in extracts
of human adipose tissue and in fish extracts using a methylpolysiloxane phase with
12–15% phenyl groups and a polyethylene glycol phase, respectively (Rimkus
1999). The successful enantioselective cGC separations of four of the polycyclic
musks shown in Fig. 8.30, including the diastereomeric pairs of enantiomers, are
reported in follow-up studies (Franke et al. 1999; Hühnerfuss et al. 1999; Kallenborn
et al. 1999a, b, c).
In the investigation carried out by Gatermann and co-workers (Kallenborn et al.
1999a, b, c; Gatermann et al. 2002a, b) two different cyclodextrin-type chiral
stationary phases were tested. Using a column coated with a 1:4 mixture of OV
1701/octakis(2,3,6-tri-O-ethyl)-γ-cyclodextrin, only a baseline separation of the
HHCB diastereomers was achieved, where cis-HHCB was the first eluting isomer.
The enantiomers of ATII were partly separated, whereas no separation of the AHTN
enantiomers was obtained (Fig. 8.31). Accordingly, this column can only be used for
a determination of the cis/trans ratio of HHCB diastereomers.
A satisfactory enantiomer separation of all chiral polycyclic musks was achieved
with a column coated with a 1:1 mixture of OV 1701/heptakis(6-Otertbutyldimethylsilyl-2,3-di-O-methyl)-β-cyclodextrin (TBDMS-CD). Selected
ion monitoring (SIM) fragmentograms (m/z ¼ 187, m/z ¼ 213, m/z ¼ 215, m/
z ¼ 229, m/z ¼ 243 and m/z ¼ 258) of a standard mixture containing HHCB,
AHTN, ATTn and AHDI (1 ng/μL each) are shown in Fig. 8.32. As the technical
formulation of HHCB used in fragrance formulations contains different chiral
by-products with the same fragmentation ions m/z ¼ 258 and m/z ¼ 243 (Kallenborn
et al. 1999a, b, c, 2001), possible co-elution of these by-products and the polycyclic
musks themselves cannot be basically excluded. However, injection of the authentic
mixture confirmed that no co-elution between HHCB and the by-products takes
place on this column (Fig. 8.32).
216
8 Enantiomer-Specific Fate and Behaviour of Chiral Contaminants