(3,5-dimethylphenylcarbamate); the enantiomers of fenamiphos were also separated
on CHIRALPAK AS; (CSP: Amylose tris[(S)-α-methylbenzylcarbamate]) the enantiomers of methamidophos, crufomate and trichloronate were separated on Chiralcel
OD (CSP: Cellulose tris(3,5-dimethylphenylcarbamate)); the enantiomers of
crotoxyphos, dialifor, fonofos, malathion, prothiophos and trichloronate were separated on CHIRALCEL OJ (CSP: Cellulose tris(4-methylbenzoate)); and the enantiomers of isofenphos were separated on Chiralcel OG (CSP: Cellulose tris
(3,5-dimethylphenylcarbamate)). Baseline or partial separation of the enantiomers
of six of these OP pesticides was obtained on Chiralcel OJ. In continued method
development, chromatographic conditions were found that gave either baseline or
near-baseline separations of the enantiomers of the 12 OPs on the Chiralcel OJ
column. The application of a chiral and non-chiral CSPs with matrix solid-phase
dispersion was used for the investigation of the stereoselective distribution of chiral
pollutants in soil (Li et al. 2003). Similar CSP combinations as already described
above were used. For this investigation, eight pesticides were investigated by liquid
chromatography (HPLC) using Chiralcel OD column (CSP: see above), as well as a
Pirkle-type Chirex 3020 column (urea derivative from the reaction of (R)-1-(α-naphthyl)ethylamine
with
(S)-tert-leucine,
chemically
bonded
to
3-aminopropylsilanised silica as CSP). The pesticides studied included one organophosphorus insecticide (phenthoate), 3 triazole fungicides (uniconazole,
diniconazole and propiconazole) and 4 pyrethroids (fenpropathrin, β-cypermethrin,
β-cyfluthrin and α-fenvalerate). The enantiomers were separated within 20 min with
a resolution of > or ¼ 1.5 using a mixture of n-hexane and 2-propanol as the mobile
phase for all the pesticides studied except propiconazole, for which only the two
diastereomers were baseline separated. This method allows the determination of the
enantiomers or stereoisomers of the above pesticides in soil. The concentrations of
the enantiomers for chiral pesticide in soil were determined by matrix solid-phase
dispersion (MSPD), followed by silica-based LC quantification. For propiconazole,
only the stereoisomeric ratio (SR) of the two diastereomers was determined. Based
on the total concentrations and the corresponding ERs, the concentration of each
enantiomer in soil was calculated. The proposed method is rapid, precise and
sensitive and is appropriate for the investigation of the stereo- and enantioselective
degradation of pesticides in environmental media (Li et al. 2003).
A new approach for multi-compound analysis primarily for the determination of
pesticides and other residues after the agricultural application was developed
roughly a decade ago, where a stronger focus was placed upon the number of target
substances, the time for the chromatographic separation and the costs associated with
the single analysis. In turn, a minor focus was given to detection limit, linear range
and other basic parameters considered essential for quantitative single compound
analysis (Kmellar et al. 2010; Fernandes et al. 2011; Bruzzoniti et al. 2014). The
quick, easy, cheap, effective, rugged and safe (QuEChERS) approach was also
applied to the enantiomer separation of 10 chiral pesticides in fruits and vegetables
(He et al. 2015). The list of target compounds included metalaxyl, famoxadone and
8 triazole compounds (myclobutanil, paclobutrazol, diniconazole, hexaconazole,
triadimefon, epoxiconazole, tetraconazole, fenbuconazole). For the quantitative
8.2 Transformation/Accumulation of Chiral Xenobiotics in Higher Organisms
207
on CHIRALPAK AS; (CSP: Amylose tris[(S)-α-methylbenzylcarbamate]) the enantiomers of methamidophos, crufomate and trichloronate were separated on Chiralcel
OD (CSP: Cellulose tris(3,5-dimethylphenylcarbamate)); the enantiomers of
crotoxyphos, dialifor, fonofos, malathion, prothiophos and trichloronate were separated on CHIRALCEL OJ (CSP: Cellulose tris(4-methylbenzoate)); and the enantiomers of isofenphos were separated on Chiralcel OG (CSP: Cellulose tris
(3,5-dimethylphenylcarbamate)). Baseline or partial separation of the enantiomers
of six of these OP pesticides was obtained on Chiralcel OJ. In continued method
development, chromatographic conditions were found that gave either baseline or
near-baseline separations of the enantiomers of the 12 OPs on the Chiralcel OJ
column. The application of a chiral and non-chiral CSPs with matrix solid-phase
dispersion was used for the investigation of the stereoselective distribution of chiral
pollutants in soil (Li et al. 2003). Similar CSP combinations as already described
above were used. For this investigation, eight pesticides were investigated by liquid
chromatography (HPLC) using Chiralcel OD column (CSP: see above), as well as a
Pirkle-type Chirex 3020 column (urea derivative from the reaction of (R)-1-(α-naphthyl)ethylamine
with
(S)-tert-leucine,
chemically
bonded
to
3-aminopropylsilanised silica as CSP). The pesticides studied included one organophosphorus insecticide (phenthoate), 3 triazole fungicides (uniconazole,
diniconazole and propiconazole) and 4 pyrethroids (fenpropathrin, β-cypermethrin,
β-cyfluthrin and α-fenvalerate). The enantiomers were separated within 20 min with
a resolution of > or ¼ 1.5 using a mixture of n-hexane and 2-propanol as the mobile
phase for all the pesticides studied except propiconazole, for which only the two
diastereomers were baseline separated. This method allows the determination of the
enantiomers or stereoisomers of the above pesticides in soil. The concentrations of
the enantiomers for chiral pesticide in soil were determined by matrix solid-phase
dispersion (MSPD), followed by silica-based LC quantification. For propiconazole,
only the stereoisomeric ratio (SR) of the two diastereomers was determined. Based
on the total concentrations and the corresponding ERs, the concentration of each
enantiomer in soil was calculated. The proposed method is rapid, precise and
sensitive and is appropriate for the investigation of the stereo- and enantioselective
degradation of pesticides in environmental media (Li et al. 2003).
A new approach for multi-compound analysis primarily for the determination of
pesticides and other residues after the agricultural application was developed
roughly a decade ago, where a stronger focus was placed upon the number of target
substances, the time for the chromatographic separation and the costs associated with
the single analysis. In turn, a minor focus was given to detection limit, linear range
and other basic parameters considered essential for quantitative single compound
analysis (Kmellar et al. 2010; Fernandes et al. 2011; Bruzzoniti et al. 2014). The
quick, easy, cheap, effective, rugged and safe (QuEChERS) approach was also
applied to the enantiomer separation of 10 chiral pesticides in fruits and vegetables
(He et al. 2015). The list of target compounds included metalaxyl, famoxadone and
8 triazole compounds (myclobutanil, paclobutrazol, diniconazole, hexaconazole,
triadimefon, epoxiconazole, tetraconazole, fenbuconazole). For the quantitative
8.2 Transformation/Accumulation of Chiral Xenobiotics in Higher Organisms
207