72 Organic compounds in soils, sediments & sludges
Cyanazine observed with gas-liquid chromatography. Peat was used in most experiments as the soil constituent which released the greatest quantity of interfering
substances an aqueous solutions.
Molecular imprinted polymers have drawn much attention as highly selective solidphase materials for handling and isolation of organic pollutants in complex matrices.
Because of the impaired retention capacity for target species as compared with reversedphase materials and irreversible sorption of interfering compounds by nonspecific
interactions, the implementation of MIP-based solid-phase reactors as permanent components in automatic flow-systems has not received widespread acceptance as of yet.
To tackle this limitation, a dynamic microscale solid phase extraction (µSPE) method
capitalising on the principle of programmable flow and bead injection analysis was
herein proposed by Boonjob et al [73] as a front end to liquid chromatography for multiresidue assays. It involves in-line renewable tandem-SPE microcolumns composed of
molecularly imprinted polymers and copolymeric N vinylpyrroilidone/divinylbenzene
beads integrated within the flow network for multimodal extraction. Chlorotriazine
herbicides (namely, Atrazine, Simazine, Propazine) (namely, deisopropylatrazine and
deethylatrazine) and principal degradation products thereof were selected as model
analytes. The effect of several parameters, including the dimensions and chemical
composition of the sorptive microcolumns, the sample loading flow rate, the type
and volume of eluent, the interface with liquid chromatography and the disposable
nature of the column on the analytical performance were investigated in detail. The
assembled flow set-up features appropriate removal of interfering organic species via
solvent switch with toluene, the circumvention of analyte band-broadening in liquid chromatography by in-line merging of the eluate with a water stream, and the
transfer of the overall analyte-containing eluate into the liquid chromatograph. For
10-mL sample percolation, limits of detection (S/N = 3) of 0.02–04 ng mL
−1 , limits
of quantification (S/N = 10) of 0.07–0.12 ng mL
−1 , absolute recovery percentages.
79%, precision within 1.4–5.5%, and enrichment factors of 46–49 were obtained
for the suite of assayed herbicides. The multimodal µSPE method with renewable
beads was applied to the multiresidue determination of the target herbicides in crude
soil extracts and untreated environmental waters at concentration levels below those
endorsed by the current EU Water Framework Directives following appropriate sample
preconcentration and/or cleanup.
Papaelakis et al [71] developed a multiresidue method developed for the analysis
of atrazine and its principal conversion products namely Deisopropylatrazine, deethylatrazine and hydroxyatrazine in soils. The method is based on microwave-assisted
extraction of soil with aqueous methanol followed by solid-phase extraction of the
extracts and subsequent analysis of LC-UV with diode array detector. Microwave
assisted extraction operational parameters (extraction, extractant volume) were optimised with respect to extraction efficiency of the target compounds from soils with
2.5% organic matter content. Recoveries above 80% were obtained for all solutes.
Soil organic matter content did not affect analyte recoveries. Recoveries from fresh
and aged residues, the latter weathered under cold storage conditions, were not statistically difference. Microwave assisted extraction was found to be superior in terms
of extraction efficiency, sample throughout, and solvent consumption to conventional
flask-shaking extraction.
Other applications of HPLC are reviewed in Table 3.5.
Cyanazine observed with gas-liquid chromatography. Peat was used in most experiments as the soil constituent which released the greatest quantity of interfering
substances an aqueous solutions.
Molecular imprinted polymers have drawn much attention as highly selective solidphase materials for handling and isolation of organic pollutants in complex matrices.
Because of the impaired retention capacity for target species as compared with reversedphase materials and irreversible sorption of interfering compounds by nonspecific
interactions, the implementation of MIP-based solid-phase reactors as permanent components in automatic flow-systems has not received widespread acceptance as of yet.
To tackle this limitation, a dynamic microscale solid phase extraction (µSPE) method
capitalising on the principle of programmable flow and bead injection analysis was
herein proposed by Boonjob et al [73] as a front end to liquid chromatography for multiresidue assays. It involves in-line renewable tandem-SPE microcolumns composed of
molecularly imprinted polymers and copolymeric N vinylpyrroilidone/divinylbenzene
beads integrated within the flow network for multimodal extraction. Chlorotriazine
herbicides (namely, Atrazine, Simazine, Propazine) (namely, deisopropylatrazine and
deethylatrazine) and principal degradation products thereof were selected as model
analytes. The effect of several parameters, including the dimensions and chemical
composition of the sorptive microcolumns, the sample loading flow rate, the type
and volume of eluent, the interface with liquid chromatography and the disposable
nature of the column on the analytical performance were investigated in detail. The
assembled flow set-up features appropriate removal of interfering organic species via
solvent switch with toluene, the circumvention of analyte band-broadening in liquid chromatography by in-line merging of the eluate with a water stream, and the
transfer of the overall analyte-containing eluate into the liquid chromatograph. For
10-mL sample percolation, limits of detection (S/N = 3) of 0.02–04 ng mL
−1 , limits
of quantification (S/N = 10) of 0.07–0.12 ng mL
−1 , absolute recovery percentages.
79%, precision within 1.4–5.5%, and enrichment factors of 46–49 were obtained
for the suite of assayed herbicides. The multimodal µSPE method with renewable
beads was applied to the multiresidue determination of the target herbicides in crude
soil extracts and untreated environmental waters at concentration levels below those
endorsed by the current EU Water Framework Directives following appropriate sample
preconcentration and/or cleanup.
Papaelakis et al [71] developed a multiresidue method developed for the analysis
of atrazine and its principal conversion products namely Deisopropylatrazine, deethylatrazine and hydroxyatrazine in soils. The method is based on microwave-assisted
extraction of soil with aqueous methanol followed by solid-phase extraction of the
extracts and subsequent analysis of LC-UV with diode array detector. Microwave
assisted extraction operational parameters (extraction, extractant volume) were optimised with respect to extraction efficiency of the target compounds from soils with
2.5% organic matter content. Recoveries above 80% were obtained for all solutes.
Soil organic matter content did not affect analyte recoveries. Recoveries from fresh
and aged residues, the latter weathered under cold storage conditions, were not statistically difference. Microwave assisted extraction was found to be superior in terms
of extraction efficiency, sample throughout, and solvent consumption to conventional
flask-shaking extraction.
Other applications of HPLC are reviewed in Table 3.5.