Organic compounds in non-saline sediments 157
collected along the Bahlui river throughout the Iassy city revealed higher mean levels of
polychlorobiphenyls (59 ng g
−1 , range 24–158 ng g
−1 ) compared with organochlorine
pesticide levels (2 and 37 ng g
−1 ) of soil for HCHs and DDTs, respectively). Furthermore polychlorobiphenyl profiles and concentrations in the sediment samples varied
considerably along the river due to a wide variety of sources, such as different industries and waste sites. Although their sources are difficult the evaluate, the presence of
these compounds at most sites (especially at the waste disposal site) may constitute a
potential health hazard.
Goldberg et al [164] studied the relationship between pesticide concentrations in
water and in sediments and its dependence on the specific surface area of the sediment.
Lopez Avila et al [70] have described a microwave assisted extraction procedure
for the separation of chlorinated insecticides from sediments.
Snyder et al [184] compared supercritical extraction with classical sonication and
Soxhlet extraction for selected pesticides and applied the procedure to river sediments.
Samples extracted with supercritical carbon dioxide modified with 3% methanol
at 350 atm and 50
◦ C gave ≤85% recovery of organochlorine insecticides including
Dichlorovos, Diazinon, Endrin, Endrin aldehyde, decahlorobiphenyls, p, p’-DDT and
Mirex.
6.7.3 Azine type herbicides
Recently there has been a growing interest in employing a highly selective analyteantibody interactions achieved by immunosorbents [186, 187]. In the immunosorbents
the antibody is immobilised onto a silica support and used as an affinity ligand to
extract the target analyte and other compounds with similar structures from the aqueous sample. In this way, any material not recognised by the antibody is not retained in
the immunosorbents while the target analyte remains bound to the antibody, leading
to a high selectivity. The development and the evaluation of two immunosorbents for
the selective trace solid-phase extraction of phenylurea and triazine herbicides have
been discussed in the literature [188–190].
As an example of this type of application Ferrer et al [191] have described
an automated on-line immunosorbents phase extraction method for the analysis of
triazine and phenylurea herbicides in sediments. This method consists of trace analyte extraction using an immunosorbents column-containing ether anti-Atrazine or
anti-Chlorotoluron antibodies-combined with a liquid chromatography by use of
an on-line sample preparation system coupled directly to an atmospheric pressure
chemical ionisation-mass spectrometer in positive mode of operation. After the percolation of 20 mL of water through the immunosorbents columns, high recoveries
in extracts were obtained for all the compounds with the exception of Deisopropylatrazine and Diflubenzuron. Calibration curves where linear in the range between
0.01 and 0.2 µg/L
−1 in groundwater. The limits of detection ranged from 0.001 to
0.005 µg/L
−1 , indicating good sensitivity achieved by both types of immunosorbents.
Wauchope and Myers et al [192] studied the adsorption-dispersion kinetics of
Atrazine and Linuron in sediment-aqueous slurries. The resulting adsorption or desorption was very rapid, approaching 75% of equilibrium values within 3–6 minutes.
Chlorinated adsorption of the herbicide on the sediment was completely reversible
after 2 hours of adsorption.
collected along the Bahlui river throughout the Iassy city revealed higher mean levels of
polychlorobiphenyls (59 ng g
−1 , range 24–158 ng g
−1 ) compared with organochlorine
pesticide levels (2 and 37 ng g
−1 ) of soil for HCHs and DDTs, respectively). Furthermore polychlorobiphenyl profiles and concentrations in the sediment samples varied
considerably along the river due to a wide variety of sources, such as different industries and waste sites. Although their sources are difficult the evaluate, the presence of
these compounds at most sites (especially at the waste disposal site) may constitute a
potential health hazard.
Goldberg et al [164] studied the relationship between pesticide concentrations in
water and in sediments and its dependence on the specific surface area of the sediment.
Lopez Avila et al [70] have described a microwave assisted extraction procedure
for the separation of chlorinated insecticides from sediments.
Snyder et al [184] compared supercritical extraction with classical sonication and
Soxhlet extraction for selected pesticides and applied the procedure to river sediments.
Samples extracted with supercritical carbon dioxide modified with 3% methanol
at 350 atm and 50
◦ C gave ≤85% recovery of organochlorine insecticides including
Dichlorovos, Diazinon, Endrin, Endrin aldehyde, decahlorobiphenyls, p, p’-DDT and
Mirex.
6.7.3 Azine type herbicides
Recently there has been a growing interest in employing a highly selective analyteantibody interactions achieved by immunosorbents [186, 187]. In the immunosorbents
the antibody is immobilised onto a silica support and used as an affinity ligand to
extract the target analyte and other compounds with similar structures from the aqueous sample. In this way, any material not recognised by the antibody is not retained in
the immunosorbents while the target analyte remains bound to the antibody, leading
to a high selectivity. The development and the evaluation of two immunosorbents for
the selective trace solid-phase extraction of phenylurea and triazine herbicides have
been discussed in the literature [188–190].
As an example of this type of application Ferrer et al [191] have described
an automated on-line immunosorbents phase extraction method for the analysis of
triazine and phenylurea herbicides in sediments. This method consists of trace analyte extraction using an immunosorbents column-containing ether anti-Atrazine or
anti-Chlorotoluron antibodies-combined with a liquid chromatography by use of
an on-line sample preparation system coupled directly to an atmospheric pressure
chemical ionisation-mass spectrometer in positive mode of operation. After the percolation of 20 mL of water through the immunosorbents columns, high recoveries
in extracts were obtained for all the compounds with the exception of Deisopropylatrazine and Diflubenzuron. Calibration curves where linear in the range between
0.01 and 0.2 µg/L
−1 in groundwater. The limits of detection ranged from 0.001 to
0.005 µg/L
−1 , indicating good sensitivity achieved by both types of immunosorbents.
Wauchope and Myers et al [192] studied the adsorption-dispersion kinetics of
Atrazine and Linuron in sediment-aqueous slurries. The resulting adsorption or desorption was very rapid, approaching 75% of equilibrium values within 3–6 minutes.
Chlorinated adsorption of the herbicide on the sediment was completely reversible
after 2 hours of adsorption.