60
River and Stream Sediments
sample is extracted with acetone, the extract is evaporated in vacuo at 40 DC and the
residue is hydrolysed with sulphuric acid. The solution is made alkaline with 15 %
aqueous sodium hydroxide and the liberated aniline (or substituted aniline) is steam
distilled and collected in hydrochloric acid. The amine is diazotized and coupled with
thymol, the solution is cleaned up on a column of MN 2100 cellulose powder and the
azo-dye is determined spectrophotometrically at 440 nm (465 nm for the dye derived
from 3-chloro- or 3.4-dichloroaniline) with correction for the extinction of a reagent
blank.
Reeves and Woodham [145] have described a gas chromatographic method for the
determination of methomyl (S-methyl-N-[(methyl carbamoyl)oxy] thioacetimidate)
insecticide in sediments. The residues were extracted with dichloromethane, and the
extracts were purified on a column of Florisil. The purified and concentrated extracts
were then analysed by gas chromatography. The limits of detection were 0.05 mg kg-I
and the recoveries were 91 %.
Mills and Thurman [735] used a mixed method for the isolation of triazine herbicide metabolites from aquter sediments using automated solid phases extraction with a
mixture of methanol and water (4:1 V IV). Following evaporation of the methanol
phases, the metabolites were collected in a column of CIS octadecyl resin. The analytes
were then stripped from the column with ethyl acetate leaving impurities on the
column. Down to a 0.11lS kg- I Triazine could be determined.
Kim In Suk et al. [736] determined chlorinated phenoxy and resin ester herbicides
in sediments by liquid chromatography particle beam mass spectrometry and achieved a detection limit of 1 mg I-lor lower.
Wauchope and Myers [146] studied the adsorption-desorption kinetics of atrazine
and linuron in river sediment-aqueous slurries. The resulting adsorption or desorption was initially very rapid, approaching 75 % of equilibrium values within 3-6 min.
Adsorption of weedkiller on the sediment was completely reversible after 2 h of adsorption.
2.4.16
Dioxins (Tetrachloro to Detachloro Dibenzo-p-dioxins) and Polychlorinated Dibenzofurans
Smith et al. [147] discussed methodology for the determination of Ilg kg- I levels of
these substances in river sediments using containment enrichment and a high resolution gas chromatography-low resolution mass spectrometry-complete data system
analysis.
2.4.17
Adenosine Triphosphate
Tobin et al. [148] give details of two extraction procedures for the determination of
adenosine triphosphate in sediment samples by luciferin -luciferase assay.
Tong et al. [738] used mass profile monitoring by gas chromatography-mass spectrometry to analyse traces of dioxins in silts.
River and Stream Sediments
sample is extracted with acetone, the extract is evaporated in vacuo at 40 DC and the
residue is hydrolysed with sulphuric acid. The solution is made alkaline with 15 %
aqueous sodium hydroxide and the liberated aniline (or substituted aniline) is steam
distilled and collected in hydrochloric acid. The amine is diazotized and coupled with
thymol, the solution is cleaned up on a column of MN 2100 cellulose powder and the
azo-dye is determined spectrophotometrically at 440 nm (465 nm for the dye derived
from 3-chloro- or 3.4-dichloroaniline) with correction for the extinction of a reagent
blank.
Reeves and Woodham [145] have described a gas chromatographic method for the
determination of methomyl (S-methyl-N-[(methyl carbamoyl)oxy] thioacetimidate)
insecticide in sediments. The residues were extracted with dichloromethane, and the
extracts were purified on a column of Florisil. The purified and concentrated extracts
were then analysed by gas chromatography. The limits of detection were 0.05 mg kg-I
and the recoveries were 91 %.
Mills and Thurman [735] used a mixed method for the isolation of triazine herbicide metabolites from aquter sediments using automated solid phases extraction with a
mixture of methanol and water (4:1 V IV). Following evaporation of the methanol
phases, the metabolites were collected in a column of CIS octadecyl resin. The analytes
were then stripped from the column with ethyl acetate leaving impurities on the
column. Down to a 0.11lS kg- I Triazine could be determined.
Kim In Suk et al. [736] determined chlorinated phenoxy and resin ester herbicides
in sediments by liquid chromatography particle beam mass spectrometry and achieved a detection limit of 1 mg I-lor lower.
Wauchope and Myers [146] studied the adsorption-desorption kinetics of atrazine
and linuron in river sediment-aqueous slurries. The resulting adsorption or desorption was initially very rapid, approaching 75 % of equilibrium values within 3-6 min.
Adsorption of weedkiller on the sediment was completely reversible after 2 h of adsorption.
2.4.16
Dioxins (Tetrachloro to Detachloro Dibenzo-p-dioxins) and Polychlorinated Dibenzofurans
Smith et al. [147] discussed methodology for the determination of Ilg kg- I levels of
these substances in river sediments using containment enrichment and a high resolution gas chromatography-low resolution mass spectrometry-complete data system
analysis.
2.4.17
Adenosine Triphosphate
Tobin et al. [148] give details of two extraction procedures for the determination of
adenosine triphosphate in sediment samples by luciferin -luciferase assay.
Tong et al. [738] used mass profile monitoring by gas chromatography-mass spectrometry to analyse traces of dioxins in silts.