Organic compounds in saline marine and estuarine sediments 193
losses and optimal conditions for maximum reproducible carbohydrates recovery were
determined for each extra stage.
Carbohydrate recovered through the analytical procedures were in the range of
101% (lyxose, xylose, galactose) to 108% (glucose) with reproducibility between
2.8% and 18.9%. Down to 0.1 µg of each monosaccharide can be determined in
a sample hydrolysate.
8.1.2.2 Surfactants
Electrospray MS has been used to determine nonylphenol polyethoxylated surfactants
in marine sediments [26].
Pablo et al [52] have described a simple and fast method for the determination in
marine sediments of the anionic and non-ionic surfactants. This group of compounds
includes linear alkylbenzene sulfonates, alkyl ethoxysulfates, nonyphenol polyethoxylates and alcohol polyethoxylates. The proposed method involves the extraction of 5 g
of dry sediment with methanol by using an accelerated solvent extraction unit, preconcentration purification by means of an octadecyl-bonded silica (C 18 ) mini-column
and analysis by high-performance liquid chromatography coupled to mass spectrometry. The recoveries varied in the range of 51–109%, with a standard deviation between
4 and 11. Limits of detection were in the range of 1–5 µg/kg for sediment samples.
This method was applied to the determination of these surfactants in a sediment core
collected in the Bay of Cadiz (SW of Spain), with concentration values up to 637 µg/kg
for linear alkylbenzene sulphonates 401 µg/kg for nonylphenol ethoxylates, 861 µg/kg
for alcohol polyethoxylates and 125 µg/kg for alkylethoxy sulphates.
8.1.3 Halogen containing compounds
8.1.3.1 Chlorophenols
Xie et al [27] determined trace amounts of chlorophenols and chloroguaiacols in
marine sediments collected off the Swedish coast. The compounds were desorbed
from sediment surfaces by a mixture of acetic anhydride and hexane, after buffering with 0.1 mol l
−1 sodium carbonate. The optimal pH was achieved by a 1:4 ratio
of buffer to acetic anhydride. The acetylated extracts were analysed by glass capillary
gas chromatography with electron capture detection. The recoveries, at the µg kg
−1
level, ranged from 85–100% with standard deviations of 4–11%.
8.1.3.2 Polychlorobiphenyls
Three different detection methods (gas chromatography with electron capture, mass
spectrometric and atomic emission detectors) have been compared for the determination of polychlorobiphenyls in highly contaminated marine sediments [28]. Only
atomic emission detection in the chlorine-selective mode provided excellent polychlorobiphenyl profiles without interferences. However, the lower sensitivity of the atomic
emission detector compound to the two other detectors required a 10 to 20 g sample
size for analysis.
Gron et al [29] has reviewed methods for the determination of halogenated
compounds (absorbable, volatile and extractable), with particular reference to their
losses and optimal conditions for maximum reproducible carbohydrates recovery were
determined for each extra stage.
Carbohydrate recovered through the analytical procedures were in the range of
101% (lyxose, xylose, galactose) to 108% (glucose) with reproducibility between
2.8% and 18.9%. Down to 0.1 µg of each monosaccharide can be determined in
a sample hydrolysate.
8.1.2.2 Surfactants
Electrospray MS has been used to determine nonylphenol polyethoxylated surfactants
in marine sediments [26].
Pablo et al [52] have described a simple and fast method for the determination in
marine sediments of the anionic and non-ionic surfactants. This group of compounds
includes linear alkylbenzene sulfonates, alkyl ethoxysulfates, nonyphenol polyethoxylates and alcohol polyethoxylates. The proposed method involves the extraction of 5 g
of dry sediment with methanol by using an accelerated solvent extraction unit, preconcentration purification by means of an octadecyl-bonded silica (C 18 ) mini-column
and analysis by high-performance liquid chromatography coupled to mass spectrometry. The recoveries varied in the range of 51–109%, with a standard deviation between
4 and 11. Limits of detection were in the range of 1–5 µg/kg for sediment samples.
This method was applied to the determination of these surfactants in a sediment core
collected in the Bay of Cadiz (SW of Spain), with concentration values up to 637 µg/kg
for linear alkylbenzene sulphonates 401 µg/kg for nonylphenol ethoxylates, 861 µg/kg
for alcohol polyethoxylates and 125 µg/kg for alkylethoxy sulphates.
8.1.3 Halogen containing compounds
8.1.3.1 Chlorophenols
Xie et al [27] determined trace amounts of chlorophenols and chloroguaiacols in
marine sediments collected off the Swedish coast. The compounds were desorbed
from sediment surfaces by a mixture of acetic anhydride and hexane, after buffering with 0.1 mol l
−1 sodium carbonate. The optimal pH was achieved by a 1:4 ratio
of buffer to acetic anhydride. The acetylated extracts were analysed by glass capillary
gas chromatography with electron capture detection. The recoveries, at the µg kg
−1
level, ranged from 85–100% with standard deviations of 4–11%.
8.1.3.2 Polychlorobiphenyls
Three different detection methods (gas chromatography with electron capture, mass
spectrometric and atomic emission detectors) have been compared for the determination of polychlorobiphenyls in highly contaminated marine sediments [28]. Only
atomic emission detection in the chlorine-selective mode provided excellent polychlorobiphenyl profiles without interferences. However, the lower sensitivity of the atomic
emission detector compound to the two other detectors required a 10 to 20 g sample
size for analysis.
Gron et al [29] has reviewed methods for the determination of halogenated
compounds (absorbable, volatile and extractable), with particular reference to their