Organic compounds in non-saline sediments 153
6.6.3 Adenosine-5’-triphosphate
Tobin et al [159] give details of two extraction procedures for the determination of
adenosine-5’-triphosphate in sediment samples by luciferin-liciferase assay.
6.6.4 Nucleotides
The structures or organic phosphorus compounds in aquatic sediments are to a large
extent unknown although these compounds are considered to play an important
role in regulating lake trophic status. To enhance identification of these compounds
Brabenden et al [160] developed a liquid chromatography method for their separation. The stationary phase was porous graphitic carbon and the mobile phases used
in the gradient elution were compatible with both inductive coupled plasma atomic
emission spectroscopy (ICP-AES) and electrospray ionisation tandem mass spectrometry (ESI-MS/MS). With liquid chromatography–ICP-AES, eight different phosphorus
containing peaks could be observed in the phosphorus chromatogram indicating that
at least eight different phosphorus compounds were separated. With the setup of an
information dependent acquisition with ESI-MS/MS, the mass over charge (m/3) of
compounds containing a phosphate group m/z (H 2 PO
−
3 , m/z 97) could be measured
and further fragmentation experiments gave additional information on the structure of
almost 40 separated phosphorus compounds, several were verified to be nucleotides.
ICP-AES was very suitable in the development of the liquid chromatographic method
and allowed screening and quantification of phosphorus compounds. This liquid
chromatograph ESI-MS/MS technique was able to identify several sediment organic
compounds.
6.7 INSECTICIDES AND PESTICIDES
6.7.1 Organophosphorus insecticides
A gas chromatographic procedure using electron capture detection has been described
for the determination of Dursban (O,O-diethyl-O-(3,5 6-trichlorlo-2-pyridyl phosphorothioate) in water and silt (Rice and Dishberger [161]). In this method, water samples
are extracted with dichloromethane, the extract is evaporated, and a solution of the
residue is cleaned up on a column of silicic acid, Dursban being eluted with hexane. The
eluate is evaporated to dryness under reduced pressure, and a solution of the residue
in hexane is subjected to gas chromatography. Down to 0.1 ug kg
−1 of Dursban in
sediment could be determined; average recoveries from sediment was 83%.
Deutsch et al [162] determined Dursban in sediments by an extraction gas chromatographic procedure which was capable of determining down to 0.01 mg kg
−1
Dursban using a 10 g sample.
To determine traces of organophosphorus insecticides and related compounds in
sediment, Kjolholt et al [45] homogenised the samples and subjected them to Soxhlet extraction with acetone-n-hexane. The extract was partitioned between methylene
chloride and water and subjected to adsorption chromatography and analysed using
gas chromatography and nitrogen-phosphorus detection. The influences of freezedrying and of pH on extraction efficiency were studied. Interference by elemental
6.6.3 Adenosine-5’-triphosphate
Tobin et al [159] give details of two extraction procedures for the determination of
adenosine-5’-triphosphate in sediment samples by luciferin-liciferase assay.
6.6.4 Nucleotides
The structures or organic phosphorus compounds in aquatic sediments are to a large
extent unknown although these compounds are considered to play an important
role in regulating lake trophic status. To enhance identification of these compounds
Brabenden et al [160] developed a liquid chromatography method for their separation. The stationary phase was porous graphitic carbon and the mobile phases used
in the gradient elution were compatible with both inductive coupled plasma atomic
emission spectroscopy (ICP-AES) and electrospray ionisation tandem mass spectrometry (ESI-MS/MS). With liquid chromatography–ICP-AES, eight different phosphorus
containing peaks could be observed in the phosphorus chromatogram indicating that
at least eight different phosphorus compounds were separated. With the setup of an
information dependent acquisition with ESI-MS/MS, the mass over charge (m/3) of
compounds containing a phosphate group m/z (H 2 PO
−
3 , m/z 97) could be measured
and further fragmentation experiments gave additional information on the structure of
almost 40 separated phosphorus compounds, several were verified to be nucleotides.
ICP-AES was very suitable in the development of the liquid chromatographic method
and allowed screening and quantification of phosphorus compounds. This liquid
chromatograph ESI-MS/MS technique was able to identify several sediment organic
compounds.
6.7 INSECTICIDES AND PESTICIDES
6.7.1 Organophosphorus insecticides
A gas chromatographic procedure using electron capture detection has been described
for the determination of Dursban (O,O-diethyl-O-(3,5 6-trichlorlo-2-pyridyl phosphorothioate) in water and silt (Rice and Dishberger [161]). In this method, water samples
are extracted with dichloromethane, the extract is evaporated, and a solution of the
residue is cleaned up on a column of silicic acid, Dursban being eluted with hexane. The
eluate is evaporated to dryness under reduced pressure, and a solution of the residue
in hexane is subjected to gas chromatography. Down to 0.1 ug kg
−1 of Dursban in
sediment could be determined; average recoveries from sediment was 83%.
Deutsch et al [162] determined Dursban in sediments by an extraction gas chromatographic procedure which was capable of determining down to 0.01 mg kg
−1
Dursban using a 10 g sample.
To determine traces of organophosphorus insecticides and related compounds in
sediment, Kjolholt et al [45] homogenised the samples and subjected them to Soxhlet extraction with acetone-n-hexane. The extract was partitioned between methylene
chloride and water and subjected to adsorption chromatography and analysed using
gas chromatography and nitrogen-phosphorus detection. The influences of freezedrying and of pH on extraction efficiency were studied. Interference by elemental