Organic compounds in sludges 223
10.2.5 Surface active agents
10.2.5.1 Anionic types
High performance liquid chromatography
Petrovic and Barcelo et al [53] have reported a broadly applicable method based on
liquid chromatography-mass spectrometry for the determination of anionic and non
ionic surface active agents and their degradation products in sewage.
Less polar compounds were determined by reverse phase liquid chromatography in
atmosphere pressure chemical ionisation mode (ADCI-MS)positive ion mode, whereas
the more polar analytes were determined by ion-pair liquid chromatography/ES1-MS
under negative ion conditions.
Supercritical fluid chromatography
Fernandez et al [54] used supercritical fluid extraction combined with ion pair liquid
chromatography to determine quaternary ammonium compounds in digested sludges
and marine sediments. Carbon dioxide modified with 30% methanol was used as the
extractant at an operating pressure of 380 atm. Between 0.2 and 3.7 g kg
−1 surfactant was found in Swiss works effluent sludges, determined with a relative standard
deviation of 7%.
Spectrometry
Taylor and Waters et al [56] and Taylor and Williams et al [55] studied the extraction
constants of association compounds of anionic surfactants with iron II chelates of the
ferroin type. The extraction constants of these chelates distributed between water and
chloroform were correlated with the structure of the surfactant and the ligand. Taylor
and Williams et al [55] also studied the use of iron II chelates of 1, 10-phenanthrolene
and its derivatives, bipyridyl and terpyridyl in the estimation of anionic surfactants in
chloroform extracts of water samples. The extent of extraction increases with increasing chain length of surfactants and is characterised by a breakthrough-point (i.e. the
chain length above which the surfactant is extracted and below which it is not). This
point depends on the choice of iron II chelate and extracting solvent A selective procedure for determining surfactants in sewage based on experimental control of the
‘breakthrough point’ and involving spectrophotometric determination of the extracted
complexes, is described. The effect of foreign ions is also discussed by the workers.
Taylor and Fryer et al [57] determined anionic detergents in sewage using iron
III chelates (ferroin). The buttered sample was extracted with chloroform and the
spectrophometric measurement made at 512 nm.
Workers at the Water Research Centre [58] have described a methylene-blue-based
auto analysis method for determining 0–1 µg L
−1 anionic detergents in water and
sewage effluents. The report described the method in detail and discusses its precision
and accuracy.
10.2.5.2 Cationic detergents
McEvoy and Giger et al [59] give details of techniques developed for the determination of linear alkylbenzenesulphonates in stabilised sewage sludges, including a rapid
10.2.5 Surface active agents
10.2.5.1 Anionic types
High performance liquid chromatography
Petrovic and Barcelo et al [53] have reported a broadly applicable method based on
liquid chromatography-mass spectrometry for the determination of anionic and non
ionic surface active agents and their degradation products in sewage.
Less polar compounds were determined by reverse phase liquid chromatography in
atmosphere pressure chemical ionisation mode (ADCI-MS)positive ion mode, whereas
the more polar analytes were determined by ion-pair liquid chromatography/ES1-MS
under negative ion conditions.
Supercritical fluid chromatography
Fernandez et al [54] used supercritical fluid extraction combined with ion pair liquid
chromatography to determine quaternary ammonium compounds in digested sludges
and marine sediments. Carbon dioxide modified with 30% methanol was used as the
extractant at an operating pressure of 380 atm. Between 0.2 and 3.7 g kg
−1 surfactant was found in Swiss works effluent sludges, determined with a relative standard
deviation of 7%.
Spectrometry
Taylor and Waters et al [56] and Taylor and Williams et al [55] studied the extraction
constants of association compounds of anionic surfactants with iron II chelates of the
ferroin type. The extraction constants of these chelates distributed between water and
chloroform were correlated with the structure of the surfactant and the ligand. Taylor
and Williams et al [55] also studied the use of iron II chelates of 1, 10-phenanthrolene
and its derivatives, bipyridyl and terpyridyl in the estimation of anionic surfactants in
chloroform extracts of water samples. The extent of extraction increases with increasing chain length of surfactants and is characterised by a breakthrough-point (i.e. the
chain length above which the surfactant is extracted and below which it is not). This
point depends on the choice of iron II chelate and extracting solvent A selective procedure for determining surfactants in sewage based on experimental control of the
‘breakthrough point’ and involving spectrophotometric determination of the extracted
complexes, is described. The effect of foreign ions is also discussed by the workers.
Taylor and Fryer et al [57] determined anionic detergents in sewage using iron
III chelates (ferroin). The buttered sample was extracted with chloroform and the
spectrophometric measurement made at 512 nm.
Workers at the Water Research Centre [58] have described a methylene-blue-based
auto analysis method for determining 0–1 µg L
−1 anionic detergents in water and
sewage effluents. The report described the method in detail and discusses its precision
and accuracy.
10.2.5.2 Cationic detergents
McEvoy and Giger et al [59] give details of techniques developed for the determination of linear alkylbenzenesulphonates in stabilised sewage sludges, including a rapid