222 Organic compounds in soils, sediments & sludges
was collected after secondary biological treatment but before chlorination. The most
important result of this study was the rapid loss of phenolics from the samples at 4
◦ C
with no addition of any chemical preservative. The percentage loss of phenolics within
24 hours for the industrial waste, raw and treated sewage samples was 85, 80 and
40% respectively.
Methods for the determination of phenols in sewage are reviewed below.
Gas chromatography
Extractive alkylation using pentafluorobenzylation and glass capillary gas chromatography using electron capture detection has been used [48] to determine phenols and
carboxylic acids in sewage effluents. Excess of alkylating reagent in the combined
extraction/alkylation is minimised and there is no need to remove it before the gas
chromatography. By suitable selection of the extraction and derivatisation conditions by-product formation can also be minimised. The detection limit is in the range
1–10 µg l
−1 and can be lowered at the expense of the range of compounds which can
be determined.
High performance liquid chromatography
The HPLC of alkyl phenols and alkylphenol mono- and di-ethoxylates on Zorbox
NH2 columns in amounts down to 0.2 µg with fluorescence detection has been
discussed [49].
Flow injection analysis
Moller and Martin et al [50] describe a flow injection analysis method for determining
phenols in sewage based on the condensation of phenols with 4-amino antipyrine,
followed by alkaline oxidation and spectrophotometric detection.
Enzyme electrode
Kjellen and Neujahr et al [51] have discussed an enzyme electrode for the determination
of total phenols in sewage works samples. The most sensitive electrodes were obtained
by immobilisation of the enzyme covalently bound to AH-Sepharose 4B or to nylon
nets, as well as by enzyme adsorption on ion-exchangers. Optimal conditions include
pH 6.5–9.5, 40
◦ C and incubation in a buffer for a few minutes before addition of
the sample in order to make the electrode response independent of the diffusion rate
of the substrate. Readout is achieved within 30s of sample addition and the maximum rate of oxygen consumption is linearly dependent on phenol concentration in the
0.5–50 µM range.
Solid phase extraction
Lee and Peart et al [52] used solid phase extraction to determine levels of biphenol-A
down to 0.05 mg g
−1 in sludge.
was collected after secondary biological treatment but before chlorination. The most
important result of this study was the rapid loss of phenolics from the samples at 4
◦ C
with no addition of any chemical preservative. The percentage loss of phenolics within
24 hours for the industrial waste, raw and treated sewage samples was 85, 80 and
40% respectively.
Methods for the determination of phenols in sewage are reviewed below.
Gas chromatography
Extractive alkylation using pentafluorobenzylation and glass capillary gas chromatography using electron capture detection has been used [48] to determine phenols and
carboxylic acids in sewage effluents. Excess of alkylating reagent in the combined
extraction/alkylation is minimised and there is no need to remove it before the gas
chromatography. By suitable selection of the extraction and derivatisation conditions by-product formation can also be minimised. The detection limit is in the range
1–10 µg l
−1 and can be lowered at the expense of the range of compounds which can
be determined.
High performance liquid chromatography
The HPLC of alkyl phenols and alkylphenol mono- and di-ethoxylates on Zorbox
NH2 columns in amounts down to 0.2 µg with fluorescence detection has been
discussed [49].
Flow injection analysis
Moller and Martin et al [50] describe a flow injection analysis method for determining
phenols in sewage based on the condensation of phenols with 4-amino antipyrine,
followed by alkaline oxidation and spectrophotometric detection.
Enzyme electrode
Kjellen and Neujahr et al [51] have discussed an enzyme electrode for the determination
of total phenols in sewage works samples. The most sensitive electrodes were obtained
by immobilisation of the enzyme covalently bound to AH-Sepharose 4B or to nylon
nets, as well as by enzyme adsorption on ion-exchangers. Optimal conditions include
pH 6.5–9.5, 40
◦ C and incubation in a buffer for a few minutes before addition of
the sample in order to make the electrode response independent of the diffusion rate
of the substrate. Readout is achieved within 30s of sample addition and the maximum rate of oxygen consumption is linearly dependent on phenol concentration in the
0.5–50 µM range.
Solid phase extraction
Lee and Peart et al [52] used solid phase extraction to determine levels of biphenol-A
down to 0.05 mg g
−1 in sludge.