and 220 nm wavelength were selected for the analysis of

pentachlorophenol and the mixture of all three phenols.

Both mobile phase solutions were adjusted to pH 2 with

phosphoric acid (approximately 0.15% by volume), filtered,

and degased. Mobile phase flow rates were 2 to 3 ml per

minute.

 Analytes were identified by comparing the retention

times of the standards and the retention times of the

samples while concentrations were calculated by comparing

the peak heights of the standards and the peak heights of

the samples. At 2 ml/min flow rate with 72% methanol in the

mobile phase, retention times for phenol, 2,4-DCP and PCP

were 1.3, 1.9 and 5.1 minutes, respectively. At 2 ml/min

flow rate when 58/42 methanol/water mixture was used as the

mobile phase, retention time was 1.6 minutes for phenol and

3.9 minutes for 2,4-DCP. The detection limit for phenol was

0.01 mg/1, for 2,4-DCP was 0.02 mg/l and PCP was 0.03 mg/i.


 Optical absorbance measurement. Optical absorbance of

INTF in the biological activity assay (Section 4.2.4) was

measured by a Perkin-Elmer Model 552 Spectrophotometer with

the wavelength set at 465 nm.


 Dissolved oxygen measurement. A Yellow Spring

Instrument, (YSI) Model 54 Oxygen Meter was used for the

measurement of dissolved oxygen concentration. A strip

chart recorder was connected when continuous monitoring was

required.