224
Phytoplankton
electron capture detector to changes in temperature, programming the column resulted in severe baseline drift at the beginning of the run. However, neither class of
components affected the detection of the other. Thus, both the mineral oil and
halogenated compounds can be conveniently analysed and quantified simultaneously
after single injection.
Liquid scintillation counting of [14C] DDT has been used to study the pick-up and
metabolism of DDT by fresh water algae [638]. Neudorf and Khan [764] investigated the
uptake of 14C labelled DDT, dieldrin, and photodieldrin by Ankistrodesmus amalloides.
The results of liquid scintillation spectrometric analyses show that the total pick-up of
DDT during a 1-3 h period was 2-5 times higher than that of dieldrin, and 10 times
higher than that of photodieldrin. The algae metabolized 3-5 % of DDT to DDE and
0.8 % to DDD. The metabolism of DDT by Daphnia pulex was also monitored by
exposing 100 organisms to 0.31 ppm of the labelled pesticide for 24 h without feeding.
The metabolites were then extracted and separated by thin-layer chromatography and the
R f values of radioactive spots were compared to R f values for non-radioactive DDD and
radioactive DDE. The results show a conversion of DDT to DDE of about 13.6 %.
9.4.6
Chlorophyllous Pigment
Visible Spectrometry. Youngman [639] of the Water Reasearch Centre (UK) has
studied methods of extracting these pigments from algae and the spectrophotometric
determination of chlorophylls in the extracts.
Jensen [640] showed that there was no difference between the chlorophyll extracted
by either methanol or acetone from fresh diatom material, but, with green algae,
methanol gave 30 % higher results than acetone. Low levels were found in stored
fUters, and this was most pronounced with methanol. Immediate analysis of the
sample is recommended; even storage by freezing should be avoided.
Wun et al. [641] have described a method for the simultaneous extraction of the
water quality marker algal chlorophyll a and the faecal sterol coprostanol from water.
This method utilizes a column of Amberlite XAD-1 for the simultaneous extraction of
both markers. Chlorophyll content was determined by the trichromatic method [70]
usinq a double beam spectrophotometer.
Wun et al. [641], using 14C-Iabelled cholesterol c, showed that 100 % of this substance is adsorbed from a 500 to 1000 ml water sample by XAD-1 resin. When the
column was subsequently eluted with 50 ml of basic methanol and 30 ml of benzene,
up to 97 % of the added sterol was recovered in the benzene eluate.
To ascertain the suitability of the column method for the simultaneous extraction of
coprostanol and chlorophyll a in actual field testing situations, various unialgal cultures
were mixed with sewage samples. The effectiveness of the neutral resin column extraction
for these markers was evaluated with that of the conventional procedures.
The efficiency of the resin column for the simultaneous extraction of coprostanol
and phytoplankton chlorophyll a is comparable to or better than the conventional
extraction procedures for the respective compounds. Dilution of the samples and the
presence of extraneous materials did not affect the recovery efficiency significantly.
The column technique was effective in isolating chlorophyll a from various algae. The
Phytoplankton
electron capture detector to changes in temperature, programming the column resulted in severe baseline drift at the beginning of the run. However, neither class of
components affected the detection of the other. Thus, both the mineral oil and
halogenated compounds can be conveniently analysed and quantified simultaneously
after single injection.
Liquid scintillation counting of [14C] DDT has been used to study the pick-up and
metabolism of DDT by fresh water algae [638]. Neudorf and Khan [764] investigated the
uptake of 14C labelled DDT, dieldrin, and photodieldrin by Ankistrodesmus amalloides.
The results of liquid scintillation spectrometric analyses show that the total pick-up of
DDT during a 1-3 h period was 2-5 times higher than that of dieldrin, and 10 times
higher than that of photodieldrin. The algae metabolized 3-5 % of DDT to DDE and
0.8 % to DDD. The metabolism of DDT by Daphnia pulex was also monitored by
exposing 100 organisms to 0.31 ppm of the labelled pesticide for 24 h without feeding.
The metabolites were then extracted and separated by thin-layer chromatography and the
R f values of radioactive spots were compared to R f values for non-radioactive DDD and
radioactive DDE. The results show a conversion of DDT to DDE of about 13.6 %.
9.4.6
Chlorophyllous Pigment
Visible Spectrometry. Youngman [639] of the Water Reasearch Centre (UK) has
studied methods of extracting these pigments from algae and the spectrophotometric
determination of chlorophylls in the extracts.
Jensen [640] showed that there was no difference between the chlorophyll extracted
by either methanol or acetone from fresh diatom material, but, with green algae,
methanol gave 30 % higher results than acetone. Low levels were found in stored
fUters, and this was most pronounced with methanol. Immediate analysis of the
sample is recommended; even storage by freezing should be avoided.
Wun et al. [641] have described a method for the simultaneous extraction of the
water quality marker algal chlorophyll a and the faecal sterol coprostanol from water.
This method utilizes a column of Amberlite XAD-1 for the simultaneous extraction of
both markers. Chlorophyll content was determined by the trichromatic method [70]
usinq a double beam spectrophotometer.
Wun et al. [641], using 14C-Iabelled cholesterol c, showed that 100 % of this substance is adsorbed from a 500 to 1000 ml water sample by XAD-1 resin. When the
column was subsequently eluted with 50 ml of basic methanol and 30 ml of benzene,
up to 97 % of the added sterol was recovered in the benzene eluate.
To ascertain the suitability of the column method for the simultaneous extraction of
coprostanol and chlorophyll a in actual field testing situations, various unialgal cultures
were mixed with sewage samples. The effectiveness of the neutral resin column extraction
for these markers was evaluated with that of the conventional procedures.
The efficiency of the resin column for the simultaneous extraction of coprostanol
and phytoplankton chlorophyll a is comparable to or better than the conventional
extraction procedures for the respective compounds. Dilution of the samples and the
presence of extraneous materials did not affect the recovery efficiency significantly.
The column technique was effective in isolating chlorophyll a from various algae. The