66 Organic compounds in soils, sediments & sludges
The instruments contained an electron capture detector with a tritium foil source.
For gas chromatography-mass spectrometry, a Varian 1400 gas chromatograph coupled to a Finnegan 3000 mass spectrometer was used, The 1400 was equipped
with a glass column (180 cm × 2 mm i.d.) packed with 4% SE-30, 6% SP-4201 on
Supelcoport (100–120 mesh). The operating conditions were: column temperature,
210
◦ C; transfer-line temperature, 250
◦ C, gas jet separator temperature, 255
◦ C, flow
rate of helium gas, 12 ml min
−1 , sensitivity, 10
−7 A/V; electron multiplier voltage,
2.25 kV; electron ionisation current, 6.95 eV.
A summation of the elution of the chlorinated organic insecticides and the polychlorobiphenyls from the alumina column ranged between 10% for γ chlordane up to
100% (hepta chloraldrin). Heptachlor epoxide and Dieldrin were removed from the
column by extending the elution solvent beyond the 30 ml volume with an additional,
but separate elution volume of 30 ml. The polychlorobiphenyls remained an integral
part of the mixture containing the insecticides in the first 30 ml of eluate. The elution
pattern of alumina column fraction one on the charcoal column, showed that the insecticides were separated from the polychlorobiphenyls by means of acetone-diethyl ether
eluent. The polychlorobiphenyls were subsequently removed from the charcoal column
with benzene. Known amounts of insecticides and polychlorobiphenyls (Aroclor 1254)
were added to soils and oyster samples; the samples were analysed as described above
to check the efficiency of the analytical procedure. Overall recoveries ranged from
8.5% (Hepta Chlor) and 112% (l-chloride one)
Various other methods for the determination of chlorinated insecticides are
reviewed in Table 3.2.
High performance liquid chromatography
Vega et al [38, 307] have discussed the application of microwave assisted miscellar
extraction combined with solid-phase microwave assisted solid phase extraction and
high performance liquid chromatography with UV detection for the determination of
organochlorine pesticides in mud samples. This method allows detection limits to be
reduced with respect to microwave assisted miscellar extraction and also enables target
organochlorine pesticides to be determined in complex matrices due to the clean up
procedure. Several new variables that effect the microwave assisted miscellar extraction
process were introduced and optimised. A non-ionic detergent polyoxyethylene bound
on to ether polydimethylsiloxane-divinylbenzene fibre on 60 µm polydimethylsiloxane
fibre were used for this approach. Optimum conditions provide satisfactory precision (relative standard deviation less than 10%), good recoveries (79.78–117.70%)
and detection limits ranging between 28 and 136 ng g
−1 for the pesticides studied.
This method was successfully applied to the determination of target organochlorine
pesticides in several kinds of mud samples of different physicochemical characteristics. Microwave miscellar extraction-solid phase micro extraction method was also
validated and applied to a certified reference material.
The samples were analysed using HPLC-UV. The chromatogram obtained for the
mixture of pesticides (0.8 µg g
−1 for 4,4
-DDD, 4,4
-DDT, 2,4
-DDT, and 4,4
-DDE,
and 1.6 µg g
−1 for Aldrin and Dieldrin) extracted from a spiked Hoya Pozuelo mud
sample using microwave assisted miscellar extraction-solid phase micro extraction
procedure is shown in Figure 3.2. It can be seen that the mobile phase used (methanol:
water, 84: 16 v/v) allows a good separation of analytes and a short analysis time.
The instruments contained an electron capture detector with a tritium foil source.
For gas chromatography-mass spectrometry, a Varian 1400 gas chromatograph coupled to a Finnegan 3000 mass spectrometer was used, The 1400 was equipped
with a glass column (180 cm × 2 mm i.d.) packed with 4% SE-30, 6% SP-4201 on
Supelcoport (100–120 mesh). The operating conditions were: column temperature,
210
◦ C; transfer-line temperature, 250
◦ C, gas jet separator temperature, 255
◦ C, flow
rate of helium gas, 12 ml min
−1 , sensitivity, 10
−7 A/V; electron multiplier voltage,
2.25 kV; electron ionisation current, 6.95 eV.
A summation of the elution of the chlorinated organic insecticides and the polychlorobiphenyls from the alumina column ranged between 10% for γ chlordane up to
100% (hepta chloraldrin). Heptachlor epoxide and Dieldrin were removed from the
column by extending the elution solvent beyond the 30 ml volume with an additional,
but separate elution volume of 30 ml. The polychlorobiphenyls remained an integral
part of the mixture containing the insecticides in the first 30 ml of eluate. The elution
pattern of alumina column fraction one on the charcoal column, showed that the insecticides were separated from the polychlorobiphenyls by means of acetone-diethyl ether
eluent. The polychlorobiphenyls were subsequently removed from the charcoal column
with benzene. Known amounts of insecticides and polychlorobiphenyls (Aroclor 1254)
were added to soils and oyster samples; the samples were analysed as described above
to check the efficiency of the analytical procedure. Overall recoveries ranged from
8.5% (Hepta Chlor) and 112% (l-chloride one)
Various other methods for the determination of chlorinated insecticides are
reviewed in Table 3.2.
High performance liquid chromatography
Vega et al [38, 307] have discussed the application of microwave assisted miscellar
extraction combined with solid-phase microwave assisted solid phase extraction and
high performance liquid chromatography with UV detection for the determination of
organochlorine pesticides in mud samples. This method allows detection limits to be
reduced with respect to microwave assisted miscellar extraction and also enables target
organochlorine pesticides to be determined in complex matrices due to the clean up
procedure. Several new variables that effect the microwave assisted miscellar extraction
process were introduced and optimised. A non-ionic detergent polyoxyethylene bound
on to ether polydimethylsiloxane-divinylbenzene fibre on 60 µm polydimethylsiloxane
fibre were used for this approach. Optimum conditions provide satisfactory precision (relative standard deviation less than 10%), good recoveries (79.78–117.70%)
and detection limits ranging between 28 and 136 ng g
−1 for the pesticides studied.
This method was successfully applied to the determination of target organochlorine
pesticides in several kinds of mud samples of different physicochemical characteristics. Microwave miscellar extraction-solid phase micro extraction method was also
validated and applied to a certified reference material.
The samples were analysed using HPLC-UV. The chromatogram obtained for the
mixture of pesticides (0.8 µg g
−1 for 4,4
-DDD, 4,4
-DDT, 2,4
-DDT, and 4,4
-DDE,
and 1.6 µg g
−1 for Aldrin and Dieldrin) extracted from a spiked Hoya Pozuelo mud
sample using microwave assisted miscellar extraction-solid phase micro extraction
procedure is shown in Figure 3.2. It can be seen that the mobile phase used (methanol:
water, 84: 16 v/v) allows a good separation of analytes and a short analysis time.