Organometallic Compounds
63
tracting the alkylmercury iodides into benzene. These iodides are then determined by
gas chromatography on the benzene extract with electron capture detection CH foil).
Good separation of chromatographic peaks is obtained for the mercury compounds as
either chlorides, bromides or iodides.
Batti et al. [172] determined methylmercury in river sediments from industrial and
mining areas.
Gas chromatographic methods have been described for the determination of alkylmercury compounds in sediments [173].
Bartlett et al. [174] observed unexpected behaviour of methylmercury-containing
river Mersey sediments during storage. They experienced difficulty in obtaining
consistent methylmercury values; supposedly identical samples analysed at intervals
of a few days gave markedly different results. They followed the levels of methylmercury in selected sediments over a period, to determine if any change was occurring on
storage. They found that the amounts of methylmercury observed in the stored
sediments did not remain constant; initially there was a rise in the amount of methylmercury observed, and then, after about 10 days, the amount present began to decline
to levels which in general only approximated those originally present. They observed
this phenomenon in nearly all of the Mersey sediment samples they examined. It was
noted that sediments sterilized, normally by autoclaving at approximately 120 °c, did
70
20
o
I
10
I
20
I
30
I
40
Time after collection (d)
50
60
Fig. 2.9
Analyses of sterilized and unsterilized sediments from Hale Point, for methylmercury.
Total mercury is 7.24 J1g g-l. Results up to day 25 are the mean of eight determinations; results
beyond day 25 are the mean of four determinations. Error bars represent range limits for each
analysis series. The samples were stored at room temperature (18 °C): ----*-- 2 untreated samples; ---0--- = sterilized samples (from [174]).
63
tracting the alkylmercury iodides into benzene. These iodides are then determined by
gas chromatography on the benzene extract with electron capture detection CH foil).
Good separation of chromatographic peaks is obtained for the mercury compounds as
either chlorides, bromides or iodides.
Batti et al. [172] determined methylmercury in river sediments from industrial and
mining areas.
Gas chromatographic methods have been described for the determination of alkylmercury compounds in sediments [173].
Bartlett et al. [174] observed unexpected behaviour of methylmercury-containing
river Mersey sediments during storage. They experienced difficulty in obtaining
consistent methylmercury values; supposedly identical samples analysed at intervals
of a few days gave markedly different results. They followed the levels of methylmercury in selected sediments over a period, to determine if any change was occurring on
storage. They found that the amounts of methylmercury observed in the stored
sediments did not remain constant; initially there was a rise in the amount of methylmercury observed, and then, after about 10 days, the amount present began to decline
to levels which in general only approximated those originally present. They observed
this phenomenon in nearly all of the Mersey sediment samples they examined. It was
noted that sediments sterilized, normally by autoclaving at approximately 120 °c, did
70
20
o
I
10
I
20
I
30
I
40
Time after collection (d)
50
60
Fig. 2.9
Analyses of sterilized and unsterilized sediments from Hale Point, for methylmercury.
Total mercury is 7.24 J1g g-l. Results up to day 25 are the mean of eight determinations; results
beyond day 25 are the mean of four determinations. Error bars represent range limits for each
analysis series. The samples were stored at room temperature (18 °C): ----*-- 2 untreated samples; ---0--- = sterilized samples (from [174]).