Studies of aliphatic amines and other volatile organic compounds in the marine environment.
A highly sensitive and reproducible method for the determination of
aliphatic amines namely monomethylamine (MMA), dimethylamine (DMA) , and
trimethylamine (TMA) in marine environmental samples (water and
sediments) has been developed. This involves an initial stage in which
the amines are preconcentrated by microdiffusion and subsequently
determined using a gas chromatograph equipped with a packed column and
Nitrogen Phosphorus Selective Detector (NPSD) . The detection limit is
at sub ppb level (ng/l), and the method recoveries are in the ranges of
58-68% for MMA, 55-84.3% for DMA, and 83-105.5% for TMA for the range
of concentrations between 2-40 ppb. The percentage standard deviations
of the chromatographic measurements are <15.1% for MMA, <11.1% for DMA,
and <10% for TMA. The untreated Chromosorb 103 column packing was found
to be very stable for more than a year with little deterioration in
Using this method, the production of methylamines by a marine
phytoplankton has been studied, and has been shown to be greatly
influenced by the growth conditions i.e bacteriostatic and nonbacteriostatic
culture media, different levels and types of N sources,
and zooplankton grazing on the phytoplankton. Maximum concentrations of
methylamines were observed in the N03- enriched bacteriostatic medium.
Zooplankton grazing also increases their levels.
Methylamines were found to be distributed in a range of marine
environments, with highest concentrations detected in marine sediments.
Their levels were also higher in polluted Mersey waters than in the
water off the Isle of Man (10M). MMA was found to be the dominant
species in all of these samples (phytoplankton, sediment, and water)
and also in the marine atmosphere.
Using the same approach, l-Arninopropan-2-one, which has long been known
to be a compound of urine, has been shown to be a stable indicator of
raw sewage pollution. Its identity has been confirmed by GC-MS of its
trifluoro acyl-derivative. Its distribution in estuarine water (Mersey
Estuary) and coastal water (Port Erin, 10M) is presented.
Volatile organic compounds (VOCs) in phytoplankton cultures, marine
sediments, and Mersey Estuary water samples have been determined by a
modified Grob closed-loop stripping method and GC-MS analysis. VOCs in
the Mersey estuary water samples were dominated by methylated benzenes
and methylated naphthalenes. In contrast, chlorinated compounds were
the dominant compounds in the sediments, and methylated alkanes in the
non-bacteriostatic phytoplankton culture. Some methylated benzenes were
also found in the plankton sample, which might explain their
observation in some of the remote unpolluted marine environment.
This thesis is dedicated to my parents, my wife and