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370 Multidimensional Chromatography

GC column. The system enables volumes of up to 1.0 ml to be enriched in the
packed liner in the PTV injector without breakthrough. By injecting 100 l,
the detection limits for alachlor and metolachlor in SPETD–GC–MS/MS were
1
0.1–0.2 g l .

13.5 CONCLUSIONS AND TRENDS

Multidimensional chromatography is a very powerful technique which can help
solve complex problems in environmental analysis. Since it requires more complex
instrumentation, it has not been widely used in routine analysis, although some of
the coupled techniques may become important in control laboratories in the future.
GC–GC in environmental analysis will be limited to solving specific problems
that can not easily be solved by other techniques. Coupling LC to LC or GC will
therefore become very common, not only because of the significantly greater
sensitivity, but also because of the greater selectivity and high powers of automation
which implies fewer sources for possible errors and a higher throughput, both of
which are very important in routine analysis.
When these techniques are coupled to selective detection techniques, such as the
increasingly used mass spectrometry, very powerful techniques for determining pol-
lutants in environmental samples are achieved.
When such systems are commercialized, their use will become more widespread.
Most laboratories have so far only used systems which they have designed them-
selves.

ACKNOWLEDGEMENTS

The author would like to acknowledge the contributions made to this work by
Dr F. Borrull, Dr E. Pocurull and S. Peñalver.

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