Chemistry Reference
In-Depth Information
(a)
Donor phase
Sample
Waste
−
X
N
Organic membrane
XH
+
N
Acceptor phase
Aqueous donor phase
(b)
Sample
Waste
X
Organic membrane
Organic acceptor phase
Polymeric nonporous membrane
(c)
Organic acceptor phase
Aqueous donor phase
Aqueous donor phase
(d)
Polymeric nonporous membrane
Sorbent trap
To GC
Acceptor stream of gas
Figure 7.4
Schemes of different solutions based on membrane techniques (a) SLM; (b) MMLLE;
(c) MASE; (d) MESI.
be conditioned, which consumes more organic solvent [45]. After conditioning, however, the membrane is
reusable for extraction purposes. With MASE hydrophobic compounds are extracted from aqueous samples.
For comparison of different solutions see Figure 7.4.
7.2.5.5
Applications of membrane extraction
Applicable in many areas of analytical sample preparation (see Table 7.1), membrane techniques significantly
reduce the consumption of reagents.
7.2.6 Gas extraction
One of the most commonly used techniques for the isolation of VOCs from water samples is extraction into
the gaseous phase. Headspace analysis techniques are based on the partition of analytes between the liquid
and the gaseous phase. The gaseous phase (headspace) is analysed together with the volatile compounds
