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demonstrated that the head space pattern would be characteristic for bruised fruit, over-ripe fruit and
fruit infected with penicillium digitatum Sacc. or P. italicum Wehmer.

Another interesting application of headspace analysis is in the measurement of certain types of
contaminant found in pharmaceutical products that are volatile. These contaminants usually arise from
the solvents used to purify the product by crystallization, or from flavor additives. It follows that as
some solvents used in the crystallization process are toxic, their measurement is important. Schuberth
[42] developed a procedure involving head space analysis followed by GC/MS evaluation, to assay
drugs for volatile materials. The technique used has been simply described by Mulligan and McCauley
[43]. A sample of the drug is carefully weighed and placed in a tube (often about 10 ml in volume) and
usually filled with an inert gas such as helium, at a pressure of about 5 psi. The tube is then heated for a
predetermined amount of time at an appropriate temperature, and an aliquot of the head space gas then
allowed to flow into a gas sampling tube. The sample tube is then placed in line with the carrier gas to
the GC column and the contaminants separated. Schuberth employed an ion trap mass spectrometer to
detect and identify the volatile components recovered from the drug. Ethanol, acetone, 2-propanol,
methyl acetate, toluene, eucalyptol and menthol were identified in various pharmaceutical products, at
levels ranging from 1-10 µmol./kg.

Novel Interfaces for Specific Applications

Most of the interfaces described so far have been developed for general use and have been utilized for a
wide range of different applications. However, a number of interfaces have been developed for use in
specific types of analysis and, although all the different forms cannot be described in this book, a
number of them will be discussed, particularly those that have been used in GC, LC and/or capillary
electrophoresis tandem systems.

Affinity Membrane Mass Spectrometry Interfaces

The affinity membrane can be used as the separation system itself, or it can be used as the interface
between a liquid chromatograph and a mass