Development of a Novel Mass Spectrometric ... - Jacobs University

Conclusions
In conclusion we could show that using APCI-MS n-alkanes can be investigated not
only in model systems but as well in real life complex samples. Using [M-H] + ions of
n-alkanes in reference mixtures as external calibrant, close to 1000 molecular
formulas can be obtained from an APCI-MS spectrum in a light shredder waste
sample. The results demonstrated that a dehydrogenation process is releasing an
array of unsaturated olefins believed to make up the GC hump. The presence of few
harmful PCBs was explored using negative APCI-MS. This method could show a
typical chemical content for the light shredder waste complex mixture.
Further tandem MS experiments could confirm the identity of the compounds within
the waste sample. The n-alkanes showed a linear response in calibration curves
allowing the acquisition of a quantification figure of selected hydrocarbons in waste
sample. The method developed here is certainly not applicable for a routine analysis
of waste samples due to high instrument investment costs. However, the method
developed, allows a clear identification of hydrocarbons in complex waste samples
and a spot check screening of waste samples, very heterogeneous by nature, for the
presence of alkanes. Furthermore the techniques allow a critical re-evaluation of
legally binding analytical methods for the determination of hydrocarbons in
unresolved complex mixtures, by identification of the actual components of such
samples. The extent of biodegradation and weathering conditions over the complex
mixture of light shredder waste was monitored successfully by the employment of
Kendrick plot. This innovative methodology yielded important fundamental and
compositional information of the waste mixture.
Another intriguing aspect of this study is the success of the APCI methodology in
examining various hydrocarbon analytes previously considered as difficult to ionize.
The applicability of APCI-MS method was successfully extended for the
examination of various model non-polar hydrocarbons like high mass linear,
branched and cyclic hydrocarbons. This was demonstrated by the production of
intact abundant stable [M-H] + ion observed for each hydrocarbon within a large
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