Surface enhanced Raman spectroscopy detection of trace chemicals in inhomogeneous fluid mixtures

摘要

Detecting trace chemicals in heterogeneous fluid mixtures has a variety of possible applications for example in food industry. The drivers of this development have not only been build on consumer awareness but have also been emphasized by decision makers at the EU level. The current laboratory methods are laborious, expensive and slow, which challenges their application in milk quality control especially in terms of qualitatively detecting such chemical residues an melamine. More studied are therefore needed of methods that are applicable as field devices for consumer use and as on-line analysers for industrial contexts.The more complex the media the more challenging the detection of a chemical. Separating relevant information from the raw measurement data poses a difficult task. Moreover the sample preparation should be designed to guarantee stable measurement performance for obtaining usable data. In this thesis work the sample preparation chain and substrate handling are looked into. The issues most severely hindering the detection are stem from sample preparation and Surface Enhanced Raman Spectroscopy substrate performance. Which constitute fundamental issues requiring further examination. Due to the high amount of uncontrolled variables, the results stated here are not statistically tested.The project achieved to produce sample preparation schemes that result in samples of different types of spreading on the substrates. Furthermore different kind of noise noise was seen in the spectra of the two sample preparation schemes. The development in data treatment and possible further investigation of the sampling chain together dictate the direction in which sample pretreatment ought to be taken.