Abstract:

To establish an efficient and accurate differential Raman spectroscopy method for the detection of wire plastic skin， the differential Raman spectroscopy data with 35 different brands and types of wire plastic skin were measured by a portable standard differential Raman spectrometer. The samples were preliminarily classified according to their different main components and fillers. A principal component analysis was used to reduce the dimension of the Raman data after preliminary classification. The samples could be grouped by hierarchical clustering， and a K?means clustering analysis was used to test the accuracy of the grouped results. For the same group of the samples， the relative peak height ratio of Raman characteristic peaks was used to distinguish. The results indicated that the samples of group I?1（white sample containing only talc） were divided into 7 groups at a distance of 1， and they could be distinguished. This method is easy to operate without any damages in the sample. It can provide help for the detection of trace evidence and the public security organs to handle cases.

Key words: differential Raman spectroscopy, plastic sheath, principal component analysis, hierarchical clustering, K?means clustering