A chemical fingerprint of a sample is the unique composition of chemicals that the sample is made of. Chemical fingerprinting is to analyze the composition of these chemicals. The challenges in chemical fingerprinting are to select sample preparation techniques and analytical platforms that combined can lead to the deciphering of the complete chemical composition of a sample. In many situations a sub group of the chemicals in a sample can be chosen which can ease the choice of a sample preparation protocol as well as an analytical platform. Upon chemical analysis of a sample the data need to be processed. As with sample preparation and choice of analytical platform, the choice of a mathematical tool to process the data is among numerous.
Sample preparation protocols
For chemical analysis, there is a vast array of analytical platforms. The choice of analytical method will depend on the focus of the analysis. In many cases, standard gas or liquid chromatography (GC or LC) coupled with a mass spectrometer (MS) can get you far. For more advanced chemical analysis you can use multidimensional chromatographic platforms such as comprehensive two-dimensional gas chromatography (GC×GC) with high-resolution mass spectrometry detection (HR-MS) and two-dimensional liquid chromatography (LC×LC) with HR-MS that provide 3D data (e.g. rt1 × rt2 × m/z) for each sample.
For each application, a custom-made signal processing procedure can be created. Signal processing consists of a number of steps such as import and cropping of different types of analytical data, feature detection and pixel-based analysis of multidimensional data. Issues to deal with that arise for multidimensional separation systems are e.g. retention time shifts in multiple dimensions, complex baselines and the very large number of variables compared to samples.