Comprehensive two-dimensional chromatography is a powerful technology for analyzing the patterns of constituent compounds in complex samples, but matching chromatographic features for comparative analysis across large sample sets is difficult. Various methods have been described for pairwise peak matching between two chromatograms, but the peaks indicated by these pairwise matches commonly are ...

In addition to the quantification of individual components, chromatographers are frequently called upon to compare two different samples, or a sample to a reference, focusing on the overall fingerprint of the chromatograms rather than individual components. Typically, this is achieved by overlaying the chromatograms to manually examine the chromatographic traces and judge how well the two chrom...

Non – negative matrix factorization (NMF) was generally used to obtain representation of data using non – negativity constraints. It lead to parts – based (or) region based representation in the vector space because they allow only additive combinations of original data. NMF has been applied so far in image and text data analysis, audio signal separation, signal separation in bio-medical applic...

We describe recent developments in the use of a stable free radical, diphenylpicrylhydrazyl, as a colorimetric detector of reducing metabolites in melanoma urines. A procedure for buffering aqueous/solvent reagent solutions is presented, and examples of the baseline stability achieved for reference chromatograms and urine samples are provided. Chromatograms of phaeomelanin precursors and of an ...