Evaluation of freeze-dried human sera as a novel approach for ATR-FTIR spectroscopic analysis as compared to conventionally used thin dry film sera

Objective Evaluation of the diagnostic potential of freeze dried sera in comparison to thin dry film analysis for recording ATR-FTIR spectra. Results For this purpose, we compared our novel sample preparation technique i.e. freeze dried with conventional technique i.e. thin dry film sera. Using both methods ATR-FTIR spectra were recorded from Salmonella Typhi infected and healthy control human sera samples. When PCA was applied PC1 scores showed more inter-class variation among infected and healthy controls when freeze dried sample was used (90 %) as compared to thin dry film method (46 %). Conclusions Potential of ATR-FTIR for discrimination of bio-molecules between two classes of samples is enhanced when freeze dried sera instead of thin dry film method is used.