This dataset contains spectral and reference values information used for the publication "Calibration model transfer in mid-infrared process analysis with in situ attenuated total reflectance immersion probes". It contains a single mat file (Matlab Data file) which when loaded into matlab contains spectra data as matrices labelled A, B, C,.. to refer to spectrometer probe combinations 1, 2, 3.. etc. (see article for details on spectrometer-probe combination) the same sample order is used in each set. Also contained within the dataset is the corresponding reference values for each sample with the fraction of each of the three components used in the model ternary mixture studied in the article.