Reduction of package-induced error for the composition analysis of in-package liquid products based on transmission spectrum

The influence of packaging on the spectral analysis of in-package liquid products was studied in this work, and a method was proposed to formulate a calibration model to inhibit the effect of different absorptions of the package due to different thicknesses of the package. Based on the characteristics of partial least square regression, the strategy is to construct a model that is insensitive to the thickness variation of the package. This method involves the use of collected spectra for the model establishment under different thicknesses of the package, where the obtained model is found to satisfactorily inhibit the influence of the package thickness variation. An experiment using an Intralipid suspension and India ink as the analyte was designed, and a polyethylene film was used to simulate the packing material of the sample analyte. Analysis of the experimental data shows that the model established via the novel modeling strategy could well inhibit the error caused by variation in the external packaging.