Direct analysis of volumetric absorptive micro sampling (VAMS) devices by ATR-FT-MIR and chemometric analysis: a new challenge

Volumetric Absorptive Micro Sampling (VAMS) strategy, in its simplicity, has made a major contribution to the development of at-home sampling strategies. Mainly used for blood analysis, it absorbs a fixed volume of sample. Folded into its cover, the VAMS device dries, and it can be sent to a lab via mail. In this article, for the first time in our knowledge, we explored the possibility to use this sampling strategy to expand the scope of VAMS to other samples than clinical ones. In this way we used VAMS to sample and analyze milk, which is one of the most important and analyzed samples all over the world. VAMS devices were employed to sample commercial milk samples from Italy, Switzerland and Spain, and for the first time the device was directly analyzed by ATR-FT-IR to predict protein, carbohydrate and fat content in the milk samples. Samples were collected in different sessions from different persons and analyzed by different lab operators to include in the models these sources of variability. Multivariate regression was used to correlate ATR-FT-IR spectra with the investigated properties: models were validated with external validation.