The Fundamental Sampling Principle (FSP) for PAT
DOI: 10.62178/sst.004.005
Abstract
The critical success factor in Process Analytical Technology solutions, whether this is in the form of analysis of an extracted process sample brought to the laboratory, or in the form of a calibrated sensor analytical prediction characterising an in-situ stream segment, is the performance of the process sampling interface. The role of the interface is closely related to the Fundamental Sampling Principle (Theory of Sampling, TOS) regarding both stationary as well as moving lots. This article argues that the functionality of the process sampling interface determines whether Process Analytical Technology solutions can be implemented to furnish analytical fit-for-purpose representativity, or not. Non-compliance with a simple geometrical requirement results in biased analytical determination with unavoidable reduction in representativity. This criterium determines the fate of Process Analytical Technology solutions and their engineering implementations for most vibrational spectroscopic modalities. Thus, a single TOS-informed inspection of a process sampling interface is able to render a principal qualifying/disqualifying assessment regarding representativity - but there are important exceptions in the radio wave and gamma ray parts of the electromagnetic spectrum. This is all about the inherent heterogeneity of the material subjected to PAT sensor technology. This article presents TOS’ Fundamental Sampling Principle for the Process Analytical Technology realm. There is still a way to go for further process sampling interface development.
Published in Issue 4 · December 2025
Citing this article
Esbensen, K. H. (2025). The Fundamental Sampling Principle (FSP) for PAT. Sampling Science & Technology, December 2025(4), 42-53. https://doi.org/10.62178/sst.004.005
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