Author(s)

Hong Yi¹, Wei Yi²

¹Division of Metrology in Chemistry, National Institute of Metrology, Beijing, China.
²Department of Biology, New York University, New York, USA.

The core objective of a chemical composition measurement is to determine its true value. However, when measuring the composition of a macroscopic sample with a large number of atoms or molecules, realizing the true value of the measurand at both the macroscopic and microscopic levels remains an unsolved theoretical problem. We find that the true value of a sample composition exists in any subsample of a homogeneous molecular population of the sample. Here, we propose the Central Law of Measurement of the Amount of Substance: “The homogeneity of a sample molecular population represents the measurement accuracy of the sample composition in an analytical procedure”. The Central Law is based on a homogeneous molecular population axiom in which the molecular composition of a sample is identical for any homogeneous subsample. Furthermore, we point out that, at the microscopic scale, Avogadro’s law does not hold true.

Amount of Substance, Avogadro Constant, Mole, Accuracy, Homogeneity, Central Law

Yi, H. and Yi, W. (2015) The True Value of a Sample Composition Is There. American Journal of Analytical Chemistry, 6, 285-296. doi: 10.4236/ajac.2015.64027.