An emergent optimal precision in chemical measurement at low concentrations

Abstract

Collaborative trials are interlaboratory studies of the precision of data obtained from particular analytical methods. Increasingly many of these trials in the food sector are addressing analytes present at mass fractions between 10⁻¹¹ and 10⁻⁷, that is, between 10 parts per trillion and 100 parts per billion. In 2000 the statistics from then-recently conducted collaborative trials of this type were examined. The trend of the inter-laboratory relative standard deviation took a value of 0.22. A similar trend can be seen in both older and more recent compilations of statistics. This paper demonstrates that the value emerges naturally in a fitness-for-purpose context and shows why a similar outcome would be likely in other application sectors.