Measurement Uncertainty on a Certificate
A primary benzoic acid standard is certified at 999.92 mg/g with an expanded uncertainty of 0.05 mg/g. What that interval promises, what the coverage factor does, and what the number never covers.
The Complete Guide to Analytical Reference Standards
Two bottles, same compound, same purity figure, and only one can calibrate a method. This guide works through reference materials, certification, traceability, uncertainty and impurity standards using openly published metrology sources.