A data frame containing reported results for lead (in mg/kg) from CCQM Key Comparison CCQM-K30.
PbA data frame containing 11 reported results with uncertainty data:
Factor giving abbreviated laboratory identifier
The reported value for lead (mg/kg)
Standard uncertainty (mg/kg). The values in Pb were calculated from
the reported expanded uncertainty U and coverage factor k using u=U/k.
Coverage factor. Conventionally, the coverage factor is set to a suitable
quantile of Student's t based on the Welch-Satterthwaite effective degrees of freedom
or simply set to 2 for approximately 95% confidence. In this data set, labs all quoted
k for approximately 95% confidence.
Expanded uncertainty as reported by labs.
Factor indicating general measurement methodology:
Isotope dilution mass spectrometry
Inductively coupled plasma spectrometry
Graphite furnace atomic absorbtion spectrometry
logical; Whether the reported result was included in the calculation of the Key Comparison Reference Value for the study.
The study involved circulation of a homogeneous set of samples of wine for analysis for lead (Pb) content by a number of National Measurement Institutes.
The Key Comparison Reference Value, or assigned value for the lead content, was set at 2.99 mg/kg with expanded uncertainty 0.06 mg/kg.
See source.