Description
A data frame containing reported results for lead (in mg/kg) from
CCQM Key Comparison CCQM-K30.
Format
A data frame containing 11 reported results with uncertainty data:
- lab
- Factor giving abbreviated laboratory identifier
- value
- The reported value for lead (mg/kg)
- u
- Standard uncertainty (mg/kg). The values in
Pb were calculated from
the reported expanded uncertainty U and coverage factor k using u=U/k. - 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. - U
- Expanded uncertainty as reported by labs.
- method
- Factor indicating general measurement methodology:
- IDMS
- Isotope dilution mass spectrometry
- ICP
- Inductively coupled plasma spectrometry
- GFAAS
- Graphite furnace atomic absorbtion spectrometry
- include
- logical; Whether the reported result was included in the calculation
of the Key Comparison Reference Value for the study.
Source
Hearn, R., Santamaria-Fernandez, R. and Sargent, M. (2008)
Final report on key comparison CCQM-K30: Determination of lead in wine.
Metrologia
45, 08001, 2008Details
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.