Certification of Matrix Reference Materials in Chemical Measurement: A New Basis for Adopting a Consensus Value Derived from a Proficiency Test

<p>ISO Guide 35 (2017) specifies conditions for the certification of matrix reference materials via information from proficiency tests. Many scientists involved in the provision of proficiency tests for analytical chemistry have concluded that the Guide 35 conditions are <i>effectively</i> fulfilled by identifying certified values with properly-derived consensus values. However, the claim that such reference materials are ‘certified’ is likely to be challenged by traditional metrologists. This paper proposes to move beyond this unresolved situation to put certification <i>via</i> proficiency testing on an unassailable footing. The proposal therefore is not a questionable fulfilment of the Guide 35 conditions but an unrelated paradigm for certification.</p>

Certification of Matrix Reference Materials in Chemical Measurement: A New Basis for Adopting a Consensus Value Derived from a Proficiency Test

<p>ISO Guide 35 (2017) specifies conditions for the certification of matrix reference materials via information from proficiency tests. Many scientists involved in the provision of proficiency tests for analytical chemistry have concluded that the Guide 35 conditions are <i>effectively</i> fulfilled by identifying certified values with properly-derived consensus values. However, the claim that such reference materials are ‘certified’ is likely to be challenged by traditional metrologists. This paper proposes to move beyond this unresolved situation to put certification <i>via</i> proficiency testing on an unassailable footing. The proposal therefore is not a questionable fulfilment of the Guide 35 conditions but an unrelated paradigm for certification.</p>

Stoichiometric Characteristics of Soil in Several Different Communities

The content of nitrogen, phosphorus, potassium and organic matter in soil is an important index to determine soil nutrient status. In this paper, the contents of nitrogen, phosphorus, potassium, organic matter and soil salt in the soil of several different plant communities in the campus were measured by the chemical measurement characteristics of several different communities in University of Jinan. The differences in the measurement characteristics of soil chemical measurement in different plant communities were analyzed. The results showed that the highest organic matter content in several communities was Cherry Blossom community, 76.33mg/kg, and the highest ammonium nitrogen content was 196.08mg/kg; the highest content of available phosphorus was the community of Begonia, 168.14mg/kg, and the highest content of available potassium was the community of Robinia pseudoacacia, which was the highest salt content in 64.99mg/kg soil. The community of cherry blossoms is 569 μs. There was little difference in soil organic matter, available phosphorus and available potassium in different plant communities..