Evaluation of sample homogeneity for geochemical standard reference materials used in microanalysis

1987 ◽  
Vol 110 (1) ◽  
pp. 147-158 ◽  
Author(s):  
R. H. Filby ◽  
S. Nguyen ◽  
S. Campbell ◽  
A. Bragg ◽  
C. A. Grimm
Keyword(s):  
Reference Materials ◽  
Standard Reference Materials ◽  
Materials Used ◽  
Sample Homogeneity

Preparation and Certification of Standard Reference Materials to be Used in the Determination of Retained Austenite in Steels

1982 ◽  
Vol 26 ◽  
pp. 137-140
Author(s):  
George E. Hicho ◽  
Earl E. Eaton
Keyword(s):  
Reference Materials ◽  
Retained Austenite ◽  
Solid Phase ◽  
Standard Reference Materials ◽  
Face Centered Cubic ◽  
X Ray Diffraction ◽  
X Ray ◽  
Face Centered ◽  
Materials Used ◽  
Steel Hardening

In the steel hardening process, steel is heated to a temperature where a face-centered-cubic solid phase called austenite is formed. After a stabilization period, the steel is quenched into a medium which transforms the austenite into a metastable, body-centered-tetragonal solid phase called martensite. On occasion the austenite is not entirely transformed into martensite and some austenite remains. This untransformed (retained) austenite is sometimes detrimental to the finished product, and often there are requirements as to the amount of retained austenite permitted In the finished product.X-ray diffraction procedures (XRD) are normally used to determine the amount of retained austenite and this paper describes the preparation and characterization of the Standard Reference Materials used to calibrate x-ray diffraction units.

scholarly journals Effect of NaCl and HCl concentrations on primary pH measurement for the certification of standard materials

2006 ◽  
Vol 49 (spe) ◽  
pp. 79-86 ◽  
Author(s):  
V. Souza ◽  
Alberto Pires Ordine ◽  
I. C. S. Fraga ◽  
Monique Audrey Getrouw ◽  
P. P. Borges ◽  
...  
Keyword(s):  
Reference Materials ◽  
Ph Value ◽  
Ph Measurement ◽  
Standard Reference Materials ◽  
National Metrology Institute ◽  
Buffer Solution ◽  
Regional Comparison ◽  
Primary Measurement ◽  
Primary Ph Measurement ◽  
Materials Used

pH is an important parameter to control the production of food, medicine, petrochemical products and others. Thus, standard reference materials used to calibrate pH meters are necessary to guarantee reliability of the measurements. The Chemical Metrology Division (Dquim) of the National Metrology Institute of Brazil (Inmetro) has as one of its missions the certification of standard reference materials. In the case of pH, it will be done by the pH primary measurement system of Inmetro, in operation at Dquim since 2003. The buffer solution of nominal pH value equal to 6.865 will be the first to be certified. The study of some measurement parameters has already been accomplished, and will lead to the improvement of the primary pH measurement. In this paper, the effect of NaCl and HCl concentrations on the primary pH measurement is discussed, based on the results obtained by Inmetro in the regional comparison SIM 8.11P.

Thermal behavior study of biodiesel standard reference materials

2011 ◽  
Vol 106 (2) ◽  
pp. 347-354 ◽  
Author(s):  
Eveline De Robertis ◽  
Gabriela F. Moreira ◽  
Raigna A. Silva ◽  
Carlos A. Achete
Keyword(s):  
Thermal Behavior ◽  
Reference Materials ◽  
Standard Reference Materials ◽  
Behavior Study

Two new marine sediment standard reference materials (SRMs) for the determination of organic contaminants

2004 ◽  
Vol 378 (5) ◽  
pp. 1251-1264 ◽  
Author(s):  
Stephen A. Wise ◽  
Dianne L. Poster ◽  
Michele M. Schantz ◽  
John R. Kucklick ◽  
Lane C. Sander ◽  
...  
Keyword(s):  
Reference Materials ◽  
Marine Sediment ◽  
Organic Contaminants ◽  
Standard Reference Materials

Introduction to Statistical Methods for Outlier Detection and Sample Homogeneity Assessment of Reference Materials and Proficiency Test Items

2021 ◽  
Author(s):  
Yi-Ting Chen ◽  
Keyword(s):  
Data Analysis ◽  
Outlier Detection ◽  
Reference Materials ◽  
Proficiency Test ◽  
Test Items ◽  
Homogeneity Assessment ◽  
Iso 13528 ◽  
Scope Of Application ◽  
Iso 5725 ◽  
Sample Homogeneity

Due to the homogeneity of the product or sample, it will affect whether it meets the scope of application and purpose. For example, the reference materials(RM) produced by the reference material producer(RMP), and the proficiency test items selected by the proficiency testing provider(PTP), in order to ensure the reference materials or proficiency test items have consistent characteristics or comparability, they should be proved to have certain homogeneity. However, before performing homogeneity assessment, it is necessary to measure the characteristic parameters of the reference materials or proficiency test items to obtain a sufficient number of measured values for data analysis, but there may be outliers in the measured values that may affect data analysis and interpretation of the results. Therefore, this article will refer to ASTM E178-16a:2016[1], ISO 5725-2:1994[2], ISO 13528:2015[3], etc., to introduce several outlier detection and homogeneity assessment methods, supplemented by case studies. Finally, this article will remind the precautions for the use of the method, so that readers can choose the appropriate method for use in the actual analysis.

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