Certified Reference Materials Ioannis Papadakis I Certified

(Certified) Reference Materials Ioannis Papadakis, I. : (Certified) Reference Materials In: Wenclawiak, Koch, Hadjicostas (eds. ) © Springer-Verlag Berlin Heidelberg 2003 Quality Assurance in Analytical Chemistry – Training and Teaching

Index § § § definitions - documentation types of (C)RMs production of (C)RMs selection and use of (C)RMs CRMs and traceability suppliers/producers of (C)RMs Papadakis, I. : (Certified) Reference Materials In: Wenclawiak, Koch, Hadjicostas (eds. ) © Springer-Verlag Berlin Heidelberg 2003 Quality Assurance in Analytical Chemistry – Training and Teaching

ISO Guides § ISO 30 (1992) terms and definitions used in connection with RMs § ISO 31 (2000) certificates of RMs § ISO 32 (1997) calibration in analytical chemistry and use of CRMs § ISO 33 (2000) uses of CRMs § ISO 34 (2000) general requirements for the competence of RM producers § ISO 35 (1989) certification of RMs Papadakis, I. : (Certified) Reference Materials © Springer-Verlag Berlin Heidelberg 2003

Reference Material Definition material or substance one or more of whose property values are sufficiently homogeneous and well established to be used for the calibration of an apparatus, the assessment of a measurement method, or for assigning values to materials Papadakis, I. : (Certified) Reference Materials In: Wenclawiak, Koch, Hadjicostas (eds. ) © Springer-Verlag Berlin Heidelberg 2003 Quality Assurance in Analytical Chemistry – Training and Teaching

Reference Material (RM) § a reference material may be in the form of a pure or mixed gas, liquid or solid § examples are water for the calibration of viscometers, sapphire as a heatcapacity calibrant in calorimetry, and solutions used for calibration in chemical analysis Papadakis, I. : (Certified) Reference Materials © Springer-Verlag Berlin Heidelberg 2003

Certified Reference Material Definition reference material, accompanied by a certificate, one or more of whose property values are certified by a procedure which establishes traceability to an accurate realisation of the unit in which the property values are expressed, and for which each certified value is accompanied by an uncertainty at a stated level of confidence Papadakis, I. : (Certified) Reference Materials In: Wenclawiak, Koch, Hadjicostas (eds. ) © Springer-Verlag Berlin Heidelberg 2003 Quality Assurance in Analytical Chemistry – Training and Teaching

Certified Reference Material (CRM) § all CRMs lie within the definition of “measurement standards” or “etalons” § CRMs are generally prepared in batches for which the property values are determined within stated uncertainty limits by measurements on samples representative of the whole batch Papadakis, I. : (Certified) Reference Materials © Springer-Verlag Berlin Heidelberg 2003

Classification of RMs § physical character § gases, liquids or solids § supplied property § pure chemical species, physico-chemical property § preparation method § synthetic mixtures, natural materials § metrological qualification § primary RM, secondary RM § intended use § calibration of instruments, validation of analytical methods Reference Materials in Analytical Chemistry - A Guide for Selection and Use, edited by A Zschunke, Springer, 2000 Papadakis, I. : (Certified) Reference Materials © Springer-Verlag Berlin Heidelberg 2003

CRM Production According to ISO-35 § producing a CRM is: § the integrated process of correct preparation, homogeneity and stability demonstration, and accurate and traceable characterisation, § whereby all components of uncertainty of “the sample on the desk of the user” should be properly accounted for according to the ISO-GUM (Guide for the expression of uncertainty in measurement) Papadakis, I. : (Certified) Reference Materials In: Wenclawiak, Koch, Hadjicostas (eds. ) © Springer-Verlag Berlin Heidelberg 2003 Quality Assurance in Analytical Chemistry – Training and Teaching

CRM Production Non-trivial Job! § it requires. . . § skills and installation to process the material in a suitable form, especially for matrix CRMs (e. g. making 2000 containers of orange juice sample for heavy metals content measurement, with demonstrated homogeneity and stability) § demonstrated measurement capability, to produce reference value Papadakis, I. : (Certified) Reference Materials In: Wenclawiak, Koch, Hadjicostas (eds. ) © Springer-Verlag Berlin Heidelberg 2003 Quality Assurance in Analytical Chemistry – Training and Teaching

CRM Production Process § § § § select the material prepare the units (e. g. bottles) labelling measure homogeneity measure stability assignment of reference values distribution/marketing Papadakis, I. : (Certified) Reference Materials In: Wenclawiak, Koch, Hadjicostas (eds. ) © Springer-Verlag Berlin Heidelberg 2003 Quality Assurance in Analytical Chemistry – Training and Teaching

Select the Material § depends on the needs of the analytical community § measurement that needs to be supported § depends on availability of material Papadakis, I. : (Certified) Reference Materials In: Wenclawiak, Koch, Hadjicostas (eds. ) © Springer-Verlag Berlin Heidelberg 2003 Quality Assurance in Analytical Chemistry – Training and Teaching

Prepare the Units § select appropriate container (size, shape, material, properties …) § prepare the units (e. g. vials) under the appropriate conditions § each unit should contain the appropriate amount of material § prepare appropriate number of units Papadakis, I. : (Certified) Reference Materials In: Wenclawiak, Koch, Hadjicostas (eds. ) © Springer-Verlag Berlin Heidelberg 2003 Quality Assurance in Analytical Chemistry – Training and Teaching

Measure Homogeneity § fast measurement method § small sample quantity § good reproducibility § within containers § between containers Papadakis, I. : (Certified) Reference Materials In: Wenclawiak, Koch, Hadjicostas (eds. ) © Springer-Verlag Berlin Heidelberg 2003 Quality Assurance in Analytical Chemistry – Training and Teaching

Measure Stability § fast measurement method § small sample quantity § good reproducibility § different storing temperatures § different times Papadakis, I. : (Certified) Reference Materials In: Wenclawiak, Koch, Hadjicostas (eds. ) © Springer-Verlag Berlin Heidelberg 2003 Quality Assurance in Analytical Chemistry – Training and Teaching

Assignment of Reference Value § by measurement (CRM) § by designation (RM) Papadakis, I. : (Certified) Reference Materials In: Wenclawiak, Koch, Hadjicostas (eds. ) © Springer-Verlag Berlin Heidelberg 2003 Quality Assurance in Analytical Chemistry – Training and Teaching

Assignment of Reference Value by Measurement § one method in one lab (e. g. a primary method) § one method in several labs § several methods in several labs Papadakis, I. : (Certified) Reference Materials In: Wenclawiak, Koch, Hadjicostas (eds. ) © Springer-Verlag Berlin Heidelberg 2003 Quality Assurance in Analytical Chemistry – Training and Teaching

Traceability of the Assigned Value § needs to be stated § … and demonstrated § information available in certification report Papadakis, I. : (Certified) Reference Materials In: Wenclawiak, Koch, Hadjicostas (eds. ) © Springer-Verlag Berlin Heidelberg 2003 Quality Assurance in Analytical Chemistry – Training and Teaching

Uncertainty of the Assigned Value (UCRM) UCRM uncertainty of the average concentration of 1 unit (of the n prepared) after storage for time T and after transport UCRM [%]=k*(u 2 assign+u 2 bb+u 2 lts+u 2 sts)1/2 uassign uncertainty value assignment measurement ubb uncertainty bottle to bottle variation ults uncertainty long term stability usts uncertainty short term stability (transport) Papadakis, I. : (Certified) Reference Materials In: Wenclawiak, Koch, Hadjicostas (eds. ) © Springer-Verlag Berlin Heidelberg 2003 Quality Assurance in Analytical Chemistry – Training and Teaching

Labelling § equally important § clear and concise Papadakis, I. : (Certified) Reference Materials In: Wenclawiak, Koch, Hadjicostas (eds. ) © Springer-Verlag Berlin Heidelberg 2003 Quality Assurance in Analytical Chemistry – Training and Teaching

Distribution / Marketing § certification report § appropriate price § appropriate delivery § appropriate storage § reach scientific community Papadakis, I. : (Certified) Reference Materials In: Wenclawiak, Koch, Hadjicostas (eds. ) © Springer-Verlag Berlin Heidelberg 2003 Quality Assurance in Analytical Chemistry – Training and Teaching

In General High Quality CRMs Should… § state traceability of certified value (e. g. traceability to S. I. , or to values obtained with method XYZ) § state an ISO-GUM uncertainty of certified value § demonstrate traceability & uncertainty of certified value (e. g. in a certification report; experimental evidence of demonstrated capability from participation to international comparisons) § preferably be produced according to the guidelines of ISO-35 Papadakis, I. : (Certified) Reference Materials In: Wenclawiak, Koch, Hadjicostas (eds. ) © Springer-Verlag Berlin Heidelberg 2003 Quality Assurance in Analytical Chemistry – Training and Teaching

Use of CRMs § (ideally) supplier should give advice § storage temperature § influence of moisture on long term stability (e. g. biological activity) § influence of contamination § possibility to divide in different portions after opening Papadakis, I. : (Certified) Reference Materials In: Wenclawiak, Koch, Hadjicostas (eds. ) © Springer-Verlag Berlin Heidelberg 2003 Quality Assurance in Analytical Chemistry – Training and Teaching

Use of CRMs how can CRMs help my measurements? § calibration (? ) § validation (? ) § measurement control (? ) Papadakis, I. : (Certified) Reference Materials In: Wenclawiak, Koch, Hadjicostas (eds. ) © Springer-Verlag Berlin Heidelberg 2003 Quality Assurance in Analytical Chemistry – Training and Teaching

Calibration use as a matrix matched calibrant (direct or via working standards) to ensure traceability of results to an external reference (the CRM) Papadakis, I. : (Certified) Reference Materials In: Wenclawiak, Koch, Hadjicostas (eds. ) © Springer-Verlag Berlin Heidelberg 2003 Quality Assurance in Analytical Chemistry – Training and Teaching

Validation certified concentration check the measurement results in terms of validity: is there any method specific bias ? is there any systematic error ? Papadakis, I. : (Certified) Reference Materials In: Wenclawiak, Koch, Hadjicostas (eds. ) © Springer-Verlag Berlin Heidelberg 2003 Quality Assurance in Analytical Chemistry – Training and Teaching

Measurement Control 18 17 16 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 (Upper) Control line (Upper) Warning line -1 s 0 1 s 2 s 3 s Papadakis, I. : (Certified) Reference Materials In: Wenclawiak, Koch, Hadjicostas (eds. ) -2 s (i. e. of proven homogeneity and stability; sometimes named in-house RMs or laboratory RMs) -3 s § Abuse of CRM § Instead : use inhouse materials or quality control materials (Lower) Warning line (Lower) Control line © Springer-Verlag Berlin Heidelberg 2003 Quality Assurance in Analytical Chemistry – Training and Teaching

Use of CRMs how can CRMs help my measurements? § calibration (? ) YES X § validation (? ) YES X § measurement control (? ) NO X Papadakis, I. : (Certified) Reference Materials In: Wenclawiak, Koch, Hadjicostas (eds. ) © Springer-Verlag Berlin Heidelberg 2003 Quality Assurance in Analytical Chemistry – Training and Teaching

How CRMs are Used in Terms of Traceability? ra b on ti li a c S. I. to calibrate own analytical instrument value 1 value 2 my result Papadakis, I. : (Certified) Reference Materials In: Wenclawiak, Koch, Hadjicostas (eds. ) © Springer-Verlag Berlin Heidelberg 2003 Quality Assurance in Analytical Chemistry – Training and Teaching

How CRMs are Used in Terms of Traceability? da li on ti S. I. va value 1 to validate own analytical method value 2 my result Papadakis, I. : (Certified) Reference Materials In: Wenclawiak, Koch, Hadjicostas (eds. ) value CRM © Springer-Verlag Berlin Heidelberg 2003 Quality Assurance in Analytical Chemistry – Training and Teaching

Selection of CRMs § § § availability (problem with matrix CRMs) concentration range of certified property uncertainty of certified property traceability of certified property what is your uncertainty requirement contribution of CRM uncertainty on your measurement uncertainty § demonstrated competence of CRM producer § CRM matrix § cost Papadakis, I. : (Certified) Reference Materials In: Wenclawiak, Koch, Hadjicostas (eds. ) © Springer-Verlag Berlin Heidelberg 2003 Quality Assurance in Analytical Chemistry – Training and Teaching

CRM Producers § general § COMAR database: http: //www. bam. de § individual suppliers § § § IRMM: BAM: LGC: NIST: others. . . Papadakis, I. : (Certified) Reference Materials In: Wenclawiak, Koch, Hadjicostas (eds. ) http: //www. irmm. jrc. be http: //www. bam. de http: //www. lgc. co. uk http: //www. nist. gov © Springer-Verlag Berlin Heidelberg 2003 Quality Assurance in Analytical Chemistry – Training and Teaching

General Statement I use a CRM, therefore my measurement result is automatically correct Papadakis, I. : (Certified) Reference Materials In: Wenclawiak, Koch, Hadjicostas (eds. ) © Springer-Verlag Berlin Heidelberg 2003 Quality Assurance in Analytical Chemistry – Training and Teaching

Things to Remember § very important component § production is not trivial § selection and use is not easy § CRMs do not automatically ensure quality outcome Papadakis, I. : (Certified) Reference Materials In: Wenclawiak, Koch, Hadjicostas (eds. ) © Springer-Verlag Berlin Heidelberg 2003 Quality Assurance in Analytical Chemistry – Training and Teaching