Kemiallisten mittausten jäljitettävyys 1. EURACHEM / CITAC ...kemianseurat.fi/finntesting/wp-content/uploads/2014/03...1. EURACHEM/CITAC Guide (2003) Examples of Establishing Traceability

EURACHEM / CITAC -ohjeen yleisesittely

Prof., TkT Veikko Komppa, VTT ProsessitPL 1602, 02044 [email protected]

Kemiallisten mittausten jäljitettävyys

1. EURACHEM / CITAC ohje ja esite

2. LGC VAM -ohjelman ohje

Veikko Komppa 8.11.2004

EURACHEM / CITAC -ohjeen yleisesittely

Prof., TkT Veikko Komppa, VTT ProsessitPL 1602, 02044 [email protected]

1. EURACHEM / CITAC Guide (2003)Traceability in Chemical Measurement:A guide to achieving comparable results in chemical measurementhttp://www.eurachem.ul.pt/guides/EC_Trace_2003.pdf

2. LGC VAM (2003)An Analyst's Guide to Meeting the Traceability Requirements

of ISO 17025 (2nd Edition)http://www.vam.org.uk/themes/theme_publications_item.asp?intThemeID=2&intPublicatio

nID=839

3. EURACHEM/CITAC Leaflet (2004)Traceability of Analytical Resultsvain painettuna


EURACHEM/CITAC -ohjeen yleisesittely

1. EURACHEM/CITAC Guide (2003)Traceability in Chemical Measurement: A guide to achieving

comparable results in chemical measurement

UUSI VIM (2004) voting draftmetrological traceabilityproperty of a measurement result relating the result to a stated metrological

reference through an unbroken chain of calibrations of a measuringsystem or comparisons, each contributing to the stated measurementuncertainty

NOTES (1-5)1 For this definition, a ‘stated metrological reference’ can be a definition of a measurement

unit through its practical realization, or a measurement procedure, or a measurementstandard.

2 A prerequisite to metrological traceability is a previously established calibrationhierarchy.



1. EURACHEM/CITAC Guide (2003)Contents page 11 Scope and Field of Application 32 Introduction 33 Principles of traceability 63.1 Methods, Measurands and Results 63.2 Measurement scales, standards and units 63.3 Calibration 73.4 Effects on measurement results 73.5 Controlling fixed conditions 83.6 Controlling variables with calibration standards 93.7 Common references allow arbitrary definition 113.8 Role of method development 113.9 Role of method validation 113.10 Traceability and measurement uncertainty 12



1. EURACHEM/CITAC Guide (2003)

4 Traceability: The International Definition 135 International System of Quantities and Units (SI) 136 Establishing Traceability 156.1 Essential activities in establishing traceability 156.2 Specifying the measurand and required uncertainty 156.3 Choosing a suitable method 166.4 Validation 166.5 Importance of different influence quantities 186.6 Choosing and applying appropriate reference standards 186.7 Uncertainty estimation 19



1. EURACHEM/CITAC Guide (2003)7 Choice of the Reference 207.1 Introduction 207.2 Physical measurements 207.3 Confirmation of identity 217.4 Calibration with certified reference materials 217.5 Calibration with other materials 227.6 Calibration using reference data 237.7 Reference materials for Method Development, Validation … 237.8 Assessing the traceability of commercial reference materials 248 Reporting Traceability 249 Conclusion 2510 Bibliography 26Appendix: Examples of Establishing Traceability (MU Guide) 271. Preparation of a calibration standard 282. Cadmium Release from Ceramic Ware 32



1. EURACHEM/CITAC Guide (2003)the key elements in establishing traceabilityi) Specifying the measurand, scope of measurements and the requireduncertaintyii) Choosing a suitable method of estimating the value, that is, ameasurement procedure with associated calculation - an equation - andmeasurement conditionsiii) Demonstrating, through validation, that the calculation and measurementconditions include all the “influence quantities” that significantly affect theresult, or the value assigned to a standard.iv) Identifying the relative importance of each influence quantityv) Choosing and applying appropriate reference standardsvi) Estimating the uncertainty



1. EURACHEM/CITAC Guide (2003)Summary of basic principles1. We assume that an acceptable estimate y of the measurand value can

be obtained fromy = f(x1, x2,…xm) | xm+1…xnthat is, y is calculated from x1…xm using a relationship f which is validunder measurement conditions specified by xm+1…xn.

2. Validation checks that the equation above is sufficient using suitabletests.

3. y is then considered traceable to x1…xn4. Given that Eq 1 is sufficient, all that is necessary for complete traceability

to appropriate references is that all the values x1 to xn are themselvestraceable or defined values.



1. EURACHEM/CITAC Guide (2003)

Examples of Establishing Traceability are taken from

EURACHEM/CITAC Guide

Quantifying Uncertainty in Analytical Measurement (2000)

1. Preparation of a calibration standard (Cd in water)

2. Cadmium Release from Ceramic Ware (BS 6748)



2. LGC VAM: Traceability GuideKaliumjodidin määritys vitamiinipillereistäMenetelmän jäljitettävyys- / epävarmuustarkastelun

perusteella neljä tekijää on merkittävää:

• Kaliumjodaatin puhtaus (99,5 … 99,96 %)• Natriumtiosulfaatin molaarisuus (titraus kaliumjodaatilla ja

volymetriset astiat)• Vitamiinipillerin punnitus (massa)• Kaliumjodaatin ja -jodidin moolimassat

(3 desimaalia)



2. LGC VAM: Traceability Guide

Anionien määritys IC:llä vedestä

Kriittiset muuttujat ovat

• Kalibrointistandardit (NaF, NaCl, NaNO3, KH2PO4,K2SO4)

• Varmennettu vertailuaine (CRM)



2. LGC VAM: Traceability Guide

Muut esimerkit:

• Ruoan ja biologisten materiaalien alkuaineiden

määritys (ICP MS: Na, K, Ca, Mg, P, Cu, Fe, Mn, Zn)

• Vesiliukoisten alkuaineiden määritys (ICP MS)

• Dimetyylitriatsolin määritys rehusta (HPLC)

• Kuningasvesiliukoiset metallit maaperässä (ICP

MS)



3. EURACHEM/CITAC Leaflet (2004)Traceability of Analytical ResultsEsimerkki: tonnikalan Hg• Elohopea mikroaaltoliuotuksen jälkeen AAS kylmähöyrytekniikalla

• Punnitukset tehtiin kalibroiduilla vaa'oilla (SI jäljitettävyys)

• Liuotus ja laimennukset astioissa, joilla on valmistajan todistus (SIjäljitettävyys)

• Kalibrointi varmennetulla vertailuaineella (CRM)0.998± 0.005 mg Hg/kg (k=2) jäljitettävyys puhtaaseen elohopeaan

• Menetelmä validoitu matriisivertailuaineella tasolla1.97 ± 0.04 mg Hg/kg (k=2).



3. EURACHEM/CITAC Leaflet (2004)Traceability of Analytical ResultsEsimerkki: tonnikalan Hg

Jäljitettävyysvakuutus1. Elohopeapitoisuus <===> CRM:n todistus

2. Näytteenmassa <===> vaakojen todistus/kalibrointi

3. Astioiden tilavuudet <===> valmistajien todistukset

4. Kuivatuslämpötila <===> uunien kalibrointi

5. Kuivatusaika <===> kellojen kalibrointi

6. Liuotusolosuhteet <===> validointi ja olosuhteiden seuranta



Lisää tietoa löytyy esimerkiksiEURACHEM:n verkkosivut:

http://www.eurachem.ul.pt/

CITAC:n verkkosivut:

http://www.citac.cc/

LGC VAM -ohjelman verkkosivut:

http://www.vam.org.uk/Veikko Komppa 8.11.2004

Documents

Kemiallisten mittausten jäljitettävyys 1. EURACHEM / CITAC ...kemianseurat.fi/finntesting/wp-content/uploads/2014/03...1. EURACHEM/CITAC Guide (2003) Examples of Establishing Traceability