METROLOGY PERSPECTIVE Jan Herrmann WG2, NT-001 4 July 2012 - - PowerPoint PPT Presentation

METROLOGY PERSPECTIVE

4 July 2012

Jan Herrmann WG2, NT-001

Metrology People make decisions involving [nano]technologies.

Researchers, manufacturers, workers, regulators, consumers, …

They need [nanoscale] measurements that are fit for purpose, accurate, recognised. “To measure is to know.” (Lord Kelvin)

Metrology questions

1. Why are we measuring ?

What is the purpose of the measurement ?

2. What should be measured ?

What is the quantity that matters ?

3. How accurate does the result need to be ?

How is the purpose affected by the accuracy ?

4. What can actually be measured ?

What methodology/infrastructure is available ?

5. How accurate is the measurement result ?

What is the uncertainty budget of the measurement ?

6. How comparable is the measurement result ?

Is the measurement traceable to a reference ?

What should be measured?

Measurand (VIM): Quantity intended to be measured Several published lists of physical/chemical properties relevant for safety testing of nanomaterials:

• EC / SCENIHR (2009)

“Risk Assessment of Products of Nanotechnologies”

• OECD WPMN Sponsorship program (2010)

Series on the Safety of Manufactured Nanomaterials, No. 27

• ISO/TR 13014:2012 (ISO/TC229 WG3, PG5)

“Nanotechnologies -- Guidance on physico-chemical characterization

• f engineered nanoscale materials

for toxicologic assessment”

Set of physical-chemical properties

• Agglomeration/aggregation
• Water solubility
• Crystalline phase
• Dustiness
• Crystallite size
• Representative TEM picture(s)
• Particle size distribution
• Specific surface area
• Zeta potential
• Surface chemistry
• Photocatalytic activity
• Pour density
• Porosity
• Octanol-water partition coefficient
• Redox potential
• Radical formation potential

Nanometrology challenges

• Nano properties cannot be extrapolated from the macro scale.
• Enormous variety of nanomaterials and characterisation

techniques, growing rapidly.

• No consensus about which properties are most relevant,

e.g. for risk assessment.

• Statistical relevance of measurement results for ensembles
• f nano-objects is often limited.
• Interaction of nanomaterials with their environment is crucial,

but often not well understood.

• Number of methods available for analysing nanomaterials in

matrices (e.g., in tissue, soil, food) is very limited.

• Physico-chemical metrology of nanomaterials is still in its

infancy.

60 nm Au V Coleman ZnO V Coleman

How to describe ensembles of [nano-]objects?

30 nm

Au V Coleman Al2O3 T Tsuzuki ZrO T Tsuzuki CeO2 T Tsuzuki

100 nm

ZnO V Coleman

Complex particle systems require complex descriptors. “Size” is (almost) never enough !

Guidance: ISO 9276 Series, e.g., ISO 9276-6:2008

“Representation of results of particle size analysis -- Part 6: Descriptive and quantitative representation of particle shape and morphology”

What is the ‘right’ particle diameter?

Choose a measurand that matches the application. Be aware of limitations of methodology/infrastructure.

Sphere of same 2D projection area Sphere of same hydrodynamic mobility Sphere of same surface area Sphere of same sieve aperture Sphere of same sedimentation rate Sphere of same mass Sphere of same volume dec ds dsieve dsed dw dv dh

ISO/TC229 – IEC/TC113 JWG2 Metrology SG

1. Has the system / body / substance that will be subjected to the measurement procedure clearly been described, including its state? 2. Is the definition of the system / body / substance not unnecessarily restrictive? 3. Is the measurand clearly described? 4. Has it been clearly indicated whether the measurand is operationally or method defined, or whether the measurand is an intrinsic, structurally defined property? 5. Is the measurement unit defined? Are the tools required to obtain metrological traceability available? 6. Has the method already been validated in one or more laboratories? 7. Are any quality control tools available to enable the demonstration of a laboratory's proficiency with the test method? 8. Have the results of measurements using the proposed method already been published in peer-reviewed journals by several laboratories? 9. Is the instrumentation required to perform the test widely available?

• 10. Does the document propose a measurement uncertainty budget?

Metrology Checklist (N095)

for use in preparation and evaluation of ISO/TC229 NWIPs and WDs

ISO/TC229 – IEC/TC113 JWG2 Metrology SG

1. Has the system / body / substance that will be subjected to the measurement procedure clearly been described, including its state? 2. Is the definition of the system / body / substance not unnecessarily restrictive? 3. Is the measurand clearly described? 4. Has it been clearly indicated whether the measurand is operationally or method defined, or whether the measurand is an intrinsic, structurally defined property? 5. Is the measurement unit defined? Are the tools required to obtain metrological traceability available? 6. Has the method already been validated in one or more laboratories? 7. Are any quality control tools available to enable the demonstration of a laboratory's proficiency with the test method? 8. Have the results of measurements using the proposed method already been published in peer-reviewed journals by several laboratories? 9. Is the instrumentation required to perform the test widely available?

• 10. Does the document propose a measurement uncertainty budget?

Metrology Checklist (N095)

for use in preparation and evaluation of ISO/TC229 NWIPs and WDs

ISO/TC229 – IEC/TC113 JWG2 Metrology SG

1. Has the system / body / substance that will be subjected to the measurement procedure clearly been described, including its state? 2. Is the definition of the system / body / substance not unnecessarily restrictive? 3. Is the measurand clearly described? 4. Has it been clearly indicated whether the measurand is operationally or method defined, or whether the measurand is an intrinsic, structurally defined property? 5. Is the measurement unit defined? Are the tools required to obtain metrological traceability available? 6. Has the method already been validated in one or more laboratories? 7. Are any quality control tools available to enable the demonstration of a laboratory's proficiency with the test method? 8. Have the results of measurements using the proposed method already been published in peer-reviewed journals by several laboratories? 9. Is the instrumentation required to perform the test widely available?

• 10. Does the document propose a measurement uncertainty budget?

Metrology Checklist (N095)

for use in preparation and evaluation of ISO/TC229 NWIPs and WDs ISO/IEC Guide 99:2007 (JCGM 200:2008); International vocabulary of metrology — Basic and general concepts and associated terms (VIM), 3rd edition.

ISO/TC229 – IEC/TC113 JWG2 Metrology SG

1. Has the system / body / substance that will be subjected to the measurement procedure clearly been described, including its state? 2. Is the definition of the system / body / substance not unnecessarily restrictive? 3. Is the measurand clearly described? 4. Has it been clearly indicated whether the measurand is operationally or method defined, or whether the measurand is an intrinsic, structurally defined property? 5. Is the measurement unit defined? Are the tools required to obtain metrological traceability available? 6. Has the method already been validated in one or more laboratories? 7. Are any quality control tools available to enable the demonstration of a laboratory's proficiency with the test method? 8. Have the results of measurements using the proposed method already been published in peer-reviewed journals by several laboratories? 9. Is the instrumentation required to perform the test widely available?

• 10. Does the document propose a measurement uncertainty budget?

Metrology Checklist (N095)

for use in preparation and evaluation of ISO/TC229 NWIPs and WDs ISO/IEC Guide 99:2007 (JCGM 200:2008); International vocabulary of metrology — Basic and general concepts and associated terms (VIM), 3rd edition. ISO/TC229 – IEC/TC113 JWG2_N096 Guidelines on the metrological content in the documentation of measurement methods

Metrology When developing standards/regulations/guidelines for [nano]technologies that involve measurements … talk to a [nano]metrologist ! “To measure is to know.” (Lord Kelvin)

THANK YOU