Martin Hassell Martin Hassell ö ö v v Environmental Nanochemistry group, Environmental Nanochemistry group, Department of Chemistry, Department of Chemistry, University of Gothenburg, Sweden University of Gothenburg, Sweden Reference material needs to support Reference material needs to support nanometrology and risk assessment nanometrology and risk assessment of engineered nanoparticles of engineered nanoparticles
44
Embed
Reference material needs to support nanometrology … · Reference material needs to support nanometrology and risk assessment of engineered nanoparticles. ... ppt NTA ppb-ppm ...
This document is posted to help you gain knowledge. Please leave a comment to let me know what you think about it! Share it to your friends and learn new things together.
• Nanoparticles (all three dimensions in nanoscale)
• Nanofibres (2 dimensions in nanoscale)
• Nanoplates
BenefitsBenefits
Nanotechnologies are forecasted to have a major impact in all areas of the future society
Contribute to solve the grand challenges
Energy production (e.g. Photovoltaics)
Energy storage (e.g. Batteries and fuel cells)
Carbon capture
Lighter and stronger vehicles
Faster and smaller computers (e.g quantum or spintronics)
Water treatment
Greener chemical production
Efficient healthcare (e.g. better treatments and diagnostics)
But you have to know what you are producing
Measure, image, analyse
Tasks for the Nanometrology field
NanometrologyNanometrology
Nanometrology is the science of measurement at the nanoscale level.
“Nanometrology must be seen as indispensable part of all kinds of nanotechnology”
Novel subfield of metrology that has large expectations from the needs of nanotechnol. and nanomanufacturing
Accurate, high-precision, traceable measurements of size, length and other physicochemical properties at the nanoscale
Reference materials and methods
Critical for nanometrology
Also standard methods, protocols, strategies all through the
analytical chain are needed
AUS NMI 3 slides
Enhanced reactivity compared to bulk
Reactivity may give adverse biological effects
Small enough to be mobile
in air, water and organisms
Some have been shown to penetrate biological barriers
Nanomaterials comparable in size to many protein structures in cells
Peristent nature
Toxic potential of nanomaterialsToxic potential of nanomaterials
Measurement needs in risk assessment Measurement needs in risk assessment
of engineered nanoparticlesof engineered nanoparticles
Environmental and human health risk assessmentconsists of Hazard assessment (how toxic) and
Exposure assessment (how high concentration of X)
Both requires analysis and physicochemical characterization
Nanometrology needs in environmental risk assessment Nanometrology needs in environmental risk assessment
At a recent horizon scanning workshop with ~60 international experts, metrology development was put at highest importance and where current knowledge were lacking, thus one of the most urgent priorities
(Alvarez et al. Research Priorities to Advance Eco-Responsible Nanotechnology. ACS Nano, Vol 3, p 1616-1619 (2009)
Hassellöv, M., Readman, J., Ranville, J. and Tiede, K.
Nanoparticle analysis and characterization methodology
in environmental risk assessment of engineered nanoparticles. Ecotoxicology 2008. Vol. 17, p. 344–361
Tiede, K., Boxall, A., Lewis, J., David, H., Tear, S. and
Hassellöv M. Detection and characterization of
engineered nanoparticles in food and the environment – a
review. Food Additives and Contaminants 2008, Vol. 25,
p. 1-27.
Hassellöv M. and Kaegi, R. Analysis and Characterization of Manufactured Nanoparticles in Aquatic Environments.
In: Nanoscience and Nanotechnology: Environmental and
human health implications. (Eds. Lead J.R. and Smith E.)
Wiley 2009, p. 211-266
But...for complex environmental or But...for complex environmental or
biological samples...biological samples...
Free nanoparticles, aggregates, mixed agglomerates of engineered NP with background nanomaterials (e.g. proteins or humic substances), dissolved ions of the same element, biological cells...
Broad size distributions
Heterogeneity in several physicochemical properties
Such samples has very different requirements on sample preparation and analysis methods than typical nanomaterial analysis.
Method Size (nm)
1 10 100 1000
PSD
capability
ShapeA
capability
Agglomeration
state
capabilityB
Concentr.
range
AFM
ppb − ppm
BET powder
Centrifugation
det. dep.
Dialysis
det. dep.
DLS
ppm
Electrophor.
ppm
EELS/EDX ppm in sp
ESEM
ppb − ppm
Filtration
det dep
Flow FFF
Sed FFF
UV: ppm,
ICPMS: ppb
HDC
det. dep.
ICP-MS ppt − ppb
LIBD
ppt
NTA
ppb-ppm
SEC
det dep
SEM
ppb − ppm
SLS
ppm
SAED
Spectrometry
ppb − ppm
TEM
ppb − ppm
Turbidimetry
ppb − ppm
Ultrafiltration det. dep.
XPS powder
XRD powder
Surface
Chemistry /
Charge / Area
Structure /
Crystallinity
Single
part./
population
Dynamics
capabilityC
Level of
perturbation
+
+
+
++
++
+
++ sp
medium
pp high
pp
low
pp low
pp
minimum
++
+
++
++
+
++ pp
minimum
sp high
sp
medium
pp
low-medium
pp
low
pp
low
pp N/A
sp
minimum
sp
minimum
pp
medium
sp
high
pp
minimum
sp high
pp
minimum
(HR) sp
high
pp
minimum
pp medium
pp
pp high
SSASSA
From Hassellöv and Kaegi, 2009
Electron microscopy detection modes
TEM interaction volume
Electron beam (parallell in
TEM, focussed in S-TEM and
SEM
Characteristic
X-rays
Inelastically
scattered electrons
Electron energy loss
spectroscopy
Secondary
electrons
Back scattered
electrons
Elastically scattered
electrons
Transmitted beam
SEM interaction volume
ESEM ESEM –– Backscattered electron detectionBackscattered electron detectionBSE detection: high contrast for high atomic numbers
Selectivity for heavy metal NPs
Example: Characterization of earthworm toxicity test 10 nm Ag NP
Yields aggregates in 50 - 4000 nmsize range ESEMESEM--BSEBSE ESEMESEM--SESE
NP Emissions (Samsung silver washing machine)Scanning TEM-High Angle Annular Dark Field: high contrast for heavy elements
Goethite iron oxide dispersion from NIST with certified positive zeta potential value
Many non certified size standards exists
e.g. Polystyrene (from 20nm upwards)
Reference nanomaterialsReference nanomaterials
Thermodynamically unstable nature
May be kinetically stable against aggregation or cold sintering, ostwald ripening, phase transformations etc
Stability is sensitive to environmental factors
Temp, pressure?, shaking/stirring, pH (CO2)
These factors may influence shelf life
Nanoscale calibration artifacts
Nanoscale objects defined in 1, 2, or 3D
Used for calibration of microscopes and as transfer standards from one microscope to another
Variations of measurands
e.g. Size and Size distributions
Only a perfect sphere can be described with only one number
Various equivalent spherical diameters
Hassellöv and Kaegi, 2009
Comparability and harmonizationComparability and harmonization
Different types of averagesDifferent types of averages
Hassellöv and Kaegi, 2009
Future needs of Reference nanomaterialsFuture needs of Reference nanomaterials
Certified for a larger variety of physicochemical properties
E.g. validation of certain methods need CRMs with certified shape (aspect ratio) and density, and core-shell type of chemical composition, and multimodal distributions
++
+
++
Concentration Shape
Size
Size
Distribution
Composition
Structure /
Crystallinity
Porosity /
Surface Area
Surface
Functionality
Surface
Speciation
Surface
Charge
Agglomeration State
Reference nanomaterial needs in toxicologyReference nanomaterial needs in toxicology
Interlaboratory comparisons of the same toxicants(bench-marking) is important in toxicology studies.
Homogeneity and shelf-life important criteria
Lesser degree of certification has been suggested, but still thorough physicochemical characterization
JRC (IHCP) is hosting and distributing the OECD sponsorship programme batches
Some FP7 projects MARINA, Qnano will also contribute to this work