Registration Dossier

Administrative data

Endpoint:
nanomaterial specific surface area
Type of information:
experimental study
Adequacy of study:
key study
Study period:
April 2013
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
test procedure in accordance with generally accepted scientific standards and described in sufficient detail

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
2013
Report date:
2013

Materials and methods

Test guideline
Qualifier:
equivalent or similar to guideline
Guideline:
ISO 9277 Determination of the specific surface area of solids by gas adsorption - BET method
Version / remarks:
The specific surface area of a powder is determined by physical adsorption of a gas on the surface of the solid and by calculating the amount of adsorb gas corresponding to a monomolecular layer on the surface. Physical adsorption results from relatively weak forces (van der Waals forces) between the adsorbate gasmolecules and the adsorbent surface area of the test powder. The determination is usually carried out at the temperature of liquid nitrogen.
The amount of gas adsorbed can be measured by a volumetric or continuous flow procedure
Deviations:
not specified
GLP compliance:
yes
Type of method:
BET
Details on methods and data evaluation:
Equipment: Micromeritics Tristar II 3020 Porosimeter (with Nitrogen as Absorbate gas) with Micromeritics
SmartPrep. The analysis was performed according to SOP 099.02 Issue 1
Special Reagents - Glass Reference Material with a surface area of 7.7m2/g.
Reference material results were satisfactory
Instrument Parameters:
The samples were conditioned overnight (i.e. minimum of 16 hours) at 40°C, with a Nitrogen gas purge, cooled and then run on the porosimeter
A relative nitrogen pressure range of 0.05 – 0.30 P/Po was assessed, with a minimum of 3 points within this range used to obtain acceptable
correlation coefficients of > 0.9975

Test material

Constituent 1
Chemical structure
Reference substance name:
Silicic acid, lithium magnesium sodium salt
EC Number:
258-476-2
EC Name:
Silicic acid, lithium magnesium sodium salt
Cas Number:
53320-86-8
Molecular formula:
Na0.7+ [(Si8Mg5.5Li0.3) O20(OH)4]0.7-
IUPAC Name:
Silicic acid, lithium magnesium sodium salt
Constituent 2
Reference substance name:
Laponite T2
IUPAC Name:
Laponite T2
Specific details on test material used for the study:
Laponite XLG powder. Batch number 12-228

Data gathering

Instruments:
Micromeritics Tristar II 3020 Porosimeter (with Nitrogen as Absorbate gas) with Micromeritics SmartPrep.
Calibration:
Glass Reference Material with a surface area of 7.7m2/g was used to calibrate the instrument
Reproducibility:
Within 10% of the certified value, which was deemed to be acceptable according to the SOP

Results and discussion

Specific surface area
Key result
Specific Surface Area:
>= 306 - <= 309 m²/g
St. dev.:
1.5 m²/g

Applicant's summary and conclusion