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EC number: 215-222-5 | CAS number: 1314-13-2
- Life Cycle description
- Uses advised against
- Endpoint summary
- Appearance / physical state / colour
- Melting point / freezing point
- Boiling point
- Density
- Particle size distribution (Granulometry)
- Vapour pressure
- Partition coefficient
- Water solubility
- Solubility in organic solvents / fat solubility
- Surface tension
- Flash point
- Auto flammability
- Flammability
- Explosiveness
- Oxidising properties
- Oxidation reduction potential
- Stability in organic solvents and identity of relevant degradation products
- Storage stability and reactivity towards container material
- Stability: thermal, sunlight, metals
- pH
- Dissociation constant
- Viscosity
- Additional physico-chemical information
- Additional physico-chemical properties of nanomaterials
- Nanomaterial agglomeration / aggregation
- Nanomaterial crystalline phase
- Nanomaterial crystallite and grain size
- Nanomaterial aspect ratio / shape
- Nanomaterial specific surface area
- Nanomaterial Zeta potential
- Nanomaterial surface chemistry
- Nanomaterial dustiness
- Nanomaterial porosity
- Nanomaterial pour density
- Nanomaterial photocatalytic activity
- Nanomaterial radical formation potential
- Nanomaterial catalytic activity
- Endpoint summary
- Stability
- Biodegradation
- Bioaccumulation
- Transport and distribution
- Environmental data
- Additional information on environmental fate and behaviour
- Ecotoxicological Summary
- Aquatic toxicity
- Endpoint summary
- Short-term toxicity to fish
- Long-term toxicity to fish
- Short-term toxicity to aquatic invertebrates
- Long-term toxicity to aquatic invertebrates
- Toxicity to aquatic algae and cyanobacteria
- Toxicity to aquatic plants other than algae
- Toxicity to microorganisms
- Endocrine disrupter testing in aquatic vertebrates – in vivo
- Toxicity to other aquatic organisms
- Sediment toxicity
- Terrestrial toxicity
- Biological effects monitoring
- Biotransformation and kinetics
- Additional ecotoxological information
- Toxicological Summary
- Toxicokinetics, metabolism and distribution
- Acute Toxicity
- Irritation / corrosion
- Sensitisation
- Repeated dose toxicity
- Genetic toxicity
- Carcinogenicity
- Toxicity to reproduction
- Specific investigations
- Exposure related observations in humans
- Toxic effects on livestock and pets
- Additional toxicological data

Nanomaterial Zeta potential
Administrative data
- Endpoint:
- nanomaterial Zeta potential
- Type of information:
- experimental study
- Adequacy of study:
- weight of evidence
- Reliability:
- 4 (not assignable)
- Rationale for reliability incl. deficiencies:
- other: see 'Remark'
- Remarks:
- Limited documentation of the data evaluation was provided in the full study reports. Furthermore the procedure for subsampling and data analysis was not explained in detail. Thus, it was not possible to assess the validity of the provided data as the sample preparation could have a significant influence to the result. The provided data are not sufficient to finally conclude on the zeta potential of the 4 NMs or to identify differences or similarities. The concentration used was excessive and the results were regarded to be not self-consistent (e.g. the pH-dependence for NM111), and were not confirmed by other labs (should see positive charge at neutral pH).
Data source
Reference
- Reference Type:
- study report
- Title:
- Unnamed
- Year:
- 2 012
- Report date:
- 2012
Materials and methods
Test guideline
- Qualifier:
- no guideline followed
- GLP compliance:
- no
- Type of method:
- Laser-Doppler
- Remarks:
- Laser-Doppler-Electrophoresi
- Details on methods and data evaluation:
- Zeta potentials of samples were determined at different pH values (pH=2, 4, 6, 8 and 10) using a Brookhaven particle size analyser 90Plus equipped with a 657 nm laser. 10 mg “as-received” ZnO sample was dispersed in a cuvette containing 3 ml DI water, and the pH was adjusted by adding either 0.1M HCl or 0.1M NaOH. The cuvette was placed in an ultrasonic bath for 10 seconds and then shaken manually to ensure good dispersion of particles in the sample. The electrode was inserted into the dispersion and the Zeta potential at each pH was measured 5 times and an average was determined. The temperature of all measurements was maintained at 25 °C. The cuvette was thoroughly washed with deionised water after each measurement.
Test material
- Test material form:
- solid: nanoform
Constituent 1
Data gathering
- Instruments:
- Brookhaven particle size analyser 90Plus equipped with a 657 nm laser
Results and discussion
Zeta potentialopen allclose all
- Zeta potential:
- -5.79 mV
- St. dev.:
- 0.61 mV
- pH:
- 6.2
- Medium:
- DI water
- Remarks on result:
- other: NM110
- Zeta potential:
- -26.78 mV
- St. dev.:
- 1.77 mV
- pH:
- 6.2
- Medium:
- DI water
- Remarks on result:
- other: NM111
- Zeta potential:
- 3.74 mV
- pH:
- 6.2
- Medium:
- DI water
- Remarks on result:
- other: NM112
- Zeta potential:
- -5.51 mV
- St. dev.:
- 0.72 mV
- pH:
- 6.2
- Medium:
- DI water
- Remarks on result:
- other: NM113
Isoelectric pointopen allclose all
- Isoelectric Point:
- 3.9
- Medium:
- deionised water
- Remarks on result:
- other: NM110
- Isoelectric Point:
- 2.7
- Medium:
- deionised water
- Remarks on result:
- other: NM111
- Isoelectric Point:
- 6.5
- Medium:
- deionised water
- Remarks on result:
- other: NM112
- Isoelectric Point:
- 5.1
- Medium:
- deionised water
- Remarks on result:
- other: NM113
Any other information on results incl. tables
The table and the figure show the relationship between zeta potential and pH for the four ZnO samples tested. The pH value at which the net surface charge is zero is called the isoelectrical point (IEP). The IEPs are 3.9 for NM110, 6.5 for NM112 and 5.1 for NM113. IEPs in the range 4-6 are consistent with the dissociation of water to H+ and OH- on the particle’s surface and, where there is no surface coating, the IEP will be due solely to this dissociation. This therefore suggests that there is no specific surface coating on NM110, NM112 and NM113.
The IEP of NM111 is nominally 2.7, based on the data acquired. This IEP, which is significantly lower than IEPs determined for the uncoated NM110, NM112 and NM113, is suggestive of a different surface reaction (other than water dissociation) occurring on the coated NM111. However, NM111 is hydrophobic and observed to be very difficult to disperse in aqueous solutions; it is difficult to reconcile this observation with measurements of large zeta potential in water at most pHs. One possible explanation may be that the zeta potential data pertain to a small portion of the sample that is able to disperse. Therefore these data on zeta potential for NM111 should not be considered as representative of the sample, unless supported by other evidence.
Table Zeta potentials for ZnO samples dispersed in DI water where the pH was adjusted by adding either 0.1M HCl or 0.1M NaOH.
pH |
NM110 Zeta potential mV |
NM110 SD |
NM111 Zeta potential mV |
NM111 SD |
NM112 Zeta potential mV |
NM112 SD |
NM113 Zeta potential mV |
NM113 SD |
2.10 |
25.04 |
1.84 |
14.36 |
3.01 |
24.04 |
1.91 |
16.94 |
2.74 |
4.00 |
-1.50 |
0.6 |
-33.67 |
2.76 |
10.20 |
0.92 |
5.94 |
3.1 |
6.20 |
-5.79 |
0.61 |
-26.78 |
1.77 |
3.74 |
0.56 |
-5.51 |
0.72 |
8.10 |
-21.63 |
0.82 |
-28.20 |
1.5 |
-22.00 |
3.45 |
-13.50 |
0.76 |
10.00 |
-31.45 |
0.48 |
-19.25 |
1.06 |
-33.34 |
0.62 |
-37.38 |
1.25 |
Applicant's summary and conclusion
- Executive summary:
CSIRO, 2012 investigated the Surface charge (zeta potential) of the nanomaterials. Zeta potentials of the samples were determined at different pH values (pH=2, 4, 6, 8 and 10) using a Brookhaven particle size analyser 90Plus equipped with a 657 nm laser. 10 mg. ZnO nano samples were dispersed in a cuvette containing 3 mL deionized water, and the pH was adjusted by adding either 0.1 M HCl or 0.1 M NaOH. The cuvette was placed in an ultrasonic bath for 10 seconds and then shaken manually to ensure good dispersion of particles in the sample. The electrode was inserted into the dispersion and the Zeta potential at each pH was measured 5 times and an average was determined. The temperature of all measurements was maintained at 25 °C. The result showed the relationship between zeta potential and pH for the four ZnO samples tested. The isoelectrical point (IEP) was determined to be 3.9 for NM‑110, 6.5 for NM‑112 and 5.1 for NM‑113. IEPs in the range 4-6 are consistent with the dissociation of water to H+ and OH- on the particle’s surface and, where there is no surface coating, the IEP will be due solely to this dissociation. This therefore it was concluded that there is no specific surface coating on NM‑110, NM‑112 and NM‑113. The IEP of NM‑111 was determined to be 2.7 which was significantly lower than IEPs determined for the uncoated test samples. NM‑111 is hydrophobic and observed to be very difficult to disperse in aqueous solutions; it is difficult to reconcile this observation with measurements of large zeta potential in water at most pHs. One possible explanation may be that the zeta potential data pertain to a small portion of the sample that is able to disperse. Therefore these data on zeta potential for NM‑111 should not be considered as representative.
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