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FAQs
General Questions
- General Questions
Q: What method is used to measure the size of nanocrystals?
A: A Transmission Electron Microscope (TEM) is used to measure the size of the inorganic core.
Q: Do you have any positive-charged nanocrystals?
A: Yes. We use PDDA, a positive-charged polymer, to coat quantum dots, iron oxide nanocrystals and metallic nanocrystals. They are available upon customer’s request.
Q: What are the zeta potential measurements for the nanocrystals?
A: The zeta potentials for the polymer coated nanocrystals (QSH, SHP, AuH, AgH) (quantum dots, metallic and iron oxide nanocrystals) are between -30 and -50 mV; the zeta potentials for PDDA positive-charged nanocrystals (QSQ, SHQ) are between +30 and +40 mV.
Q: Do you provide special order and/or custom synthesis to your customers?
A: Yes, we try our best to accommodate its customers’ needs.
Q: Do you have data and/or graphs for your nanocrystals?
A: Yes. The data and/or graphs for our nanocrystals such as TEM images, are available at the “Specification” section under the “Products” and “Resource” tabs. If you need further assistance, please call us at 479 751 5500. More data is available upon customers’ request.
Q: What solvent can I use to disperse metal nanocrystals powder?
A: Gold and Silver nanocrystal powders can be dispersed in most organic solvent, such as toluene, chloroform, hexane, THF, etc.
Q: Do I need to use sonication to disperse the metal nanocrystal powder?
A: We don’t recommend that our customer use sonication to disperse any of our nanocrystal powders. Our recommended method is to add certain amount of solvent to the metal nanocrystal powder and shake. The metal nanocrystals will be dispersed in the solvent.
Q: What is the maximum concentration of the organic metallic nanocrystals?
A: Our experimentation suggested that up to 40% concentration is possible. This was tested by adding 113 mg chloroform to 87 mg Au nanocrystals. No apparent aggregation was observed.
Affinity IOs with Antibodies, Protein G or Streptavidin
- IAB-34B
IAB-34B is a group of water soluble iron oxide nanocrystals with amphiphilic polymer coating. Their surface functional group is goat anti human IgG. The zeta potential of IAB-34B is from -20mV to -40mV. The thickness of the total organic layers is about 4 nm. The hydrodynamic size of the nanocrystals is about 8-10 nm larger than their inorganic core size measured by TEM. The antibody molecules are linked to the polymer. This category of product is stable in most buffer solutions.
The antibody conjugated magnetic iron oxide nanocrystals can be used directly for biologycal assays.
The products of this category are packed with 1 mg/mL BSA and 0.02% NaN3, you can use Ocean's magnetic separator to purify before use. - IAB-36B
IAB-36B is a group of water soluble iron oxide nanocrystals with amphiphilic polymer coating. Their surface functional group is goat anti mouse IgG. The zeta potential of IAB-36B is from -20mV to -40mV. The thickness of the total organic layers is about 4 nm. The hydrodynamic size of the nanocrystals is about 8-10 nm larger than their inorganic core size measured by TEM. The antibody molecules are linked to the polymer. This category of product is stable in most buffer solutions.
The antibody conjugated magnetic iron oxide nanocrystals can be used directly for biologycal assays.
The products of this category are packed with 1 mg/mL BSA and 0.02% NaN3, you can use Ocean's magnetic separator to purify before use. - IAB-37B
IAB-37B is a group of water soluble iron oxide nanocrystals with amphiphilic polymer coating. Their surface functional group is goat anti rabbit IgG. The zeta potential of IAB-37B is from -20mV to -40mV. The thickness of the total organic layers is about 4 nm. The hydrodynamic size of the nanocrystals is about 8-10 nm larger than their inorganic core size measured by TEM. The antibody molecules are linked to the polymer. This category of product is stable in most buffer solutions.
The antibody conjugated magnetic iron oxide nanocrystals can be used directly for biologycal assays.
The products of this category are packed with 1 mg/mL BSA and 0.02% NaN3, you can use Ocean's magnetic separator to purify before use. - IAB-38B
IAB-38B is a group of water soluble iron oxide nanocrystals with amphiphilic polymer coating. Their surface functional group is goat anti rat IgG. The zeta potential of IAB-38B is from -20mV to -40mV. The thickness of the total organic layers is about 4 nm. The hydrodynamic size of the nanocrystals is about 8-10 nm larger than their inorganic core size measured by TEM. The antibody molecules are linked to the polymer. This category of product is stable in most buffer solutions.
The antibody conjugated magnetic iron oxide nanocrystals can be used directly for biologycal assays.
The products of this category are packed with 1 mg/mL BSA and 0.02% NaN3, you can use Ocean's magnetic separator to purify before use. - IAG-06B
IAG-06B is a group of water soluble iron oxide nanocrystals with amphiphilic polymer coating. Their surface functional group is mouse IgG. The zeta potential of IAG-06B is from -20mV to -40mV. The thickness of the total organic layers is about 4 nm. The hydrodynamic size of the nanocrystals is about 8-10 nm larger than their inorganic core size measured by TEM. The IgG molecules are linked to the polymer. This category of product is stable in most buffer solutions.
The mouse IgG conjugated magnetic iron oxide nanocrystals can be used directly for biologycal assays.
The products of this category are packed with 1 mg/mL BSA and 0.02% NaN3, you can use Ocean's magnetic separator to purify before use. - IPG
Please check the general questions in FAQs page. - SHS
Q: How many streptavidin molecules are on each SHS iron oxide nanocrystal?
A: The number of streptavidin molecules depends on the size of the SHS iron oxide nanocrystals. Please call our customer service for detailed information.
Q: What is the storage solution for your SHS iron oxide solutions?
A: The storage solution is Ocean's standard storage buffer (catalog: MWB-100), which contains a proprietary formulation with proteins in aqueous borate buffered solution at pH 7.4+0.1 and 0.02%NaN3.
Q: Can I use magnetic separator to purify the SHS iron oxide nanocrystals after they are conjugated with biomolecules?
A: Yes. You can use our specially designed magnetic separator SuperMag SeparatorTM to purify if sizes are larger than 10 nm.
Q: How do I purify the SHS iron oxide nanocrystals to remove the reaction regents and the excess protein after conjugation?
A: Yes. You can use our specially designed magnetic separator SuperMag SeparatorTM to purify if sizes are larger than 10 nm.
Q: Can I use biotinylated antiobodies to conjugate with the SHS crystals?
A: Please note, for biotinylated antibody conjugation to our streptavidin conjugated nanocrystals, only use mono-biotinylated antibodies. Otherwise, if multiple biotin-labeled antibodies are used, it may cause precipitation of the nanocrystals. For additional information, please contact us at (479)751-5500 or email us at info@oceannanotech.com
Active IOs with carboxylic acid, amine, or NTA-Ni
- SHA
Q: What is the coating on your SHA water soluble iron oxide nanocrystals?
A: Our SHA iron oxide nanocrystals are coated with monolayer oleic acid, monolayer amphiphilic polymer and monolayer of PEG
Q: How is the stability of your SHA iron oxide nanocrystals in buffer solutions?
A: SHP iron oxide nanocrystals are stable in most buffer solutions, for example PBS, HEPES, Tris, borate, etc. except for in MES. The concentration of the buffer solution can be up to 1 M. we haven’t fully tested their stability the buffer solutions which concentration is more than 1 M.
Q: What is the storage solution for your SHA iron oxide nanocrystals?
A: pH 5.0 20 mM borate buffer solution.
Q: What is the concentration of iron in your SHA iron oxide nanocrystal solutions?
A: The standard concentration of iron in our SHA iron oxide nanocrystal solutions is 1 mg/ml (Fe). However, this concentration can be adjusted upon customers’ request.
Q: How can I conjugate protein onto your SHA iron oxide nanocrystal?
A: Trout’s agent can be used to conjugate the SHA iron oxide nanocrystals with amine surface and thiol derived biomolecules.
Q; How can I determine whether protein is conjugated onto the surface of the SHA iron oxide nanocrystals?
A: You can run electrophoresis gel. The protein conjugated Iron oxide nanocrystals should migrate faster than the original SHA iron oxide nanocrystals.
Q: can I use magnetic separator to purify the SHA iron oxide nanocrystals after they are conjugation with biomolecules?
A: Yes, you can, however, the commercial magnetic separator is for separating magnetic beads for sizes larger than 100 nm, their magnetic gradient is not enough to separate our iron oxide nanocrystals. Ocean Nanotech has a specifically designed magnetic separator which can separate the crystal size larger than 10 nm iron oxide nanocrystals.
Q: How do I purify the iron oxide nanocrystals to remove the reaction regents and the excess protein after conjugation?
A: You can use our specially designed magnetic separator SuperMag SeparatorTM to purify if sizes are larger than 10 nm. - SHP
Q: What is the coating on the water soluble SHP iron oxide nanocrystals?
A: The coating of our SHP iron oxide nanocrystals includes monolayer oleic acid and monolayer amphiphilic polymer.
Q: What is the overall size of your water soluble SHP iron oxide nanocrystals?
A: The oleic acid coating and the polymer coating are approximately 2 nm in thickness respectively. They together add approximately 8 nm to the overall core size.
Q: How is the stability of the SHP iron oxide nanocrystals in buffer solutions?
A: SHP iron oxide nanocrystals are stable in most buffer solutions, for example PBS, HEPES, Tris, borate, etc. except for in MES. The concentration of the buffer solution can be up to 1 M. We haven’t fully tested the stability in buffer solutions which concentration is more than 1 M.
Q: What is the stability of your SHP iron oxide nanocrystals under pH and salt conditions?
A: Our SHP iron oxide nanocrystals are stable in the pH range of 5-10 and can survive in salt when the concentration of the salt is below 1 M (as tested with NaCl). We haven’t fully tested the stability in salt at higher concentrations.
Q; How can I test the stability of your SHP iron oxide nanocrystals in water?
A: You can run electrophoresis gel. Our SHP iron oxide nanocrystals should show a single band in the gel.
Q: What is the concentration of iron in your SHP iron oxide nanocrystal solutions?
A: The standard concentration of iron in our products is 5 mg/ml (Fe). However, this concentration can be adjusted upon customers’ request.
Q: What is the storage solution for your SHP iron oxide nanocrystals?
A: It’s in double distilled water.
Q: What is the shelf life of your SHP iron oxide nanocrystals in water?
A: The shelf life of our SHP iron oxide nanocrystals depends on the size of the crystals. The shelf life of iron oxide nanocrystals less than 15 is 1 year, if they are stored and handled correctly. We have been manufacturing our 10 nm iron oxide nanocrystals for over two years and have not yet seen a definitive lifetime. The shelf life of our iron oxide nanocrystals larger than 15 nm is 6 months if they are stored and handled correctly.
Q: How can I conjugate protein to SHP nanocrystals?
A: EDAC coupling method can be used to conjugate protein onto the surface of our SHP iron oxide nanocrystals. Please check the EDAC conjugation protocol in the “Conjugation Protocol” section under “Products” or “Resource” tabs.
Q; How can I determine whether the protein is conjugated on to the surface of your SHP iron oxide nanocrystals?
A: You can run electrophoresis gel. The protein conjugated Iron oxide nanocrystals should migrate slower than the original SHP iron oxide nanocrystals.
Q: How do I calculate the molar amount of 1 mg Fe for different sized SHP iron oxide nanocrystals?
A:
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Crystal Size (nm)
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Nanocrystal Molar Concentration (nmol) of 1 mg Fe
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Nanocrystal Molar Concentration (nmol) for 10 mg Fe
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Nanocrystal Molar Concentration (nmol) for50 mg
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5
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7.26
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72.6
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363.0
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10
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0.91
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9.1
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45.5
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15
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0.27
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2.7
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13.5
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20
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0.11
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1.1
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5.5
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25
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0.058
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0.58
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2.9
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30
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0.034
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0.34
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1.7
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35
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0.021
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0.21
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1.05
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40
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0.014
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0.14
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0.7
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45
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0.010
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0.1
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0.5
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50
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0.0073
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0.073
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0.365
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Q: Why do you use Fe amount as unit?
A: We use x-ray fluorescent spectra to quantify the concentration of Iron. Thus, we can only have the information about iron.
Q: Can I use a magnetic separator to purify the SHP iron oxide nanocrystals after they are conjugated with biomolecules?
A: Yes, you can. You have to use the magnetic separator we have specifically designed to separate the crystals larger than 10 nm. The commercial magnetic separator is for the separation of magnetic beads larger than 100 nm. Their magnetic gradient is not enough to separate our iron oxide nanocrystals smaller than 100 nm.
Q: How do I purify the iron oxide nanocrystals to remove the reaction regents and the excess protein after conjugation?
A: You can use our specifically designed magnetic separator SuperMag SeparatorTM to purify if sizes are larger than 10 nm.
Passive IOs with PEG or Positive Charge Coatings
- SEI
Please check the general questions in FAQs page. - SHQ
Please check the general questions in FAQs page. - SMG
Please check the general questions in FAQs page.
Organic Soluble IOs with Oleic Acid Coating
- SOR
Q: What method do you use to produce uniform iron oxide nanocrystals?
A: We use the thermolysis as iron precursor to produce iron oxide nanocrystals in organic solvent. The surface of each iron oxide nanocrystal is coated with monolayer oleic acid to prevent aggregation.
Q: How do you determine the size of the inorganic core of the iron oxide nanocrystals?
A: We determine the size of our iron oxide nanocrystals by TEM. We keep TEM data for every batch of our iron oxide nanocrystals.
Q: What is the composition of the iron oxide nanocrystals (maghemite, Fe2O3 or magnetite, Fe3O4)?
A: The iron oxide is composed of magnetite and Fe3O4 for the nanocrystals larger than 10 nm. The iron oxide is composed of the mixture of magnetite and maghemite for the nanocrystals at 5 nm.
Q: Do you have any data on the magnetization for your nanocrystals?
A: Yes, please check the specification sheet of our magnetic nanocrystals available at the “Products” and “Resource” tabs.
SuperMag SeparatorTM Series
- SuperMag SeparatorTM Series
Ocean NanoTech’s SuperMag Separator™ has a strong magnetic field. This product should not be used near magnets, metal, credit cards, or memory storage devices. Failure to follow this warning could lead to serious injury and loss of valuable data.
In Vitro Magnetic Field Generator
Passive QDs with PEG or Positive Charge Coatings
- QEI
- QSQ
Please check the general questions in FAQs page.
Active QDs with Carboxylic Acid, Amine, or NTA-Ni
- QSA
Q: What is the surface coating of the QSA QDs?
A: The QSA QDs are coated with monolayer amphiphilic polymer and monolayer PEG. - QSH
Q: What is the surface ligand for the hydrophilic QSH QDs?
A: The surface ligand is the octadecylamine coated with the amphiphilic polymer.
Q: How many carboxyl groups are on the surface of the QDs?
A: At least 120 carboxyl groups are on each quantum dot.
Q: How is the stability of QSH in buffer solutions?
A: QSH QDs are stable in most buffer solutions such as PBS, HEPES, Tris, MES, and borate. The concentration of the buffer solution can be up to 5 M for PBS solution. We haven’t fully tested their stability in the buffer solution which concentration is more than 5 M.
Q: How can I conjugate protein onto the QSH nanocrystals?
A: EDAC coupling method can be used to conjugate protein onto the surface of the QDs. Please check the “Conjugation Protocol” section available under the “Products” or “Resource” tabs.
Q; How do I determine whether the protein is conjugated onto the QDs?
A: You can run electrophoresis gel. The protein conjugated QDs should migrate slower than the original QSH QDs.
Q: How can I purify the QD-protein conjugates?
A: The sephadex column or centrifugal device is good for the purification.
Core/shell CdSe/ZnS QDs in Powder or Toluene
- QSO
Q: What is the surface ligand for the core/shell QDs?
A: The surface ligand for the CdSe/ZnS QDs is octadecylamine.
Q: What is the length of the surface ligand for the core/shell QDs?
A: It’s 2 nm.
Q: What solvent should I use to disperse the QD powders?
A: QSP QD powders can be dispersed in most organic solvents, for example toluene, chloroform, hexane, xylene, THF, etc.
Q: Do I need to use sonication to disperse the QD powders?
A: We don’t recommend that you use sonication to disperse any of our QD powders. We recommend that our customers add a certain amount of solvent to the powder and shake. The quantum dot powders will be dispersed in the solvent.
Q: How should I store QSP or QSO?
A: We recommend that our customer store QSP or QSO from -20 C to room temperature in air or nitrogen.
Q: How do we measure the quantum yield of the QDs?
A: The quantum yield is the percentage of the photons absorbed by QDs to those emitted. We use the integrating sphere to measure the quantum yield of the QDs. It is the most accurate method.
Q: What does FWHM stand for?
A: FWHM stands for full width of half maximum.
Q: Do you sell Cadmium-free QDs?
A: We are currently working on the development of Cadmium-free QDs but they are not available for commercial sale yet.
Q: Do you have data available on the absorption and emission of the QDs?
A: Yes. Please check the “Specification Sheet” section available under the “Products” or “Resource” tabs.
- QSP
Q: What is the surface ligand for the core/shell QDs?
A: The surface ligand for the CdSe/ZnS QDs is octadecylamine.
Q: What is the length of the surface ligand for the core/shell QDs?
A: It’s 2 nm.
Q: What solvent should I use to disperse the QD powders?
A: QSP QD powders can be dispersed in most organic solvents, for example toluene, chloroform, hexane, xylene, THF, etc.
Q: Do I need to use sonication to disperse the QD powders?
A: We don’t recommend that you use sonication to disperse any of our QD powders. We recommend that our customers add a certain amount of solvent to the powder and shake. The quantum dot powders will be dispersed in the solvent.
Q: How should I store QSP or QSO?
A: We recommend that our customer store QSP or QSO from -20 C to room temperature in air or nitrogen.
Q: How do we measure the quantum yield of the QDs?
A: The quantum yield is the percentage of the photons absorbed by QDs to those emitted. We use the integrating sphere to measure the quantum yield of the QDs. It is the most accurate method.
Q: What does FWHM stand for?
A: FWHM stands for full width of half maximum.
Q: Do you sell Cadmium-free QDs?
A: We are currently working on the development of Cadmium-free QDs but they are not available for commercial sale yet.
Q: Do you have data available on the absorption and emission of the QDs?
A: Yes. Please check the “Specification Sheet” section available under the “Products” or “Resource” tabs.
Core QDs in Toluene or in Water
- QCO
Q: What is the surface ligand for the CdSe core QDs?
A: The surface ligand for the CdSe core QDs at the emission range of 560-640 nm is the mixture of octadecyamine and trioctylphosphine oxide. The surface ligand for the CdSe core QDs at the emission range of 500-540 nm is octodecylphosphoric acid.
Gold and Silver Nanocrystals with Carboxyl or Amine
- AgA
Please check the general questions in FAQs page. - AgH
Please check the general questions in FAQs page. - AuA
Please check the general questions in FAQs page. - AuH
Q: What is the maximum concentration of the metallic nanocrystals with carboxyl group in water?
A: We estimate that up to 20% concentration is possible. All of our water soluble nanocrystals have a monolayer amphiphilic polymer coating, which allows high stability against aggregation in buffer solutions.
Q: What is the coating on water soluble gold nanocrystals?
A: The gold nanocrystals are coated with dodecanethiol and the monolayer amphiphilic polymer.
Q: What is the size or effective diameter of the water soluble metallic nanocrystals after a monolayer polymer coating has been added?
A: The size or effective diameter of our water soluble metallic nanocrystals depends on what ligands and coatings we use. If we use dodecanethiol as ligand, the surface coating will add 2 nm to the overall size of the nanocrystals; the addition of a polymer coating will add approximately 3-4 nm to the overall size of the nanocrystal. Therefore if the size of a gold nanocrystal is 6 nm, its overall size after modification is approximately 12-14 nm.
Q; How can I test the stability of the gold nanocrystals in water?
A: You can run electrophoresis gel. Gold nanocrystals (AuH) should show a single band in the gel.
Q: What is the shelf life of your gold nanocrystals in water?
A: If they are stored and handled correctly, their shelf life is 1 year. We have been manufacturing our gold nanocrystals for over two years, and have yet seen a definitive lifetime.
Q: How can I conjugate protein to Au nanocrystals?
A: EDAC coupling method can be used to conjugate protein onto the surface of gold nanocrystals. Please check our EDAC conjugation protocol at the “Conjugation Protocol” section under the “Products” or “Resource” tabs.
Q; How do I determine whether the protein is conjugated onto the surface of the gold nanocrystals?
A: You can run electrophoresis gel. Protein conjugated gold nanocrystals should migrate slower than original gold nanocrystals.
Q: How do I calculate the concentration of gold?
A: You can measure the optical density of the gold nanocrystal solution at 450 nm to get the information about molar concentration. The extinction conefficiency of 6 nm gold nanocrystals at 450 nm is 1.26 ×107 - GEI
- UEI
Gold and Silver Nanocrystal Powder
- AgO
Q: What solvent can I use to disperse metal nanocrystal powder?
A: Gold and Silver nanocrystal powders can be dispersed in most organic solvent, such as toluene, chloroform, THF, etc.
Q: Do I need to use sonication to disperse the metal nanocrystal powder?
A: We don’t recommend that our customers use sonication to disperse any of our nanocrystal powders. Our recommended method is to add a certain amount of solvent to the metal nanocrystal powder and shake. The metal nanocrystals will be dispersed in the solvent.
Q: What is the maximum concentration of the organic metallic nanocrystals?
A: Our experimentation suggested that up to 40% concentration is possible. This was tested by adding 113 mg chloroform to 87 mg Au nanocrystals. No apparent aggregation was observed. - AuO
Q: What solvent can I use to disperse metal nanocrystal powder?
A: Gold and Silver nanocrystal powders can be dispersed in most organic solvent, such as toluene, chloroform, THF, etc.
Q: Do I need to use sonication to disperse the metal nanocrystal powder?
A: We don’t recommend that our customers use sonication to disperse any of our nanocrystal powders. Our recommended method is to add a certain amount of solvent to the metal nanocrystal powder and shake. The metal nanocrystals will be dispersed in the solvent.
Q: What is the maximum concentration of the organic metallic nanocrystals?
A: Our experimentation suggested that up to 40% concentration is possible. This was tested by adding 113 mg chloroform to 87 mg Au nanocrystals. No apparent aggregation was observed.
Nanocrystals Coupling Kits
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