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Can I store the dye-iodoacetamide reactive dye after dissolving in DMF or any other solvent? Product FAQ

Answer

If you do not plan on using the entire vial of reactive dye, you may dissolve this into a volatile solvent*, make smaller aliquots, and then evaporate off the solvent rapidly using a vacuum pump (under a chemical safety hood). The aliquots should be stored as a dry solid, frozen, desiccated, and protected from light.
*The type of solvent is dependent upon the dye and reactive group. Please contact Technical Support at techsupport@thermofisher.com for recommended solvents. Please note that aliquoting may result in some loss of reactivity.

Find additional tips, troubleshooting help, and resources within our Cell Analysis Support Center.

Answer Id: E18298

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Can Ponasterone A be resuspended in ethanol at concentrations higher than 1 mM and can it be dissolved in other solvents such as DMSO? Product FAQ

Answer

Ponasterone A solution may be prepared as 5 mM stock in ethanol (250 µg of Ponasterone A in 100µL of ethanol). They will take a while to go into solution. Add ethanol and incubate at 37 degrees C for about 15 minutes, then vortex vigorously. Ponasterone A is also highly soluble in DMSO.

Find additional tips, troubleshooting help, and resources within our Protein Expression Support Center.

Answer Id: E3510

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My peptide is not water-soluble; can I use other solvents for conjugation when using the CarboxylLink or DADPA UltraLink resin? Product FAQ

Answer

Yes. When coupling water-insoluble peptides or other molecules, use water-miscible solvents such as ethanol, methanol, DMSO or DMF. Dissolve the peptide in 100% of the water-miscible solvent first and then add this solution to the Conjugation Buffer. Organic solvent concentrations up to 50% in the coupling reaction are compatible. When using high concentrations of organic solvent (> 25%), gradually equilibrate the resin into the organic solvent. For example, wash the resin with 2-3 column volumes of each of the following solutions before adding the sample in 50% organic solvent:

- 95% aqueous, 5% organic solvent
- 85% aqueous, 15% organic solvent
- 75% aqueous,25% organic solvent
- 60% aqueous, 40% organic solvent
- 50% aqueous, 50% organic solvent
Reverse the percent organic solvent and re-equilibrate the resin in 100% aqueous if purifying a sample in aqueous buffer.

Find additional tips, troubleshooting help, and resources within our Protein Purification and Isolation Support Center.

Answer Id: E8213

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My molecule is insoluble in aqueous buffers. Can I still label my molecule? Product FAQ

Answer

Yes. Depending upon the reaction chemistry, labeling may be carried out in organic solvents such as DMSO, DMF, acetonitrile, alcohol, or other solvents. Useful information may be found in the text Bioconjugate Techniques (Greg T. Hermanson, Academic Press) or at Labeling Small Peptides with Amine-Reactive Dyes in Organic Solvents (see link at: https://www.thermofisher.com/us/en/home/references/molecular-probes-the-handbook/technical-notes-and-product-highlights/labeling-small-peptides-with-amine-reactive-dyes-in-organic-solvents.html).

Find additional tips, troubleshooting help, and resources within our Cell Analysis Support Center.

Answer Id: E12211

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Explain the chemistry of the Thermo Scientific Ellman's Reagent assay? Product FAQ

Answer

In 1959, Ellman introduced 5,5'-dithio-bis-(2-nitrobenzoic acid), also known as DTNB, as a versatile water-soluble compound for quantitating free sulfhydryl groups in solution. A solution of this compound produces a measurable yellow-colored product when it reacts with sulfhydryls. Consequently, Ellman's Reagent became very useful as a sulfhydryl assay reagent because of its specificity for -SH groups at neutral pH, high molar extinction coefficient and short reaction time. DTNB reacts with a free sulfhydryl group to yield a mixed disulfide and 2-nitro-5-thiobenzoic acid (TNB). The target of DTNB in this reaction is the conjugate base (R—S-) of a free sulfhydryl group. Therefore, the rate of this reaction is dependent on several factors: (1) the reaction pH, (2) the pKa' of the sulfhydryl and (3) steric and electrostatic effects. TNB is the colored species produced in this reaction and has a high molar extinction coefficient in the visible range. The molar extinction coefficient of TNB was originally reported by Ellman to be 13,600M-1 cm-1 at 412 nm and pH 8.0. Later studies have shown, however, that the molar extinction coefficient is more accurately reflected by a value of 14,150M-1 cm-1 at 412 nm. The extinction of TNB is not affected by changes in pH between 7.6 and 8.6. However, the extinction of TNB is different in other solvents.

Find additional tips, troubleshooting help, and resources within our Protein Assays and Analysis Support Center.

Answer Id: E13371

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Can I use methanol or acetone for fixation of cells stained with BODIPY FL LDL? Product FAQ

Answer

If the BODIPY FL LDL is applied to live cells first and then fixed, the use of methanol or acetone fixation is not recommended. Exposure to alcohols, acetone, and other organic solvents can dissociate the BODIPY FL dye from the LDL.

Find additional tips, troubleshooting help, and resources within our Cell Analysis Support Center.

Answer Id: E16788

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What do you recommend for cleaning of the Invitrogen Semi-Dry Blotter? Product FAQ

Answer

Do not use ethanol or other organic solvents to clean the Invitrogen Semi-Dry Blotter. Organic solvents can cause acrylic to crack. Rinse the blotter with deionized water after each use to clean and let air dry. If you must wipe the surface, take particular care not to scratch or otherwise damage the platinum-coated titanium plate.

Find additional tips, troubleshooting help, and resources within our Protein Electrophoresis and Western Blotting Support Center.

Answer Id: E11371

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Are Alexa Fluor dyes compatible with common fixatives, buffers, and permeabilizing agents? Product FAQ

Answer

Yes. Avoid the use of heavy metals, extremes of pH, strong oxidizing/reducing agents, picric acid, and organic solvent-based mounting media (toluene and other aromatic solvents can quench fluorescence). Also avoid co-staining with colorimetric dyes as they may quench fluorescence.

Permeabilization and deparaffinization of tissues may cause the loss of dyes and dye-conjugates that are not covalently attached to cellular components.

Find additional tips, troubleshooting help, and resources within our Cell Analysis Support Center.

Answer Id: E18009

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Do you offer a cell viability stain compatible with fixation? Product FAQ

Answer

Our Image-IT DEAD Green Viability Stain (Cat. No. I10291) is amenable to fixation and permeabilization after the application of the stain. It is important to use fixatives free of alcohol or other organic solvents.

Find additional tips, troubleshooting help, and resources within our Cell Viability, Proliferation, Cryopreservation, and Apoptosis Support Center.

Answer Id: E21873

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Dissociation, tautomerism and electroreduction of xanthene and sulfonephthalein dyes in N,N-dimethylformamide and other solvents Citations & References

  • Authors: Mchedlov-Petrossyan NO, Kukhtik VI, Bezugliy VD
  • Journal: J Phys Org Chem
  • PubMed ID: 0
Catalog #

Amine-reactive, environment-sensitive fluorophores—Table 1.13 Molecular Probes Handbook

Do you recommend using glycerol as a mountant for samples stained with lipophilic stains? Product FAQ

Answer

No. We do not recommend using glycerol and glycerol-based mountants for samples stained with lipophilic stains. Glycerol, as well as other alcohols or organic solvents, would promote the loss of stain from the sample.

Find additional tips, troubleshooting help, and resources within our Cell Analysis Support Center.

Answer Id: E18030

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What agents are compatible with Coomassie Plus Protein Assay? Product FAQ

Answer

The assay is compatible with many agents that are incompatible in other assays. It has been shown to be compatible with amine-containing buffers, reducing agents, chaotropic agents, organic solvents, sugars, antimicrobial agents, DNA, protease inhibitors, and low concentrations of metal chelators and metals.

Find additional tips, troubleshooting help, and resources within our Protein Assays and Analysis Support Center.

Answer Id: E8312

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Why is my recombinant protein not soluble? Product FAQ

Answer

The solubility issue might be due to improper handling, or use of a solvent other than the one we recommended. We recommend that you warm the lyophilized powder to room temperature before you open the vial, and that you solubilize the protein in the buffer solution recommended in the manual (some proteins are more soluble in low pH buffer). Do not reconstitute at a protein concentration greater than 1 mg/mL. Do not vortex or mix protein solutions vigorously. Allowing the reconstituted protein to incubate overnight at 4 degrees C may help resolve any solubility issues.

Answer Id: E12200

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What agents are compatible with the Thermo Scientific Coomassie (Bradford) Protein Assay Kit? Product FAQ

Answer

The assay is compatible with many agents that are incompatible in other assays. The Coomassie Protein Assay has been shown to be compatible with amine-containing buffers, reducing agents, chaotropic agents, organic solvents, sugars, antimicrobial agents, DNA, protease inhibitors, low concentrations of metal chelators, and metals.

Find additional tips, troubleshooting help, and resources within our Protein Assays and Analysis Support Center.

Answer Id: E13420

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