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I am doing DNA solution rheology, and the DNA is dissolved in a buffer solution. I put this solution is a parallel plate of ARG2 and did some frequency sweep and creep tests, all in the linear viscoelastic regime. A silicone oil of viscosity of 0.05 Pa.s was wrapped around the edge to prevent water evaporation. But after 3 days of tests, the sample shrunk by about dV/V of 10%. I wonder what is the reason for this sample loss? Is it possible the water can dissolve a little bit in silicone oil, since the volume of the silicone oil is much large than the water solution (4 ml >> 0.02 ml). Is there a conventional way to measure the liquid-liquid solubility?
I think that it is possible for the h2o to diffuse theough the oil. In microfluidics aqeuous bubbles in silicone oil will slowly lose volume through this mechanism...perhaps another oil? Or is there anyway to do this test without waiting 3days?
If I do Lyophilization of the allantoic fluid of eggs with Polysaccharide and Amino acid for the stabilizers, what is the factor that influences solubility? And what is an improvement that we can make for increasing dissolve time for the cake dilution?
You have to use whatever the manufacturer mentioned. Sterile water for injection will be available as such. Otherwise, use deionized distilled water or millipore water. PBS/ Saline , unless specifically mentioned , is contra indicated, since it can alter the pH and isotonicity of the final solution. Quantity of water to be used is also important, becoz it can alter the absorption / can cause deterioration of the product. The quality and quantity will be specified by the manufacturer. If you are using pure chemical, get the existing literatures of already done works
How to you want to check the interaction between your proteins and cholesterol?
Cholesterol is virtually insoluble in aqueous buffers and by using cyclodextrins it is 'masked', i.e. it is in solution but it doesn't behave like 'free' cholesterol. Your proteins are most likely in some aqueous buffer, so it's going to be problematic.
Some of the possibilities, depending on your question and equipment, are lipid overlay assays (cheap, dirty but unmodified cholesterol) and surface plasmon resonance with cholesterol containing bilayers.
I am in search of some suitable organic solvents for the solubilization of sulfonated PPO polymer. These are not well solubilized in NMP, DMF, DMSO and DMAc. Could someone help me regarding this problem?
I synthesized a peptide with 22 amino acid. I tried to solubilise it in water: Acetonitrile = 1 : 1 and acetonitrile 100%. I also did sonication and gentle heat, but I am finding it difficult to solubilise the peptide.
Dissolve in minimal neat TFA first. This should fully solubilize the peptide, Dilute with acetonitrile and add water dropwise until the peptide begins to precipitate with each additional drop. This method will allow to prepare solutions of peptide in 80/20, 70/30, or 50/50 CH3CN/H2O ratios for proper purification.
We are currently using the chemical A-804598 (see attached file for molecular structure; molecular weight 315.37) in a mice in vivo study. The substance is soluble in dimethylsulfoxide (DMSO) to 100nM, but some literature suggested that DMSO might have neuroprotective effect (which is our research interest) and toxicity built up overtime. As a 56 day in vivo treatment, what alternative solvent can we use, that has a lower toxicity/side effect? Much appreciated!
A hydroxy-cyclodextrin may enhance the delivery of your compound and is not toxic or neuroprotective when dissolved in water.
Many metabolically important compounds, such as lipid-soluble vitamins and hormones, have very low solubilities in aqueous solutions. Various techniques have been used to solubilize these compounds in tissue culture, cell culture, or other water-based applications. A frequently used approach is to use cyclodextrin as a “carrier” molecule to facilitate the dissolution of these compounds.
The most important test is peroxides level which is NMT 400 ppm. The peroxides level comes from related impurities produced during its synthesis. The peroxides are known as potent oxidizer agents for drugs liable for oxidation.
An accident reported by FDA for crospovidone batch produced by Chinese Pharmaceutical Company where the peroxides level are more than 400 ppm. FDA reported that any pharmaceutical manufacturers of any products contain this crospovidone batch should be rejected. Also, FDA reported that the limit of peroxides in PVP or crospovidone should not be more than 400 ppm.
I'm not an expert on pharmacology as I did my masters in chemistry. However, I'm helping a friend out with developing a new formula so I was wondering what the possible ways of measuring the saturation solubility of a drug are.
Add an excess amount of drug to distilled water then leaving it stirred or shaken until equilibrium is established for 48 or 72 hours. Then filter this suspension, discard the first 2 ml of filterate, then analyze the drug in the filterate. The concentration is considered the saturation or equilibrium solubility of drug.
The anthocyanins are generally soluble in water. But, the polyphenolic structure adds a measure of hydrophobic character which gives the anthocyanin solubility in organic solvents. The combination of this polar and hydrophobic nature makes aqueous/organic solvent mixtures the ideal solvent. Normally, the organic solvent content varies from 50% to 100% of the mixture. The organic solvent is usually methanol and ethanol but many other solvents have also been used such as acetone or acetonitrile.
Generally solubility in supercritical CO2 decreases with increasing temperature. If you find oherwise during extraction, the reason is that you do not reach equilibrium. If you extract from larger particles, you need time for difusion of the compound from the bulk to the surface. Difusion is faster at higher temperature. So in practical application you have a problem of speed versus solubility. It may be more economical to use higher temperature although the solubility is lower.
सुबकामनाओं सहित ज़्देन्येक वाग्नेर
How can I make a polymer inclusion membrane using DMSO as a solvent?
Apr 2, 2014
I have synthesized an organic compound having solubility only in DMSO but because of the high boiling point of DMSO it is not getting vaporized thus I am not able to make a membrane. And if i take a mixture of the solvents : dicloromethane and DMSO then phase separation occurs.
Could anyone explain this? A lot of papers ( as "Resveratrol attenuates brain damage in a rat model of focal cerebral ischemia via up-regulation of hippocampal Bcl-2" e.g.) told us that they treat rats with 30 mg/kg i.p Resveratrol dissolved in 2% DMSO saline.
If we do the maths:
Resveratrol solubility in DMSO =16mg/mL ( A. Amri et Al. 2012)
Average rat weight = 300 g
Resveratrol treatment for 300 g at 30 mg/kg = 9 mg for 300 g
9mg of Resveratrol needs 562,5 microlitres to be effectively dissolved.
For 562,5 microL of DMSO we need 28,125 milliliters of solution (DMSO 2% saline). They injected 28 milliliters of This into each rat once a day? What am I missing here? Am I a complete disaster with maths or there is something strange here?
I suspect that your solubility information is not correct. Cayman Chemical states that reservatrol can be diluted in DMSO and other organic solvents at 65 mg/ml. That gives 9 mg/65 mg/ml=0.138 ml of the straight DMSO stock. That still gives a dose of 6.9 ml twice a day. It may be that the solubility can go higher, or it can also be that they are dosing with a suspension. I have had in the past to gavage rats with a suspension when solubility was not in my favor.
Many companies will print solubility data that they have, but they do not necessarily attempt to find the absolute max that you can dissolve a given chemical in a given solvent.
I am facing problems with salubrinal solubility (Tocris Biosciences). A clear stock solution made was 100mM in DMSO as per Tocris product description (10mg in approx 200ul DMSO). Our working concentration is 4mM in DMEM medium (without FBS). The salubrinal precipitated (cloudy appearance) at this stage. Heating in water bath was not effective. 100mM stock was converted to 50mM, but still the 4mM solution precipitated. There are other companies who have recommended salubrinal solubility as 10mg/ml. Why this difference?
finally i been told what the solute is. Its a powder containing xanthone and some wall material? so it seems to be a very hydrophobic fella.
I need to run antioxidant assay on it. Hmm im figuring if methanolic extract of it is a good idea (which seems to be most paper favourites). perhaps with acetone or erm other solvent that is more non polar.
Abolfazi, what a can of worms to open on a poor optics/software/electronics soul!
Can you point me to some fundamental sources (I'm between college semesters and don't have a lot of access to anything that isn't openly available on the net) to get a start in OPLS-AA force fields and MD simulation? Is GROMACS the tool of choice? All of my computing power right now is Windows-based, and I'd have some serious upheaval to clear disk space, set up a partition and establish a Linux machine (although it isn't impossible). Is there another MD-capable engine I should know about?
Which approach to MD simulations arrives at approximations of Hansen Solubility Parameters (or any other >1 parameter solubility system) which might lead to better understanding of the antagonistic (if that's the proper term) interactions between the originally-listed solvents and solute in varying quantities?
My expressed protein is being collected in the pellet fraction and I have used different strategies for making it soluble but still its coming in the pellet. I have used strategies like temperature variation(18-37), IPTG concentration gradient from 0.1mM to 1mM, Incubation (1-5hrs), Sorbitol method using betaine (CCMB method published from CCMB, India) but still the protein is coming in pellet fraction. What other possible methods are there to troubleshoot my protein solubility?
Membrane proteins are bit tough to get in soluble form till you remove your transmembrane or signal peptide part.
I had the similar problem with a protein I was working on. Removed the signal peptide and transmembrane domain and voila it solved everything, got into soluble fraction and got purified as charm, got it crystallized it also.
If the protein does not have transmembrane domain or the signal peptide, then there are various good suggestions given about to try. I have some more on those lines that I have desperately tried and saw them working for my case.
I am not suggesting that now as I know its a lot of work in wet lab even if there's a small change you need to do. Been there seen that :).
John is correct, but partial molar volumes may actually tell you a little bit about the interaction between the different components of the mixture and the local structure of the solvent. In particular in water effects in the partial molar volume may be seen due to breaking of local water structure or even creating ice like structures ("iceberg model") around hydrophobic solutes. Having said that, the line between local structure and partial molar volume is long and very convoluted. There is a theory called Kirkwood-Buff theory in which the partial molar volumes (together with other thermodynamic parameters) can be related to integrals over the pair correlation functions between solvent and solute molecules. In the past (maybe even still, but I am not familiar with current research in this area, I briefly worked with such a group in the middle 1980's) people tried to use these theories also to understand thermodynamic properties of solutions of amino acids and small peptides. Success was very limited.
As an example: try to understand the behavior of the partial molar volumes for low ethanol concentrations in water-ethanol mixtures. The figure can be found in many textbooks.
In addition there is a formal, so-called Maxwell-relation between the partial molar volume and the pressure dependence of the chemical potential of a component that may be useful if you need one and can measure the other.
I am getting variable numbers. I have been sonicating with a probe sonicator after cutting tissue into small 2 mm pieces. After rotating ON in the acetic acid/pepsin buffer(0.5 M ,2.5 mg/ml) my supernatants are not completely clear. When I spin the supernatants themselves, I get a white pellet at the bottom. Is that the insoluble collagen that has been homogenized along with the soluble collagen?
Don't forget that the skin has a lot more in it than just collagen. There could be a number of insoluble components in skin. Almost regardless of the buffer and tissue used, any homogenization is likely to have components that spin down into a pellet.
However, if you homogenize and your resulting homogenate does not have a smooth consistency, that could also indicate that the homogenization is incomplete. I wouldn't be particularly surprised by that, as sonicators generally aren't recommended for tough and / or fibrous tissue, although your tissue may be in small enough pieces that it doesn't matter.
Everybody knows that the formation of cavity in a fluid requires work W = p*V ~ R^3 (pressure times cavity volume). If it is a small cavity, the work involves also a surface term, sigma*A ~ R^2 (surface tension times cavity area) as a correction of the main term. The smallest may require also surface moment terms ~R^1, R^0 etc.; but these should be really small.
Atomistic simulations of liquid pentane-heptane [J. Comp. Chem. 35 (2014) 776] yield peculiar cavity distribution and W = const*R^1. And this is for the large cavities (R = 3-6 A). Small cavities, in fact, seem OK (they follow the Poisson distribution and W ~ R^3).
The more I think, the more I don’t see a good reason. A first hypothesis: there is a problem with the simulation. Any other suggestions? Any ideas for experimental data to confirm/reject W = const*R^1 (e.g., hydrophobic effects/solubility data/...)? Any physical explanations/physical reasons to reject it?
Not to give the answer but rather to suggest for the possible discussion: usually, solvation thermodynamic functions for a series of related compounds (but not only) in a given solvent are linear to the electronic polarizability/molecular volume ~r3 of a solute. It might be useful to look at the solvation free energies of isomers characterized by similar molecular volumes (and polarizabilities) but strongly differing in the shape, e.g., neopentane and n-pentane, hexamethylbenzene vs. hexylbenzene, or pyrene vs. tetracene (and I would vote for playing with :rigid: molecules such as pyrene and tetracene, rather than with flexible alkanes) - the differences in simulating the thermodynamic contributions to the solvation functions as well as the experimental solvation thermodynamic functions might become elucidative.
I think low pH means high degree of ionization. However frankly speaking, I want to know about the relationship between "degree of ionization" and "solubility".
There are two types of chemicals such as SnSO4, NiSO4. I dissolve two chemicals in water at same molar concentration(0.01 M). Then I could get data about the pH of two types of solutions. What I could see is that NiSO4 looks more soluble in water (SnSO4 doesn't look soluble in water perfectly), but the pH of NiSO4 solution (pH5) is much higher than SnSO4 solution(pH2.5).
Therefore I could conclude that the relationship between the degree of ionization and solubility is not valid. I couldn't accept and understand this result.
Can anybody explain the relationship between those?
As Fadhil states, you cannot make a direct correlation between degree of ionization of a material and its solubility. Organic fluids can be non-polar, yet excellent solvents. Ionization occurs best in aqueous solutions, yet they are only solvents for other hydrophilic materials. Best of luck...
I'm dealing with peptides which are on one hand polar (much lysine content) and on the other they have a fatty acid acylation. This causes problems regarding the attachment of these peptides on various surfaces. Has anyone had experiences with such peptides and what could help to avoid these unwanted sticking effects?
I already tried glassware which does not work at all. I tried low affinity binding materials, which is useful, however there is still a lot of loss. Are there any suitable buffer/solvent mixtures which can further prevent the adsorption?
Is it possible that a particular compound extracted from a biological material is soluble only in EtOAc when the other solvents with which it was extracted include DCM, Hexane, Methanol and Ether?
I find this compound shows up along with the EtOAc peak in a Gas Chomatogram run with a program which had an initial temperature >30ºC. Also, it takes a minimum 4hrs for this compound to appear in the solvent when the extracts at different times were subjected for GC, and the quantity increases with increases in the time of extraction (total time the particular substance was kept in solvent for extraction). Is it any decomposition product? Anyone to suggest how I can isolate only that compound from the mixture present in the extraction?
Please note: I am not a chemist and hence anything which I conveyed here is not clear, please feel free to ask your questions.
The low boiling point suggest that it is a small molecule. Indeed, MS analysis will help. You should consider as well that after long time boiling EtOAc you might have it partially hydrolyzed so you generate acetic acid which has a BP of 118 degrees Celsius. This could be your extra peak in the chromatogram. Indeed, degradation products are also a possibility.
Dynamic Light Scattering does only look at the fluctuations in the scattered light intensity. To determine to molar mass using light scattering you need at least a way to measure the absolute scattered intensity on a calibrated scale and the refractive index increment of your polymer in THF. See http://en.wikipedia.org/wiki/Molecular_mass#Static_light_scattering
I would start with a DLS analysis to see if your polymer does not give a broad distribution of relaxation times. If you have a (very) polydisperse sample your efforts may be wasted.
That would be difficult, for if the P is soluble in water, then it will be free to precipitate with dissolved Ca. I suppose that you could complex the P with Al or Fe to create a solution complex, short of precipitation, but that new P species will not react the same as phosphate would. Even an organic form of P such as phytate will react with soluble Ca to form a Ca-phytate.
However, something that will reduce the potential of dissolved phosphate to precipitate with dissolved Ca is adjustment of solution pH to 5 or below. Also, you could add a high concentration of fluoride, and to a less effective degree, sulfate, to complex the Ca and prevent it from being able to react with phosphate in solution. In this sense, F and Sulfate would serve as a "sacrificial" ligand to bind with Ca in solution.
To determine enzyme activities from raw human cell lysates I have to use "cremophor" (or kolliphor) according to a protocol. As I found out it is "just" at detergent. We have a lot of these in our lab but no "cremophor".
Though my questions are:
- What is the benefit of using cremophor instead for example Nonidet P40
- Are there any alternatives for cremophor?
- Is it known to inhibit soluble enzymes?
Would be great if some has experience with this detergent.
Melanin polymerization occurs through auto-polymerization of aromatic rings to form the big polymer. How do this occurs without any enzyme help? Is this polymerization contribute to its solubility? Is the aromatic ring incorporation occurs randomly in melanin structure?
Once tyrosinase catalyzes the oxidation of o-diphenols to o-quinones, the polymerization can occur and occurs spontaneously. Nevertheless, there are some enzymes involved, as the same tyrosinase or the TRPs (tyrosinase related proteins 1 and 2). See a review for details.
What is the actual assay concentration of your test compounds?
Usually, concentrations of 10µM (sometimes up to 100µM) are used for initial testing. In my opinion, any compound that cannot be dissolved at 10µM in cell culture media containing 2% DMSO does not deserve further research in drug discovery.
My answer is a general one due to the limited information given in the question.
Since the reaction is carried out in polar protic solvent (possibilities are water, alcohol, and even acetic acid… all of which are characterized by having high dielectric constants and high dipole moments), then the norm is to add to the mixture a "borderline" polar aprotic solvent (such as tetrahydrofuran, dichloromethane, ethyl acetate...all of which have moderately higher dielectric constants than the nonpolar solvents but less than the above category).
I am sure that triethylammonium bromide is insoluble in, e.g. THF, so it will come out as a white precipitate. After insuring that the product did not precipitate as well, work is done on the liquid phase to get the product from the mixture of solvents& I guess it is easy.
Henry's law is applied to predict solubility of gases in liquids. In the case of saline systems, Henry's constant is supposed to be different at different levels of salinity. I am seeking for correlation(s) or model(s) which predict Henry's constant as a function of Pressure, Temperature, and salinity, especially for Highly Saline systems
The difference in the yield may occur due to sun drying. The active constituent may have degraded due to sun drying. Also due to drying the darkening of the leaves takes place, which may be due to oxidation of pigments or polymerization of certain polyphenols. The extraction of those color pigments and polymers after drying may get enhanced compared to the active constituent. The fresh leaves have certain moisture content in it which may help the active constituent get extracted easily.
Thank you for helping me. What I want to do, is use 10 ml's of ethanol with 10mg's of pge2, but I am not sure if these preparation instructions will contradict or lessen the efficacy of the final solution. I have attached the instructions.
Can I use 10 ml's of ethanol to 10mg's of pge2? Or can I only use 1ml of ethanol to 10mg's of pge2?
Jul 23, 2014
what are you trying to do? a stock solution?
the solubility -as stated in the instructions- is 10 mg/ml meaning that you can dissolve up to 10 mgs of PGE2 in 1 ml ethanol.
Having worked with this compound before, the solubility is terrible. DMSO works OK, and can be added to help it dissolve in other solvents, but it still might not dissolve without a good amount of heat. Generally the solubility wasn't too important, I have run copper catalysed reactions using PhI=NTs in acetonitrile and the reagent dissolves as it is consumed.
Could any one suggest me what is the easiest way to dissolve PEO in water. I tried to dissolve PEO (100,000 gm/mole) in water for long hours but didn't work out very well. I want to try with other solvent which can quickly dissolve it. Please suggest the appropriate solvent and polymer ratio, temperature range and quicker ways to dissolve. I will prefer to dissolve in water. Thanks in advance.
Theoretically speaking, your PEO has a high molecular weight but it must be solublein water. However, PEO forms viscous, chewy solutions in water at concentrations less than 1 wt %. Solutions of higher concentrations are elastic gels. At 20 wt % solids, the solutions are hard & tough water-plasticized polymers. Near the boilingpoint of water, the water solubility decreases, phase separation can occur, and the solution can become cloudy.
My advice is to use a mixture of solvents instead of a single solvent. Try to dissolve PEO in the combination water/ethanol or water/methanol at a temperature which is not low & not high. I suggest warm solvent mixture, say at 40- 50 oC . Try first 0.1g polymer in 10 ml. solvent mixture in stoppered test tube overnight. If you see, a clear solution in the next day then it is fine. If not, change the concentration up or down but not far from (0.1 in 10). Best wishes for success.
If no one has exact data, you might easily test with a specific chemical titrimetric method, e.g. with a "zero grade" nitrogen purge of your O2 saturated sample (to maximize your signal) into pyrogallol (Orsat apparatus) solution (turns brown). Of course, appropriate blanks, saturation-method-testing-samples (i.e., did you saturate to a constant level => fully saturated) + standards (a slug of air into the supply) would need to be run, also.
Does anyone have knowledge on the solubility of potassium salt of 3-hydroxy glutaronitrile in aprotic organic solvent?
Jul 6, 2014
Could anybody please guide me about solubility of the attached compound in an aprotic organic solvent such as THF, Acetone, Ethyl acetate, Diethyl ether, Hexane, and etc?
Thank you in advance.
Alginate, polyacrylamide, poly(acrylic acid), poly(methacrylic acid), starch, etc. polymers are soluble in water. However, their solubility also depends on molecular weight of polymer and other structural factors. Hence as Dr. Nizar Matar said you need to taste and then finalize. It is special case for starch-out of two-only one kind of starch structure show solubility.
I'm not sure if this is what you want, but there is an article which mentions briefly about the solubility of Cr2Se3.
"The solubility of Se in (Cr) was not determined, but it is suggested that it is very small, similar to that of S in (Cr). Based on their measurements of the partial pressure of Se corresponding to the equilibrium between Cr2Se3(II) and Se (liquid), [80Zhe] concluded that the solubility of Cr in liquid Se is small."
Hi there! I want to dissolve curcumin in vegetable oil and make an emulsion but I am getting sedimentation at the bottom. How can I get rid of the sedimentation and dissolve curcumin completely? Should I dissolve curcumin in some other solvent and then in oil? I want to make a food grade emulsion.
Yes, I know. But the results for thermodynamic properties are usually tabulated at standard conditions of pressure or as a function of pressure. Regarding your question, I think that the procedure that you propose is correct, and it should work.
Solvation can be treated in exactly the same way as a chemical reaction.
When you say “Free energy of solvation” you have to also specify the thermodynamic states of the reactants and products. The specification has to be rather detailed. I will assume the temperature is constant and at a specified value. If the starting point is a gas then you have to specify the pressure or something with equivalent information, such as the number density. The same goes for the material in solution. You have to specify the concentration or some other equivalent information.
Anyway, there is a direct and rigorous relationship between the Gibbs free energy of a process and the equilibrium constant. You can find the equation in many places, such as most any book on chemical thermodynamics. Here is one link to the equation.
You will see in that equation a quantity delta G with a superscript of zero. That quantity is the Gibbs free energy of the reaction when all the reactants and products are in their "standard states." This means that you will have to learn the meaning of “standard states”, something that can sometimes be surprisingly subtle and tricky. Even chemists, who are the ones who should be experts on this topic, sometimes get confused. You will also have to learn the concept of “activity” as the term is used in chemical thermodynamics.
Anyway, in the case of solubility you are usually talking about a solid in equilibrium with a saturated solution. The activity of the solid has a value of 1. (It is 1 by definition.) The activity of the solute is related to the concentration. If the concentration of the solute is very low and the solute is otherwise pure then the activity can normally be set equal to the concentration. If the concentration of the solute is high then the solution becomes “non-ideal” and one has to deal with some quantities known as activity coefficients.
If you are interested in the solubility of a solid, and the information on free energy that is available to you is for a gas-phase starting point then you will need some additional information, namely the free energy of vaporization.
You can work out the correct expressions by considering thermodynamic cycles for chemical reactions. I won’t try to write them here, but hopefully this is enough to get you started.
Your best source of information to deal with this in more depth would be in textbooks, either chemical thermodynamics (e.g. authored by Klotz or Lewis and Randall, or other texts) or physical chemistry. The chemical thermodynamicists and physical chemists have worked this out in excruciatingly rigorous detail.
As lyophilization involved removal of water (or volatile liquid) from a product, a solution with solely its water content removed should be able to reconstitute back into desirable concentration.
Recently I have synthesized an organic compound (no salt) with pH7.4. The lyophilized compound does NOT soluble in either water nor oils (the temperatures are set to 95 degree C). What could possibly be the reason?
Hello sir, this may be attributed to the change in solubility profile of the organic compound on lyophilisation. This indicates the highly sensitive nature of the organic compound to a critical processing step like lyophilisation. Sir, you can try its solubility in organic solvents. Furthermore the changes in the compound structural features can be studied. One of the most obvious reason seems to be the sensitivity of the organic compound to freezing or any or all(in synergism) steps involved in lyophilisation.
Activation Energy is a number that indicates how temperature affects the rate of ionization of defect states in semiconductors. Different defect states have different activation energies. Thus, it is possible consider that activation energy is characteristic of the intrinsic and extrinsic defects in semiconductors.
I am working on a project where some biological material is extracted in acetonitrile, but we do not see DA or 5-HT in the GC/MS after derivitization. It could be a failure of the reaction or perhaps it is just insoluble in acetonitrile.
I prepared dicyanide anion based ionic liquids from an iodine anion containing salt, Whatever happened due to some percentage of iodine in the ionic liquid, gave a dark brown color. Please tell me how to avoid this
So far, I have managed to make solutions of up to 50 mg/ml of muconic acid in 80% ethanol and 20% water. I want to lower the % of ethanol and increase the amount of muconic acid in solution. Heating the solution is not an option as my cultures are not being heated above 30°C. Any suggestions?
Apr 13, 2013
You have to specify which muconic acid you want to dissolve. Their solubilities in H2O are: cis-trans >> cis-cis > trans-trans. Heating an aqueous cis-cis solution will cause it to isomerize to cis-trans, followed by degradation to levulinic acid, but never to trans-trans. See these 3 literature sources:
See the CRC Handbook of Chemistry and Physics (http://www.hbcpnetbase.com/). Here, you can find, e.g., the solubilities of benzoic acid in water at 10, 25, 50°C (2.09, 3.44, 8.49 g/kg). (see also J. Chem. Thermodynamics 38 (2006) 565 and/or J. Phys. Chem. 34 (1930) 1484 for a wider T range)
I need to prepare a 10M stock and as specified in the data sheet it's readily soluble in Dimethyl formamide (DMF) but DMF itself is toxic to my cells. I tried disolving it in DMSO but no luck. What should I do?
May 21, 2019
For autophagy study, you could try mRFP-GFP-LC3 and GFP-LC3 labeling system, which can detect the intensity of autophagy flux in real-time, in which GFP and/or RFP tags are fused at the N-termini of the autophagosome marker LC3. These biosensors provide an enhanced dissection of the maturation of the autophagosome to the autolysosome, which capitalizes on the pH difference between the acidic autolysosome and the neutral autophagosome. The acid-sensitive GFP will be degraded in autolysosome whereas the acid-insensitive RFP will not. Therefore, the change from autophagosome to autolysosome can be visualized by imaging the specific loss of the GFP fluorescence, leaving only red fluorescence.
Attached file is an image of mRFP-GFP-LC3 labeled A549 cells with nutrition deprivation.
Genemedi provides the production service of AAV, adenovirus and lentivirus encoding mRFP-GFP-LC3 or GFP-LC3, suitable for monitoring the intensity of autophagy flux in real-time in vivo or in vitro. You could find more on this website: www.genemedi.net/i/autophagy
In an undergraduate organic experiment, we are required to identify the functional group present via solubility tests (with H2O, HCl, NaOH and NaHCO3) and Classification Tests (Brady's, Tollen's, Iodoform, FeCl3, Aqueous Bromine, Lucas and Chromic Acid Test).
The unknown is found to be insoluble in all the solvent used in the solubility test. The results from the classification test have also shown that the unknown contains ketone. The IR spectra contains a strong peak at ~1700cm-1 which indicates the presence of a carbonyl (C=O) bond. *IR attached* The preliminary boiling point for the liquid unknown is ~ 212 degree Celsius.
Since it is most probably a ketone, I proceeded with the second part of the experiment (Crystalline derivatives for identification). Other lab mates whose unknowns have been suspected to have ketone/aldehyde managed to form semicarbazone in minutes/seconds. I am rather worried as my liquid unknown took a very long time (hours) to form semicarbazone. Could it be that the unknown has been falsely analysed?
Hi! I think that you should not be much worried…if you get a solid you may now be able to compare the melting point…
Also, yours colleagues time reaction may not be compared with your time reaction. Different ketones will have different reaction times… also that if your mates’ compound may be an aldehyde (also with a C=O) this class of compounds are much more reactive (faster) than ketones…
By the boiling point you provide your ketone must have a higher molecular weight, i.e., around the C=O may have bulky groups and although the C=O is planar (sp2) bulky groups around would slower the reaction rate. (with the boiling point you provide may be you ketone belongs to the “carvone” family…
We're trying to recycle an imidazolium-based ionic liquid after measurements of it's liquid phase behaviour in octanol. As expected, octanol is not easy to evaporate, so we've tried to add ethylacetate to lower its vapor pressure, but to no avail. We've also tried running the mixture over a silica column, but it didn't help much either. Any other ideas would be greatly appreciated.
I am not really quite sure but at this state the addition of hexane or petroleum ether will be good solvent to octanol due to its hydrophobicity then it may be separated as two layers one for octanol-hyrophobic solvent and the other for IL.
Increased temperature usually increases the solubility of solids in liquids. To understand why, we need to return to the Second Law of Thermodynamics. Increased temperature means a greater average velocity for the particles. This allows them to move from one position to another more easily. The greater freedom of movement allows the system to change its state more easily, and in keeping with the Second Law, it changes to the most probable state available, that is, the most dispersed state of which it is capable. Solids are condensed systems, so the dissolving of a solid usually leads to increased dispersal of the system. Therefore, although there are exceptions, an increase in temperature generally leads to an increase in a solid’s solubility. You can find more detials on this link:
I am unable to get a homogeneous solution after adding Doxyxycline to water. Can anyone tell me what is the best possible way to dissolve doxycycline in water?
Jul 6, 2013
I am going to try the ultrasonic first using water as solvent because i want to use the product for antibacterial assays so if i use alcohol then i won't be able to predict whether the activity is from alcohol or drug
I work on solubility of sugar alcohols in ionic liquids. I would like to compare my results with some reference data for water. I am looking for temperature-dependent data, mostly solid-liquid equilibrium phase diagrams. Does anyone know of paper(s), where I could find this data?
Solubility of xylitol in ethanol, acetone, N,N-dimethylformamide, 1-butanol, 1-pentanol, toluene, 2-propanol, and water
Wang, S., Li, Q.-S., Li, Z., Su, M.-G.
2007 Journal of Chemical and Engineering Data 52 (1) , pp. 186-188
Measurement and correlation of solubility of xylitol in binary ethanol + acetone solvent mixtures with the combined nearly ideal binary solvent/ redlich - kister equation
Wang, S., Li, Q.-S., Su, M.-G.
2007 Journal of Chemical and Engineering Data 52 (5) , pp. 1733-1735
Estudio de la solubilidad: De la xilosa, glucosa y xilitol (Solubility study of xylose, glucose and xylitol)
Acosta Martínez, E., Canilha, L., Alves, L.A., Almeida E Silva, J.B., Giulietti, M.
2009 Ingenieria Quimica (Spain) 41 (470) , pp. 96-99
Solubility of bio-sourced feedstocks in 'green' solvents
Payne, S.M., Kerton, F.M.
2010 Green Chemistry 12 (9) , pp. 1648-1653
Measurement and correlation of solubility of xylitol in binary water+ethanol solvent mixtures between 278.00 K and 323.00K
Wang, Z., Wang, Q., Liu, X., Fang, W., Li, Y., Xiao, H.
2013Korean Journal of Chemical Engineering, 30 (4) , pp. 931-936
How to dissolve Diazepam?
Feb 1, 2013
I am trying hard to dissolve Diazepam (Sigma).I am trying to dissolve in a range of 10-20mM. I am able to dissolve in 100% DMSO but at the moment whenI add a little amount of water the Diazepam starts precipitating.
it depends on the co-solvents which you want to use. there is a way for predicting the effect of a solvent on the solubility enhancement and it is to compare the Hildebrand solubility parameters of the solute and the solvent. the more similarity in the value of this parameter results in more solubility increasing. for more detail you can see these two articles: J. Phys. Chem. C, 112, 3519–3524; Koleske, J. V. (1995). Paint and coating testing manual : fourteenth edition of the Gardner-Sward handbook, Chapter 35, ASTM, Philadelphia, PA.
Are those lipid compounds are drug molecule? Please clarify the objective of that study. Because, if those are for drug delivery, then there are several approaches, and most common is Solid dispersion.
I am working on the isolation and identification of flavonoids. I have different fractions of ethyl acetate extract of a plant. I got those fractions after doing chromatography on silica gel. The second fraction is a yellowish powder. It is to some extent soluble in methanol but it is more soluble in chloroform and ethyl acetate. It is not 100% soluble in either of the above solvents. I took the dissolved portion of the extract in ethylacetate, and did tlc on silica gel (chloroform and ethyl acetate (9:1) as solvent system). It showed three spots. I am now in a dilemma about how to proceed for isolation. If I do silica then I need to apply the sample in dry form as the sample is not 100% soluble in the solvents I do have. Could anybody suggest a better alternative for the isolation?
The amount of solute (powder) would be added to water at a concentration of about 0.5 mg/mL
Dec 28, 2012
Dear colleague: here is the method previously mentioned:
"Solubility was determined according to the Eastman and Moore method (1984), with some modifications. To 100 ml of distilled H2O, 1g of powder were added by mixing at high velocity in a mixer for 5 min. The solution was placed a tube and centrifuged at 30.000 x g during 5 min. An aliquot of 25 ml of the supernatant was placed in previously weighed Petri dishes and immediately oven-dried at 105 ºC, for 5 h. Solubility (%) was calculated by weight difference."
I am working with compounds similar to dehydrosilychristin (silybin, dehydrosilybin, etc.), but each of these compounds are insoluble in water (I'm using DMSO). Dehydrosilychristin should be soluble in water, however. I have 50 mg of dehydrosilychristin and I want to determine the solubility with the smallest amount of this compound as possible. Which methods do you suggest? Perhaps filtration of the oversaturated solution and the evaporation of the saturated solution?
That will be a real challege with only 50 mg. With that said, and assuming you have a reasonbly pure compound perhaps you can prepare a super saturated solution by dissolving a measured amount in hot deionized distilled water (use sonication if necessary). Then let the solution cool slowly overnight in a controlled temperature heating block to a predeterimined temperature (ie 20C) and look for a precipitate. If no precipitate you will have to warm it up again and evaporate off some of the water using a fine stream of nitrogen and repeat. Once you can see a precipitate or crystals form note the temp (and volume) and take an aliquot of the saturated solution and compare it with a known concentration of the compound dissolved in methanol or some other proven solvent using appropriate predetermined HPLC conditions. Some careful dilutions may be needed to get the peak areas in the same range but theortetically you should be able to closely approximate the solubility of the compound in water.
I'm trying to identify streptomycetes able to solubilize phosphate. I tried Pikovskaya medium, NBRI-BPB (using bromophenol blue) both in liquid and plate, but they are very difficult to evaluate. Is there any easy test?
Sep 19, 2014
You should remember these points:
1- If you observe clarification zones on agar containing sparingly soluble phosphates source, you have to verify that this phenotype is stable or not , many strains do not possess the genes to produce PQQ. So recultivate many times.
One of my grad student used a double layer plates to enhance clarification zones, first 15 ml of agar without insoluble phosphate, and whan it solidify she added 10 ml of medium with phosphate, it worked well for her.
2- You must confirm the phenotype in liquid medium. How do you measure soluble phosphorus in your supernatant? Are you making a standard curve with soluble P?
3- If you are cultivating your microorganisms with poorly soluble P source and you have good growth, don't expect to see a lot of soluble P because it is immobilized (used rapidly for growth.
This is not a common practice and will make it difficult if not impossible to meet product specifications. But if you really want to know I suggest mixing the two together in a process simulation program such as Aspen Hysys.
I tried many buffers in achieving my protein in soluble fraction, fortunately I am successful at pH1. Moreover, I have not used any buffer for pH1: its just milliq adjusted to pH1 using conc HCL. My question is: will I be able to do further studies on this protein with affecting its solubility? Now, it is in the state of impure fraction. My proteins pI is 5.78. So, which purification method is suggested?
The HCl could serve as an "buffer" you equilibrate Superdex column, thus size-exclusion in this weird situation is the first hit I'm finding. Did it many times with HCl, seems to work for proteins like low pH. Anyway I'm afraid your protein could be slightly aggregated, just make sure before loading on the column you spin it down at highest G possible.
Aflatoxin B1 is soluble in organic solvent like Chloroform, Benzene, Methanol, Acetonitrile etc. But after time it may loose quantity. Also temperature and light are degrading aflatoxin B1. Stability depends upon exposure time of light.
I agree with the previous answer, light significantly affects aflatoxin stability in solution. According to my experience methanol is a good solvent and aflatoxins (B1, B2, G1 and G2) are stable for months if you dissolve them in methanol and keep in an amber vial at -20°C or, at least at 4°C. If you dissolve aflatoxins in a methanol: water mixture 50:50 v/v, the stability is significantly affected (no more than 1 month even at 4°C).
It will be helpful if you can clarify a few things.
First, are you interested in the equilibirium concentration of the solute or the rate of dissolution?
Second, are you dealing with high concentrations or low concentrations?
Third, are you dealing with volatile solvents or non-volatile solvents?
Fourth, what temperature range are you dealing with?
Fifth, are there any special materials considerations? For example, are the solutes or solvents corrosive or have other properties that require special considerations?
Sixth, when you say "ionic liquids" are you referring to something such as a molten salt, or perhaps a weak organic acid that is only weakly ionized in pure form, or some other type of material that one might call an "ionic liquid"?
I think if you can clarify questions such as these it will help others formulate good answers.
The experimental determination of HSP for polymers is performed using a set of solvents of known HSPs. Can a similar procedure be used for the estimation of HSP for a particular liquid mixture? Classical methods involve the use of thermodynamics and/or group contribution methods, but for multicomponent liquid mixtures these methods could be difficult or inaccurate, and a direct experimental determination would be desirable. Preliminary tests to validate this idea were done using a pure liquid of known HSP, mixing it with a standard set of solvents and calculating its HSP using the HSPiP software. However the accuracy of the results was not good enough. Any suggestion? Thanks.
I have unfolllow this subtopic, because believe that it is unequal replacement of full and direct set of data (real solubility) on indirect (calculated and approximated) set of derivatives. Some exclusions from HSPiP was corrected recently, but cited by Wiki example with poly(vinylfluoride), polymer shape dependence and your example lead to grievous resume - solubility parameters and HSPiP are templet for house painters. But not scientific instrument with predictive power.
In your case I think situation may be caused by (strong) interaction between different solvents molecules. If the interaction between the solvent is weakly dependent on their molar ratio, the parameters can be obtained. Probably) Be sure, you are not alone with such problem - I've seen similar problems question on RG from other people.
We found an efficient method to extract pigments from plants. Just after the filtration, when the pigments were still wet, we use them and paint with a brush. But after are dried and milled, its no longer possible to dissolve them again in water or other solvent (MeOH, EtOH, CH2Cl2, hexan), we obtain only aggregates. Does anyone know how we dissolve them again in water with arabic gum ? Thank you in advance.
To use madder dried extracts, I've put them in water again and leave them to ferment for a few days with a little vinegar to start it.
After that, I let it settle, get the water out, filter, and let it dry again.
Il will then be usable for different purposes.
What is the best vehicle for intravenous injection of highly water insoluble drug?
Dec 4, 2013
I am concerned about the most suitable vehicle to be used for i.v injection of highly water insoluble drug for pharmacokinetics. I have read about cremophor, DMSO been used but have resulted in too much toxicity. I am planning to use HP-beta -cyclodextrin. Will it be a good choice? Also will corn oil be used for oral delivery of same drug?
I have seen a couple of studies using propyleneglycol, but more than 0.5 mL/kg can cause hematuria and you first plasma samples will present hemolysis, therefore, your bioanalytical method has to be no problem with sample like these. About PEG I used it just in mixture with DMSO, but I think it can cause PPG similar problems. Another point you have to see is about CYP inhibition for some of these solvents. the paper Buggins 2007, "The effects of pharmaceutical excipients on drug disposition" could be a good reading.
So are your compounds already dissolved but are stored frozen? If so then sonicating probably won't help. If you are dissolving compounds it will help break the particles up but you'll have a concentration gradient (high at the bottom). I see you're from Evotec, we've been using 384-well cell carrier plates in our OPERA to screen yeast libraries and mixing on the shaker works well, but then we have only a 30 - 50 uL volume. Is your volume close to the maximum for the plates? If so it might be possible to seal the plate with aluminium foil (or something similar), shake very, very hard then spin the solution to the bottom of the plate in a centrifuge with appropriate "buckets".
Dear, Ravi Reddy, The apparent solubility increases with decreasing particle, however this solution may not be thermodynamically stable. The best way to determine the solubility is by the method of agitation from jar, takes approximately 10 mL of solvent, add asufficient solute to form two phases (liquid-saturated phases and solid-solid phase undissolved) you should let it equlibrio (about 3 days)- the thermodynamic stability-then determines the solubility for some analytical methodology. To increase the solubility, I recommend using cosolvents.
What do you mean "a very small amount" ?...100 mg, 10 mg or 1 mg? I would like to recommend you a book "Mircoscale Organic Laboratory" D.W.Mayo, R.M.Pike, D.C.Forbes, Wiley, 2011. You will find there a lot of techniques dealing with a small quantities of materials. I usually perform such tests in small vials ( 5mm width-5cm lenght). After test I evaporate solvent (sand bath or hair dryer) and do next test with another solvent.
Can someone advise on antimicrobial susceptibility testing using lipophilic substance?
Oct 23, 2013
I would like to do microdilution assay with liphophilic substances, I could not dissolve in any solvent system like DMSO. I am new to the topic and wonder if there is any method fort testing these substances? I thought about emulsions using gum arabic or Tween-80. Are these valid/accepted methods used in antimicrobial susceptibility testing?
Chemical compounds, which include ester-, azomethine-, (amide) bonds, silyl groups and ketals/acetals (strong acid medium) can be decomposed in (concentrated) acids (low pH) or bases (high pH). Isocyanates are sensitive toward a lot of nucleophiles including alcohols, amines and water.
The question doesn't contain enough details for the exact answer. I had an experience with substituted N-methylpiperazines which formed a N-methylpiperazine borane complex after reduction of the other part of the molecule with sodium borohydride. Some trialkylamine boranes are extremely stable to acidic hydrolysis, even with 1 M HCl (see R. O. Hutchins et al. Organic Preparations and Procedures Int. 1984, 16(5), pp. 335-372). The problem was solved by using water formaldehyde solution which reacted with the amine borane complex to form methanol.
In terms of lipids in fingermark residue. Why are some of the sebaceous gland originating lipids soluble in acetone and petroleum ether but not (or to a much lesser extent) in methanol or HFE7100? There are no conclusions that can be based on dielectric constant, solvent polarity, solvent BP, aprotic/protic.
There are many factors that are responsible for solubility of lipids in a particular solvent. And it occurs very frequently that a particular lipid from specified source is soluble in one solvent and not soluble in other solvent.
Many different solvents will dissolve pure single lipid classes, but they are only suitable for extracting lipids from tissues if they can overcome the strong forces of association between tissue lipids and other cellular constituents, such as proteins and polysaccharides.
The behaviour of a given solvent as a lipid extractant for a specific tissue cannot always be predicted. In order to release all lipids from their association with cell membranes or with lipoproteins, the ideal solvent or solvent mixture must be fairly polar. Yet, it must not be so polar that it reacts chemically with the lipids nor that triacylglycerols and other non-polar simple lipids do not dissolve and are left adhering to the tissues. If chosen carefully, the extracting solvent may have a function in preventing any enzymatic hydrolysis, but vice versa it should not stimulate any side reactions.
The two main structural features of lipids controlling their solubility in organic solvents are the hydrophobic hydrocarbon chains of the fatty acid or other aliphatic moieties and any polar functional groups, such as phosphate or sugar residues, which are markedly hydrophilic.
I have had problems dissolving quinidine for blocking SLICK channels in whole-cell patch-clamp experiments. It is possible to dissolve quinidine in DMSO (16 mg/200 µl DMSO) – the solution is clear. But if I prepare the final bath solution by dilution of the stock of quinidine-DMSO in a physiological solution, it drops out (white). The same happens if I dilute quinidine first in ethanol. Would be nice if someone has experience with quinidine.
I have no experience with quinidine, but clearly the problem is the polarity of the medium ... (precipitated in polar solvents), however the polarity of DMSO (26.6 (J^1/2.cm^-3/2)) is similar to ethanol (29.3(J^1/2.cm^-3/2)), and very different from that of water (47.9(J^1/2.cm^-3/2)). possibly dissolves better in:1,2-propanediol (25.8(J^1/2.cm^-3/2)), On the other hand at physiological pH, the nitrogen of the azabicyclo group, this protonated therefore presents presipitacion possibly by ionic strength of the physiological solution.solution.http://www.drugbank.ca/drugs/APRD00136
I have found different sources giving 10 differences in solubility parameters. So, I am wondering if anyone can suggest the exact trustable value for PVDF HSP. I also would appreciate it if somebody share a law according to which HSP vary with temperature.
I did ligation of a gene in pET28a vector and after transformation I got 10 colonies, I did colony PCR after growing 7 colonies and gene amplification was observed in 4 colonies, but after isolating the plasmid and doing soluble digestion gene did not pop out from the plasmid. Can somebody please suggest me what can be the reason for this?
As you said that after transformation you got only 10 colonies and after restriction digestion no insert was observed which means that you got false positives in transformation which might happen due to several reasons. And, colony PCR also sometimes gives false positives. So, what I can see that your ligation did not work.
You will need to troubleshoot your experiment step by step. Ligate your PCR product in vector and run on the gel before proceeding for transformation to see if there is any ligation or not? Also, the size of the PCR product matters. If your PCR product is greater than 1 kb than you will need to increase your insert and vector ratio to may be 3:1 and ligation time also..Only after troubleshooting closely step by step you will know what is causing hindrance in your experiment.
In the Dortmund Data Bank (www.ddbst.de) more than 160 data points (solubilities) for salts in acetonitrile are stored. More than 1000 data points are available for ternary systems such as acetonitrile + water + salt.