Science topics: MethodologyLaboratory Techniques and ProceduresFiltration
Filtration - Science method
A process of separating particulate matter from a fluid, such as air or a liquid, by passing the fluid carrier through a medium that will not pass the particulates.
Questions related to Filtration
I prepare a chitosan solution in acetic acid (0.5 M). Some of the small threads are remained in the solution. In literature it is reported that solution is filtered before using. I want to know which filter is suitable for the filtration of chitosan solution?
using KOH (10%) and incubation for 48 Hrs. was not enough because the slime of the snails was not degrade and it was effect the filtration process ...Shall i increase the concentration ? or better to have alternatives let us say Nitric Acid ?
please let me know your ideas ..
My CNF membrane cannot be transferred well after suction filtration. It will stick together after drying on the filter paper and make the filter paper brittle. What is the reason for this phenomenon?
I'm concentrating my AAV preparation using Amicon Ultra 100KDa and I observed that sometimes I need really long time to concentrate.
The point is that I have the longest centrifugation times when I start from a low concentration.
How is this possible? Is it correct or I am doing something wrong?
Thanks for all the answer!
My FBS upon thawing was full of aggregates and posing the great hindrance in imaging of my cells. I centrifuged it and use it but it did not work. when i filter it with 0.2 micron filter it works. Is it right to use a smaller size filter or any other pore size can also be used.
I'm in the process of setting our lab up for lipids analysis and I would love to hear some of your insights on filtration methods.
My background is in DNA/RNA, so I've been using columns and centrifugation, but I keep seeing people using vacuum manifolds when working on lipids. It's a very similar process, using silica-based filter columns to separate cell components, but somehow it seems both sides use their own method.
Now, my understanding is that we simply need to make our liquid sample pass through the filter, I can't see how it would make a difference whether it's pushed through by centrifugation or pulled through by a vacuum. The difference might simply be a custom in the different fields, but am I missing something?
PS.: This community's Q and A section has been a huge help during my studies (still is), I thank you all for your contributions here and with others!
Yes, I am looking for low-cost ways. Some ideas are- centrifugation, flocculation-straining, and filtration. But which one of these will have the lowest cost?
I'm currently working on the synthesis of mixed ligands metal complexes. One of the ligands is a carboxylic acid. Is it possible to get colourless filtrate for the metal complexes?
Does anyone know what type of bacteria/fungi? it could be?
These were in my filtrate after filtration of the culture through an 80um mesh size filter cloth. The "brush" form orientation was quite common all over the slide.
am trying to purify a human DNA binding protein (normally localized in nucleus and mitochondria). I am currently optimizing the conditions I tried 2 different approaches:
1. HisTrap-> TEV --> HisTrap--> Gel filtration.
2. HisTrap --> TEV--> HiTrap --> Gel filtration
The expression was performed in BL21 (DE3) E.coli, 2YT media at OD600 = 0.8 induction was performed with either 0.5 or 0.1 mM IPTG at 16oC for 12 Hrs.
In all the conditions my protein wasn't pure, after doing mass spectroscopy I figured out that the additional bands are from E.coli (the host).
Can you please suggest me how to get rid of the contaminants?
I have attached the gel for more information, the protein of interest is in red rectangle
I am using hemp fibers to make a CNF solution; how much should be the concentration to vacuum filter and get a transparent nanopaper?
I am working on Analytical 3D fabricated Honeycomb shape memory structure for grey waste water treatment. The flow simulation of this research will depend on the interaction between solid and water.
#simulation #dynamics #wastewater
Thank you very much for your time to look at my question!
On the IHSS (international humic substances society) website, filtration over a 0.2µm filter to remove the remaining mineral fraction/clays is suggested to be a replacement for the HF/HCl, but I could not really find anything about it in the literature.
Do you perhaps know any reference regarding using filtration to replace HF-HCl to remove clays when extracting humic acid from the soil?
Thank you very much in advance!
I want to separate the bacterial/fungal cells from the growth medium loaded with ointment/cream. Please, anyone, share the techniques to separate cells alone after treatment with drug
While doing filtration of solution routinely facing the filter choke issue.
The density of solution quite closer to water density.
The particles obtained in bulk are evaluated for ≥ 10 micron particles (No such observation).
Is there any other causes or is it linked with molecular weight of active?
Please suggest/comment your innovative ideas!!
I would like to consult you about the issue that I recently faced with that. I am planning to do 0.2 µm filtration of silica nanoparticles in water with a size of around 50 nm. I tried different filter types (cellulose, PTFE, PES, Nylon, hydrophilic, etc), but unfortunately, non of them worked out. Could you please recommend to me which filter type (material) I have to select to easily pass the sample through it without issue?
I have get this chromatogram in sephadex G25 column while purifying extracellular polysaccharide. I collected fractions 10 mL/ tube. I get both higher OD and activity (flocculation) at very first tube itself. After that the OD was gradually flatted but activity was little bit raised after some fractions.
Here my questions are:
1) whether the separation has taken place properly?
2) Why does the flocculation rate raise even though there polysaccharide content is absent?
3) what would be the molecular weight of EPS?
I am trying to wash reduced graphene oxide with water through centrifugation process at 10000 rpm for 10 min. However, a lot of rGO particles are also lost while removing supernatant, albeit rGO apparently seems to be separated from water at the end of centrifugation. Kindly suggest some suitable alternative except filtration (chances of product loss) and freeze drying (not available in my institute).
I am using (emulsification solvent diffusion) techniques to prepare polymer nanoparticle. according to the procedure, I have to use cross-flow filtration techniques using Minitan device (Millipore, USA-Bedford, MD), which is not available in my lab., my question is: is there any alternative method to eliminate the solvent? in the other word is it possible to use rotary evaporator for this reason?
How can I do filtration for RCT studies in Google Scholar for a systematic review?
I am considering using duckweed for research projects. Does anyone have any technical papers that explain culturing and maintaining duckweed that they have used and works?
I am imagining that I can grow it in a small aquarium with a light source. But what about aeration, nutrients, temperature, and filtration?
Is it mandatory to use RO + UV-treated double distilled water or MilliQ water? Or is it sufficient to use double-distilled water after autoclaving it?
I have collected exome data from a few literature articles. I got a thousand variants and would like to proceed in the next step which is variant filtration to determine the gene of interest. How does an automated variant filtration pipeline narrow down my gene of interest? Does anyone have an idea about this? I am new to bioinformatics tools.
My procedure which did not work was:
1. Cell lysis with 0.2% Triton X-100
2. Protein precipitation with TCA
3. SPE (I have tried without this step but results were the same)
4. Filtration through a 0.2 um membrane
5. HPLC analysis
I am trying to analyse the lysate for itaconic acid. The chromatogram did not have any major peaks exept one giant asimetrical peak (which can be triton x-100 judging by the size but not the uv absorbtion spectrum).
I am trying to find out which other cell lysis protocols do scientists use for HPLC? Thank you in advance!
I am looking for approaches to grab short peptides (5-10 mers) other than a 1000 or 3000 MWCO spin filter, do you have any suggestion?
We all are aware that metro water is contaminated due to its pipeline.so water from reverse osmosis filtration of metro water the health benefits of reverse osmosis filtration water and the content of its mineralisation.
Does anyone work with expression in S2 cells? How efficient is the transfection using Lipofectamine 2000? Everytime I try to transfect using CaCl2 I get a cloudy media, and it seems that the culture is infected with a small bacteria, even filtrating all reagents with a 0.1 filter.
Having known that in a real field scenario, shale is characterized by its average dispersive fracturing, how will you correlate the differences in filtration and inhibition properties with shale (clay content and size) and with drilling fluids
I tried to filter only water through a standard 25mm 0.2 um syringe filter. Of course, it's easy to do this manually with the syringe, but I have several litters to pass. So I connected a peristaltic pump. To my surprise, the pump was unable to push the water through the filter. This is a very powerful pump that develops high pressure. What's wrong with it? Are we providing more pressure with our hand and syringe than the pump?
Has anyone tried pump assisted filtration through 25mm / 0.2um filters successfully?
We need suggestions for a situation that has arisen in our laboratory. We are conducting catalytic photodegradation studies of Rhodamine-B. To monitor the degradation, we use conventional techniques (UV-visible spectroscopy). When we take aliquots at different irradiation times, we filter them to remove the catalyst, using 0.45 micron acrodisc filters, attached to a syringe. We have found that these filters retain the dye, so follow-up measurements by spectroscopy have meaningless fluctuations. We have used various types of filters (PTFE, nylon, cellulose, polyethersulfone) from different suppliers and pore sizes (even 0.2 microns), but the effect is repeated. We have tried other options, such vacuum filtration, or centrifugation, but these processes are not very efficient. I'd appreciate if anyone suggests any realistic alternatives.
We are doing gel filtration in our lab and encountering issues related to column length, we are not getting expected results from our process. We previously used a 24ml column with appropriate elution buffer but could not elute the desired protein fraction. We are having issues in deciding the bed volume. How do we decide column length or bed volume?
I used DMAP for the polymerization of L-Lactide. I want to completely remove DMAP from my product. I tried filtration, Soxhlet and precipitation (Diethyl ether) but none of them worked well. I only want to completely remove DMAP irrespective of percentage yield, if it is more than 30%.
I am a new researcher currently doing experiments on perovskite solar cells.
Since I haven't got much experience in this area, I confront some questions regarding the experimental techniques.
I read the experimental sections from papers, but they usually only summarize the steps.
My questions are
1. For ETL, I use SnO2 dispered nanoparticles.
What is the difference between using IPA+DI water and using DI water only for dilution?
Do I need to stir to get rid of particles, or just sonication is enough?
Is filtration required after sonication?
2. As for the perovskite layer, I normally use FAPbI3 with small amount of MAPbr3 added.
Do I need a higher temperature or room temperature when I stir the mixture? and why?
3. For HTL, do I need to stir the mixture of spiro and chlorobenzene before adding additives and again after adding additives?
4. Lastly, does the thickness of film depend on the amount of solution dropped? What I read was it mainly depends on the rotation speed and time.
These may seem stupid questions, but I still look forward to answers..
For Exosomes/Extracellular vesicles (EVs) labelling by PKH26 stain, and studying their cellular uptake.
Is there anyone who tried to mix conditioned medium with PKH26 to stain Exosomes/Extracellular vesicles (EVs) before isolation with targeted filtration?
I am using the kit "101 PureExo" for targeted filtration and isolation of EVs.
I have done hot filtration test for the catalyst to show leaching and I found no reaction after filtration. So, is it still necessary to perform ICP analysis of the catalyst??
Hello, I had purchased MS2 (freeze-dried) from ATCC: 15597-B1 (https://www.atcc.org/products/15597-b1). I revived the culture according to the method given in the product sheet. For propagation, I have used E. coli BL21 instead of the recommended strain. Also, the revival was done past the 30 day time period that was mentioned. I have separated the E.coli by centrifugation at 15000 rpm. Is it possible that the MS2 remained in the E. coli cell? Or is it that I stored the freeze-dried culture for too long before reviving it? Or is it because I have used the wrong strain of E. coli? I still have half o the free dried pellet but before using it I want to make sure that the method I am following is correct.
Is there some other way apart from plaque assay and PCR to ensure that the MS2 is present in the filtrate?
I'm working in my doctoral thesis in the purification of a lipolytic enzyme from an halophile archea. Currently, I'm trying to purificate the recombinant enzyme using Haloferax volcanii as an expression system. The problem is that suddenly when filtering my crude extract through a 0.45 um nitrocellulose membrane I lose 90 % of the enzymatic activity, when that did not happen before and at most I lost 20 % of the activity.
Has the same thing happened to someone else? Or do you have any ideas that could help me? Thanks!
I am studying and culturing marine diatom Phaeodactylum tricornutum for my PhD project.
To harvest microalgal biomass after culturing it I currently centrifuge it, even if I am about to try the filtration through GF/C filters.
In order to wash all salts (since it is a marine species) what should I use? I have read about an ammonium formate solution 0,65 M. Do you have other suggestions?
Hope someone can help.
Thank you all
I want to prepare microfiltration flat membranes with PVDF or polysulfone. I did the process by solving various concentrations of the polymers (from 13 to 15%) to NMP to produce the casting solution base on the other articles using non-solvent induced phase separation method with a fixed height of 100 μm. However, the surface of the as-prepared membranes are dense in SEM images and no obvious pores (larger than 100 nm) can be seen. I would be very appreciated if someone help me.
I am making kosaric media using artificial seawater in various salinity for microalgae cultivation. At first, I tried to filter the seawater and then add chemicals. After autoclaving, there was some deposits at the bottom of the media. I also tried to autoclave the artificial seawater and media separately, and then let both solutions cooled down and added together in laminar flow. However, once I added the kosaric media into seawater, precipitation was observed and large amount of white crystalline substance at the bottom. Is there any other way to make it?
I've been synthesizing bulk hBN powder from boric acid and urea precursors in a tube furnace. However, when I mass the finished powder into water with a stir bar (so I can run reactions with the material), the pH shoots up as the material seems to fall apart in the water. Why is that? How can I synthesize a water-stable boron nitride? (not hydrophilic, just stable)
I've been using a high molar ratio of urea: boric acid for precursors, so I've been doing 30:1 (though I've also tried lower). I add ~150 mg boric acid and ~4.5g urea to a beaker with 20 mL DI H2O + 20 mL methanol (based on:
We collected the plasma filtrate from the plasma exchange of the patients and stored it in -80℃. Now we attempt to obtain the IgG from the filtrate, however, we worry that the IgG may be degraded and inactive since the filtrate has been frozen for 2 years. Generally, how long can such IgG be stored, and whether extra preprocess is needed for the storage?
During RNA extraction I used preheated wash 1 solution( about 40C) "by mistake", discarded the filtrate, used wash2 and then the preheated elution buffer (the only buffer that should be heated according to instructions) ...
Does the heated wash solution make the RNA dissolve & go to the filtrate???
Note: we don't have the technics and materials for RNA electrophoresis
For the synthesis of MOFs many have reported purification only by filtration and washing with water/solvent. How do you make sure the MOFs are free of unreacted metal compounds/ligands by washing with water/solvents? Is there a way to confirm the complete removal of unreacted material?
I am new to hydro-chemistry and planning to analyze freshwater (pristine environment) water samples for trace element analysis using ICP-MS. I have gone through literature for identification of suitable filter type for in-situ sample filtration and found that people have used a variety of filter types Cellulose Nitrate/PES Filter/Millipore filters/Polytetrafluoroethylene/Ester cellulose millipore/Polycarbonate, etc.
I was wondering which could be the most suitable filter choice for freshwater sample filtration?
I request you to give your valuable suggestions in this respect.
Thanking you all.
I was unsuccessful to find anything in the literature about proteins that are not reabsorbed (efficiently) in the renal tubule. Maybe it was the way I searched or it doesn't occur or no one has looked for it. Sure, it's unlikely and I assume the uptake mechanisms are so "generic" that any protein/peptide will be fished out of the filtrate and taken up by tubular cells. But maybe there are some proteins that escape this?
I am planning to run a column test in a constant head permeameter setup. I plan on reducing the hydraulic conductivity of the soil and would like to monitor any change in effective porosity. I have read a paper where this methodology is utilized, however they do not explain how or reference the technique they used, except that it was done in Hydrus. They injected a salt tracer and then routinely measured the effluent to plot specific conductance vs time, this somehow was used to calculate porosity
Does anyone perhaps know how they managed to do this or know of a reference I can refer to and read up on?
I have tried some searches, but no luck. I think the terminology I am using is not sufficient to return any decent results.
Any direction or information would be greatly appreciated.
I want to synthesis a molecule based on a published paper, in the experimental section, the author said "......5 g silica and 2 drops of dibutyltindilaurate were added, and the mixture was heated at 60 C for 1 h. The silica was removed by filtration and the chloroform in resulting solution was removed in vacuo......". So, which kind of silica should I choose for this reaction? the silica gel for column chromatography? fumed silica? or other.
Thanks in advance!
I have extracted polyclonal antibodies with PEG 6000 in PH (5.2, using HCL to adjust PH). Using dialysis membrane (12000 cutoff), the PEG was successfully separated from the polyclonal antibodies and I purified my product.
Currently, I am trying to establish product in industrial scale. But, I do not know what can be used instead of dialysis membrane in industry scale???? What is your suggestion? Could you please kindly help me regarding to the separation of PEG from polyclonal antibodies (180 KDa) in industry scale??????
Hello dear researchers,
I would like to know if there is a possibility to purify antibodies using ionique exchange chromatography or gel filtration with basic equipment.
If yes, i would like to have some tips to make it possible.
Thank you in advance.
Slurries generally consists of some heavier particles which should remain suspended in solution for best coating results. Kindly suggest best way to maintain viscosity of alumina slurries. Thank you:)
I'd like to compare between mass spec. results of 2 samples that I have (each sample has 3 biological replicates).
Following several filtration steps- I have a list of proteins that were identified in 1 sample (in all of the 3 replicates), but were not identified in the second sample... (and vice versa).
How should I consider these proteins in my statistical analysis? Can I consider them significant by default? Should I include them in one list with the other proteins that were (differentialy) identified in both samples and have values to compare?
In bacterial filtration efficiency assay, staphylococcus aureus is used as challenging microbe in the aerosol form. can we use other microorganisms for the test.
I have a high density product contains 30% Oxytetracycline dihydrate dissolved in pyrrolidone, it is very difficult to filter with vacuum filtration method ( 0.2 or 0.45 micron nylon filter paper) is there any other way for filtration with 0.2 micron filter paper?
The proteins that I label always have a His-tag so I normally perform Ni-NTA purification after maleimide labeling, but it doesn't get rid of all the excess dye. Hence, I'm looking for alternate methods and gel filtration seems to be widely used. We have SEC gel filtration columns (Biorad version of Superdex) in the lab and we never use them for this application as we fear that free dye might stick to the column during runs and affect other protein purification studies. Does anyone have any experience regarding this?
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I am trying to simulate molecular filtration of fluid like Reverse osmosis of water. I am new to Ansys and I am in need to succeed it.
Is it possible to do filtration by pore size of porous material and fluid molecules size?
If yes, kindly share with me. I will be thankful to you.
Kindly provide the email id for further communication.
hIAPP monomer which is of 4 kDa. I want to do buffer exchange. is it fine to do with 3 kDa centricon filtration falcon?
And ¿Is it better to use natural or artificial seawater?
I am doing lignocellulosic extraction from biomass. After treatment with acid solution, I filtered the mixture with the help of G3 sintered frits bucchner funnel. I can see that later filtration is slow and stain over frits. Please help
I need to know the specific column and HPLC conditions required to standardize the protocol.
I'm trying to prepare R2B/R2A media with seawater to cultivate marine bacteria after autoclaving (110°C) my media. I systematically observe a important precipitate. Despite many tests (in particular at different percentage of seawater and different types of filtration, I did not succeded to find the solution. Do you have any idea to help me ?
Thank for you help !
Do we get a trifluoroacetic acid (TFA) peak during gel filtration (desalting) of the synthesised peptide after RP-HPLC purification (0.1% TFA in buffers)? The molecular weight of my peptide is 2545.9 Da. And if no, how could we confirm that the peptide is TFA free now.
I am looking for the exact recipe to make urine filtrate for analysis.
Can anyone help me along with the references, please?
I am preparing nanoparticles using alginate polymer. Before, I used syringe filter 0.45 um for alginate solution to be clean before adding CaCl2. Now I going to produce a big amount of alginate nanoparticles, so can I centerfuge alginate solution compensate to filtration
the team I am working with and I are having a problem. It is a project in which we have to eliminate the bacteria that exist in a water supply. It is a must to remove them all because we do not want to face following problems like biofilm formation in Reverse Osmsis system. it is impossible to use heat, and filtration is not preferred. ozone was tested and did not work properly. chlorine is been using and it can remove all bacteria, but it needs more than 10 hours time. this bacterium we are facing can tolerate chlorine, ozone, and can pass 0.2 micrometer fliter. can anyone help us to meet this problem?
I have been searching for the most compatible syringe filter to reach maximum protein recovery after filtration. However, I have found contradicting data which confused me. MCE syringe filters have been suggested for their very low protein binding and maximum protein recovery. PES and PVDF syringe filters have also been recommended for their low protein binding capabilities. I have a buffer solution that contains human plasma proteins, and I don't want to lose any of them during the filtration process.
I want to know about theory of the upward continuation and why do we use upward continuation and down ward continuation? Other thing is what is the relationship between the filtration and up/downward continuation?
We find these structures in the urine filtrates of humans/canines exhibiting a similar host of symptoms, of unknown etiology. They can be highlighted using a variety of stains and are along the scale of 250-500 um. We greatly appreciate any thoughts or suggestions you might have as to what may be creating these structures, or a more specific name/identify for them.
While purifying the exosomes, after ultracentrifugation, we are passing the exosomes thru a 0.2um filter. The product before and after filtration seems the same when we look at the particle size profile. Either the filtration did not work, or the exosomes aggregated after coming thru the filter. Would like to get opinions from experts. The exosomes are in PBS.
Is it necessary to filtrate S.aureus supernatant for further analysis (e.g. cytotoxic assay) - or is it possible to use it without filtration?
During a buffer exchange in a concentrator for a protein, I needed to measure the protein concentration through Nanodrop OD 280 nm. I want to know which one of the following I should use as the blanking Buffer?
1. The initial buffer ( Of course it doesn't make sense to use this, as the protein is not in the initial buffer anymore) but is it possible that traces of this buffer may still be present in the protein?
2. The final buffer to which the protein is exchanged , but then it is not 100% the environment of the protein? (when you switch buffer, there is likelihood of some amount of protein loss into degradation)
3. The filtrate through the concentrator in the bottom chamber as this represents 100% the present background of the protein?
4. or a combination of two or more of the above please?
Thanks for any logical explanation please.
The aquaculture industry's endeavour to avoid diseases casing microbes/carrier/macro predator to keep the farm-reared animals healthy to achieve good profit in the aquaculture business. Has the subsurface intake system has the ability to solve this problem?
I need to prepare or dilute TGF-B3 in the mentioned solutions: sterile-filtered 10mM acetic acid with 20% ethanol, or 4mM HCl.
I have just searched through videos from YouTube, sterile filtration is to simply filter any solutions through a 0.2um pore size filter unit using a sterile syringe, to remove microorganisms. I am wondering if this so-called "sterile-filtered" solution safe for use to dilute or reconstitute the growth factors and used for cell culture? Are they considered aseptically clean for cell culture work? I hope I will not introduce any contaminants to my neuron differentiation work which is very tedious. Thank you.
How do you achieve mass purification of Coxsackie virus B3? Is it through an ultrafiltration concentrator?
Due to limited laboratory conditions, membrane encapsulation, tangential flow filtration and ion-exchange chromatography cannot be deployed. Density gradient centrifugation cannot achieve a large number of purification.
After soaking costus powder in hexane for 72 hour .
The filtrate was concentrated using vacuum rotary evaporator.
I got oily extract and some crystals .
I want to convert this oily extract to powder extract .
I bought a dialysis tube of 10kD of molecular weight. But I need the actual pore size of this dialysis tube as I am going to use it for filtration purpose. It will be very helpful if anybody can help in this regards.
I am working on developing a thin film for solar steam evaporation.
In these papers, the common technique used to deposit the nanoparticles onto the substrate, to form the film, is vacuum filtration.
In my current lab I do not have a standard vacuum filtration set up available and I was planning on purchasing a pump to use for this purpose.
Given the high cost