Questions tagged [separation-techniques]

For questions about the separation of mixtures and solutions into pure compounds

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Is it possible to separate/remove sugar from common drinks, such as juice?

Is it possible to remove sugar from a drink (for example, juice) using common household equipment?
R S's user avatar
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11 votes
1 answer
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What is the scientific term to describe the operation of a bong?

What is the scientific term for the separation of dust particles from air by suction through a specialized flask in a way similar to the operation of a bong? The thing that led me to this was a ...
soundslikefiziks's user avatar
8 votes
1 answer
1k views

How to choose a proper chromatography method to separate substrates?

I'm a freshman and I recently learned how to do TLC and column chromatography. I also know a little about other ways to separate things by chromatography, such as affinity chromatography, gel ...
Asydot's user avatar
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7 votes
2 answers
1k views

How to separate Cu and Ni from alloy containing different metals such as Al, Cu, Ni, (Zn, Pb, Sn < 5%)?

I have an alloy containing different metals such as Al, Cu, Ni, (Zn, Pb, Sn, Ag, Si in small amount < 5%). How can I separate Cu and Ni from this alloy? I tried to dissolve alloy in sulfuric acid, ...
Dhruvin's user avatar
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7 votes
0 answers
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Distilling milligram quantities of oil like it's late 1970s

In a currently retracted* manuscript by Tomas Hudlicky [1, Retraction Watch] the following has been noted: Fifty years ago professors took an active part in all laboratory instructions and they ...
andselisk's user avatar
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6 votes
1 answer
624 views

What is the correct unit of a RI detector used for HPLC analysis?

I analyze sugar compounds in soft drinks with HPLC using refractive index detection (RID) on Agilent 1260 Infinity Binary LC (System User Guide (PDF)). I am not sure which unit to put next to the $y$-...
Johanna's user avatar
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5 votes
1 answer
279 views

How to effectively replace DMSO with LC–MS-compatible solvent for the samples from a well plate?

I want to do LC–MS analysis of the samples from a 384-well plate where each compound (at around 1–10 μM) is dissolved in 10–15 μL of DMSO. I am worried about the DMSO dwarfing the analyte’s signal, as ...
Eric J's user avatar
  • 441
5 votes
2 answers
6k views

Reaction of amines with diethyl oxalate (Hofmann amine separation method)

Why does only one molecule of secondary amine react with diethyl oxalate and two molecules of primary amine react with diethyl oxalate? I feel secondary amine also should have reacted similar to ...
Ritwik Das's user avatar
  • 2,189
4 votes
2 answers
460 views

What solvent dissolves calcium nitrate but not ammonium nitrate?

I am experimenting with a precipitation reaction between ammonium sulfate solution and calcium nitrate. Calcium sulfate precipitates and can be filtered out easily. I am wondering if there's a way I ...
Dominic Jung's user avatar
4 votes
1 answer
248 views

etymology of supernatant

Why do we call a solution that has been centrifuged a supernatant? It seems to me that a "natant" should be something that floats (from Latin "natare" meaning "to swim"), and a "supernatant" should be ...
danielsadowsky's user avatar
4 votes
2 answers
1k views

Shea Stearin Extraction by Dry Fractionation

I have been able fractionate palm oil and extract palm stearin using the following method: Melt the palm oil (over 80 °C) Keep the melted oil at 33.5 °C for 24 hours (using an immersion circulated ...
zetaprime's user avatar
  • 145
4 votes
1 answer
204 views

Recover Solder (Sn-Pb) from wires

I have began to do an "art project" which utilizes solder as main material. While I know that solder is cheap and easily found in multiple shops, I have set my mind on using recycled solder from out ...
Vlad Gamfaleanu's user avatar
4 votes
1 answer
159 views

Using cryptands to make a negatively-charged solution?

In our discussion group, my friend mentioned that metal cations can be separated from other cations in solution using cryptands. After addition of the cryptands to the solution of the cations, ...
Tan Yong Boon's user avatar
4 votes
1 answer
166 views

How to conveniently separate Cd impurities from ZnO without contaminating it?

How could I separate Cd impurities from ZnO without contaminating it and without using overly expensive equipment or extremely dangerous solvents? I don't want to contaminate it by introducing other ...
Veritas's user avatar
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4 votes
1 answer
833 views

What is the state of stationery phase in paper chromatography?

As per my textbook: Partition Chromatography: Partition chromatography is based on continuous differential partiotioning of components of a mixture between stationary and mobile phases. Paper ...
JM97's user avatar
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4 votes
2 answers
524 views

How much does oxygen enrichment improve some combustion engines?

This question is about how much the combustion efficiency increases with oxygen enrichment in modern combustion engine designs. A desirable way to answer is to give the fuel efficiency dependency on ...
David Jonsson's user avatar
4 votes
0 answers
452 views

How can should one separate and purify benzophenone from salicylic acid?

I am working with two solids and I know that they are benzophenone (s)(ketone) and salicylic acid (s) (carboxylic acid). I am curious to know what is/are the best method of extraction and ...
Boo's user avatar
  • 71
3 votes
3 answers
1k views

Can I separate paint thinner into acetone and toluene by simply boiling it?

I have a paint thinner that contains 60% toluene and 40% acetone. I would like to obtain some more-or-less pure toluene. Considering the big difference in boiling points (110°C toluene vs 56°C acetone)...
MaxD's user avatar
  • 149
3 votes
3 answers
3k views

How to separate a mixture of sodium chloride and sodium hydroxide?

I recently did a double displacement reaction in which I formed a solution of water with sodium hydroxide and sodium chloride dissolved in it. Now I want to separate both of them. How can I do this?
zuha's user avatar
  • 39
3 votes
2 answers
5k views

What does all chromatography have in common?

We're learning about chromatography in class, and I'm confused about all the different types (e.g. those that separate liquid-liquid solutions vs. those that separate liquid-solid solutions vs. those ...
Jonathan Lam's user avatar
3 votes
1 answer
334 views

How can I read an Anschütz/Bennert manometer and how can I make sense of it?

Recently I have come across a mercury-filled manometer for vacuum distillation that somewhat resembles a U-tube shaped manometer, but with one arm sealed and completely filled with mercury. Searching ...
Fractal's user avatar
  • 202
3 votes
3 answers
2k views

Why does a molecular sieve work for gas separation?

I was looking at membrane separation of air to nitrogen / oxygen and saw some details on the molecular sieve which on Wikipedia states you can get much higher purity from an adsorber / sieve, but when ...
Alan's user avatar
  • 143
3 votes
1 answer
883 views

Why does HgCl2 react with HCO3^- but not with CO3^2-?

I have started learning Qualitative Salt analysis recently. When I was reading about tests to distinguish $\ce{CO3^2-}$ and $\ce{HCO3-}$, I came across a line in a book which states $\ce{HgCl2}$ ...
Chem-Learner's user avatar
3 votes
1 answer
6k views

Separating lanthanides using ion-exchange method

Following statements are on Separation of rare earth metals (lanthanides) via in-exchange method The tripositive ions are strongly sorbed by cation exchange resin: $\ce{La^{3+}}$, the largest is ...
Zenix's user avatar
  • 1,350
3 votes
1 answer
133 views

How are Silanol groups functionalized unto mesoporous silica structures?

As described in this research paper: Immobilization of Jacobsen type catalysts on modified silica, Jairo Cubillos , Edwing Grajales, Santiago Vásquez, Consuelo Montes de Correa, Rev. Fac. Ing. Univ. ...
C-Consciousness's user avatar
3 votes
1 answer
283 views

Do companies recover carbon dioxide and water from the purification step of cryogenic air separation, and how?

In the 3rd step of cryogenic air separation, filtered air is purified to remove water, $\ce{CO2},$ and hydrocarbons from the $\ce{N2}$-$\ce{O2}$-$\ce{Ar}$ stream. Im interested in knowing what happens ...
dlight's user avatar
  • 337
3 votes
1 answer
120 views

Why can I extract all metabolites from blood plasma with one solvent, but to extract only fatty acids I must use many solvents?

I want to do a metabolite study using GC- without derivatization and UPLC-MS (RP and NP) on samples of plasma and urine. My hypothesis is agnostic about which metabolite will correlate with the ...
Mikkel Rev's user avatar
3 votes
1 answer
92 views

Is the pressure in an HPLC system the same throughout?

I'm not sure if I'm articulating myself well enough, but here's my problem: I have a current HPLC system, where we typically have backpressure readouts of around 15 MPa. We are looking to get a new ...
Shocked's user avatar
  • 87
3 votes
1 answer
332 views

How do you separate microcrystalline cellulose from amino acids in a powder mixture?

I am looking to separate out the microcrystalline cellulose that has been mixed in with amino acids in a powder mixture. I have tried suspending the powder mixture in water and then filtering out the ...
supervincent's user avatar
3 votes
1 answer
267 views

Separation of methanol–water mix in a plate distillation column

I conducted an experiment to separate methanol and water. I am trying to determine the mole fraction of the distillate collected but having a little trouble with the calculation. The flow rate was $\...
Emm's user avatar
  • 31
3 votes
2 answers
2k views

What is the principle of “scrubbing” in liquid extraction or solvent extraction?

There are many steps in solvent extraction: Extraction Scrubbing Back extraction I understand the 1st and the 3rd. What is the principle of scrubbing? Is it just washing the organic phase? How ...
ggs's user avatar
  • 107
3 votes
0 answers
46 views

How to adjust selectivity of gas-permeable PDMS membranes for environmental applications?

I have an idea about making an environmental sensor that uses a gas-permeable membrane (GMP) and how its probe could be submerged in a water source with an off the shelf gas sensor. So far, my ...
John P Santos's user avatar
2 votes
1 answer
225 views

How do I separate an Indium-Gallium alloy into Indium and Gallium?

I've recently learned more about Indium and Gallium, and I find them quite interesting, especially how an alloy can be manually made simply by rubbing them together. I'm curious though, is there a ...
JShoe's user avatar
  • 131
2 votes
1 answer
110 views

Has anyone added dyes to a mixture about to separated by chromatography in order to visualize where the desired product lies?

Usually in preparative chromatography one needs to know when the desired substance to be separated is coming down the pike. Often this required some sophisticated instrumentation. But, it occurred to ...
stephen penguin's user avatar
2 votes
1 answer
4k views

Separating glucose and fructose

If I have a mixture of glucose and fructose in aqueous solution, what is the simplest method to separate them? Heating to 110 °C to melt only the fructose would probably work theoretically, but this ...
sadljkfhalskdjfh's user avatar
2 votes
1 answer
6k views

How to remove sugar from juice

My son has autism and we noticed that blueberries make him feel much better. The problem is blueberries contain sugars which interfere with diet he has (low carbohydrate). How do I filter out the ...
blueb's user avatar
  • 47
2 votes
1 answer
236 views

Is Silica Gel fit for Ultra-High Dessication?

I had the (perhaps wrong) notion that silica gel wasn't that strong of a dessicant, especially compared to CaO, MgO, CaSO4, H2SO4, KOH, Mg(ClO4)2), but I've been exposed to information* that might ...
Hans's user avatar
  • 1,097
2 votes
1 answer
249 views

Separating sodium sulfate from chromium trioxide solution

I was looking at the industrial process for the production of chromium trioxide by treating sodium chromate or the corresponding sodium dichromate with sulfuric acid. This results in the formation of ...
FoundABetterName's user avatar
2 votes
1 answer
77 views

HPLC Columns For Compounds Not Soluble In Non- Or Low Polar Solvents [closed]

Can someone recommend HPLC columns for compounds which are not soluble in no- or low polar solvents (hexane, isopropanol, toluene, and dichloromethane)?
Barcelona's user avatar
2 votes
1 answer
7k views

How viable is production of magnesium oxide and sulfuric acid from Epsom salt?

Epsom salt $(\ce{MgSO4})$ is really cheap (less than 0.5 €/kg), whereas $98\,\%$ or better grade magnesia $(\ce{MgO})$ is much more expensive (3 to 4 €/kg). Is it possible to convert magnesium sulfate ...
made2hack's user avatar
  • 157
2 votes
2 answers
233 views

Ways to determine the concentration of alkyl halides in organic solvents

I have a volatile alkenyl bromide dissolved in hexanes. I have to use the halide in a Grignard reaction but separating it from hexanes is hard (the bromide is light sensitive and very volatile). I ...
Raul Luciano's user avatar
  • 1,361
2 votes
1 answer
164 views

Is it possible to separate $\ce{CO2}$ from exhaled air? How?

Just for fun, I would like to see if I could make my own concentrated $\ce{CO2}$ by separating it from my own exhaled breath. I would also love to see if I could pressurize it so I could make my own ...
Mailbox's user avatar
  • 259
2 votes
1 answer
93 views

Does the distillation of alcohol cause the fractioning of isotopes and carbon-12 enrichment?

In water, distillation causes fractioning of the $\ce{^{18}O}/\ce{^{16}O}$ oxygen isotopes (Wikipedia). Does something similar happen to the $\ce{^{13}C}/\ce{^{12}C}$ and possibly $\ce{^{14}C}$ ...
HannesH's user avatar
  • 483
2 votes
1 answer
6k views

How to separate sodium carbonate from sodium hydroxide?

I got a drain cleaner in dust form, which consists of $\ce{Na2CO3}$ and $\ce{NaOH}$. I wanted to extract the $\ce{NaOH}$ so I tried to heat the mixture in order to just melt the sodium hydroxide, but ...
GeorgeTsak's user avatar
2 votes
1 answer
372 views

How do I get calcium citrate to precipitate in experiment on extraction of citric acid from juice?

I was planning to extract citric acid from mango juice by first using Aspergillus niger fungus by fermentation to convert the mango juice to citric acid, then extracting by first adding sodium ...
Edward Addy's user avatar
2 votes
3 answers
3k views

Which process would separate the mixture of toluene, cyclohexane and water?

I think that answer would be: Toluene and cyclohexane do not dissolve in water (since they are nonpolar), so I would first separate the water from the mixture with a separator funnel. A mixture of ...
user108385's user avatar
2 votes
1 answer
208 views

Separating specific components of a PUREX raffinate

The PUREX extraction in nuclear fuel reprocessing leaves behind a nitric acid raffinate full of (mainly) 'fission products', which are a diverse set of elements produced by fission in a nuclear ...
Noah Harris's user avatar
2 votes
0 answers
132 views

How to choose the solvent gradient for the flash column chromatography of a complex mixture?

When performing a flash column chromatography, it is advised to select an eluent in which the desired compound has an $R_\mathrm{F}$ of about $0.25$ in TLC. However, if I want to separate and isolate ...
user avatar
2 votes
0 answers
1k views

Purification of Red Phosphorus

The Boring Stuff I'm well acquainted with various fields of science & engineering, but my foray into the world of chemistry is relatively recent. I'm in a location (probably most of us are to some ...
voices's user avatar
  • 159
2 votes
0 answers
100 views

Is there a way to form only ortho product without using fractional distillation?

Using benzene and ethane as your only source of carbon in the final molecule, synthesize the following using any useful reagents. Reaction must form pure ortho compound. I have to form the product ...
Sydney Clark's user avatar