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Oven

The oven, as referenced before, exists to heat the mobile phase to its desired temperature. In the case of SFC, the desired temperature is always the critical temperature of the supercritical fluid. These ovens are precisely controlled and standard across SFC, HPLC, and GC.

Restrictor

As suggested by its name, the restrictor aims to restrict the flow through the columns. In altering the flow, the speed at which the sample elutes, the resolution at which it elutes, and the properties of the supercritical fluid can be altered, thus allowing for each SFC column to be tailored to the sample in question.

Detector

So far, there has been one largely overlooked component of the SFC machine: the detector. Technically not a part of the chromatographic separation process, the detector still plays an important role: identifying the components of the solution. While the SFC aims to separate components with good resolution (high purity, no other components mixed in), the detector aims to define what each of these components is made of.

The two detectors most often found on SFC instruments are either flame ionization detectors (FID) or mass spectrometers (MS):

  • FIDs operate through ionizing the sample in a hydrogen-powered flame. By doing so, they produce charged particles, which hit electrodes, and the particles are subsequently quantified and identified.
  • MS operates through creating an ionized spray of the sample, and then separating the ions based on a mass/charge ratio. The mass/charge ratio is plotted against ion abundance and creates a “fingerprint” for the chemical identified. This chemical fingerprint is then matched against a database to isolate which compound it was. This can be done for each unique elution, rendering the SFC even more useful than if it were standing alone.

Sample

Generally speaking, samples need little preparation. The only major requirement is that it dissolves in a solvent less polar than methanol: it must have a dielectric constant lower than 33, since CO 2 has a low polarity and cannot easily elute polar samples. To combat this, modifiers are added to the mobile phase.

Stationary phase

The stationary phase is a neutral compound that acts as a source of “friction” for certain molecules in the sample as they slide through the column. Silica attracts polar molecules and thus the molecules attach strongly, holding until enough of the mobile phase has passed through to attract them away. The combination of the properties in the stationary phase and the mobile phase help determine the resolution and speed of the experiment.

Mobile phase

The mobile phase (the supercritical fluid) pushes the sample through the column and elutes separate, pure, samples. This is where the supercritical fluid’s properties of high density, high diffusivity, and low viscosity come into play. With these three properties, the mobile phase is able to adequately interact with the sample, quickly push through it, and strongly plow through the sample to separate it out. The mobile phase also partly determines how it separates out: it will first carry out similar molecules, ones with similar polarities, and follow gradually with molecules with larger polarities.

Questions & Answers

do you think it's worthwhile in the long term to study the effects and possibilities of nanotechnology on viral treatment?
Damian Reply
absolutely yes
Daniel
how to know photocatalytic properties of tio2 nanoparticles...what to do now
Akash Reply
it is a goid question and i want to know the answer as well
Maciej
characteristics of micro business
Abigail
Do somebody tell me a best nano engineering book for beginners?
s. Reply
what is fullerene does it is used to make bukky balls
Devang Reply
are you nano engineer ?
s.
fullerene is a bucky ball aka Carbon 60 molecule. It was name by the architect Fuller. He design the geodesic dome. it resembles a soccer ball.
Tarell
what is the actual application of fullerenes nowadays?
Damian
That is a great question Damian. best way to answer that question is to Google it. there are hundreds of applications for buck minister fullerenes, from medical to aerospace. you can also find plenty of research papers that will give you great detail on the potential applications of fullerenes.
Tarell
what is the Synthesis, properties,and applications of carbon nano chemistry
Abhijith Reply
Mostly, they use nano carbon for electronics and for materials to be strengthened.
Virgil
is Bucky paper clear?
CYNTHIA
so some one know about replacing silicon atom with phosphorous in semiconductors device?
s. Reply
Yeah, it is a pain to say the least. You basically have to heat the substarte up to around 1000 degrees celcius then pass phosphene gas over top of it, which is explosive and toxic by the way, under very low pressure.
Harper
Do you know which machine is used to that process?
s.
how to fabricate graphene ink ?
SUYASH Reply
for screen printed electrodes ?
SUYASH
What is lattice structure?
s. Reply
of graphene you mean?
Ebrahim
or in general
Ebrahim
in general
s.
Graphene has a hexagonal structure
tahir
On having this app for quite a bit time, Haven't realised there's a chat room in it.
Cied
what is biological synthesis of nanoparticles
Sanket Reply
what's the easiest and fastest way to the synthesize AgNP?
Damian Reply
China
Cied
types of nano material
abeetha Reply
I start with an easy one. carbon nanotubes woven into a long filament like a string
Porter
many many of nanotubes
Porter
what is the k.e before it land
Yasmin
what is the function of carbon nanotubes?
Cesar
I'm interested in nanotube
Uday
what is nanomaterials​ and their applications of sensors.
Ramkumar Reply
what is nano technology
Sravani Reply
what is system testing?
AMJAD
preparation of nanomaterial
Victor Reply
Yes, Nanotechnology has a very fast field of applications and their is always something new to do with it...
Himanshu Reply
good afternoon madam
AMJAD
what is system testing
AMJAD
what is the application of nanotechnology?
Stotaw
In this morden time nanotechnology used in many field . 1-Electronics-manufacturad IC ,RAM,MRAM,solar panel etc 2-Helth and Medical-Nanomedicine,Drug Dilivery for cancer treatment etc 3- Atomobile -MEMS, Coating on car etc. and may other field for details you can check at Google
Azam
anybody can imagine what will be happen after 100 years from now in nano tech world
Prasenjit
after 100 year this will be not nanotechnology maybe this technology name will be change . maybe aftet 100 year . we work on electron lable practically about its properties and behaviour by the different instruments
Azam
name doesn't matter , whatever it will be change... I'm taking about effect on circumstances of the microscopic world
Prasenjit
how hard could it be to apply nanotechnology against viral infections such HIV or Ebola?
Damian
silver nanoparticles could handle the job?
Damian
not now but maybe in future only AgNP maybe any other nanomaterials
Azam
Hello
Uday
I'm interested in Nanotube
Uday
this technology will not going on for the long time , so I'm thinking about femtotechnology 10^-15
Prasenjit
how did you get the value of 2000N.What calculations are needed to arrive at it
Smarajit Reply
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Mueller Reply
advantages of NAA
Sai Reply
how I can reaction of mercury?
Sham Reply

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Source:  OpenStax, Physical methods in chemistry and nano science. OpenStax CNX. May 05, 2015 Download for free at http://legacy.cnx.org/content/col10699/1.21
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