| Pages:
1
2
3 |
aga
Forum Drunkard
Posts: 7030
Registered: 25-3-2014
Member Is Offline
|
|
Home Made Analysis gear
What kind of stuff do the Pros use to analyse chemicals, and Why cannot that equipment be made by home-brewers ?
I have heard of Gas Spectrometry.
I assume that means zapping a specimen material and analysing the spectra of the resultant gas.
What analysis kit is actually useful, and why cannot it be home-made ?
|
|
|
aga
Forum Drunkard
Posts: 7030
Registered: 25-3-2014
Member Is Offline
|
|
I saw a TV programme where Australian Border Control had a machine that picked up on any trace of a controlled substance really fast, using just a
swab of the suspect container, not touching the actual chemical material itself.
How does that work ?
I would very much like to make one, but for all materials, not just drugs.
E.G. : Is this Benzene ? Put sample in machine ..... Beeep! No. It's water.
|
|
|
gdflp
Super Moderator
Posts: 1320
Registered: 14-2-2014
Location: NY, USA
Member Is Offline
Mood: Staring at code
|
|
There is your answer. Most things used to analyze chemicals are way beyond the
reach of an amateur, they require special machining to ensure they are precisely cut. Other equipment includes gas chomatographs, spectral analyzers,
spectrophotometers, and NMR's(which are about .5 million per).
|
|
|
aga
Forum Drunkard
Posts: 7030
Registered: 25-3-2014
Member Is Offline
|
|
Where there is a will, there is a way.
Machining : i was born in Sheffield. Machining to 0.001 mm is done routinely these days.
Etching to near-molecular tolerances is also a modern fact.
Gas chromatograph ? So measure the spectra of a gas. Do-able.
NMR i have no idea what that is.
OK.
That's some very good reasons why Not, so suggestions about 'How To' welcome.
[Edited on 11-4-2014 by aga]
|
|
|
aga
Forum Drunkard
Posts: 7030
Registered: 25-3-2014
Member Is Offline
|
|
If the several brains in this forum could actually cause a home-brew Substance Identifier (hopefully quantifier as well) to be Possible, wouldn't
every chemist want one ?
I would.
|
|
|
DrAldehyde
Hazard to Self
Posts: 82
Registered: 12-1-2014
Member Is Offline
Mood: No Mood
|
|
Quote: Originally posted by aga  | If the several brains in this forum could actually cause a home-brew Substance Identifier (hopefully quantifier as well) to be Possible, wouldn't
every chemist want one ?
I would. |
I want one, I propose we call it a Tricorder. 
|
|
|
aga
Forum Drunkard
Posts: 7030
Registered: 25-3-2014
Member Is Offline
|
|
OK. TriCorder is the project name.
[Edited on 12-4-2014 by aga]
|
|
|
hyfalcon
International Hazard
Posts: 1003
Registered: 29-3-2012
Member Is Offline
Mood: No Mood
|
|
These multiple posts are going to get you no where but detritus.
|
|
|
gdflp
Super Moderator
Posts: 1320
Registered: 14-2-2014
Location: NY, USA
Member Is Offline
Mood: Staring at code
|
|
NMR = Nuclear Magnetic Resonance. Have fun making one of those, they are very dangerous, magnetic fields and radiation and such.
|
|
|
aga
Forum Drunkard
Posts: 7030
Registered: 25-3-2014
Member Is Offline
|
|
Sorry for the multiple posts.
Alcohol and the inherrent excitement about a project to make something good are to blame.
Mainly the alcohol.
[Edited on 12-4-2014 by aga]
|
|
|
aga
Forum Drunkard
Posts: 7030
Registered: 25-3-2014
Member Is Offline
|
|
Thank you gdlfp for explaining, to some extent, NMR.
|
|
|
HgDinis25
Hazard to Others
Posts: 439
Registered: 14-3-2014
Location: Portugal
Member Is Offline
Mood: Who drank my mercury?
|
|
C'mon aga here is bringing an important topic that hasn't been done yet. So stop saying you can't and let's start brainstorming to get somewhere.
hyfalcon, with all due respect, your post deserves much more to go to detritus. You didn't post neither to help nor to give new ideas, you simply post
to warn about a little mistake (doublepost). Everyone here could see that, so if you are the "obvious pointer" guy, go point the obvious somewhere
else. Otherwise, quit that attitude and say something interesting.
Now, on topic. I've made some CD spectometers just for fun. You can easily see some spectrum lines. I wonder if, by placing a sample in the
spectometer, we could analyse it's spectrum? It seems doable to me. For those who don't know, here is one:
https://www.cs.cmu.edu/~zhuxj/astro/html/spectrometer.html
I prefer this aproach on making it:
http://www.youtube.com/watch?v=D_gT2dl3B5Q
I'm out of time to test it out, but as it is really simple to make someone here could test it?
Density tests using a Pycnometer and a good analytical scale are also pretty acurate determining a sample density. One could then compare it to a
density table and look for your compound. Determining the melting or boiling point of a sample also helps do determine the compound and purity.
ChemicalMyst speaks about this in a video of his (right in the end of it):
http://www.youtube.com/watch?v=k7ZDSFEsrGg
Any more ideas to add on the table?
|
|
|
Chemosynthesis
International Hazard
Posts: 1071
Registered: 26-9-2013
Member Is Offline
Mood: No Mood
|
|
Most forensic drug testing uses mass spec heavily. I'm most familiar with MALDI TOF. You need different systems for liquid, solid, or gas phase
analytes. Flame ionization would probably be simpler than laser for LCMS (maybe), definitely GCMS.
http://en.wikipedia.org/wiki/Mass_spectrometry
http://en.wikipedia.org/wiki/Matrix-assisted_laser_desorptio...
I can't imagine making most analytical instruments because here you need precise timers, magnetic focusing and acceleration, an inert gas flow/vacuum,
sensitive ion sensors, possibly a quadrupole. I can't even begin to give it justice. The combination of everything makes it harder than just
spraying sample through a purged nichrome wire and hitting a screen.
My favorite analytical technique, and one also used in the drug industry frequently is NMR. NMR uses extremely strong magnetic fields under liquid
helium, with an insulating layer of liquid nitrogen. This is expensive, hard to maintain, can lead to very difficult to diagnose issues, and is
dangerous if you get a "purge." It requires dedicated space away from all magnetic object, computers, credit cards, and the software to run them
tends to be licensed and is designed to run on Solaris/sunOS UNIX on every system I've used (Varian). It is also extremely sensitive, so you need
very pure sample, a standard (generally TMS), deuterated solvent, and very fine calibration to compare spin-anisotropies to get Knight and chemical
shifts through perturbing the nuclear spin states. It's pretty complicated, I've forgotten a lot about it (except how to read some of the spectra),
and I was never considered an expert in the technique. People get paid fulltime to do these kinds of things, including mass spec... and I never was.
It's so sensitive (ppb/ppt), there were plenty of times I had to rotovap material repeatedly and high vac overnight to get a clean spectra without
extra solvent peaks. Maybe not necessary for home science, or even all publications, but it can be annoying.
HPLC is also complicated. You have special columns, pumps, etc. I think you'd be best off faking this with flash chromatography after TLC, but I
could theoretically see someone plumbing this together. Won't be a Waters or Agilent UPLC, but I could see it, maybe.
Now you move into things like IR spec, Raman, and UV-Vis. I could actually see you making these, though I have seen FT-IR for hundreds used, and
Raman for a grand. At the very least, you can easily get these in your choice, used for a couple grand any day of the week, so I don't see why you
would make one unless for fun.
http://www.sciencemadness.org/talk/viewthread.php?tid=23422
http://www.youtube.com/watch?v=-lVMYa25jtU
doi:10.1021/ed800081t
All in all, though machining is amazing, don't underestimate how electronic a lot of this will be, including calibration and maintenance. I do want
to emphasize I am impressed by your machining background. Don't laugh, but I bought a CNC Taig micro mill (the larger one... can PM model numbers),
thinking I would learn how to use it, and never found the time or anyone willing to teach me, so I am fascinated. I would love a Sheffield and some
experience!
Edit- are you more interested in the fun and accomplishment of building your own, or just the end result? A lot can be done with melting point
analysis, rf values in various solvents, and even a density estimation, as well as various chemical characterization techniques for functional group
presence.
[Edited on 12-4-2014 by Chemosynthesis]
|
|
|
Dr.Bob
International Hazard
Posts: 2733
Registered: 26-1-2011
Location: USA - NC
Member Is Offline
Mood: No Mood
|
|
Some instruments require very complex electronics, complex gases, cold temps, or expensive parts. But if you look through the other parts of this
forum, you will see discussions on home made, portable, or smaller NMRs, home made GC and HPLCs, and polarimeters. There are smaller versions of
many instruments which could be adapted for home or hobby use. The reality is that if you could build most of these items for cheap and they worked
well, someone would be working on it already. But some instruments like CG and MS have been miniaturized recently and are much smaller and less
expensive than they were just a few years ago, I would not be surprised if that trend does not continue.
That may be true of analytical tools, but preparative equipment, larger scale instruments used for purification of larger amounts of material, where
the purified material is the product, not the analytical information, are still expensive in general, like prep HPLC, flash chromatography instruments
(although they have dropped in prices due to being more common now.)
High quality NMR is still expensive, mostly due to the cost of the superconducting magnets used for most higher quality machines, but if anyone can
make higher temp superconductors work for NMR magnets, then that could make a huge impact on NMR, as the magnets often cost $100,000's alone, and the
electronics (like radio freq. probes and ppm signal amplifiers) are very complex and not trivial to build cheaply, but that also may change also.
|
|
|
Bert
Super Administrator
Posts: 2821
Registered: 12-3-2004
Member Is Offline
Mood: " I think we are all going to die. I think that love is an illusion. We are flawed, my darling".
|
|
If we start to see some hard references and , this is going to stay. I really hope that happens, I've seen "amateurs" and "makers" pull off things
pros are hard put to do, and on a shoe string.
If it continues as blue sky, but has educational links to information on instrument design & theory, it's beginnings... Already enough info here
to take it past detritus.
Whoo hoo! 30 + years ago, I got to help build an NMR.
[Edited on 12-4-2014 by Bert]
Rapopart’s Rules for critical commentary:
1. Attempt to re-express your target’s position so clearly, vividly and fairly that your target says: “Thanks, I wish I’d thought of putting it
that way.”
2. List any points of agreement (especially if they are not matters of general or widespread agreement).
3. Mention anything you have learned from your target.
4. Only then are you permitted to say so much as a word of rebuttal or criticism.
Anatol Rapoport was a Russian-born American mathematical psychologist (1911-2007).
|
|
|
aga
Forum Drunkard
Posts: 7030
Registered: 25-3-2014
Member Is Offline
|
|
Wonderful !
I knew it was worth waiting for some Enthusiastic Thinkers to turn up.
Thanks for the references - i will follow up each of them.
I suppose to be practical, the machine needs to characterise as much of the substance is is feasible.
Complex electronics and computer software are not an issue for me, neither is a modest degree of cost.
It sounds like NMR will not be an option, due mostly to the Hazards and immense cost.
Currently i'm thinking along the lines of :-
Freezing point
Melting point
Boiling point
Spectral analysis, including visible, IR and UV.
Without knowing what frequencies might be required (will look it up), RF resonance may be useful.
Then there's Excited/Activated state responses, such as spectra after zapping with 30kV, spectra after exposure to the collapse of a large magnetic
field etc etc.
Piezo electric effect ? - maybe some substances squeak (in some sense) when exposed to high pressures, or a vacuum.
These all spring to mind because they should be measurable with electronic sensors.
Things like solubility in solvent x, y and z would be much harder to do electronically.
[Edited on 12-4-2014 by aga]
|
|
|
aga
Forum Drunkard
Posts: 7030
Registered: 25-3-2014
Member Is Offline
|
|
| Quote: Originally posted by Chemosynthesis | | I bought a CNC Taig micro mill (the larger one... can PM model numbers), thinking I would learn how to use it, and never found the time or anyone
willing to teach me, so I am fascinated. I would love a Sheffield and some experience! |
I found this to be excellent, and should help you to get your Milling machine cutting metal :
http://littlemachineshop.com/Info/getting_started.php
A first task would be to mill a straight slot in a piece of aluminium or brass (they're soft, so tolerate mistakes better and are less likely to snap
your tooling).
|
|
|
hyfalcon
International Hazard
Posts: 1003
Registered: 29-3-2012
Member Is Offline
Mood: No Mood
|
|
My only problem was the rapidity of his posts. If he has another thought that quick then he could just edit the previous post instead of making post
after post. Look at the time stamp on the first posts.
And I'm sorry, the OP lost me with "My ass".
[Edited on 12-4-2014 by hyfalcon]
|
|
|
Bert
Super Administrator
Posts: 2821
Registered: 12-3-2004
Member Is Offline
Mood: " I think we are all going to die. I think that love is an illusion. We are flawed, my darling".
|
|
| Quote: Originally posted by hyfalcon | My only problem was the rapidity of his posts. If he has another thought that quick then he could just edit the previous post instead of making post
after post. Look at the time stamp on the first posts.
And I'm sorry, the OP lost me with "My ass".
[Edited on 12-4-2014 by hyfalcon] |
Agree. I got to this late last night from a SPAM report, caused by that repeated posting. Also, "My ass" might JUST be suitable for whimsy, if you
smile while you say that, Pardner! Definitely suitable for Hot Electron Death otherwise.
aga:
Please go back and edit/remove your earlier posts, for civility and content? Make it something worth keeping around- you've got 24 hours.
The first time I saw one of these, I have to admit I DID think "TRICORDER! WHOOT!!!"
Rapopart’s Rules for critical commentary:
1. Attempt to re-express your target’s position so clearly, vividly and fairly that your target says: “Thanks, I wish I’d thought of putting it
that way.”
2. List any points of agreement (especially if they are not matters of general or widespread agreement).
3. Mention anything you have learned from your target.
4. Only then are you permitted to say so much as a word of rebuttal or criticism.
Anatol Rapoport was a Russian-born American mathematical psychologist (1911-2007).
|
|
|
neptunium
National Hazard
Posts: 989
Registered: 12-12-2011
Location: between Uranium and Plutonium
Member Is Offline
|
|
how about neutron activaction?
depanding on the cross section of your sample you can identify metals (mostly)
How about XRF ?
withe the same equipment used for neutron activation plus a xray tube your in business!!!
http://www.sciencemadness.org/talk/viewthread.php?tid=27963
|
|
|
hyfalcon
International Hazard
Posts: 1003
Registered: 29-3-2012
Member Is Offline
Mood: No Mood
|
|
XRF, That's what I was trying to remember and couldn't.
http://goldrefiningforum.com/~goldrefi/phpBB3/viewtopic.php?...
[Edited on 12-4-2014 by hyfalcon]
|
|
|
packetforger
Harmless
Posts: 48
Registered: 21-2-2014
Member Is Offline
Mood: Condensing
|
|
I always did wonder why no one had thought to try make a homebrew IR spec. or UV-VIS setup.
AFAIK the main problems would be obtaining IR/UV sources and sensors which could emit all the different wavelengths and detect them with high degrees
of precision and accuracy. After that, it would simply be a case of analysing the output data.
I actually know how most of these machines work inside (and if anyone wants proof of me being a capable analytical chemist, I can now provide it!),
the main issue for the homebrewer is obtaining the detectors and emittors of various wavelengths/signals IMO. That and the tight tolerances, etc.
How a UV-VIS works, for example, is a very basic principle. Shine a certain wavelength through a sample, see if any of the light is absorbed. Record
how much is passed through compared to how much was emitted on one side. Try this with a bunch of wavelengths of UV light. Different materials absorb
at different wavelengths.
A = E.C.L where A is absorptivity, E is the molar absorptivity coefficient, C is the concentration of the material (moles per decimeter cubed) and L
is path length of the cell, normally 1 centimeter. That is the basis of that.
An NMR machine would require extremely precise sensors, radio-wave sources, and strong electromagnets, among other kit. I doubt someone will be making
one of those anytime soon.
If you want your samples analysed, your best bet IMO is to make friends with a chemistry student at a nearby Uni with a good lab. Most of us have no
problem running a few samples out every now and then, and our lecturers often tend to be somewhat supportive of us getting more practice with the
techniques.
Perhaps some genius will find a cheap source of IR and UV sensors/emittors capable of the frequency ranges needed with decent accuracy/precision,
knock up a bit of software (probably Arduino based) and put up a kickstarter someday...
Edit: as for multiple-stuff-machines, I did once sketch out an "extension" for a HPLC machine that would take the fractions coming out (using a UV
detector), do both IR/UV-VIS analysis on them to determine what wavelengths they absorb at (IR is useful for obtaining functional groups and suchlike,
UV I have only ever used for concentration data, but it may come in handy), then pass it along to a little collection device that would neatly collect
each fraction. A complete pipe-dream device, one I lack the expertise to build, but was fun to come up with. You could then run NMR and MS on the
samples to gain more information.
[Edited on 12-4-2014 by packetforger]
|
|
|
Etaoin Shrdlu
National Hazard
Posts: 724
Registered: 25-12-2013
Location: Wisconsin
Member Is Offline
Mood: Insufferable
|
|
I've never been much for mechanical work, but I have a lot of experience working with spectral data and quite a fair bit of programming knowledge. I
recently cobbled together an excel spreadsheet with programming tagged on* to analyze the output of our visible-light spectrophotometer, express how a
material appears under different light sources and through different receptors, etcetera, with a high degree of customizability for non-real-world
scenarios, and I'm currently building an add-on to see if I can get it to pick up on specific patterns and output likely pigments/dyes contained in a
sample, based on their spectral data. I can simplify readings to a "pure" color curve based on the spectrum of the light source, and (theoretically)
known absorbance from the container (edit: or based on a reference sample if that's available). I think a lot of this could be adapted to UV/VIS/IR
spectrometry, and all of it can be transferred to something standalone if necessary, though I'd have to learn how to get a program to talk to the
machine, or have some way of retrieving data through an intermediary. So if anyone does try their hand at this, I'd be interested in offering
assistance on the software side of things, however fumbling it may be.
*(Oh I know this would be better served by a separate database and program, but Excel allows me to have both together without fussing with compiling
code or compatibility issues. Shhhhh.)
[Edited on 4-12-2014 by Etaoin Shrdlu]
|
|
|
aga
Forum Drunkard
Posts: 7030
Registered: 25-3-2014
Member Is Offline
|
|
| Quote: Originally posted by packetforger | | I actually know how most of these machines work inside (and if anyone wants proof of me being a capable analytical chemist, I can now provide it!),
|
Invaluable knowledge !
Do you also have access to 'proper' tst gear so that any results could be checked ?
(assuming a TriCorder gets built)
The incredible work done by radagast last year looks like a very promising place to start :-
[Edited on 12-4-2014 by aga]
|
|
|
aga
Forum Drunkard
Posts: 7030
Registered: 25-3-2014
Member Is Offline
|
|
My apologies hyfalcon.
I did not intend to offend anyone.
Now i have a yardstick as how easily that can happen, i will make an effort to moderate my posting behaviour.
--------------
To avoid annoying anyone further, i am editing this post rather than posting a new one.
I do not feel that i will be able to avoid annoying people, as i do drink, think and post.
As new ideas crop up (in my mind) i find that sending them out as-is for discussion works well, as people react, flame, argue, and contribute.
So, best if i do not post anything further.
Thank you all for your very informative and detailed answers to questions i have asked, and please continue supporting beginners in the future.
Kind regards,
Adrian.
[Edited on 12-4-2014 by aga]
|
|
|
| Pages:
1
2
3 |
![[*]](images/xpblue/default_icon.gif){kind=icon}
