dormouse
(Member)
04-19-00 14:10
No 122767
      automating production: the use of home-made monochromatic spectrophotometers? -drone
(Rated as: excellent)
    

Author  Topic:   automating production: the use of home-made monochromatic spectrophotometers? 
drone 342
Member   posted 11-17-98 05:18 PM          
--------------------------------------------------------------------------------
One very bright bee, in the mass production discussion, made the astute observation that in order to maximize pilot plant-scale production, automation ought to be utilized whenever possible. Perhaps one of the seemingly simplest means of making life a lot sweeter would be to use simple monochromatic spectroscopy to monitor a reaction's progress. A common practice in industry; by selecting a wavelength primarily absorbed by the starting product, shooting a beam through your reactor vessel, and measuring the absorbance on the other side with a photomultiplier tube, one can successfully measure the concentration of reactants, products, etc, and thus monitor a reaction's rate and progress.
By using this technology, a reaction's time can be minimized, while the final product and its purity can be maximized as well. The question is: how?

By using UV/IR spectroscopies of products and their starting materials, one can select which wavelengths to use to monitor each species, but how does one go abot constructing a home-made monochromator and transducer? Aside from purchasing expensive filters and other overpriced equiptment, is there a cheap way of doing this?

While I do know my chemistry, I must admit I'm no expert in electronics. I suspect though there might be a few out there reading this. How would you do this? I feel this technology would greatly advance our cause.

-drone #342


Rhenium
Member   posted 11-18-98 07:29 AM          
--------------------------------------------------------------------------------
Drone,
I do remember reading a while back in an article (I forget where) that a handy spectrometer grating for the visible spectrum can be made using a common CD. Because the grooves are the correct ditance apart you get the diffraction of the light. I'm not sure of the exact range of wavelengths, but this would depend upon the spacings.
I don't know whether the hassle would be worth it though, in my undergraduate days we used to use the old Varian 20's which covered most of the visible and IR pretty well, and they didn't look particularly expensive.
How exactly you would program the automated facility to operate I don't know. Maybe instuct the machine to continue stirring, heating or whatever until the peak at (~1400 cm-1) disappears (or where ever the ketone comes).
Actually, maybe another idea (IMHO) would be automated TLC (Thin Layer Chromatography). Every hour or so the machine takes a sample (via syringe), drops it onto a plate and lowers the plate (mechanical arm or whatever) into an automated developing tank (fills and empties on computer command). The plate develops over x number of minutes and is taken out (arm again) and sprayed with nihydrin or examined under UV light. Computer takes a snapshot with digital camera, and emails it to your anonymous account on the other side of town. By doing many small scale synthesis, you could pretty much tell straight away what you've got, and this could be used in paralell with automated UV-vis/IR. Now that would be the ultimate in long distance synthesis. Maybe someone with a bit of robotics knowledge could suggest an improvement, I'm just thinking of the automated sample dispensor which operates on the GC-MS here, it's pretty damn nifty, yet incredibly simple. But this is just an idea.

Take care,

Rhenium


Rhenium
Member   posted 11-18-98 08:28 AM          
--------------------------------------------------------------------------------
Drone,
I've just had a look at what I wrote, and I'm sorry for getting off the topic. I'm much more of an ideas person than a practical application person. Hope you understand.
Anyway, for the monochrometer, you have two main options, a diffraction grating (Czerny-Turner type) versus a Prism (Bunsen) type.
For totally at home I would recommend the prism type, since prism are relatively easier to obtain then good diffraction gratings.
Both types require either focussing mirrors or lenses, and collimating slits. Since the width of the collimating slit will determine the width of the wavelengths you will be looking at, the smaller the better. Making tiny regular width slits at home wouldn't be enormously fun.
Alternatively, use a photodiode array with a simple grating and a polychromatic source. This will do scan the whole spectrum in a very quick period of time, but photodiodes are cheap.
Writing the software or making the hardware to contol any of these is something I wouldn't like to think about.

Take care,

Rhenium


drone 342
Member   posted 11-18-98 03:41 PM          
--------------------------------------------------------------------------------
The software is not actually that big a deal, nor would you even really need any. By hooking up your photomultiplier tube to a simple voltmeter, you get a useful readout. The part I think would suck would be angling the prisms, etc. until you managed to find the the wavelength you want to select.
Alternatively, I know of a few companies that sell monochromatic filters. Perhaps puting one of these in front of a garden-variety incandescent is all you'd need?

Another thing: which would be better for spectroscopic monitoring -- IR or UV?

-drone #342


ChemHack
Member   posted 11-18-98 08:15 PM          
--------------------------------------------------------------------------------
That probably depends on the substance but remember that IR will add heat, especially if it is contantly on for realtime monitoring.
Using a visable wavelength would be ideal because you could do the rxn in the dark and use a simple photodetector switch possibly even diverted from consumer products such as nightlight or yard lighting. Connect the switch to a relay and the software requirement goes down even lower.

Computer takes a snapshot with digital camera, and emails it to your anonymous account on the other side of town.
Nice digital cameras for use in control systems have OCR software that could be configured to make the determination for you. Encapsalate the OCR component in a OLE server and then, when the rxn is done, take the next action like turning off heat, flooding to a certain level, etc...


drone 342
Member   posted 11-18-98 09:45 PM          
--------------------------------------------------------------------------------
IR *may* add heat, but not much. We're talking about the kinetic energy gained by the absorbance of light from a monochromatic spectrographic source -- the quantity is *ridiculously* negligible. Aside from photosensetive situations and maybe microscale chemistry, I can't think of a single situation where the effect of this amount of light would amount to a hill of beans.
Imagine with me for a moment, what complexity would go into automated TLC and hooking that up to a computer: the act of TLC is a mechanicly complex process, meaning a robotic component may be needed. The equiptment needed to take a snapshot and everything else is expensive by anybody's budget. Since such a procedure isn't continuous, and wouldn't be able to automatically know exactly when the reaction is complete, I really am not sure if this labor-0saving devise would be much use.

But, for arguement's sake. Let's say there were a situation where it would be practical for you to remotely observe a reaction's progress. Using the system I described, with continuous monitoring, and simply an op amp hooked to a voltmeter for measuring the progression of the reaction. A computer monitoring the voltmeter has a program that essentially reads "If the voltage is greater than X, send an e-mail to crackhead@chemfreak.com". Somewhere on the other side of the planet, our chemical hero is sitting by a computer, when a little "beep" signals that incoming mail has arrived. Its the news she was looking for!

Even if our chemist isn't remotely observing the reaction, (that is to say, that they're in the lab), this still would be quite nice, since it would tell the chemist precisely when the reaction was completed -- always a useful, time-saving thing. This cuts production cost, production time, and improves yield.

-drone #342


Wizard X
Moderator   posted 11-18-98 11:18 PM          
--------------------------------------------------------------------------------

Drone
I understand what you want to achieve and I can help you in the IR detectors and the IR monochromator , but the IR radiation source is difficult to build and the sample holding cell ( pure NaCl or NaBr crystal ). For UV the phototube detector is very difficult to build , the UV source and UV monochromator are not to difficult. Look at secondhand shops. Give me a little time and I will write-up the info. My E- mail wizardx14@hotmail.com


 
ChemHack
Member   posted 11-18-98 11:28 PM          
--------------------------------------------------------------------------------
I disagree that a UV detection system is always hard to build. The question is what wavelength are you interested in? Detectors for UV and even X-Ray are often constructed by passing the wave through a substance that absorbs that wavelength and emits visible light in return. Then you can concentrate only on detecting the visible light. This is how industrial non-distructive X-Ray examination is done...
 
drone 342
Member   posted 11-19-98 04:45 PM          
--------------------------------------------------------------------------------
Wizard X,
The sample cell need not be KBr nor NaCl -- quartz, among several other common materials, will still do nicely. In fact, wouldn't garden-variety borosilicate work?

Looking around on the net, its not difficult to find dozens of sites selling high-performance monochromatic filters, some site even accept credit cards. Seeing that even a regular incandescent light bulb, coupled with one of these filters, would work effectively as a light source, it looks like making one of these thing-a-ma-jiggies would be cake.

Chemhack,

Non-destructive X-ray spectroanalysis, eh? Sort of like high-energy Raman spectroscopy? Very clever. The question is, how would you begin looking for an appropriate wavelength of UV/X-rays to use, and which visible wavelengths to look for?


Judging by the posts in the industrial discussion, so far the only reactions we've been able to establish with certainty as current candidates for viable industrial production are the Wacker oxidation and the subsequent reductive amination, this seems alike a fine set of reaction to turn our interest to here. (I recognise that other reactions, inculding halosafrole-related chemistry, *may* at some time be useful, their chemistry isn't as thoroughly established.) Let's use these as hypothetical models for our discussion.

-drone #342


Mobius
Member   posted 11-20-98 08:27 PM          
--------------------------------------------------------------------------------
Here's a note from the bright (well I'm not bright, only very lazzy) bee (thanx drone) that said that automatizating production was the way to go:
Before geting into chemistry, I (probably like many of us here) was... a nerd... I was at this age (12-16) facinated by lasers and robotics... I was building small robots that I was able to controle using my Commodore 64 (tm)... Here are my advices to you fellow bees...

1) Using a narrow band monochromatic filter would be a waist of money... Wide band filters are cheap and available in a wide range of colors (wave lenght)! Wide range filters = Colored acetates... Deep purple ones are cool for near UV monitoring...

2) No need to be precise here... most absorbtion peeks are not sharp... Any change in absorption around a given frequency could be used to monitor reaction evolution...

3) Ever tought of using a pair of optical fibers (inert to most solvents; most are borosilicate-quartz) immersed in the reaction medium ? One send in some light the other catches it... Use Radio-shack IR photo-couple or any other proper emiter-reciver couple... Any change in transmitance-absorbtion could be used as a reference... Just keep an eye on the set-up the first time you do it ;-)...

I think an other way to do it (I think I prefer this one) would be to use a small semi-conductor laser (Radio shack againg) and to send the beem trough the mix and right on a photo detector... If I remember well as soon as the nature of the coumpounds in the solution are going to change, it's refraction indice is going to change too, which will bend the beem more and send it out (or at a different spot) of the detector sight, triggering whatever action...

Any other ideas...

-Moby: reminding you that... Auto is the way to go !

------------------


 
Arthur Dent
Member   posted 11-23-98 12:35 AM          
--------------------------------------------------------------------------------
Great idea guys. I'd like to suggest that if one wanted to set up a reliable and extremely versatile monitoring system, you could implement a LC pump which would feed into a quartz flow cell in a desktop spectrophotometer. I think that, with some creative sourcing, this might be done for under US$350. You would'nt need constant calibration as with a home made instument. You would also be able to use the setup for any reaction you like, having a variable wavelength spec. I know, sounds expensive. It doesn't have to be.
There are lots of wierd places to scrounge small flow pumps from. Just be sure to use the right tubing to connect it.

The quartz flow cells are made by all manufacturers of desktop specs as accessories. Whatever spec you get, contact the maker.

Used desktop specs are easy to find. They're one of the most common instruments in labs. A lot of internet resellers stock lab equipment from analytical labs that go under. And beleive me, there's always a lot of 'em going out of business. When they go under their creditors have a fire sale and the not-so-high-tech equipment like specs end up in the wierdest places. Among other places is dantiques.com - they sell a variety of used lab equipment. You won't believe their prices on some of this stuff.

BTW- another cool result of using a desktop spec flowcell is that they're pretty much standardized and fit into all kinds of other detectors .

AD


Wizard X
Moderator   posted 11-24-98 08:56 PM          
--------------------------------------------------------------------------------
Drone
It will take me too long to write up the information you require as work commitments are overwhelming.
So, read the sections in Vogel 5th Ed on IR/UV spectrometers. All circuits, differential amplifiers, current amplifiers can be found in the " Encyclopedia of Electronic Circuits ", by Graf Vol 1-6 , look under Instrument amplifiers.
A very basic circuit is a Wheatstone bridge circuit ( basic comparator circuit which compares the sample transmitted radiation with the reference transmitted radiation ) can be constructed easy.
IR , the monochromator prism and sample cells and all optics must be made of alkali salts (NaCl , KBr) as glass or fused silica transmit IR very little.
UV , glass prisms and lenses can be used in the UV region , but fused silica and quartz can not.
If you need more info or can't find the Wheatstone bridge circuit , then E-mail me. Good Luck !


 
drone 342
Member   posted 11-28-98 03:40 PM          
--------------------------------------------------------------------------------
I really think that using a narrow pass filter is the way to go; true, they can be spendy, but what we're looking at are some pretty narrow bandwidth of interest.
-drone #342
 

 
 
 
 
    Bozakium
(Hive Bee)
10-12-01 17:07
No 223656
      Re: automating production: the use of home-made monochromatic spectrophotometers? -drone     

Thanx for the point here, lowtech!,
WOW, I never knew this thread existed, as this has been one of my pet projects for a while. I'm currently hunting down IR spec schematics, and I do have the electronics background to build one. IR, I believe would be most useful as a spec curve gives the relative proportions of the functional groups, and hence allows rxn monitoring, and comparison to published spec data. An interface/data aquisition board for the PC will allow much of the electronics to be replaced with programming. An infrared LED and IR phototransistor(s) are the "working guts" of the device, the method of frequency sweep can be done in a few different ways (electronically or optically)and is the focus of my currernt research. I missed an oportunity to get a commercial model for free and am still kicking myself in the ass. I should hopefully bee done by this time next year, as my life is in a shambles right now and I have other projects on the burner, but it WILL happen. Now where can I get the specs of cadaverine and putrecine so I can monitor decomposition for the the correct time to harvest?Heh, heh--Bz138
 
 
 
 
    UTFSE
(Hive Bee)
10-25-01 00:34
No 228466
      Re: automating production: the use of home-made monochromatic spectrophotometers? -drone     

exactly what do you mean by "IR spec schematics" cause I might have some refs for you. they are older homebrew spectophotometers if that will help.

always appreciate your time and consideration
 
 
 
 
    Bozakium
(Hive Bee)
10-25-01 18:22
No 228709
      Re: automating production: the use of home-made monochromatic spectrophotometers? -drone     

I am looking specifically for the electronic circuit diagram, commonly known as a schematic, so that I can understand HOW the circuit works so that I may adapt it to build my own. I was hoping someone had the servicemans's paperwork for their own unit, which would contain as well as the schematic a listing or diagram of voltages, waveforms and logic states at various points in the circuit which are used for troubleshooting purposes. One could easily build a "ghetto" visible spectrophotometer with a couple of prisms and comparing a reference spectrum(rainbow) side-by-side with the spectrum of light sent through the sample.This ghetto job is impractical for me for a number of reasons:this necessitstes a large sample so it ain't good for rxn monitoring, I don't know jack about visible spectroscopy, and even if I did, I still think IR is the most useful. I never liked UV for a reason....
  Any info is appreciated, even if it is homebrew. I don't see why Cole-Palmer(sp?) wouldnt send my electronics repairman the info if he's got my spec in his shop, for example. Perhaps I should try the direct approach....
 
 
 
 
    PolytheneSam
(Master Searcher)
10-28-01 02:27
No 229421
      Re: automating production: the use of home-made monochromatic spectrophotometers? -drone     

I'm working on a page about Ir specs.  Typical IR diodes and IR transistors which are used in IR remote controls won't work with IR spectrophotometers.  All the answers are in books the library.  Not all electronic schematics work with all spectrophotometers, either.

http://www.geocities.com/apis_mellifica2002/IRspecs.html

http://www.geocities.com/dritte123/PSPF.html
 
 
 
 
    PolytheneSam
(Master Searcher)
11-18-01 17:18
No 238042
      Re: automating production: the use of home-made monochromatic spectrophotometers? -drone     

Here's something interesting.  This was in an electronics catalog that I got in the mail.  Notice it says that the 'optical' bandwidth is 7-14 m.  The most important part of the 'chemical' IR region in the IR spectrum is between 2 and about 15 or 16 m (in the mid IR region).  The first IR spectrophotometers typically had that bandwidth.  Later ones went up (down in energy) to 25 m.  There's some that even work in the far and/or near IR region.  The near IR region is between visible light and the mid IR region and the far IR region is between the mid IR region and the microwave region.  The detector costs $3.25 for one and $2.59 for 10 or more.  Not too long ago I had some conversations over the phone with someone that works at a company that repairs lab equipment including IR specs.  He said that he sells used and repaired IR specs starting at $3,000 and would sell me an untested one (no guarantee) for $500.  He also said sometimes detectors go bad and old ones cost at least $1000, but he did mention that lower cost solid state detectors exist and also emphasized that you can't take parts from one spec and use then in another.  In my opinion you can if you know enough electronics to do the modifications to make it work.  Typical detectors are based on vacuum thermopiles, bolometers, etc. and don't work on the photoelectric effect.  From my extensive reading on the subject as well as studying physics, I don't think practical photoelectric detectors exist (even today) for the mid IR region which would work over the whole region.  I've searched through the patents and on the internet and found IR detectors which are made using similar methods for making integrated circuits (chips) but these use vacuum thermopiles, too.  The thermopiles are etched in the silicon along with any other electronics.  The cost is lower that an older type of thermopile detector. So, I think this might be a vacuum thermopile type detector here.



http://www.geocities.com/dritte123/PSPF.html
 
 
 
 
    PolytheneSam
(Master Searcher)
11-18-01 18:29
No 238051
      Re: automating production: the use of home-made monochromatic spectrophotometers? -drone     

Here's something else I started working on.  http://www.geocities.com/apis_mellifica2002/IRramble.html
Two main differences between visible and IR spectrophotometers is that visible light covers a region that is less than a factor of 2 in wavelength and visible light photons have a higher energy than IR photons.  E = hf where E = energy of the photon, h is Plank's constant and f is frequency of the photon.  Energy reaching the detector in typical IR prism and grating spectrophotometers is in the microwatt range.  Also, the fact the the 2-16 or the 2-25 m range is more than a factor of 2 means that spectral orders from the grating overlap and require filters or a prism to seperate them.  Visible light covers 450-700 nm.

nm = 10 -9 meters
m = 10 -6 meters

http://www.geocities.com/dritte123/PSPF.html
 
 
 
 
    terbium
(Old P2P Cook)
11-18-01 22:37
No 238087
      Re: automating production: the use of home-made monochromatic spectrophotometers? -drone     

I always hated trying to interpret IR spectra, far too ambiguous for me. NMR spectra are so much nicer. Does anyone have ideas on how to build a (hydrogen) NMR spectrometer for, say, less than a $1000 ?
 
 
 
 
    Osmium
(Stoni's sexual toy)
11-19-01 18:08
No 238397
      Re: automating production: the use of home-made monochromatic spectrophotometers? -drone     

Well, I don't think you tried to imply that Sam, but I say it anyway so that nobody gets the wrong ideas:
It is highly doubtful that a $3 IR detector will work in a IR spectrometer, since it lacks in linearity, sensitivity, resolution etc.

> Does anyone have ideas on how to build a (hydrogen) NMR
> spectrometer for, say, less than a $1000 ?

No way.
I have seen tabletop models (which apparently recorded F or P NMR spectra), but for a proton NMR you need a huge electrical magnet capable of producing a very uniform magnetic field of high strenght. Building these isn't trivial at all!.
While data processing can be done by an old Pentium, there is the transmitter/receiver problem. Let's say you go for a 60MHz device, then you need a way to detect the shifts, which will just be several Hz (ppm!). Not an easy sunday afternoon task.
 
 
 
 
    Greensnake
(Stranger)
11-19-01 18:20
No 238400
      Re: automating production: the use of home-made monochromatic spectrophotometers? -drone     

Homebuilt NMR... ouch. Well, electronics is not that much complicated (if you are good with RF stuff that is) but not the faintest idea how to even start making NMR grade magnet at home. Probably the best course would be finding old 60 mhz NMR gear and outfitting it with new brains. There was an article in not so old (few years max) Journal of Chemical Education about how to do this. I do have a copy but unfortunately - buried somewhere VERY deep in my papers.

Greensnake
 
 
 
 
    yellium
(Hive Bee)
11-19-01 22:26
No 238432
      Re: automating production: the use of home-made mo     

It appears to be possible, if you have to believe http://www.exstrom.com/persimon.html

Unfortunately, for details you have to contact the author.
 
 
 
 
    PolytheneSam
(Master Searcher)
11-20-01 01:44
No 238501
      Re: automating production: the use of home-made mo
(Rated as: good read)
    

The sensitivity of the IR detector doesn't have to be flat across the whole mid IR band.  In reality it isn't because the IR energy drops off  as the spectrum is scanned (shorter wavelength to longer wavelength)  The reason two beams are used, the reference and sample beams, is to cancel the change in sensitivity over the IR bandwidth.  Also, using a beam chopper (ie. rotating sector mirror) produces an AC signal.  DC amplifiers tend to be unstable whereas AC amplifiers can be made more stable.  Resolution of the spectrum bands (peaks) depends more on the monochromator system and the optics.  It might seem hard to believe that a $3 detector would work in an IR spectrophotometer, but the way electronics has been advancing I wouldn't say it wouldn't work until someone tries it.  An IR motion detector has to be pretty sensitive, too.  I've seen some information on the web site from one company that makes IR spectrophotometers about lower cost detectors (thermopile type) made using techniques similar to making integrated circuits.  They didn't list any price.  I've got a couple lists of patents relating to IR specs.  I could sort them out and post them later.  Here's some NMR patents.

Patent US2561489
Patent US2793360
Patent US2799823
Patent US2955252
Patent US3015072


http://www.geocities.com/dritte123/PSPF.html
 
 
 
 
    Greensnake
(Stranger)
11-22-01 20:03
No 239448
      Re: automating production: the use of home-made mo     

Thanks, yellium, for link. (Man, I just LOVE the collective wisdom of Hive)

About rare earth magnets - yes, old NMR gears used them (up to 60 Mhz I think), stronger fields and consequently higher resolutions aparently were (are?) not possible. I once even helped to haul around such a magnet - it weighted 900 pounds! Maybe now are available better magnetic materials.
 
 
 
 
    PolytheneSam
(Master Searcher)
11-23-01 01:56
No 239498
      Re: automating production: the use of home-made mo     

Here's some patents on IR specs.

Perkin Elmer:

3560098
3733131
3062088 null, double beam, prism
3063043 block diagram, servo and pot.
2870343 diagram, prism, waveforms
2888623 like one in book, thermocouple 60 Hz, tube circuit
2900866
2984149
3011389
3039353
3179798
4095896
2817769
3586440 grating and chart recorder mechanism similar to model 727
3052795 dispersion, gratings, blaze

Other IR spec patents:

3058388 Baird Atomic, vibrator, servo, etc.
3537797 Beckman
3472595 Shimadzu, F1-F4
3335281 servo system, chopper, transistor circuit details
3449050 Beckman, vibrator, shows multiplex, demodulator after preamp
5471321 Stepped and blazed grating
5875043 Fig 2 B preamp
2359734 IR spec, 2 thermocouples, flicker
2683220
3633012 pot. --> DC feedback, balance
3663106 Hitachi, similar

FTIR:

3558229 480 Hz interrupter, 15 Hz chopper
4029416 Michelson interferometer
4054384 Michelson interferometer
4511986 IBM,
4654530 scanning refractive
4847878 mirror position detect using laser
5028864 similar to Sagnac interferometer


http://www.geocities.com/dritte123/PSPF.html
 
 
 
 
    PolytheneSam
(Master Searcher)
11-23-01 03:29
No 239517
      Re: automating production: the use of home-made mo     

Here's some links on gratings:

http://www.its.bldrdoc.gov/fs-1037/dir-011/_1628.htm
http://physics.nm.ru/Physics/English/DG10/theory.htm
http://physics.okstate.edu/courses/experiments/o5.html
http://enrich.sdsc.edu/SE/opticsdiffract.html


http://www.geocities.com/dritte123/PSPF.html
 
 
 
 
    Greensnake
(Newbee)
11-23-01 13:26
No 239669
      Re: automating production: the use of home-made mo     

Here's the reference for NMR building:

Journal of Chemical Education Vol.75 No.8 August 1998 pp.1008-1013

Fourier Transform Nuclear Magnetic Resonance Spectroscopy Experiment for Undergraduate and Graduate Students

And aparently this book would be a great help too

Experimental Pulse Nmr: a Nuts and Bolts Approach
by Eiichi Fukushima, Stephen B.W. Roeder


Greensnake
 
 
 
 
    PolytheneSam
(Master Searcher)
11-23-01 16:42
No 239693
      Re: automating production: the use of home-made mo     

This link's pretty good, too. http://www.thespectroscopynet.com/Educational/diffraction.htm

This is a must read here. Very interesting, too.  http://www.wooster.edu/chemistry/is/brubaker/ir/ir_landmark.html

I'm going to see if I can find J. Chem. Ed. somewhere.

http://www.geocities.com/dritte123/PSPF.html
 
 
 
 
    PolytheneSam
(Master Searcher)
11-25-01 03:02
No 240140
      Re: automating production: the use of home-made mo     

I got a copy of that NMR article.  Here's 2 pictures of the set up.
http://wsphotofews.excite.com/014/D3/sL/HI/K020432.jpg
http://wsphotofews.excite.com/023/7v/bw/kp/K417843.jpg

Here's an IR spectrum of safrole from the Sadtler collection.  They also have isosafrole, methamphetamine, methamphetamine HCL, I think 3,4-MDP2P, etc. etc.  and about 10,000? other spectra.  With standard spectra like this you probably don't need to learn how to interpret IR spectra.


http://wsphotofews.excite.com/015/eo/H3/qe/JP28932.jpg

http://www.geocities.com/dritte123/PSPF.html
 
 
 
 
    PolytheneSam
(Master Searcher)
11-30-01 03:08
No 242328
      Re: automating production: the use of home-made mo     

Here's a couple pictures of and inside a PE model 700.

http://www.geocities.com/apis_mellifica2002/Inside700.html

http://www.geocities.com/dritte123/PSPF.html
 
 
 
 
    TrickEMethod
(Hive Bee)
12-01-01 01:42
No 242749
      Re: automating production: the use of home-made mo     

I am no expert, in fact I don't know much about how to read one of those plots, but I do think the complexity comes from mixtures.  If you have a pure sample, then you can just do a comparison I would assume.  But what if you have some unreacted E, along with some remaining pill Gak and a portion of you product that was converted to 3,4 trans di-putrified-phlem-enol HCL salt due to impurities planted by the government onto the inner surphace of all bear bottles to render them useless for the production of illegal substances.

I think each of these signatures bleed together, in some way.  Seperation is where FFT processing and column size, temp, configuration, mobile phase, stationary phase come into play, if my 20min of extensive research in not in error.



And on the eight day, God created Meth...
... and hasn't done much of anything usefull since!
 
 
 
 
    PolytheneSam
(Master Searcher)
12-01-01 16:02
No 243004
      Re: automating production: the use of home-made mo     

You'll see bands from all the components of the mixture in the spectrum.  If there's any chemical interaction between the components (such as hydrogen bonding, for example) it would tend to affect the spectrum.  The length (strength) of a band in the spectrum depends on the concentration of the component and path length (among other things) of the sample.  If the concentration is too low and/or the spectrophotometer is not sensitive enough then the bands won't show up for that component.  They teach Beer's Law in Chem101.  The molar extinction coefficient or molar absorptivity seems related.  Note that concentration and path length are factors in the equation.



http://www.geocities.com/dritte123/PSPF.html
 
 
 
 
    PolytheneSam
(Master Searcher)
12-03-01 00:28
No 243375
      Re: automating production: the use of home-made mo     

Here's something that shows animations of molecular vibrations relating to various spectra bands.
http://www.cem.msu.edu/~parrill/AIRS/

http://www.geocities.com/dritte123/PSPF.html
 
 
 
 
    TrickEMethod
(Hive Bee)
12-10-01 01:15
No 245961
      Re: automating production: the use of home-made mo     

Would it not make more sense to start somewhat smaller than NMR or spec?  What about temp, pressure, liquid levels, drop counters, colorimeter, conductivity, ph/or specific ion probe monitoring.  All of which could be done using a PC game port or $60 rs232 multi-meter from radioshack and a VB application...

or a palm if you are on the run.

I have a setup like this that runs my reaction controls, but does minimal monitoring.  Mostly I just monitor temp/pressure, drop counting(flaky, but I'm working on it) and liquid levels(flaky, but I really don't need it for anything yet so WGAF).  The software runs my bath pumps/peltiers(about 1deg temp control unless reaction gets really frisky), metering pumps, exhaust fans and rewinds my porn so I'm not interupted.  Who could ask for more?


And on the eight day, God created Meth...
... and hasn't done much of anything usefull since!
 
 
 
 
    UTFSE
(Hive Bee)
12-11-01 02:23
No 246282
      Re: automating production: the use of home-made monochromatic spectrophotometers? -drone     


   
  
 
 
United States Patent  6,327,398 
Solgaard ,   et al.  December 4, 2001 

--------------------------------------------------------------------------------
Multi-wavelength cross-connect optical switch


Abstract
A cross-connect switch for fiber-optic communication networks employing a wavelength dispersive element, such as a grating, and a stack of regular (non-wavelength selective) cross bar switches using two-dimensional arrays of micromachined, electrically actuated, individually-tiltable, controlled deflection micro-mirrors for providing multiport switching capability for a plurality of wavelengths. Using a one-dimensional micromirror array, a fiber-optic based MEMS switched spectrometer that does not require mechanical motion of bulk components or large diode arrays can be constructed with readout capability for WDM network diagnosis or for general purpose spectroscopic applications.


This is a very small rendition of the guts of a spectrometer
built for intergration into OEM units.

Don't know the price - pretty high probably but this would be the majority of a basic unit. Then interface to your PC.



just glad to bee here-----he he he
 
 
 
 
    UTFSE
(Hive Bee)
12-11-01 02:27
No 246286
      Re: automating production: the use of home-made mo     


   
  
 
 
United States Patent  6,327,398 
Solgaard ,   et al.  December 4, 2001 


Multi-wavelength cross-connect optical switch


Abstract
A cross-connect switch for fiber-optic communication networks employing a wavelength dispersive element, such as a grating, and a stack of regular (non-wavelength selective) cross bar switches using two-dimensional arrays of micromachined, electrically actuated, individually-tiltable, controlled deflection micro-mirrors for providing multiport switching capability for a plurality of wavelengths. Using a one-dimensional micromirror array, a fiber-optic based MEMS switched spectrometer that does not require mechanical motion of bulk components or large diode arrays can be constructed with readout capability for WDM network diagnosis or for general purpose spectroscopic applications.


--------------------------------------------------------------------------------
Inventors:  Solgaard; Olav (Davis, CA); Heritage; Jonathan P. (Davis, CA); Bhattarai; Amal R. (Davis, CA) 
Assignee:  The Regents of the University of California (Oakland, CA) 
Appl. No.:  748025
Filed:  December 21, 2000


Solid state fiber optic spectral grating and sensing miniature devise aka spectrometer.






just glad to bee here-----he he he
 
 
 
 
    UTFSE
(Hive Bee)
12-12-01 02:49
No 246646
      Re: automating production: the use of home-made mo     

These articles appeared in Scientific American:
 
January, 1980. A Homemade Spectrophotometer Scans the Spectrum in a Thirtieth of a Second
Cost:$100+ Difficulty:  Danger 3: (Serious injury possible)  Utility: 

January, 1975. A High School Student Builds a Recording Spectrophotometer
Cost:$100+ Difficulty:  Danger 1: (No hazards)  Utility: 

March, 1974. A New Kind of Spectrohelioscope for Observing Solar Prominences
Cost:$100+ Difficulty:  Danger 2: (Minor injury possible)  Utility: 

July, 1970. How to Construct a Molecular-Beam Apparatus and a Mass Spectrometer
Cost:$100+ Difficulty:  Danger 3: (Serious injury possible)  Utility: 

October, 1968. An Ultraviolet Spectrograph Designed By the Illustrator of This Department
Cost:$100+ Difficulty:  Danger 2: (Minor injury possible)  Utility: 

May, 1968. A Spectrophotometer Is Built for Less Than $75
Cost:$0-100 Difficulty:  Danger 3: (Serious injury possible)  Utility: 

September, 1966. On the Making of an Inexpensive Diffraction-Grating Spectrograph
Cost:$100+ Difficulty:  Danger 3: (Serious injury possible)  Utility: 

April, 1959. How Amateurs Can Build a Simple Magnetic-Resonance Spectrometer
Cost:$100+ Difficulty:  Danger 3: (Serious injury possible)  Utility: 

September, 1958. How a Group of High School Students Constructed a Beta-Ray Spectrometer
Cost:$100+ Difficulty:  Danger 3: (Serious injury possible)  Utility: 

September, 1956. About a Diffraction Grating Spectrograph Made of Materials Costing Under $100
Cost:$0-100


just glad to bee here-----he he he
 
 
 
 
    Greensnake
(Newbee)
12-12-01 20:48
No 246850
      Re: automating production: the use of home-made mo     

Well, onna certain auction site right now there's one NMR gear for sale, cheapie - 49$ no reserve.
 
 
 
 
    PrimoPyro
(Hive Addict)
12-13-01 21:34
No 247204
      Re: automating production: the use of home-made mo     

yellium: In regards to Post 238432 (yellium: "Re: automating production: the use of home-made mo", Serious Chemistry) I have contacted the representative of Exstrom, Inc. through email, requesting such information on the persimon. I was told that a price has yet to be set. They will be manufacturing it themselves (its not yet ready) and more information will be coming out soon. He said he'd keep me updated.

                                                 PrimoPyro

Vivent Longtemps la Ruche!
 
 
 
 
    ChemGrrl
(Guilty of Contempt)
12-24-01 09:02
No 250203
      Re: automating production: the use of home-made mo     

I would think that you could take the reference spectra for what you knew that you put into the reaction to begin with and estimate a wavelength that would change dramatically from inception to completion.  A little bit of tweaking would be necessary the first couple of times running the reaction to find the best wavelength for the pathway chosen.  Ultimately though, since the best solution would be to look for a peak that either appears or disappears, a simple comparison between the control data (before the reaction fires) and the current time data woulbe all that is needed. 

However, the real-world is seldom ideal, and there is likely to be a lot of interference from extra stuff in the mix, coupled with any transient species that are generated during the reaction.  Care would have to be taken to choose a wavelength that would not return a false positive due to these factors.  Much time should be invested in determining these factors before relying too heavily on the data collected for deciding when the reaction is complete.

ChemGrrl

"All I wanted was a Pepsi..."
 
 
 
 
    PolytheneSam
(Master Searcher)
12-29-01 03:20
No 251024
      Re: automating production: the use of home-made mo     

Maybe we'll be seeing spectrometers on a chip soon.

Infrared micro-spectrometer based on a diffraction grating,
S.H. Kong, D.D.L. Wijngaards, R.F. Wolffenbuttel, pp.88-95
http://www.elsevier.nl/PII/S0924424701005441

Microspectrometer based on a tunable optical filter of porous silicon,
G. Lammel, S. Schweizer, P. Renaud, pp.52-59
http://www.elsevier.nl/PII/S0924424701005398


http://www.geocities.com/dritte123/PSPF.html
 
 
 
 
    UTFSE
(Hive Bee)
01-04-02 20:35
No 252661
      Re: automating production: the use of home-made mo     

US5695720  

A computer-controlled fluid manipulation and analysis apparatus for chemical, biochemical and clinical analysis, sample preparation, and microscale chemical and biochemical synthesis, having one or more stream selection hubs with multiple ports through which microliter volumes of multiple fluid streams may be accessed, stacked, mixed and otherwise transferred by two or more cooperant pumping systems in a highly repeatable and fully software programmable manner. The inherent or resulting properties of said fluids may be automatically recorded via one or more appropriate electronic detectors and data recording systems. Systems comprised of two or more hubs exhibit higher properties of a flow network, and allow more than one fluid segment to be processed simultaneously. Bi-directional flow may occur in each inter-hub connection, and a plurality of possible transport routes can exist between hubs. This leads to enhanced flexibility in sequential processing of each fluid segment.


just glad to bee here-----he he he
 
 
 
 
    UTFSE
(Hive Bee)
01-04-02 20:40
No 252666
      Re: automating production: the use of home-made mo     

they are already on a chip. complete with d/a's, diffraction gratings, et al.

Go to espace and do search on "monolithic spectrometers".

they are also already on pc cards that just plug into your laptop and use a fiber optic probe to access data.

just glad to bee here-----he he he
 
 
 
 
    PolytheneSam
(Master Searcher)
01-06-02 01:07
No 253007
      Re: automating production: the use of home-made mo
(Rated as: good read)
    

I was looking for some specifications for the RE200B in this post Post 238042 (PolytheneSam: "Re: automating production: the use of home-made monochromatic spectrophotometers?  -drone", Serious Chemistry) and found these links.  Its appears the sensor is made up of two back to back crystal sensors (opposing signals) which detect the IR, a field effect transistor for amplification/impedance matching, a resistor for biasing the transistor and a window which has a bandwidth of about 7-14 m.  Note that 7-14 is a factor of 2 and therefore there would be no need for another filter to filter out diffraction grating orders with this sensor in this band.  The "field of view" of each sensor is at a different angle.  These things seem to be very sensitive, ie. can detect the heat from someone walking in front of (across) it.

explanation of sensor, internal diagram, circuits, testing
http://www.komantech.com/product/re200b.htm

various pyroelectric sensors and specs
http://www.nicera.co.jp/sd/item/sensor/pyro/

price, internal diagram, specs, circuit
http://home.netcom.com/~gtb/sensor/sensor.html

2 pages, specs, diagrams
http://www.ciss.at/DATA/Sensor_RE200B.pdf

specs.
http://www.ciss.co.at/PRODUCTS/KEYCOMP/sensors.html

weather station, shows various circuits and specs
http://www.tubbs.net/EcoPod/proposal2/final report.pdf

good pictures of devices, need Chinese charactor plug-in
http://www.china-sunny.com/Sensor/Pyroelectric sensor/Pyroelectric-produce1.htm

Pyroelectric motion detector
http://www.glolab.com/pirparts/pirparts.html

How they work
http://www.glolab.com/pirparts/infrared.html



http://www.geocities.com/dritte123/PSPF.html
 
 
 
 
    UTFSE
(Hive Bee)
01-09-02 23:33
No 254507
      Re: automating production: the use of home-made mo     

I am sorry for that slight Foxy - I just really want some tangible things and I got overwrought and tried to  force the issue.   Sorry maam!!!!

(thanks Lugh)
 
 
 
 
    LaBTop
(Daddy)
01-14-02 14:02
No 256206
      Re: automating production: the use of home-made mo     

Tripping the fantastic light beam.

BALTIMORE A technology originally developed during the NASA Mars program now delivers precise on-line monitoring and control in demanding chemical, petrochemical and pharmaceutical production applications. According to technology developer Brimrose Corp., based here, the FreeSpace AOTF NearInfraRed (NIR) instrument provides the laboratory or plant manager with precise, real-time analytical data about the material flowing through a pipe, or about what is occurring in a reactor or a blender.

The instrument has no moving parts a major benefit in difficult environments. "For space technology, vibration was a huge problem with moving parts," explained Thomas Borheck of Brimrose. "Our instrument has no moving parts. Once it was working for space, where temperature changes very drastically and there are enormous impacts from G forces and all that, [we discovered] it's applicable for process applications. You can put it right in the plant, right over whatever it is [you want to monitor]."

The instrument works well with polymer, film coating, pharmaceutical, fluid bath dryer and homogeneity monitoring applications, said Borheck. "It can analyze the chemical components on thin film online," he said. "There's no alternative to that. You can use it for anything organic whatever you can analyze with NIR for organics, you can analyze online."

A key advantage in process applications is the instrument's high speed. According to Borheck, no other technology comes close. And because it provides real-time results, it helps prevent product loss and reduces waste.

In pharmaceutical applications, said Borheck, "it can analyze online every single tablet that is leaving the plant, and check if the chemical component the active ingredient in the tablet or capsule is exactly what's supposed to be in there. Or in other chemical applications, you can hook it up to a valve to open or close the value, to adjust, for example, fat content or oil content. So it's for monitoring and control, not just monitoring."

Light entering the instrument is put through an optical device, said Borheck. When the light hits the chemical components whether they're solids, or fluids or powders it is reflected off the material. A detector then analyzes the difference between what's been put in and what is put out, in the range between 900 nanometers and 2400 nanometers. It can be placed into a company's overall control system, he added.

For more information about the technology, visit the company's Web site at www.brimrose.com, or contact Borheck via e-mail at tborheck@Brimrose.com.
LT/

WISDOMwillWIN
 
 
 
 
    Bozakium
(Hive Addict)
04-03-02 21:31
No 291904
      IR specs, again     

Beez,
  Thanks for the research.
Motion detector circuitry is 5 buck radio shack stuff, the meat is in the spectral scanning. Computer can do the graphing, even that old 386.
   Shit, if they're 2B had used for a few hundred buck, thats the way to go. Run a few test samples and calibrate. Take to repair shop or self repair if electronics are bad. I know of a school that moved its chem dept and just threw out the old ones. (I missed the dumpster due to being away on sabbatical, frown.)
  If they become available on achip with solid-state variable-wavelength emitter or detector, and no moving parts, the cost could become practical in home labs, otherwise its auction and used equipment shop time.
   For those of you who need a strong permanent magnet for NMR experiments a la science mag articles, cannabalize an old disk drive. you WONT bee dissapointed.
    I'd still like some schematic diagrams and service info, but dont have much online time available yet. Ill keeep ya posted.
--Bz138
 
 
 
 
    ClearLight
(Newbee)
04-10-02 08:03
No 294913
      SciAm CD ROM Disk     

All of the scientific american amateur scientist articles are on the Scientific american cd rom, put out by the tinker's guild.  The homemade atomsmasher, the xray machine, the gas chromatograph, the mass spectrometer, along with a bunch of tlc and liquid chromatograph articles.  Very searchable, and may even have something on NMR if I recall correctly...

 As to a good sensor, you can order a IC from digikey that has a pin photodiode in it. with a 2.2k ohm resistor across two pins and a 9v battery, it will turn milliwatts of energy to millvolts of electricity on your digital voltmeter... makes a cheap laser power meter, or monospec for under $6.00


Infinite Radiant Light - THKRA
 
 
 
 
    PolytheneSam
(Master Searcher)
04-11-02 05:12
No 295327
      links     

Here's some interesting links.
http://www.ijvs.com/

http://www.ijvs.com/volume6/edition1/section1.htm#Feature

http://spectra.galactic.com/SpectraOnline/Default_ie.htm




http://www.geocities.com/dritte123/PSPF.html
The hardest thing to explain is the obvious
 
 
 
 
    quantum
(Hive Bee)
05-21-02 21:15
No 312028
      some thoughts from a novice newbee     

well I personaly dont think it would be hard.
in au dicksmiths (i think its radio shack in the US
sell a pcb with parts to make a parralel port io control
card. it takes variable volatage in and out and then
converts it into code on your pc.  it can be run
on say linux with in ioperm C/C++ command or with
a pointer made to the address of your prt port 0x378 what eva.
as far as infra red no go in my consideration as the spectrum is to slow and I dont think it would cut through
thick emulsions. much like sound going through rubber
uv leds and sensors are available the card costs about $50
and the sensors and leds cost about 5 to 10 each.
I have used this in hydro for moving lights about my plants
to the exact location.
so what problems would I have doing this with this info.
hmm well what spec would you need.
well I could work out plank bla particle in a box thingy
but what about emulsions. you have mutiple chemicals with
diffrent orbitals and you dont know were they are or exactly
how much there is.
so I think your code is going to be the hard part.
somthing on the lines of a tree storing all of you wavelenghts for your possible pure chems in it (I dont think
in this situation you want the proccesor to be calculating
plank and quantum on the fly unless you are running
more than one proccessor)
the some sort of algarithem to find out what the possible
mixes are from the reflected and refracted light.
well thinking on this i think that your program would
come up with more than one possible combonation of
chemicals.
I dont know as I am not an expert on chemistry but it is
something I would love to get a grip on and maby
some help on how to work this out would be good.
I personaly belive that if the chemistry side could be figured I could write the code and give you guys schematics
(I have a few schematics on light sensors and pc operated
plc units at home (still in singapore back soon))
and I think we could also make it so any one here could
write in reactions so and make the software open hive code.
maby make everyones life easier and more profitable.
all in all my light sensor and nutrient system ran on a
486 with custom code writen by me.
it had about $100 worth of electronics including relays
and it cost me about $30 for a gass soliniod.
I think you could also get stuff like water solinoids and
gass ones and get them powder coated so as the didont
corode or react.
anyway there just ideas

keep up the good thinking



remeber its not about the drugs mate its about the music
ye right :)
 
 
 
 
    ClearLight
(Hive Bee)
05-22-02 09:13
No 312373
      make life easy...     

Use a basic stamp programmable controller board, use rs232 if you want to do a terminal read on the process on the  pc, and let that control everything..all your a2d built in, digital and analog io.. 

www.parallaxinc.com


Infinite Radiant Light - THKRA
 
 
 
 
    quantum
(Hive Bee)
05-22-02 09:42
No 312384
      i want one     

have you got one clear light I would love to know
if they give you enough info to code your own interface.
dont want to use there code if possible otherwise I will
make my own.
not to expensive either.
nice one :)


remeber its not about the drugs mate its about the music
ye right :)
 
 
 
 
    ClearLight
(Hive Bee)
05-22-02 18:19
No 312493
      Yes
(Rated as: good idea!)
    


  Yes I have one, actually more than one... they are very slick, program in basic, there's a ton of stuff on the web, check out the site... you can do just about ANYTHING with them... I build instruments and use them for the A/D conversion and stuff.. one of the one's I'm working on is a temperature/vaccumn controller with gas inlet that will allow you to run your pump full bore, adjust the picoliters of gas you need to keep a constant pressure, and take the temp off the condensor head... push a button and you get the  time/temp/pressure for your fraction...I call it a fraction cutter... $19.00 for the pt temp resistor sensor, I got the absolute vacumn gauge as a sample ( normally $45 ) and the picoliter air valve is about $75.00. LCD screen runs $7-125 depending on how much graphics you want...

  Use fuzzy logic to code it, so you don't have to do PID loops and other nasty differentials in your code..

enjoy!


Infinite Radiant Light - THKRA
 
 
 
 
    Rhodium
(Chief Bee)
05-22-02 22:03
No 312566
      fraction cutter     

CL: When your design is finished, I'll GLADLY buy one of those things for you!
 
 
 
 
    ClearLight
(Hive Bee)
05-23-02 07:45
No 312894
      Sure...     


  Two software projs ahead of this one, and then I'll let you know...



Infinite Radiant Light - THKRA
 
 
 
 
    quantum
(Hive Bee)
05-23-02 12:45
No 313066
      hmm very nice     

I dont like basic much though :)
it does seem to be the way most plc's go though
its just so limited when you want to hook it to other
peices of software like sql servers ect.
were do you get vacum gauges from ?
and do you insert your electronic therm in a glass tube
or some other way.
found a site full of schematics dont know if it
is of any use to any one but what the heck
http://www.commlinx.com.au/schematics.htm

thanx CL this will save me a heap of time :)


remeber its not about the drugs mate its about the music
ye right :)
 
 
 
 
    ClearLight
(Hive Bee)
05-24-02 07:42
No 313467
      Sql Servers???     


  Right, well then you'll buy a board on a chip, but hey, wadda ya wanna do? Run a server farm or collect data...besides access is easier to program than sql, and you get it in office...can't get sql for free anymore...

 Vacuumn gauges are all over, omega sells a bunch, and then you can try sensym as well...

  Therm is in a sand packed thinwalled glass tube, use the 3 wire so you can measure accurately...


Infinite Radiant Light - THKRA
 
 
 
 
    Bozakium
(Hive Addict)
06-12-02 20:21
No 320326
      solenoids     

Want a cheep source of rugged, solvent-resistant 12V solenoids? look no further than the junkyard. Fuel injectors! They can be triggered by a square wave from a one-shot timer for any length of time. If timing is real critical use a power transistor instead of a relay for switching the 12V power from the 5V signal pulse.
 
 
 
 
    Whizard
(Newbee)
06-12-02 21:59
No 320376
      WOW and OFOM     

That paralink product is about too cool! Been wanting a lot of instrumentation and control equipment and a couple of those daisycahined to my PC via RS232 is just the ticket. Since the documentation and software is free all you gottas get is the board of your choice and add some programming experience and WHAM .... automated  lab!

The product is really good and the documentation is great

Thanks dude!

I dunno, but I been told ... You never slow down, you never grow old!
 
 
 
 
    PolytheneSam
(Master Searcher)
11-17-02 18:39
No 380503
      See also Post 377439     

See also Post 377439 (PolytheneSam: "For anyone that's interested I uploaded some ...", Chemicals & Equipment)

http://www.geocities.com/dritte123/PSPF.html
The hardest thing to explain is the obvious
 
 
 
 
    lugh
(Moderator)
07-04-04 23:12
No 517437
      JCE articles on automating lab work
(Rated as: excellent)
    

These articles on automating various operations in the chemical laboratory will undoubtedly help many bees wink

Journal of Chemical Education 43 A589-94 (1966)



Journal of Chemical Education 43 A652-7 (1966)



Journal of Chemical Education 43 A737-44 (1966)



cool

Chemistry is our Covalent Bond