Forgot your password?
typodupeerror

Comment: Re:Cringe-worthy (Score 1) 62

by threeplustwo (#41426719) Attached to: All Over But the Funding: Open Hardware Spectrometer Kit
Read the TFA, if you have not yet.

"We are working on a cheap version which we hope to use to identify oil contamination in water and soil, as well as a range of other possible toxins."

It is in the first paragraph, right at the top of the page. I did not invent it. Also, they are trying to make an absorbance spectrometer. It has nothing to do with planets or astronomy.

I would not call their goals "lackluster" either. I wish I had something like that in my lab. Problem is, the execution is very poor. The guys behind this are really clueless, to the point of having visible light spectra on their Kickstarter page backwards.

Comment: Re:Blood sugar test? (Score 3, Informative) 62

by threeplustwo (#41421007) Attached to: All Over But the Funding: Open Hardware Spectrometer Kit
Non-invasive glucose measurement is one of the holy grails of portable spectrometer design. As it happens, it is most practical using NIR and IR. There are products that will be on the market soon. The kit from TFA won't do it, of course. Spectral resolution is too low, and it looks at all the wrong wavelengths.

Comment: Re:Cringe-worthy (Score 1) 62

by threeplustwo (#41420929) Attached to: All Over But the Funding: Open Hardware Spectrometer Kit
Sure, fluorescence spectrometry is pretty useful. So is UV-Vis. In my lab, I use the latter to estimate the size of gold nanoparticles we are making (there, I said the "nano" word!). We use a cheap-ish Lambda XLS+ machine built by Perkin-Elmer. However, there is a very big gap between observing fluorescence of PAHs (not really possible with their specific setup) and the sweeping claim that they "...imagine a kind of 'SHAZAM for materials' which can help to investigate chemical spills, diagnose crop diseases, identify contaminants in household products, and even analyze olive oil, coffee, and homebrew beer." Sounds more like something that can save the world and change lives, and less like a useless (and poorly executed) toy it is. Sometimes, real science can be done by gifted amateurs in their backyards. Sometimes, you actually do need to go to grad school and then spend $2M to outfit a lab. Building a real spectrophotometer and (more importantly) interpreting the results requires the latter.

Comment: Cringe-worthy (Score 3, Informative) 62

by threeplustwo (#41419951) Attached to: All Over But the Funding: Open Hardware Spectrometer Kit
I don't want to sound all negative here, but... I don't have a choice, do I? A visible light spectrophotometer will not "detect toxins", no matter how much you try to make it open-source or crowd-sourced. The very concept of identifying compounds by visible light absorbance is very much flawed. Thing is, *most* molecules will not absorb visible or near UV light in a way that is specific enough. Real Chemists (TM) traditionally use the so-called IR fingerprint region for this purpose. This region is from approx. 700 to 1500 cm-1 (about 6 to 20 uM - that is 6000 to 20000 nanometers). A special detector is needed for these wavelengths. The one we have in our lab is cooled with LN2 and costs south of $15K. We also have a UV-Vis spectrophotometer, which has its own purpose. That purpose is not "identifying toxins", or analyzing any unknowns. Now, on to my next point. Identifying molecules is challenging, because they are very, very, very mindbogglingly small. Chemists have been grappling with this challenge for a long time. There are many spectrometric methods out there, including IR and UV-Vis (briefly discussed above), near-IR (900 to ~1800 nm, useful for *some* fingerprinting), and NMR (60-1000 MHz, very informative, bit needs a BIG magnet). Spectral data for many molecules of interest has been compiled into readily accessible databases, and is easily accessible. Some of the databases are proprietary/pay-per-view: https://ftirsearch.com/features/libraries/sea407.htm Some are semi-public: http://riodb01.ibase.aist.go.jp/sdbs/cgi-bin/direct_frame_top.cgi And some are government/public: http://webbook.nist.gov/chemistry/ The people who started this project do not seem to grasp of the very basic concepts of chemistry, nor did they do any research on the subject. Reading a Wikipedia article on UV-Vis would have been a good start. What is even more disconcerting is that the fundraising effort behind this cardboard spectroscope has been a success. One just has to hope that nobody buys this to screen their food for "toxins", or to teach their kids chemistry.

Center meeting at 4pm in 2C-543.

Working...