RareEarth - 3-8-2015 at 05:21
*I do not want to build one*. I would much rather purchase it, but I cannot seem to find any sites that are selling them outright. Most of the sites I
found do not have prices listed or even a way to simply order it.
Can anyone suggest any good places I can order one?
DutchChemistryBox - 3-8-2015 at 06:00
Despite you don't want to build one yourself, I still recommend you to do so. This will save you a lot of money.
Such boxes cost several hundred dollars.
[Edited on 3-8-2015 by DutchChemistryBox]
Dr.Bob - 3-8-2015 at 09:29
You can buy a handheld shortwave UV light for $50-100 on Ebay, you don't need a fancy box or other gadgets. You juts need to make sure that it is a
short wave lamp, and works. The UVP type are very good, and reasonably priced: such as
http://www.ebay.com/itm/UVP-MINERALIGHT-UVS-54-SHORT-WAVE-UL...
I would ask to make sure that it works before bidding on it.
Ozone - 3-8-2015 at 09:45
I'd go for the SW/LW UV-type, typically switchable from 254 to 365 nm.
Shame, though. It's incredibly easy to build one on the cheap now that UV-LEDs are available at a reasonable price (280 and 360 nm).
O3
byko3y - 3-8-2015 at 10:23
But there's no 254 nm LEDs, this is why a mercury lamp with expensive filter is the only solution. However, you can use a mercury lamp without filter,
and it works well for good ZnSiO3-Mn fluorescent plates, because you can easily distinguish between a blue background and green fluorescence.
Does anyone know what materials are used for the 254 nm lamp? Because I have no idea about what meterial can be transparent at 254 nm while absorb
longer wavelenths (IR fluorescent?).
RareEarth - 3-8-2015 at 11:06
What about something like this?
http://www.batteryjunction.com/9-uv-led.html?gclid=CjwKEAjwo...
Says it is used at airports to verify UV ink on ID's, but I think it is only active for longwave and not shortwave.
There's some other more powerful UV lights online that I've found that can do shortwave, but the cheapest one starts at $100
I could look for a germicidal lamp which function in the 254 range, but I am not sure if they have non-UV light as well.
[Edited on 3-8-2015 by RareEarth]
Ozone - 3-8-2015 at 13:58
255 nm close enough for you? There is more than enough spectral overlap with 254.
http://www.s-et.com/spec-sheets/255nm.pdf
byko3y - 6-8-2015 at 09:39
Deep UV light emitting diode, 200-300uW @ 255nm, UVTOP255
Gallium Nitride
Online price: $296.00
Wow... okay, I will call you later. Bye.
Ozone - 6-8-2015 at 13:40
I'm just saying that they exist. I found some a couple of years ago that were cheap. I'll try and remember where I got the things...
O3
byko3y - 6-8-2015 at 17:30
You are totally right, I just realized the reason why they are not used commonly.
The market is small, so the price is higher than it could be. But at the same time you can see that their power is really low, less than 1mW, so they
are pretty much useless for most applications.
Ozone - 6-8-2015 at 19:43
So long as your sensor is sensitive, and with the path lengths generally employed in a spectrophotometer, you don't need a lot of power. 0.5 mW is
more than sufficient for most applications like this (provided you dilute your samples into the linear range, whatever that might be). You would need
to serially dilute a typical sample and see.
For more power, 403nm, or so, is as low as they go in the "high-power" class for laser diodes (about 0.35 W, IIRC, at that wavelength). I should
mention that my 1W blue (445nm) laser will fluoresce a tennis ball so brightly that you can't look at at.
But, for most lab applications (like looking at TLC plates), a simple LED will do. I have made a "flashlight" with adjustable LEDs ranging from
280-500 nm, and they are fine with UV (254-360) applications, and many others, if you have a pair of laser shaders (or cheap glasses that might come
with a laser level) to screen out blue/green fluorescence.
O3
DJF90 - 6-8-2015 at 22:53
There was a fairly recent thread on this:
http://www.sciencemadness.org/talk/viewthread.php?tid=29250
[Edited on 7-8-2015 by DJF90]
lullu - 7-8-2015 at 03:30
PURITEC HNS 254nm by OSRAM work quite good and are cheap
The TLC boxes use a bandpass filter to get a very narrow spectrum around 254nm, that's why they are so expensive I believe.