soma
Hazard to Others
Posts: 297
Registered: 31-7-2010
Member Is Offline
Mood: No Mood
|
|
uv for tlc
Information on the web says to use a 254 nm uv lamp to visualize tlc spots. I've got a "black light" tube that's similar to a fluorescent and is about
1 1/2' long. I don't know what the wave length is for it. Would a light made for tlc at 254 nm be a big difference?
Thanks.
|
|
|
Sulaiman
International Hazard
Posts: 3558
Registered: 8-2-2015
Location: 3rd rock from the sun
Member Is Offline
|
|
Low pressure mercury vapour lamps have two main emission wavelengths,
184 nm which is usually absorbed by glass, less by quartz
253 nm which passes through quartz and glass
https://en.wikipedia.org/wiki/Mercury-vapor_lamp
|
|
|
chemrox
International Hazard
Posts: 2961
Registered: 18-1-2007
Location: UTM
Member Is Offline
Mood: LaGrangian
|
|
black lights are usually low wattage and won't illuminate spots that well. Also it's good to have a 2 wavelength lamp. so called "mineral lamps" work
well.
"When you let the dumbasses vote you end up with populism followed by autocracy and getting back is a bitch." Plato (sort of)
|
|
|
DJF90
International Hazard
Posts: 2266
Registered: 15-12-2007
Location: At the bench
Member Is Offline
Mood: No Mood
|
|
http://www.sciencemadness.org/talk/viewthread.php?tid=29250
|
|
|
XeonTheMGPony
International Hazard
Posts: 1636
Registered: 5-1-2016
Member Is Offline
Mood: No Mood
|
|
http://www.hexatechinc.com/uv-c-led.html
A manufacturers page but if you search online you can find more.
In the beams focal point the emission is very powerful, never look directly at led when running.
http://www.ebay.ca/itm/UV-LED-torch-250nm-curing-glue-solder...
250Nm 23 cad apx.
[Edited on 22-4-2016 by XeonTheMGPony]
[Edited on 22-4-2016 by XeonTheMGPony]
|
|
|
soma
Hazard to Others
Posts: 297
Registered: 31-7-2010
Member Is Offline
Mood: No Mood
|
|
Thanks.
|
|
|
soma
Hazard to Others
Posts: 297
Registered: 31-7-2010
Member Is Offline
Mood: No Mood
|
|
I got the uv-led torch.
I'm wondering how safe it is to use without safety glasses as long as you don't look directly at it. Could the uv beams reflect off and still cause
damage?
Also -- anyone know where I could get an inexpensive 254 nm uv protective face shield?
Thanks.
[Edited on 4-5-2016 by soma]
|
|
|
XeonTheMGPony
International Hazard
Posts: 1636
Registered: 5-1-2016
Member Is Offline
Mood: No Mood
|
|
Yes reflective energy at that wave length is dangerous. Any normal UV filter will do the job. Just to remind the UV bulbs used in air purifiers are
the right wave length as well.
|
|
|
Twospoons
International Hazard
Posts: 1282
Registered: 26-7-2004
Location: Middle Earth
Member Is Offline
Mood: A trace of hope...
|
|
250nm is short enough you need to be very careful. I'd avoid any skin exposure, not just eyes. Any sheet of clear acrylic or polycarbonate should
filter out the UV. Especially stuff intended or outdoor use - there's usually a UV blocker added which cuts off everything under ~400nm.
Helicopter: "helico" -> spiral, "pter" -> with wings
|
|
|
soma
Hazard to Others
Posts: 297
Registered: 31-7-2010
Member Is Offline
Mood: No Mood
|
|
Thought to mention that I found an inexpensive clear polycarbonate face shield for ~$7 at https://www.northernsafety.com/Product/20935/Huntsman-Model-...
I already had the head gear for it but it's also fairly cheap.
From the information I've read, polycarbonate filters out the harmful uv.
[Edited on 22-5-2016 by soma]
|
|
|
PHILOU Zrealone
International Hazard
Posts: 2893
Registered: 20-5-2002
Location: Brussel
Member Is Offline
Mood: Bis-diazo-dinitro-hydroquinonic
|
|
In the black light neon tube, you also have NiO to allow for only UV light to pass through.
PH Z (PHILOU Zrealone)
"Physic is all what never works; Chemistry is all what stinks and explodes!"-"Life that deadly disease, sexually transmitted."(W.Allen)
|
|
|
NEMO-Chemistry
International Hazard
Posts: 1559
Registered: 29-5-2016
Location: UK
Member Is Offline
Mood: No Mood
|
|
I got a cheap mineral lamp from ebay, it has two tubes one very short UV and the other similar to the black light. The filters on it look like the
very dark welding mask glass for arc welders.
I have had the lamp around 5-6 weeks and so far the short wave length has shown way more up on paper chromatography anyway. My uncle is a welder in
Newcastle, he has strongly advised me to be extremely careful with the shortwave length UV. It might be an idea to buy a welding filter to be on the
safe side with the short wave length, i only mention it because it isnt normally like him to be so careful with things, so i took it seriously when he
mentioned it.
Anyone know what the chemical is they use to glow on TLC plates at short wave lengths?
|
|
|
byko3y
National Hazard
Posts: 721
Registered: 16-3-2015
Member Is Offline
Mood: dooM
|
|
Usually manganese-doped willemite (Zn2SiO4) is used as a fluorescent mineral. http://www.sigmaaldrich.com/catalog/product/sial/02554?lang=...
It's much easier to safely perform visualization by protecting all the surrondings by placing the lamp and plate into box having a sight glass, thus
even your kids can look at the working device without a danger. It's more convenient than covering your body and protecting your eyes separately.
[Edited on 2-6-2016 by byko3y]
|
|
|
NEMO-Chemistry
International Hazard
Posts: 1559
Registered: 29-5-2016
Location: UK
Member Is Offline
Mood: No Mood
|
|
Quote: Originally posted by byko3y  | Usually manganese-doped willemite (Zn2SiO4) is used as a fluorescent mineral. http://www.sigmaaldrich.com/catalog/product/sial/02554?lang=...
It's much easier to safely perform visualization by protecting all the surrondings by placing the lamp and plate into box having a sight glass, thus
even your kids can look at the working device without a danger. It's more convenient than covering your body and protecting your eyes separately.
[Edited on 2-6-2016 by byko3y] |
Thanks for the info, i am not sure if the filters on the lamp mean you dont need glasses or not? but the mineral lamp is on a stand so you dont look
directly at the light anyway.
I am way too young to have my own kids 
|
|
|
![[*]](images/xpblue/default_icon.gif){kind=icon}
