UV Spec Filters - (May/28/2009 )

Hi Guys,

I'm trying to buy some filters for our plate reader but I'm really not sure I understand the nomenclature. I need two standard filters (1 inch) and 10 mm thickness which will read absorbance at 570 and 600 nm respectively. All the filters I've seen on Chroma.com show excitation and emission numbers, which would mean that they are for fluorimetry right? Can you use a fluorimetry filter for photometry? Or are they completely different?

Thanks!

The Chroma filters are all fluorescence filters. These should work for your application as typically you will use just one filter for absorbance to filter the light before passing through your sample, and then reading total light at the end i.e. put the excitation filter in and use lens for reading. Be aware that there are a few different types of filter, the two most common are band-pass and long-pass. Band-path gives you a specific range of wavelengths of light getting through e.g. 350-375 nm, while long-pass lets all the light above or below (depending on the filter) a specific wavelength. It looks like you want a specific range, so make sure you buy the right band-pass filter.

Hmm, so I ran the experiment using what I thought were the correct filters. However my absorbance readings seem to be a bit on the high side. Everything is above 1.0 including my media only control. Does that mean the filters are wrong? Or can numbers that high be trusted?

bob1 on May 28 2009, 04:33 PM said: