MadSci Network: Chemistry |
Not to my knowledge, but you can get non-plastic quartz materials, here is why: In the chemistry department at Carleton University, Ottawa, Canada, as an undergrad I learned to use UV, Vis, and IR spectroscopy for the determination of molecular structure. I also learned some very practical points. Wavelengths of about 340nm (often used to measure NADH levels) and above fall into the visible light region (ie. from a tungsten light bulb) and we could use glass or plastic cuvettes to measure absorbance spectra. However, not all plastics were transparent to light around 340 nm, just some. Once you move to lower wavelengths (ie. < 330 nm) we enter the UV regions. There are no plastics or glasses that are transparent to UV to my knowledge. In this region of the spectrum, we have to use quartz cuvettes, very expensive little containers indeed. As a molecular biologist using site-directed mutagenesis and constucting DNA plasmids/vectors etc, I use absorbance at 260 nm (near UV-A) everyday to measure the concentration of DNA in my solutions. I have to use the quartz cuvettes to do this. In past colaborations with John Trevithick, Biochemistry, University of Western Ontario, I have studied the metabolism of tocopherols (vitamin E) in the skin during mild sunburn and recovery from sunburn. We made our own mouse-tanning bench with UV-A/B lights, and we use sensors to measure the UV A, B and C components of light in the lab and outside in sunlight. For fun we would take the light sensors outside and measure the UV blocking of expensive vs cheap sunglasses using students hanging on the "concrete beach" at the student centre. Many students, were kind of angry to find out that $5 plastic glasses blocked as much UV A/B as $300 designer glasses from those fancy shops in the upscale malls. The plain fact is that plastics are not very transparent to UV light. If someone has recently designed a unique plastic that is transparent, i have not heard of it myself. Some plastics will pass some near UV, ie. close to 330 nm, but UVA,B and C will not pass. Tinting may not affect the UV transparency, but clear plastic blocks UV just a good as green plastic. My clear prescription glasses, plastic, block UV light as good as dark sunglasses. Ken Mitton, Ph.D., Kellogg Eye Center
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