[mamech]

Hello everyone

I have a question regarding the ability to identify using spectroscopy (IR or Raman) the existence of DNA in a liquid. I am not neither chemist, nor biologist, but what I undertand is that DNA in general is formed of nucleotide each composed of: a five-carbon sugar ( 2-deoxyribose ), a phosphate group, and one of the four bases adenine, cytosine, guanine, and thymine. So my question is, What I suppose that these compounds and bases are chemical compounds and should have a specific foortprint in frequency spectrum, that can give some insight about if the liquid is DNA-free, or it has DNA chains (that may exist from pathogens that were inactivated or so), is my assumption valid?


Thanks

[Babcock_Hall]

Your question is very broad; can you provide some context?

There are certain tests one could run that would rule out the presence of DNA (at the level of detection of the tests) if negative.  Yet a positive result in the ones that I can think of offhand would be positive for other substances as well.  For example there are some very sensitive colorimetry tests for inorganic phosphate.  One could also look for absorbance in the ultraviolet region near 260 nm.  One might apply ultrafiltration or some related technique that would concentrate macromolecules such as DNA relative to small molecules, in order to make the analysis easier. 

It would not surprise me to learn the infra red or Raman spectroscopy could be used, but I don't have any specific knowledge of how to apply them to the question at hand.  There are also dyes such as ethidium bromide that bind to DNA, although my guess is that they only bind well to double stranded (duplex) DNA.  Enzymatic analysis is also a possibility.