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Showing results for tags 'volatiles'.
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Having a think.... I have fifty non-homogeonous biological samples I want to send to a NATA accredited lab for analysis. They contain volatiles, so heating the samples will drive off some of the compounds I want to check the levels off. Heating the samples is part of the standard process of digesting them so they can be analysed. Freeze drying is an option, but for that number of samples the prep would be expensive and out of my range The compounds I'm looking at are relatively stable at ambient temperatures, or at least any variations for the more volatile compounds which come off at above 60C aren't compounds of interest. I was thinking of grinding samples to dryness under liquid nitrogen in a not-fully-sealed stainless lab blender- because I have one here ( or should I seal it? ) but was told that as soon as the liquid nitrogen evaporates , water will rush in and the sample won't be dry any more. Is this true? How fast does the water rush back in if I quickly place the dried samples into a -20 freezer I've previously dried and ground biological samples under liquid nitrogen and found that most suitable, but that was for DNA analysis, not chem analysis. Next option is to grind and dry at 50C under air. Neither will give me consistent moisture levels for all samples, and it will prolly be up to the NATA lab to standardise these before analysis Does anyone reckon grinding under liquid nitrogen to be the superior method in this case? Ta for help, this place is fulla smarties :D