We have collected Holothuria mexicana and Isostichopus badionotus for stable isotope analysis. We have tried drying, freeze-drying, mortar and pestle, coffee grinders, tissue grinders, etc., with no success at grinding the tissues up fine enough to homogenize the sample and run on the spec. Anyone try to do this? Suggestions?
I had the same issue trying to homogenise various reef fish species for the same purpose. My solution: a Kenwood food processor followed by freeze drying, followed by a ball-mill grinder. This worked wonders despite being somewhat time-consuming!
Although I haven't tried for sea cucumber try grind freeze-dired samples in liquid-N2 in a mortar. It worked for my most fibrous samples
Try the liquid N2 method suggested by Bernardo Duarte. There is also a specialized homogenizer you can use with specimens frozen in N2, but try the mortar first.
Another more efficient and quicker method is the Spex Cryomill. I use this instrument all the time for all my modern and even fossil samples (if required). It can grind almost anything by having samples placed in a tube with a metal rod, and then submersed in liquid nitrogen. When the lid is closed you set it into operation and high-power magnets move the steel rod from end to end in the tube. This grinds the material in a freezing environment. It is often used in the biological sciences because it grind without introducing heat. You can grind modern wood, muscle tissue, fat, blubber and chitin for example in about 2 minutes. When you remove the samples it becomes a bit like sludge but one air dried it can be easily hand mortared back into the powder it was. Cheers, Darren
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