Help me grind or pulverize my radioactive radishes.
June 2, 2010 4:02 PM   Subscribe

Help me grind or pulverize my radioactive radishes.

I am analyzing some radishes for radioactivity. I have a procedure that calls for finely cut dried plant tissue. My problem is after drying a radish at 60 C the radish is very hard. How can I reduce a dried radish to a homogeneous mass of finely cut (or ground) dried tissue that I can dissolve in acid for analysis?

Food processor didn't work, using a knife or blade is impractical, I've tried a glass mortar and pester which didn't work well. On tonight's list is my home blender (on a nonradioactive dried radish), a nutcracker, and a ceramic mortar and pestle.

I have considered cutting the radish up before drying, but don't want to interfere much with the sample. Any suggestions from the hive are welcomed.
posted by pseudonick to Science & Nature (28 answers total) 3 users marked this as a favorite

- a rotary cheese grater
- a nutmeg grater or other spice grater/grinder
- a woodworking rasp?
posted by peachfuzz at 4:04 PM on June 2, 2010

Best answer: Freeze them in liquid nitrogen and use a hammer.
posted by jamjam at 4:07 PM on June 2, 2010 [1 favorite]

Coffee grinder?
posted by RobotHero at 4:08 PM on June 2, 2010

Heavy grit sandpaper?
posted by The White Hat at 4:11 PM on June 2, 2010

slice a fresh radish really thin using a carrot peeler. Once dried those should be easy to grind into a powder. I doubt the whole dried radish can be cut up by anything short of a hydraulic press.
posted by GuyZero at 4:12 PM on June 2, 2010 [1 favorite]

Coffee grinder. You want the cheapass variety with the spinning blades, not the nice burr grinders. You might also consider whacking them with a hammer before grinding them, so as to start out with smaller pieces.

Coffee grinders work a charm for grinding up the very tough stems of...uhh..herbaceous plants for human consumption. I'm sure they'll grind your radishes.
posted by Netzapper at 4:16 PM on June 2, 2010

Best answer: You might or might not use liquid nitrogen with a sledge microtome, if you don't want a mess on your hands or need consistent samples. As I'm sure you know, if you're handling radioactivity you'll want to think about device contamination, and liquid nitrogen has its own safe handling requirements.
posted by Blazecock Pileon at 4:19 PM on June 2, 2010

How is a knife impractical? Like, it won't cut the radish, or it's too time consuming? If the latter, i.e., if a knife can cut it, a really sharp mandoline will make quick work of it, give paper-thin slices, and be very safe. Or hit it with the slicer before drying.
posted by supercres at 4:20 PM on June 2, 2010

Electric carving knife? I'm assuming knives aren't practical due to speed.
posted by fairytale of los angeles at 4:34 PM on June 2, 2010

posted by Cool Papa Bell at 4:35 PM on June 2, 2010

Yeah I would totally go the liquid nitrogen route. You can freeze and powder just about anything with enough liquid nitrogen and while there are some safety/handling issues it's really not all that bad (small splashes evaporate off the skin before it has time to do any damage)
posted by Captain_Science at 4:36 PM on June 2, 2010

Seconding liquid nitrogen, if you can get it. Microtome isn't necessary unless it has to be a thin slice, but if finely ground is just as good, liquid nitrogen and a mortal and pestle are SOP.
posted by dephlogisticated at 4:39 PM on June 2, 2010

a microplane! or indeed anything else that claims to be able to grate nutmeg. (actually, not necessarily anything that works for nutmeg, we have a grinder that looks kind of like a pepper mill for nutmegs, it works fine but I imagine would be a bitch to clean between samples. a little grater/microplane should be fine so long as you wash it up with a brush).
posted by Lebannen at 4:42 PM on June 2, 2010

Overkill suggestion: are you near a university with a geology department? You could ask if you could use their jaw crusher / pulverizer.
posted by Paragon at 4:44 PM on June 2, 2010

nthing Coffee grinder. Look for Krupps brand
posted by notned at 4:44 PM on June 2, 2010

In the lab we'd just use a waring blender (strong metal blender, works just like a home one but better). I've used it to blend dried or frozen plant material before and voom, powder. Alternatively, when grinding bark, I used a big grinder which looked and worked like a meat grinder. I assume your radishes don't get that hard so a meat grinder may be another way to go. I'd mostly be worried about how fibrous they are though, I imagine once they start to break down they're kind of stringy.

A big heavy ceramic mortar and pestle can be used to break down all kinds of stuff including fibrous plant material (I've used them on apple branches for example). You just bang really hard until it starts to fragment. That might at least get you started enough to move on to a blender. This works better if the material is freeze dried or frozen in liquid N, but remember all the safety rules about working with the latter (safety glasses and appropriate gloves at the minimum).

You might find that pulping it before drying is the much easier way to go. Freeze drying would also make powdering much easier. I assume if you're using acid you're in a lab? Because the waring blender really is the go to tool for this exact scenario.
posted by shelleycat at 4:48 PM on June 2, 2010

I would be tempted to use a Waring blender (metal one) with or without liquid nitrogen. You could also look into bead disruptors but they might make a lot of mess.
posted by pombe at 5:17 PM on June 2, 2010

Garlic press?
posted by iamabot at 5:32 PM on June 2, 2010

I would also try a microplane grater. I mean, they're intended to be used on wood, so a dried radish should be no problem.
posted by pullayup at 7:09 PM on June 2, 2010

I don't mean to derail here, but why do you have radioactive radishes? Even by Metafilter's standrds, this is far too unusual to take in stride.
posted by schmod at 7:25 PM on June 2, 2010 [4 favorites]

In our biochem lab, we use a mortar and pestle, but introduce a pinch or two of fine, pure sand to it to aid in grinding. We use this for grinding vegetable (e.g., cauliflower) samples for mitochondria extraction. Without the sand, the mortar and pestle just doesn't grind these samples well but with it, it works like a charm.

Before we do the grinding, we use razor blades OR potato peelers to thin slice the raw samples.

No LN2 needed in this method.
posted by darkstar at 8:06 PM on June 2, 2010 [1 favorite]

Response by poster: Thanks everyone, I think liquid nitrogen is my best bet at this point. Lots of other good advice I'll try if needed, I'll try the liquid nitrogen in the next day or two and see how it goes.

I'm doing this in a hood (to avoid dust inhalation), and with proper safety gear. and it's for some studies about nutrient movement inside plants.
posted by pseudonick at 8:19 PM on June 2, 2010

OTOH, call Blendtec and see if they'll lend you a blender if you promise to video it for them.
posted by InsanePenguin at 8:46 PM on June 2, 2010

We used a plant grinder. I'm sure that's not the technical term, but it looked very similar to this. It pulverized dried plant matter in seconds.
posted by buckaroo_benzai at 9:44 PM on June 2, 2010

Just a note: If you do go the liquid nitrogen route, do not put the freshly-ground material in a sealed container while it is still frozen. If the material thaws in a closed microfuge or conical tube, for instance, it runs a good chance of exploding your powdered tissue all over the lab.

Not that I've ever made that mistake.
posted by dephlogisticated at 9:54 PM on June 2, 2010 [1 favorite]

Pulping the radish before drying may or may not be a good idea. You may find that after drying you have a nice dense brick of dried radish paste on your hands. I would suggest the LN2 route as well, let us know how it turned out.
posted by Dr Dracator at 10:15 PM on June 2, 2010

Response by poster: The liquid nitrogen worked great. It looks like I'll double or triple bag the radishes in ziplock bags and smack them with rubber mallet. Gets me a nice powder.

Thanks mefi!
posted by pseudonick at 1:36 AM on June 3, 2010 [2 favorites]

Best answer: You might find wrapping it in baking paper works better (the nonstick stuff, fold it into a parcel). The powder doesn't stick (either by goopyness or static) and done right is less likely to break than the plastic (plastic can go weird when it's very cold). But it depends on what your powder ends up like and how messy it is and how careful you are with the mallet and how much there is and if it defrosts at all and other stuff. Still, something to consider if you find the bags less than optimal.
posted by shelleycat at 5:19 AM on June 3, 2010

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