Dry Ice instead of Liquid Nitrogen?

[federico luciani]

Good morning, I'm new in this group (glad to know you !) and I am
already wondering a thing... to disrupt cells from plants, grinding
them in a mortar, I usually used liquid nitrogen poured on the sample,
but I found out that some methods on the 'net use instead dry ice...
being this one cheaper and more affordable I wondered why is usually
used LN2 instead...

Many thanks !

Fede

[Dakota Hamill]

1. I think Liquid Nitrogen is readily available in most labs, and isn't that expensive.  It's also a liquid, so throwing your samples into it is quite easy.  How are you supposed to put your sample into a solid chunk of dry ice? (I'm wondering that myself too not trying to sound demeaning) 

2. I believe the faster something freezes (in this case plants/cells) the smaller the ice crystals formed inside the cell.  I used to use Liquid nitrogen to freeze my plant samples, then cut a nice cross section from it, and the inside xylem and phloem was left uncrushed.  If I hadn't frozen it, when I went to cut it, all the xylem and phloem would have collapsed on themselves and my electron microscope image would have been a smooshed plant stem.  

So basically, if you freeze the cells too slowly, the ice crystals inside them get big  enough to lyse the cell and destroy it, but freeze them really fast and they remain small.

-Dakota

[leaking pen]

Oh, you put dry ice in glacial ethanol. you get a thin gel (thinner
the more pure the ethanol) that readily replaces liquid nitrogen.

Its not QUITE as cold, but i know using it to flash freeze veggies
leaves them looking like wax fruit, untouched. I don't know about the
microscopic level on the ice crystals though.

Alex

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[Simon Quellen Field]

Acetone and dry ice chips are also used (and it's easy to come by

at the hardware store).

Acetone has three times the heat capacity of liquid nitrogen, which

allows it to freeze things faster than you might expect just looking

at temperature differences.  Ethanol has almost four times the heat

capacity of liquid nitrogen.

My liquid nitrogen Dewar cost me $500, and only holds 10 liters.

Dry ice can be stored in a Styrofoam ice chest (don't add the

acetone to it there!).  And I have to drive across town to fill the

Dewar, but dry ice is sold at the supermarket and at Baskin Robbins.

For DIY, there are lots of reasons why dry ice and acetone or ethanol

are good substitutes for liquid nitrogen.

[Cathal Garvey]

They sell dry ice in shops over there? What for?

On Apr 14, 2010 5:19 p.m., "Simon Quellen Field" <sfi...@scitoys.com> wrote:

Acetone and dry ice chips are also used (and it's easy to come by

at the hardware store).

Acetone has three times the heat capacity of liquid nitrogen, which

allows it to freeze things faster than you might expect just looking

at temperature differences.  Ethanol has almost four times the heat

capacity of liquid nitrogen.

My liquid nitrogen Dewar cost me $500, and only holds 10 liters.

Dry ice can be stored in a Styrofoam ice chest (don't add the

acetone to it there!).  And I have to drive across town to fill the

Dewar, but dry ice is sold at the supermarket and at Baskin Robbins.

For DIY, there are lots of reasons why dry ice and acetone or ethanol

are good substitutes for liquid nitrogen.

On Wed, Apr 14, 2010 at 8:02 AM, leaking pen <itsa...@gmail.com> wrote: > > Oh, you put dry ice ...

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[leaking pen]

Putting in coolers to keep things cool without wetting them with ice
(especially popular with hunters preserving bodies till they get the
pelts removed) superchilling things, and the ever popular dry ice fog

[Simon Quellen Field]

Ice cream shops sell it to transport ice cream cakes to picnics and

birthday parties at parks.  Keeps the cake solid until it's time to

blow out the candles.

[federico luciani]

Thank you ! Really useful! I was just wondering...for PCR purposes and
RNA extraction would the acetone-dry ice mix suitable? And how long
the LN2 dewar lasts without using it? ....so many question.... you've
been all very kind :)

On 14 Apr, 19:19, Simon Quellen Field <sfi...@scitoys.com> wrote:
> Ice cream shops sell it to transport ice cream cakes to picnics and
> birthday parties at parks.  Keeps the cake solid until it's time to
> blow out the candles.
>

> On Wed, Apr 14, 2010 at 9:54 AM, leaking pen <itsat...@gmail.com> wrote:
> > Putting in coolers to keep things cool without wetting them with ice
> > (especially popular with hunters preserving bodies till they get the
> > pelts removed) superchilling things, and the ever popular dry ice fog
>

> > On Wed, Apr 14, 2010 at 9:40 AM, Cathal Garvey <cathalgar...@gmail.com>

> > wrote:
> > > They sell dry ice in shops over there? What for?
>
> > > On Apr 14, 2010 5:19 p.m., "Simon Quellen Field" <sfi...@scitoys.com>
> > wrote:
>
> > > Acetone and dry ice chips are also used (and it's easy to come by
> > > at the hardware store).
>
> > > Acetone has three times the heat capacity of liquid nitrogen, which
> > > allows it to freeze things faster than you might expect just looking
> > > at temperature differences.  Ethanol has almost four times the heat
> > > capacity of liquid nitrogen.
> > > My liquid nitrogen Dewar cost me $500, and only holds 10 liters.
> > > Dry ice can be stored in a Styrofoam ice chest (don't add the
> > > acetone to it there!).  And I have to drive across town to fill the
> > > Dewar, but dry ice is sold at the supermarket and at Baskin Robbins.
> > > For DIY, there are lots of reasons why dry ice and acetone or ethanol
> > > are good substitutes for liquid nitrogen.
>

> > > On Wed, Apr 14, 2010 at 8:02 AM, leaking pen <itsat...@gmail.com> wrote:
>
> > > Oh, you put dry ice ...
>
> > > --
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> > > You received this message because you are subscribed to the Google Groups
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> > .
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[federico luciani]

Errata corrige: (ETHANOL, not ACETONE, sorry !)

On 14 Apr, 19:19, Simon Quellen Field <sfi...@scitoys.com> wrote:
> Ice cream shops sell it to transport ice cream cakes to picnics and
> birthday parties at parks.  Keeps the cake solid until it's time to
> blow out the candles.
>

> On Wed, Apr 14, 2010 at 9:54 AM, leaking pen <itsat...@gmail.com> wrote:
> > Putting in coolers to keep things cool without wetting them with ice
> > (especially popular with hunters preserving bodies till they get the
> > pelts removed) superchilling things, and the ever popular dry ice fog
>

> > On Wed, Apr 14, 2010 at 9:40 AM, Cathal Garvey <cathalgar...@gmail.com>

> > wrote:
> > > They sell dry ice in shops over there? What for?
>
> > > On Apr 14, 2010 5:19 p.m., "Simon Quellen Field" <sfi...@scitoys.com>
> > wrote:
>
> > > Acetone and dry ice chips are also used (and it's easy to come by
> > > at the hardware store).
>
> > > Acetone has three times the heat capacity of liquid nitrogen, which
> > > allows it to freeze things faster than you might expect just looking
> > > at temperature differences.  Ethanol has almost four times the heat
> > > capacity of liquid nitrogen.
> > > My liquid nitrogen Dewar cost me $500, and only holds 10 liters.
> > > Dry ice can be stored in a Styrofoam ice chest (don't add the
> > > acetone to it there!).  And I have to drive across town to fill the
> > > Dewar, but dry ice is sold at the supermarket and at Baskin Robbins.
> > > For DIY, there are lots of reasons why dry ice and acetone or ethanol
> > > are good substitutes for liquid nitrogen.
>

> > > On Wed, Apr 14, 2010 at 8:02 AM, leaking pen <itsat...@gmail.com> wrote:
>
> > > Oh, you put dry ice ...
>
> > > --
>
> > > You received this message because you are subscribed to the Google Groups
> > > "DIYbio" group. To post to...
>
> > > --
> > > You received this message because you are subscribed to the Google Groups
> > > "DIYbio" group.
> > > To post to this group, send email to diy...@googlegroups.com.
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> > > diybio+un...@googlegroups.com<diybio%2Bunsu...@googlegroups.com>

> > .
> > > For more options, visit this group at
> > >http://groups.google.com/group/diybio?hl=en.
>
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[Cory Tobin]

> Thank you ! Really useful! I was just wondering...for PCR purposes and
> RNA extraction would the acetone-dry ice mix suitable?

For extracting DNA you don't actually need the low temperature. For
RNA, the ethanol/dry ice method works fine in place of LN2. I've used
it a couple of times myself when I have run out of LN2. No problems
with degradation.

-Cory

[Simon Quellen Field]

A ten liter Dewar of liquid nitrogen lasts about six weeks if not used.

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[Stanley Han]

I wonder if contamination is an issue. I used to use ethanol and dry ice to cool down mortar and then ground tissue. To use LN, I dump tissue into it. Does anybody mix dry ice-ethanol with tissue? I did it once but it didn't work well as there will be ethanol left behind.

[Cathal Garvey]

One big disadvantage I guess, is Ethanol as a solvent. Nitrogen cools your sample, but when you mash it up it's still effectively a pure sample and the Nitrogen will evaporate off in no time. Ethanol will dissolve some things, break up associations, etc.. not sure to what extent.

That said, it's probably just as good if you simply want something cold-inert.

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[Nathan McCorkle]

Why not just place your sample in an eppendorf tube and throw the tube in the cold bath? (that's how I extracted RNA two days ago from plant leaf tissue)

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Nathan McCorkle
Rochester Institute of Technology
College of Science, Biotechnology/Bioinformatics