Login

Join for Free!
118340 members


How to measure dry mass?

Discussion of the distribution and abundance of living organisms and how these properties are affected by interactions between the organisms and their environment

Moderator: BioTeam

How to measure dry mass?

Postby l0sthart » Tue May 13, 2008 12:50 pm

How to measure dry mass? is there any equation or so? Hope to get a reply soon. Thanks (:
l0sthart
Garter
Garter
 
Posts: 3
Joined: Tue May 13, 2008 12:46 pm

Postby canalon » Tue May 13, 2008 1:38 pm

No equation. One simple experimental procedure:
take sample put in the oven/desiccator until totally dehydrated and weigh. That simple.
Patrick

Science has proof without any certainty. Creationists have certainty without
any proof. (Ashley Montague)
User avatar
canalon
Inland Taipan
Inland Taipan
 
Posts: 3909
Joined: Thu Feb 03, 2005 2:46 pm
Location: Canada

Postby Cristgonz » Thu Jun 26, 2008 3:30 am

canalon is right.
you don't need an equation.
just weigh it and then put it into a "furnace" and then weigh it again (you could know your water and dry mass weight).
~~Agronomist Engineer, Dekalb Seeds
Anasac, Chile
User avatar
Cristgonz
Garter
Garter
 
Posts: 40
Joined: Thu Nov 15, 2007 8:59 pm


Postby MichaelXY » Sat Jun 28, 2008 6:04 am

All bets are off if you try this on the moon however :)
User avatar
MichaelXY
King Cobra
King Cobra
 
Posts: 885
Joined: Fri Jun 15, 2007 7:03 pm
Location: San Diego, Ca

Postby canalon » Sun Jun 29, 2008 1:58 am

Not really. If you use a balance calibrated to measure the actual weight in the moon gravity field, it will give you the exact same answer. Why wouldn't it. Just use properly calibrated instruments. That is what Quality control is used for ;)
Patrick

Science has proof without any certainty. Creationists have certainty without
any proof. (Ashley Montague)
User avatar
canalon
Inland Taipan
Inland Taipan
 
Posts: 3909
Joined: Thu Feb 03, 2005 2:46 pm
Location: Canada

Re: How to measure dry mass?

Postby MichaelXY » Mon Jun 30, 2008 5:39 am

Yes I realize this, my point was that gravity plays a role in weight.
User avatar
MichaelXY
King Cobra
King Cobra
 
Posts: 885
Joined: Fri Jun 15, 2007 7:03 pm
Location: San Diego, Ca

Postby MrMistery » Mon Jun 30, 2008 2:45 pm

or simply measure with the same instrument and multiply by six.
"As a biologist, I firmly believe that when you're dead, you're dead. Except for what you live behind in history. That's the only afterlife" - J. Craig Venter
User avatar
MrMistery
Inland Taipan
Inland Taipan
 
Posts: 6832
Joined: Thu Mar 03, 2005 10:18 pm
Location: Romania(small and unimportant country)

Re:

Postby canalon » Mon Jun 30, 2008 3:43 pm

MrMistery wrote:or simply measure with the same instrument and multiply by six.


Calibration can often be just that ;-)
Patrick

Science has proof without any certainty. Creationists have certainty without
any proof. (Ashley Montague)
User avatar
canalon
Inland Taipan
Inland Taipan
 
Posts: 3909
Joined: Thu Feb 03, 2005 2:46 pm
Location: Canada

Postby Cristgonz » Wed Jul 02, 2008 3:03 pm

go to the moon and measure haha.
Canalon is right again, just a well calibrated instrument and wuala.
~~Agronomist Engineer, Dekalb Seeds
Anasac, Chile
User avatar
Cristgonz
Garter
Garter
 
Posts: 40
Joined: Thu Nov 15, 2007 8:59 pm

Re: How to measure dry mass?

Postby hsoroosh » Thu Aug 04, 2011 2:58 pm

I need to measure micro algae dry mass. I'm looking for a way measure it indirectly by spectrophotometer (absorbance) simply. is it possible? immediate reply needed! :) I mean if there is a way I can find an equation to figure out algae dry mass by the solution/culture/chlorophyll/etc absorbance in a certain wavelength.

Thank you :)
hsoroosh
Garter
Garter
 
Posts: 4
Joined: Thu Aug 04, 2011 2:53 pm

Postby canalon » Thu Aug 04, 2011 3:04 pm

Easy... Or maybe not.
Find a relaible measure of the density of your culture for your algae. It does not matter what you are using, as long as you can confidently say that there is a relationship between your measured parameter and the cell density of your culture. And check that it works (do dilutions and count).
Once you have that measure the relationship between your cell density and the dry mass: i.e. measure the dry masss of the samples that you have used in the calibration of the step above. Redo a few times independantly to make sure that it works nicely.

Congrats you have your conversion parameters. Enjoy.
Patrick

Science has proof without any certainty. Creationists have certainty without
any proof. (Ashley Montague)
User avatar
canalon
Inland Taipan
Inland Taipan
 
Posts: 3909
Joined: Thu Feb 03, 2005 2:46 pm
Location: Canada

Re: How to measure dry mass?

Postby hsoroosh » Thu Aug 04, 2011 5:23 pm

Thank for quick reply :)
So if I understood truly, I can make a chart with different absorbance and their respective dry mass. and there should be a linear correlation between dry mass-abs . what wavelength you recommend me for that? is 680nm ok? would you please any scientific literature which I can refer to in my writing and references?

Thank you very much
hsoroosh
Garter
Garter
 
Posts: 4
Joined: Thu Aug 04, 2011 2:53 pm

Next

Return to Ecology

Who is online

Users browsing this forum: No registered users and 1 guest