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Author Topic: Sig Figs, Volumetric Flask Tolerance, What? How? Who?  (Read 237 times)

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Cracked_Flask75

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Sig Figs, Volumetric Flask Tolerance, What? How? Who?
« on: June 14, 2018, 09:29:42 AM »

Can I even make this solution (0.022 mg/l PO43-) at the scale of a 1000ml Volumetric flask (tolerance of .30ml)?
Do the sig figs work out?



Dilution example with a 1 L volumetric flask as the target volume:
(200 mg/l) * (unknown volume) = (0.022 mg/l) * (1 L)
Unknown volume        = 1.1 x 10^-4 L
                                 = 0.1 ml
                                = 110 ul

Then I take 110 ul out of the standard bottle using a 100 ul syringe and then a 10 ul syringe (not directly of course), put the 110 ul into a 1lL volumetric flask. Then fill the flask up to the Calibrated marking with DO.
I'll also do this for a .011 mg/l, .055 mg/l, and other small concentrations.



The Reason i'm interested in making such large amounts of small concentrations is because i'm doing an experiment where i'll need 100 Liters of varying solutions at the .011-1.4 mg/l range.

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Borek

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Re: Sig Figs, Volumetric Flask Tolerance, What? How? Who?
« Reply #1 on: June 14, 2018, 10:18:53 AM »

I don't see why it shouldn't work, although it is not clear to me if making 1 L when you need hundreds of liters is practical.

Can't you use adjustable eppendorf pipette instead of 100 μL + 10 μL?
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Cracked_Flask75

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Re: Sig Figs, Volumetric Flask Tolerance, What? How? Who?
« Reply #2 on: June 14, 2018, 12:07:39 PM »

Is there a more practical way of making these solutions with good enough accuracy and precision of making solutions that are only .01 mg/l different?
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Borek

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Re: Sig Figs, Volumetric Flask Tolerance, What? How? Who?
« Reply #3 on: June 18, 2018, 08:51:59 PM »

None that I can think of.
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