30 % H2O2 is 8.84 M solution. Dilute 8.84 times. The problem is solved.
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1. R: buffer preparation (Prof. Piero Sestili)
2. Dulbecco`s PBS vs PBS pH7.4 (AS)
3. Re: How to prepare 1M H2O2 using 30% hydrogen peroxide?
(Pow Joshi)
4. RE:Induction of apoptosis (Ozan Aygun)
5. Re: Dulbecco`s PBS vs PBS pH7.4 (DK)
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Message: 1
Date: Wed, 6 Feb 2008 16:02:26 +0100
Subject: R: buffer preparation
Content-Type: text/plain; charset="iso-8859-1"
First prepare a 2 M solution by diluting 2.26 ml of your stock to 10 ml,
then make serial 1:10 dilutions down to 2 mM
or
prepare a 200 mM solution first diluting 226 ul of your stock to 10 ml
and then another 1:100 dilution to 2 mM. As you prefer....
Piero
Prof. Piero Sestili
Istituto di Farmacologia e Farmacognosia e
Centro di Ricerca sull'Attività Motoria
Università degli Studi di Urbino "Carlo Bo"
Via "I Maggetti" 26
61029 URBINO (PU)
Tel. 0722 303414; 0722 305524
Fax 0722 303401
-----Messaggio originale-----
Inviato: mercoledì 6 febbraio 2008 12.11
Oggetto: buffer preparation
Hello,
How do i work this out?
I need 2mM H2O2 from a stock solution H2O2 of 30%, density 1.11 gr/ml,
M.W. 34
anybody?
thanks upfront
b
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Message: 2
Date: Wed, 6 Feb 2008 11:39:05 -0800 (PST)
Subject: Dulbecco`s PBS vs PBS pH7.4
Content-Type: text/plain; charset=ISO-8859-1
What is the difference between Dulbecco`s PBS vs PBS pH7.4?
Does it make a difference if I just use it to wash cells (293, MEFs
etc) before trypsination or lysation?
Thanks!
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Message: 3
Date: Wed, 6 Feb 2008 13:09:45 -0500
Subject: Re: How to prepare 1M H2O2 using 30% hydrogen peroxide?
Content-Type: text/plain; charset=ISO-8859-1
In article <
Post by WSDear Lao,
that's the real issue. All your assumptions may be true.
IMHO is is *absolutely* necessary to specify m/v (mass/volume), m/m or
v/v. It even makes a difference if you (in this case rather
hypothetically as solid H2O2 does not exist [at least for a long
time]) mix 300 ml of H2O2 and 700ml of water, put 300 ml H2O2 in a
beaker and add water up to 1liter or vice versa.
Industrial % concentrations tend to be m/m. This is clearly
the case, for example, with concentrated HCl (~ 37% ~ 12M)
or concentrated H3PO4 (85% = 15.2M).
MSDS for 30% H2O2 says "balance water", suggesting
that indeed we are talking about 300 g + 700 g water.
In which case precise molarity calculattion become
troublesome even knowing density of 100% H2O2
because water solutions can change volume
appreciably (e.g. 500 ml ethanol + 500 ml H2O
will result in less than 1000 ml solution).
Not that any of that matters in the experiment in
question! Assuming no volume change and m/m
for 30% and density off 199% of 1.4 g/ml from
Wikipedia, we get 22-28% error depending on the
direction. With the "1 M" being clearly an arbitrary
round number, I wouln't worry about potential
25% error as long as the way the solution is prepared
is clearly stated.
yes, that is true.... H2O2 would be w/w.... the MSDS generally does'nt
give
the information, however, calling the company would give. Frankly, I
did'nt
know that this is true for all industrial preparation..... Thank you Dima.
Pow
DK
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Message: 4
Date: Wed, 6 Feb 2008 13:45:51 -0800 (PST)
Subject: RE:Induction of apoptosis
Content-Type: text/plain; charset=iso-8859-1
Hi,
You may want to give try alpha-amanitin, which is a
highly specific inhibitor of RNA polymerase II. It is
known that exposure to this reagent causes apoptosis
in human cells.
Good luck,
Ozan
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Message: 5
Date: Wed, 06 Feb 2008 22:25:02 GMT
Subject: Re: Dulbecco`s PBS vs PBS pH7.4
In article <
What is the difference between Dulbecco`s PBS vs PBS pH7.4?
Probably none. Gibco used to specify its Dulbecco's PBS
PH as 7.0-7.5. "PBS" is a mess. It can refer to a number of
similar solutions, each with and without Ca2+ and/or Mg2+.
Does it make a difference if I just use it to wash cells (293, MEFs
etc) before trypsination or lysation?
In the range in question, pH won't make a difference but for
trypsinization there might be a diffrence between PBS
containing divalents or not. Don't think it will be significant
if you use trypsin-EDTA.
DK
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