Re: [ccp4bb] preparing DL-Malic acid stock solution

2017-06-09 Thread Sebastiano Pasqualato 
Dear Janet,
thanks for the excellent tip! It worked like charme!
I think the reason why our solution turned milky was that we were adding NaOH 
pellets without controlling the temperature, and possibly its increase caused 
the (seemingly irreversible) transition to the “porridge” state.
Your method allowed to get a solution which remained clear, despite the 
increase in temperature.
Thanks again!
I have also to thank Edward A. Berry, Diana R. Tomchick and Edward E. Pryor for 
the answers to my post and the valuable information.
Have a nice weekend,
ciao,
Sebastiano


> On 9 Jun 2017, at 01:35, Janet Newman <janet.new...@csiro.au> wrote:
> 
> The way I have done it (and it was sort of fun in a mad scientist way) was to 
> mix up solid DL-malic acid and sodium hydroxide in the right amounts and add 
> water as needed.  This generates  of heat, but gets around the 
> solubility minimum which is impossible to get out of:
> 
> I mixed 40.23 g of DL-malic acid powder (MW=134.1) with 24g of NaOH pellets 
> (MW=40) in a large beaker with a stirrer bar.  Put the beaker in a larger 
> container of ice, and put that on a stirrer in the cold room. Add 80 mL H20 
> to the beaker containing the chemicals, stand back - lots of heat evolved.
> when everything has quietened down, make up to 100 mL with water (we filtered 
> through a 0.22 um filter).
> 
> Cheers, Janet
> 
> -Original Message-
> From: CCP4 bulletin board [mailto:CCP4BB@JISCMAIL.AC.UK] On Behalf Of Edward 
> A. Berry
> Sent: Friday, 9 June 2017 2:53 AM
> To: CCP4BB@JISCMAIL.AC.UK
> Subject: Re: [ccp4bb] preparing DL-Malic acid stock solution
> 
> (di)Sodium D,L-malate is available from Sigma-Aldrich (# CDS023113) and
> probably dissolves to give a 3M solution which is slightly alkaline.
> If pK2 is 5.1, then an insignificant amt of malic acid should bring the
> pH down to 7 (If you have to add a significant amount, just add more
> water to dilute to a final conc of 3M Malate + Malic acid)
> 
> 
> On 06/08/2017 12:32 PM, Diana Tomchick wrote:
>> As the pKa1 of malic acid is 3.4, it may be that the partially neutralized 
>> malic acid salt is less soluble than the acid or the fully neutralized salt.
>> 
>> The pKa2 of malic acid is 5.1.
>> 
>> Contact the people at Hampton Research
>> 
>> https://www.hamptonresearch.com/contact_us.aspx
>> 
>> and ask them. They sell it as a 3.0 M solution, pH neutralized to 7.0.
>> 
>> It is possible that you need to fully neutralize it before it turns clear, 
>> or that you may also need to gently heat it.
>> 
>> Diana
>> 
>> **
>> Diana R. Tomchick
>> Professor
>> Departments of Biophysics and Biochemistry
>> University of Texas Southwestern Medical Center
>> 5323 Harry Hines Blvd.
>> Rm. ND10.214A
>> Dallas, TX 75390-8816
>> diana.tomch...@utsouthwestern.edu <mailto:diana.tomch...@utsouthwestern.edu>
>> (214) 645-6383 (phone)
>> (214) 645-6353 (fax)
>> 
>> On Jun 8, 2017, at 9:54 AM, Sebastiano Pasqualato 
>> <sebastiano.pasqual...@gmail.com <mailto:sebastiano.pasqual...@gmail.com>> 
>> wrote:
>> 
>> 
>> Dear all,
>> we’ve recently having trouble preparing a 3 M stock solution of DL-Malic 
>> Acid, pH 7 (which we had, so it’s doable!).
>> When we reach pH 3 - 4 the solution turns milky white and does not goes back 
>> to a clear solution even when the pH is raised.
>> Does anybody have any advice on how to get a clear solution? Has anyone gone 
>> through the same?
>> Thanks in advance,
>> ciao,
>> Sebastiano
>> 
>> 
>> --
>> *Sebastiano Pasqualato, PhD*
>> Crystallography Unit
>> Department of Experimental Oncology
>> European Institute of Oncology
>> IFOM-IEO Campus
>> via Adamello, 16
>> 20139 - Milano
>> Italy
>> 
>> tel +39 02 9437 5167
>> fax +39 02 9437 5990
>> web http://is.gd/IEOXtalUnit
>> 
>> 
>> 
>> --
>> 
>> UTSouthwestern
>> 
>> Medical Center
>> 
>> The future of medicine, today.
>>

Re: [ccp4bb] preparing DL-Malic acid stock solution

2017-06-08 Thread Janet Newman 
The way I have done it (and it was sort of fun in a mad scientist way) was to 
mix up solid DL-malic acid and sodium hydroxide in the right amounts and add 
water as needed.  This generates  of heat, but gets around the 
solubility minimum which is impossible to get out of:

I mixed 40.23 g of DL-malic acid powder (MW=134.1) with 24g of NaOH pellets 
(MW=40) in a large beaker with a stirrer bar.  Put the beaker in a larger 
container of ice, and put that on a stirrer in the cold room. Add 80 mL H20 to 
the beaker containing the chemicals, stand back - lots of heat evolved.
when everything has quietened down, make up to 100 mL with water (we filtered 
through a 0.22 um filter).

Cheers, Janet

-Original Message-
From: CCP4 bulletin board [mailto:CCP4BB@JISCMAIL.AC.UK] On Behalf Of Edward A. 
Berry
Sent: Friday, 9 June 2017 2:53 AM
To: CCP4BB@JISCMAIL.AC.UK
Subject: Re: [ccp4bb] preparing DL-Malic acid stock solution

(di)Sodium D,L-malate is available from Sigma-Aldrich (# CDS023113) and
probably dissolves to give a 3M solution which is slightly alkaline.
If pK2 is 5.1, then an insignificant amt of malic acid should bring the
pH down to 7 (If you have to add a significant amount, just add more
water to dilute to a final conc of 3M Malate + Malic acid)


On 06/08/2017 12:32 PM, Diana Tomchick wrote:
> As the pKa1 of malic acid is 3.4, it may be that the partially neutralized 
> malic acid salt is less soluble than the acid or the fully neutralized salt.
>
> The pKa2 of malic acid is 5.1.
>
> Contact the people at Hampton Research
>
> https://www.hamptonresearch.com/contact_us.aspx
>
> and ask them. They sell it as a 3.0 M solution, pH neutralized to 7.0.
>
> It is possible that you need to fully neutralize it before it turns clear, or 
> that you may also need to gently heat it.
>
> Diana
>
> **
> Diana R. Tomchick
> Professor
> Departments of Biophysics and Biochemistry
> University of Texas Southwestern Medical Center
> 5323 Harry Hines Blvd.
> Rm. ND10.214A
> Dallas, TX 75390-8816
> diana.tomch...@utsouthwestern.edu <mailto:diana.tomch...@utsouthwestern.edu>
> (214) 645-6383 (phone)
> (214) 645-6353 (fax)
>
> On Jun 8, 2017, at 9:54 AM, Sebastiano Pasqualato 
> <sebastiano.pasqual...@gmail.com <mailto:sebastiano.pasqual...@gmail.com>> 
> wrote:
>
>
> Dear all,
> we’ve recently having trouble preparing a 3 M stock solution of DL-Malic 
> Acid, pH 7 (which we had, so it’s doable!).
> When we reach pH 3 - 4 the solution turns milky white and does not goes back 
> to a clear solution even when the pH is raised.
> Does anybody have any advice on how to get a clear solution? Has anyone gone 
> through the same?
> Thanks in advance,
> ciao,
> Sebastiano
>
>
> --
> *Sebastiano Pasqualato, PhD*
> Crystallography Unit
> Department of Experimental Oncology
> European Institute of Oncology
> IFOM-IEO Campus
> via Adamello, 16
> 20139 - Milano
> Italy
>
> tel +39 02 9437 5167
> fax +39 02 9437 5990
> web http://is.gd/IEOXtalUnit
>
>
>
> --
>
> UTSouthwestern
>
> Medical Center
>
> The future of medicine, today.
>

Re: [ccp4bb] preparing DL-Malic acid stock solution

2017-06-08 Thread Edward A. Berry 

(di)Sodium D,L-malate is available from Sigma-Aldrich (# CDS023113) and
probably dissolves to give a 3M solution which is slightly alkaline.
If pK2 is 5.1, then an insignificant amt of malic acid should bring the
pH down to 7 (If you have to add a significant amount, just add more
water to dilute to a final conc of 3M Malate + Malic acid)


On 06/08/2017 12:32 PM, Diana Tomchick wrote:

As the pKa1 of malic acid is 3.4, it may be that the partially neutralized 
malic acid salt is less soluble than the acid or the fully neutralized salt.

The pKa2 of malic acid is 5.1.

Contact the people at Hampton Research

https://www.hamptonresearch.com/contact_us.aspx

and ask them. They sell it as a 3.0 M solution, pH neutralized to 7.0.

It is possible that you need to fully neutralize it before it turns clear, or 
that you may also need to gently heat it.

Diana

**
Diana R. Tomchick
Professor
Departments of Biophysics and Biochemistry
University of Texas Southwestern Medical Center
5323 Harry Hines Blvd.
Rm. ND10.214A
Dallas, TX 75390-8816
diana.tomch...@utsouthwestern.edu 
(214) 645-6383 (phone)
(214) 645-6353 (fax)

On Jun 8, 2017, at 9:54 AM, Sebastiano Pasqualato > wrote:


Dear all,
we’ve recently having trouble preparing a 3 M stock solution of DL-Malic Acid, 
pH 7 (which we had, so it’s doable!).
When we reach pH 3 - 4 the solution turns milky white and does not goes back to 
a clear solution even when the pH is raised.
Does anybody have any advice on how to get a clear solution? Has anyone gone 
through the same?
Thanks in advance,
ciao,
Sebastiano


--
*Sebastiano Pasqualato, PhD*
Crystallography Unit
Department of Experimental Oncology
European Institute of Oncology
IFOM-IEO Campus
via Adamello, 16
20139 - Milano
Italy

tel +39 02 9437 5167
fax +39 02 9437 5990
web http://is.gd/IEOXtalUnit



--

UTSouthwestern

Medical Center

The future of medicine, today.

Re: [ccp4bb] preparing DL-Malic acid stock solution

2017-06-08 Thread Diana Tomchick 
As the pKa1 of malic acid is 3.4, it may be that the partially neutralized 
malic acid salt is less soluble than the acid or the fully neutralized salt.

The pKa2 of malic acid is 5.1.

Contact the people at Hampton Research

https://www.hamptonresearch.com/contact_us.aspx

and ask them. They sell it as a 3.0 M solution, pH neutralized to 7.0.

It is possible that you need to fully neutralize it before it turns clear, or 
that you may also need to gently heat it.

Diana

**
Diana R. Tomchick
Professor
Departments of Biophysics and Biochemistry
University of Texas Southwestern Medical Center
5323 Harry Hines Blvd.
Rm. ND10.214A
Dallas, TX 75390-8816
diana.tomch...@utsouthwestern.edu
(214) 645-6383 (phone)
(214) 645-6353 (fax)

On Jun 8, 2017, at 9:54 AM, Sebastiano Pasqualato 
> wrote:


Dear all,
we’ve recently having trouble preparing a 3 M stock solution of DL-Malic Acid, 
pH 7 (which we had, so it’s doable!).
When we reach pH 3 - 4 the solution turns milky white and does not goes back to 
a clear solution even when the pH is raised.
Does anybody have any advice on how to get a clear solution? Has anyone gone 
through the same?
Thanks in advance,
ciao,
Sebastiano


--
Sebastiano Pasqualato, PhD
Crystallography Unit
Department of Experimental Oncology
European Institute of Oncology
IFOM-IEO Campus
via Adamello, 16
20139 - Milano
Italy

tel +39 02 9437 5167
fax +39 02 9437 5990
web http://is.gd/IEOXtalUnit





UT Southwestern


Medical Center



The future of medicine, today.

[ccp4bb] preparing DL-Malic acid stock solution

2017-06-08 Thread Sebastiano Pasqualato 

Dear all,
we’ve recently having trouble preparing a 3 M stock solution of DL-Malic Acid, 
pH 7 (which we had, so it’s doable!).
When we reach pH 3 - 4 the solution turns milky white and does not goes back to 
a clear solution even when the pH is raised.
Does anybody have any advice on how to get a clear solution? Has anyone gone 
through the same?
Thanks in advance,
ciao,
Sebastiano


-- 
Sebastiano Pasqualato, PhD
Crystallography Unit
Department of Experimental Oncology
European Institute of Oncology
IFOM-IEO Campus
via Adamello, 16
20139 - Milano
Italy

tel +39 02 9437 5167
fax +39 02 9437 5990
web http://is.gd/IEOXtalUnit