Wikipedia states " Phytic acid and phytate have a strong binding affinity to the dietary minerals, calcium, iron, and zinc, inhibiting their absorption.[1]"  Sigma-Aldrich sells USP grade phytic acid solution and has not purity listed.  I expect the color is due to binding to a trace metal contaminate.

Paul Weller

Paul Weller
Senior Science Laboratory Manager-Chemistry
Elon University
2625 Campus Box
Elon, NC 27244
Phone  336.278.6225
Location MCMI 302
wellerp**At_Symbol_Here**elon.edu

 
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-----Original Message-----
From: ACS Division of Chemical Health and Safety <DCHAS-L**At_Symbol_Here**Princeton.EDU> On Behalf Of DCHAS Membership Chair
Sent: Thursday, August 20, 2020 9:29 AM
To: DCHAS-L**At_Symbol_Here**Princeton.EDU
Subject: [DCHAS-L] wondering where the yellow went

From: Monona Rossol <actsnyc**At_Symbol_Here**cs.com>
Re: wondering where the yellow went

Phytic acid is described in the literature as a yellow to brownish liquid.  There is a thread on the American Institute for Conservation's (AIC) forum about art conservators switching away from Sigma's phytic acid more brownish acid to another provider's whose phytic acid is pale yellow.  The assumption is the Sigma product has "degraded."

Danged if I have a clue.  I just know as vegetarian, I eat more of it than they do.  Does anyone out there have a clue what this reagent color difference actually is? 

Monona

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