Book chapter
[8] Use of ascorbate as test for catalytic metals in simple buffers
Methods in Enzymology, pp.125-127
Elsevier Science & Technology
1990
DOI: 10.1016/0076-6879(90)86100-A
PMID: 2233289
Abstract
Ascorbate can be used to test for the presence of adventitious catalytic metals in simple near-neutral buffer solutions. This chapter discusses the use of ascorbate as test for catalytic metals in simple buffers. Ascorbic acid is a diacid, AH2, with pKa values of 4.2 and 11.6. Thus, at near-neutral pH, the dominant species is the monoanion, AH–. Ascorbate is an easily oxidizable reducing agent. However, the rate of air oxidation of ascorbate in aqueous solution is pH- and catalytic metal-dependent. In the presence of catalytic metals, AH2 oxidizes very slowly, whereas AH– oxidizes much more rapidly. In the absence of catalytic metals, AH– is quite stable in air-saturated buffer. It appears that metals are required for this oxidation. Thus, the rate at which ascorbate solutions air oxidizes can be used to monitor for the presence of contaminating catalytic metals. Using ascorbate method, it is easy to verify that the procedures used to demetal buffer and salt solutions are successful. The method provides a tool for troubleshooting when problems occur, and it is an easy and repeatable way to determine and report experimental conditions.
Details
- Title: Subtitle
- [8] Use of ascorbate as test for catalytic metals in simple buffers
- Creators
- Garry R Buettner
- Resource Type
- Book chapter
- Publication Details
- Methods in Enzymology, pp.125-127
- Publisher
- Elsevier Science & Technology
- DOI
- 10.1016/0076-6879(90)86100-A
- PMID
- 2233289
- eISSN
- 1557-7988
- ISSN
- 0076-6879
- Language
- English
- Date published
- 1990
- Academic Unit
- Radiation Oncology
- Record Identifier
- 9984047892802771
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