Electrochemical evidence of surfactant activity of the hepes pH buffer which may have implications on trace metal availability to cultures in vitro

• Type: Article in International Scientific Journal
• Date: 1996

Authors

Vasconcelos, MTSD (Author) Other; Azenha, MAGO (Author) Other; Lage, OM (Author) FCUP

Journal

Title: Analytical Biochemistry

Vol. 241

Pages: 248-253

ISSN: 0003-2697

Publisher: Elsevier

Indexing

ISI Web of Knowledge - 37 Citations

Scopus - 38 Citations

Scientific classification

FOS: Natural sciences > Chemical sciences

Other information

Authenticus ID: P-001-DH9

DOI: 10.1006/abio.1996.0406

Abstract (EN): Hydrogen ion buffers are required for many different types of in vitro biological and chemical studies, but they may not be inert enough, thus interfering with the system under study. N-Hydroxyethylpiperazine-N'- ethanesulfonic acid (Hepes), a zwitterionic buffer in the 7.0-8.0 pH range, has been used in different biological studies. In this work, surfactant activity of Hepes and the buffer's capability to bind copper(II) were investigated through different electrochemical techniques: ion-selective electrode potentiometry, potentiometric stripping analysis, differential pulse anodic stripping voltammetry, normal pulse anodic stripping voltammetry, and alternating current polarography. Hepes concentrations between 0.1 (0.24 g liter(-1)) and 25 mmol liter(-1) (6.0 g liter(-1)) were studied at pH 8.0 (and at pH 6.5 for comparison). At pH 8.0 Hepes displayed surfactant activity, particularly when \Hepes\ > 10 mmol liter(-1) (2.4 g liter(-1)). The ability of Hepes to bind copper(II) was detected when Hepes was in large excess (\Hepes\/\Cu\ between 10,000 and 2000). Eventual implications in the bioavailability of copper(II) are also discussed. (C) 1996 Academic Press, Inc.

Language: English

Type (Professor's evaluation): Scientific

No. of pages: 6