Enantioselective Potentiometric Membrane Electrodes Based on Antibiotics for the Determination of L- and D-Glyceric Acids

Raluca-Ioana Stefan-Van Staden,R'Afat M Nejem,Jacobus Frederick Van Staden,Hassan Y Aboul-Enein

doi:10.4061/2011/427238

Abstract

Glyceric acid (GA) is a human metabolite existing in L- and D-configurations, which are considered the markers for the diseases L- and D-glyceric aciduria/academia, respectively. Enantioselective, potentiometric membrane electrodes based on carbon paste modified with antibiotics as chiral selectors, vancomycin, and teicoplanin were designed for the assay of L- and D-GA, respectively, in the concentration ranges of 10−9–10−7and 10−4–10−2 moL/L with very low detection limits (1.5 × 10−10 moL/L for L-GA and 1.6 × 10−4 moL/L for D-GA, resp.). The surface of the electrodes can be regenerated simply by polishing in order to obtain a fresh surface ready to be used in a new assay. The proposed electrodes can be successfully applied for the enantioanalysis of L- and D-glyceric acids in serum samples.

Highlights

The enantiomers of the urinary organic acids are important markers for inborn errors of metabolism
This paper describes the design, response characteristics, selectivity, and applications of two EPMEs based on vancomycin and teicoplanin for the enantioanalysis of Glyceric acid (GA)
The response obtained for L-GA was linear and near-Nernstian only for the EPME based on vancomycin, while the response obtained for D-GA was linear and near-Nernstian only for the EPME based on teicoplanin

Summary

Introduction

The enantiomers of the urinary organic acids are important markers for inborn errors of metabolism. Glyceric acid (2,3-dihydroxypropionic acid, GA) is a human metabolite existing in L- and D-configurations. These two enantiomers are vital biological markers for the diagnosis of two different metabolic diseases, primary hyperoxaluria type II (L-glyceric aciduria, PH2) and D-glyceric aciduria [1,2,3,4,5,6]. Enantioselective analysis of glyceric acid is necessary to differentiate between the two inherited metabolic diseases. Macrocyclic antibiotics represent a new class of chiral selectors used in the design of EPME, offering a high selectivity and enantioselectivity [17]. 206.0 a All measurements were made at 25◦C; all values are the average of ten determinations

Experimental

Results and Discussion

Conclusions