Macrocyclic antibiotics as chiral selectors in the design of enantioselective, potentiometric membrane electrodes for the determination of l- and d-enantiomers of methotrexate.

Three enantioselective, potentiometric membrane electrodes (EPMEs) based on macrocyclic glycopeptide antibiotics-vancomycin and teicoplanin (modified or not with acetonitrile)-were proposed for the determination of l- and d-enantiomers of methotrexate (Mtx). The linear concentration ranges for the proposed enantioselective membrane electrodes were between 10(-6) and 10(-3)moll(-1) for l- and d- methotrexate. The slopes of the electrodes were 58.

Determination of l-carnitine using enantioselective, potentiometric membrane electrodes based on macrocyclic antibiotics.

In order to determine the enantiopurity of l-carnitine three enantioselective, potentiometric membrane electrodes were proposed for the assay of l-carnitine. The electrodes were designed using macrocyclic glycopeptide antibiotics-vancomycin and teicoplanin. Acetonitrile was added to the teicoplanine to design a modified teicoplanine based electrode.

Bienzymatic amperometric sensor for protein assay in milk.

A new bienzymatic amperometric sensor is proposed for the assay of the protein content of milk. The sensor is based on two enzymes: carboxypeptidase A and L-amino acid oxidase. The response characteristics obtained for this sensor (detection limit of 1.