Organic-phase biosensors open new opportunities for assays of challenging pharmaceutical products. Such opportunities are illustrated for the rapid determination of phenol and peroxide antiseptics in different anti-infective formulations. The tyrosinase and peroxidase enzyme electrodes offer reliable quantification of these antibacterial agents following sample dissolution in the organic solvent. The dynamic properties of these enzyme electrodes are exploited for rapid and reproducible flow-injection assays of the pharmaceutical products (relative standard deviation = 1.6–1.9%). Such developments should facilitate rapid quality control testing in the pharmaceutical industry and should be applicable to other therapeutic agents and products. Applicability to cosmetic products containing hydrogen peroxide is also demonstrated.

Organic-phase biosensors for monitoring phenol and hydrogen peroxide in pharmaceutical antibacterial products

Hydrogen peroxide determination in pharmaceutical formulations and cosmetics using a new catalase biosensor

Organic phase enzyme electrodes: kinetics and analytical applications

Improvement of the analytical characteristics of an enzyme electrode for free and total cholesterol via laponite clay additives

A rapid procedure for determining phenols in olive oils, based on an organic-phase enzyme electrode, is described. Direct assays are performed in chloroform solutions which support the tyrosinase activity. This class (phenol)-specific enzyme strongly adheres to the surface of the graphite transducer. The resulting wall-jet detector offers effective flow injection operation, with a detection limit of 4×10−7 M (0.8 ng) phenol and sample frequency of 60 h−1. Applicability to olive-oil samples of different origins is illustrated.

Organic-Phase Enzyme Electrode for the Determination of Phenols in Olive Oils

An enzyme electrode is described for the determination of cholesterol dissolved in chloroform/hexane (1:1). The enzyme electrode is shown to be applicable to the determination of cholesterol in samples of butter and margarine.

G. F. Hall

Papers

An Organic Phase Enzyme Electrode for Cholesterol