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Biomedical subjects

H Gunasingham

Publications and source records attributed to H Gunasingham.

6 recordsLinked to original sources
PubMed1992

Electrochemically modulated optrode for glucose.

One of the problems with fibre-optic sensors is the difficulty of finding reversible indicator reagents. This is a particular problem for fibre-optic glucose sensors. The development of an electrochemically modulated fibre-optic probe or optrode has been proposed as a convenient solution. Here the indicator reagent is regenerated electrochemically. In this work a design is proposed that offers considerable advantages in practical applications. In particular, it can be used in the same way as conventional optrodes. The optimization of working parameters and the application of the optrode to flow analysis under steady-state and flow-injection conditions is described.

Biosensing Techniques↗
PubMed1990

Carbon paste-tetrathiafulvalene amperometric enzyme electrode forthe determination of glucose in flowing systems.

The development of a carbon paste-tetrathiafulvalene amperometric enzyme electrode for the determination of glucose in flowing streams is described. The enzyme electrode is operated in a flow-through detector based on the wall-jet configuration under flow injection (FI) and steady-state (SS) conditions. Under FI conditions, high precision (0.6%) and sample throughput (120 samples h-1) are possible. Moreover no pre-conditioning of the electrode is required. The flow system is suitable for the determination of glucose in whole blood without sample dilution. With proper orientation of the jet with respect to the enzyme electrode, high accuracy can be obtained under SS conditions.

Blood Glucose↗
PubMed1990

Clinical evaluation of amperometric enzyme electrodes in continuous-flow analysis for glucose in undiluted whole blood.

We have evaluated the carbon-paste enzyme/wall-jet electrode in continuous-flow analysis for glucose in undiluted whole blood. Responses of the electrode to protein-based and aqueous samples under wall-jet configuration are described. Imprecision in the flow-injection mode was less than 2% for glucose values in the usual analytical range (1-25 mmol/L). The dynamic range for glucose was from 0.03 to 45 mmol/L, with about 100% recovery of added substrate. The performance of the electrode (y) in flow-injection and steady-state modes was compared with a colorimetric method (x; Kodak Ektachem XR700), yielding linear-regression equations of y = 1.152x + 0.295 and y = 0.979x + 0.500, respectively. Among the anticoagulants, blood preservatives, and interfering substances investigated, only ascorbic acid gave a significant positive bias. The electrode exhibited good stability for analyses of undiluted whole-blood samples.

Autoanalysis↗
PubMed1985

Determination of oestriol in pregnancy urine by normal-phase high-performance liquid chromatography with electrochemical detection.

A method for the determination of oestriol in pregnancy urine by normal-phase high-performance liquid chromatography with electrochemical detection is described. A large-volume wall-jet cell with an Ag-Ag+ reference electrode was used as the detector system. The limit of detection obtained is comparable to that of electrochemical detection following reversed-phase liquid chromatography. One of the advantages of electrochemical detection with normal-phase systems is that adsorption problems are minimized.

Chemical Phenomena↗