“No calibration” type sensor in routine amperometric bio-sensing: An example of a disposable hydrogen peroxide biosensor

The predicted potential market size for the use of biosensors in the biomedical sector has correlated closely to the actual global market sales of biosensor devices. Unlike glucose measurement in blood, biosensors for environmental or food analysis are niche markets in which the demand varies and the sale volumes are low. Until now the use of biosensors in these markets has been limited. In contrast, spectrophotometric methods, and particularly enzyme-coupled assays, packaged in simple to use kit form, have proved successful in such fragmented markets and have become, in many cases, the recommended standard method for industrial analysis. The popularity of such kits is the result of disposable consumables, reliable detection methods and most importantly, no requirement for tedious calibration steps (if the Beer-Lambert law is applicable). Disadvantages include sample preparation, multiple and sequential addition of several reagents during the analysis process. We believe that within the environmental and agri-food industries, amperometric biosensor technology could be a valid competitor to the standard spectrophotometric methods; provided that cheap and easy to use methods are proposed. According to industrial users within these fragmented markets, the biggest obstacle for the take up of biosensor technology as a standard method is the requirement for complex pre-calibration. It seems that, to meet the demand of these markets, an essential improvement would be the removal of calibration steps before the use of the biosensor. The electrochemical signal of a large number of amperometric biosensors is dependent upon enzymatic or chemical kinetics that are reliant on operating conditions (enzyme concentrations, temperature, pH) and so necessarily requires a calibration step prior to use. Despite their excellent analytical performances this makes them unattractive for industries that want to use these analytical tools in remote locations using unskilled operators. With spectroscopic methods these calibration steps are unnecessary because, for a given wavelength and a fixed light path, the measured absorbance is directly proportional to the concentration of sample material. This is true for a concentration range for which the Beer-