Abstract:
The commercial development of a disposable aqueous chlorine sensor based on a novel
microelectrode array fabrication process is described.
Non-conducting poly(o-phenylenediamine) films are firstly used to passivate
conductive surfaces. Ultrasonic ablation of passivated electrode assemblies then results
in the formation of a plurality of wells to expose the underlying conductive substrate,
thereby forming a microelectrode array.
Microelectrode arrays produced in this manner can be exploited within many
electrochemical sensing applications; however, portable aqueous chlorine detection has
been selected by Microarray Limited (the industrial sponsors of this project) as a
primary vehicle for launching its generic production technology. The scale of
microelectrode array production has been extended from that of individual gold sputtercoated
glass slide electrodes - to the simultaneous production of hundreds of low-cost
screen printed carbon-ink based sensors.
A focus has been directed at all stages towards permitting the cost-effective
large-scale mass production of sensors with a view to challenging existing portable
aqueous chlorine measurement technologies both in terms of performance and unit cost.
Based on volume batches of 250,000, it has been calculated that Microarray Limited
sensors can be manufactured for a unit cost of approximately 2.5 pence, sufficiently
low to provide scope for a competitive yet profitable sale price. The
Microarray Limited aqueous chlorine detection system has improved the limit of
detection from 0.01 ppm to 0.005 ppm total chlorine without sacrificing accuracy.
Furthermore, this novel approach to aqueous chlorine detection offers numerous key
benefits to the customer including reduced testing time, a more straightforward
operation and the elimination of harmful reagents.
Product development has been described from an initial concept through to a
pre-production phase. The development of an innovative generic sensor packaging
technology is also described.
