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Singapore, Singapore

Ma K.,Optiqua Technologies Pte. Ltd | Ekblad T.,Optiqua Technologies Pte. Ltd | Koerkamp M.K.,Optisense | Kelderman H.,Optisense | And 6 more authors.
International Journal of Environmental Analytical Chemistry | Year: 2015

An inhibition assay for detection of Bisphenol A (BPA) in treated water has been developed and validated for the MiniLab™ system from Optiqua Technologies. This biosensor-based analytical system can be used for detection of specific contaminants in solution. The system uses an integrated optic Mach-Zehnder interferometer chip that is functionalised with a biochemical interface layer. The sensor chip surface was first coated with aminodextran which formed a hydrophilic layer suitable for further modification. 4,4-bis(4-hydroxyphenyl) valeric acid (BVA), which is a structural analogue of BPA, was then successfully coupled to the aminodextran layer. This surface chemistry was used in a qualitative inhibition assay format for the selective detection of the presence of BPA. The assay was developed and optimised using a polyclonal anti-BPA antibody. Samples from 12 different water matrices of Singapore were spiked with known amounts of BPA and tested with the MiniLab™ system. The working range of the BPA inhibition assay is from 0.5 to 5 µg/L. Intra- and inter-assay variations were measured, with calculated relative standard deviation averaging of about 15%. BPA concentrations of the spiked samples were also verified and confirmed with LC-MS. Such functionalised biosensor chip can be reused for more than 200 sample injections over a period longer than 6 months. Developed as a robust, user-friendly and cost-effective system that can be field deployed, the MiniLab™ system enables target-specific assays currently only available in the lab to become available in the field. © 2015, © 2015 Taylor & Francis. Source

de Graaf B.R.,Vitens | Williamson F.,Optiqua Technologies Pte. Ltd | Koerkamp M.K.,Optiqua Technologies Pte. Ltd | Verhoef J.W.,Optiqua Technologies Pte. Ltd | And 4 more authors.
Water Practice and Technology | Year: 2012

For safe supply of drinking water, water quality needs to be monitored online in real time. The consequence of inadequate monitoring can result in substantial health risks, and economic and reputational damages. Therefore, Vitens N.V., the largest drinking water company of the Netherlands, set a goal to explore and invest in the devel- opment of intelligent water supply. In order to do this Vitens N.V. has set up a demonstration network for online water quality monitoring, the Vitens Innovation Playground (VIP). With the recent innovative developments in the field of online sensoring Vitens kicked off, in 2011, its first major online sensoring program by implementing a sensor grid based on EventLab systems from Optiqua Technologies Pte Ltd in the distribution network. EventLab utilizes bulk refractive index as a generic parameter for continuous real time monitoring of changes in water qual- ity. Key characteristics of this innovative optical sensor technology, high sensitivity generic sensors at low cost, make it ideal for deployment as an early warning system. This paper describes different components of the system, the technological challenges that were overcome, and presents performance data and conclusions from deployment of Optiqua's EventLab systems in the VIP. © IWA Publishing 2012. Source

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