Name:

Contact details

	CLARITY: Centre for Sensor Web Technologies, Research and Engineering Building, N205, Dublin City University, Collins Avenue, Dublin 9
	+353 1 700 5273
	+353 1 700 7995
	conor.slater@dcu.ie

Qualifications

B.Eng. in Mechatronic Engineering (Bachelor Honours Degree), Dublin City University, 2005

Project Summary

Discrete Metered Fluid Injection: A Concept for a Robust Autonomous Reagent Based Optical Chemical Sensor

This project is based on the development of an autonomous sensor for monitoring phosphate in lake and river water in-situ. The goal is to design, build and validate a sensor that is sensitive, low-power, low cost and, most importantly, robust.

To tackle these design challenges a new concept of discrete metered fluid injection was developed. This concept combines robust solenoid metering pumps with a microfluidic lab-on-a-chip. Separate pumps can inject a precise volume of reagent and sample into the lab-on-a-chip. The layout of the microchannels within the chip direct the flow from the pumps to achieve precise mixing and the subsequent presentation of the reacted sample to a spectrophotometer for an absorbance measurement. This concept is scalable allowing pumps for dispensing calibration and cleaning solutions to be integrated into the design.

A prototype analyser was built to validate this concept. It is completely autonomous and self calibrating. It contains enough reagent, calibration and cleaning solution to carry out 4000 phosphate assays. The unit powered by a 12V lead-acid battery is equipped with a GSM modem to transmit data collected, thus allowing it to be deployed at a remote location.

Images

Advantages

Sensitivity. In laboratory benchtop trials the sensor demonstrated a limit of detection of 0.3 mg/L phosphate and a linear range up to 5 mg/L.

Low power. Although the current draw of a solenoid is high, the duty cycle is short. The pumps used draw 330 mA for 1 second. Each time a pump is cycled it dispenses 20 uL.

Robustness. When validated against a commercially available phosphate monitor the prototype was capable of providing high quality data over period of almost 40 days at an hourly sample rate.

Current and future work

The phosphate analyser itself can be described as a generic platform for colorimetric reagents. Future research will adapt the analyser for sensing nitrate and ammonia.

Currently the phosphate analyser is being commercialised in partnership with an Irish SME EpiSensor. (See article)

Award for EpiSensor academic partner

Publications

Peer-Reviewed Journal Articles

Lau, K. -T., Guo, W., Kiernan, B., Slater, C. & Diamond, D. (2009) Non-linear carbon dioxide determination using infrared gas sensors and neural networks with Bayesian regularization. Sensors and Actuators B: Chemical, 136(1), pp. 242-247.

Scarmagnani, S., Walsh, Z., Slater, C., Alhashimy, N., Paull, B., Macka, M. & Diamond, D. (2008) Polystyrene bead-based system for optical sensing using spiropyran photoswitches. Journal of Materials Chemistry, 18(42), pp. 5063-5071.

Cleary, J., Slater, C., McGraw, C. M. & Diamond, D. (2008) An autonomous microfluidic sensor for phosphate: on-site analysis of treated wastewater. IEEE Sensors Journal, 8(5), pp. 508-515.

Radu, A., Scarmagnani, S., Byrne, R., Slater, C., Lau, K. -T. & Diamond, D. (2007) Photonic modulation of surface properties: a novel concept in chemical sensing. Journal of Physics D: Applied Physics, 40(23), pp. 7238-7244.

O’Toole, M., Lau, K. -T., Shepherd, R., Slater, C. & Diamond, D. (2007) Determination of phosphate using a highly sensitive paired emitter-detector diode photometric flow detector. Analytica Chimica Acta, 597(2), pp. 290-294.

McGraw, C. M., Stitzel, S., Cleary, J., Slater, C. & Diamond, D. (2007) Autonomous microfluidic system for phosphate detection. Talanta, 71(3), pp. 1180-1185.

Conference proceedings

Hayes, J., Beirne, S., Kiernan, B., Slater, C., Lau, K. -T. & Diamond, D. (2008) Chemical species concentration measurement via wireless sensors. Proceedings of the World Academy of Science, Engineering and Technology, Venice ITALY, pp. 158-162.

Morris, D., Shazmann, B., Wu, Y. -Z., Fay, C., Beirne, S., Slater, C., Lau, K. -T., Wallace, G. & Diamond, D. (2008) Wearable technology for the real time analysis of sweat during exercise. Proceedings of the 1st International Symposium on Applied Sciences in Biomedical and Communications Technologies, Aalborg DENMARK.

Cleary, J., Slater, C. & Diamond, D. (2008) Monitoring of phosphate levels in wastewater using an autonomous microfluidic sensor. Proceedings of the 12th International Conference on Miniaturized Systems for Chemistry and Life Sciences - MicroTAS, San Diego USA.

Morris, D., Shazmann, B., Wu, Y. -Z., Coyle, S., Brady, S., Hayes, J., Slater, C., Fay, C., Lau, K. -T, Wallace, G., Diamond, D. (2008) Wearable Sensors for Monitoring Sports Performance and Training. Proceedings of the 5th International Summer School and Symposium on Medical Devices and Biosensors, Hong Kong PEOPLES R CHINA, pp. 37-40.

Morris, D., Shazmann, B., Wu, Y. -Z., Coyle, S., Brady, S., Hayes, J., Slater, C., Fay, C., Lau, K. -T., Wallace, G. & Diamond, D. (2008) Bio-Sensing textiles for real-time chemical analysis of body fluids. Proceedings of the 5th International Workshop on Wearable Micro- and Nanosystems for Personalised Health, Valencia SPAIN.

Cleary, J., Slater, C. & Diamond, D. (2007) Field-deployable microfluidic sensor for phosphate in natural waters. Proceedings of the 6th IEEE Sensors Conference, Atlanta USA, pp.1001-1004.

Hayes, J., Slater, C., Kiernan, B., Dunphy, C., Guo, W., Lau, K. -T. & Diamond, D. (2007) A wireless sensor network for methane monitoring. The proceedings of the Conference on Advanced Environmental, Chemical, and Biological Sensing Technologies V, Boston USA, pp. 75504-75504.

Slater, C., Cleary, J., McGraw, C. M., Yerazunis, W. S., Lau, K. -T. & Diamond, D. (2007) Autonomous field-deployable device for the measurement of phosphate in natural water. The proceedings of the Conference on Advanced Environmental, Chemical, and Biological Sensing Technologies V, Boston USA, pp. L7550-L7550.

Radu, A., Scarmagnani, S., Byrne, R., Slater, C., Alhashimy, N. & Diamond, D. (2007) Photoswitcable surfaces: A new approach to chemical sensing. Proceedings of the Conference on Remote Sensing for Environmental Monitoring, GIS Applications, and Geol VIII, Florence ITALY, pp. Z7491-Z7491.

Hayes, J., Cleary, J., Slater, C., Lau, K. -T. & Diamond, D. (2007) Intelligent environmental sensing with a phosphate monitoring system and online resources. Proceedings of the International Conference on Computational Methods in Science and Engineering, Corfu GREECE, pp. 1216-1219.

Slater, C., Corcoran, B. & Diamond, D. (2007) Fabrication of a multi-layer microfluidic chip from PMMA. Proceedings of the 24th International Manufacturing Conference, Waterford IRELAND.

McGraw, C. M., Slater, C., Stizel, S. & Diamond, D. (2006) Autonomous microfluidic system for phosphate detection. Proceedings of the 231st National Meeting of the American-Chemical-Society, Atlanta USA.

Further Information