Side illuminated optical fiber sensor for nitrate in hydroponic solutions

• Grant number: 13/13469-7
• Support Opportunities: Research Grants - Visiting Researcher Grant - International
• Duration: December 14, 2013 - February 13, 2014
• Field of knowledge: Physical Sciences and Mathematics - Chemistry - Analytical Chemistry
• Principal Investigator: Sidney José Lima Ribeiro
• Grantee: Sidney José Lima Ribeiro
• Visiting researcher: Claudio Oliveira Egalon
• Visiting researcher institution: Science & Sensors Technologies, United States
• Host Institution: Instituto de Química (IQ). Universidade Estadual Paulista (UNESP). Campus de Araraquara. Araraquara , SP, Brazil

Abstract

Nitrate is one of the most essential nutrients in hydroponic solutions and it has a direct effect in the yield and quality of plants. However, despite its importance, it is often applied on a rule-of-thumb basis and, many times, over applied. If its concentration is thought to be incorrect, the original solution is discarded and replaced. This result in nutrient waste and widespread environmental contamination of aquatic, ground and drinking water which leads to illness and even death. To address this problem, our group at UNESP of Araraquara proposes to develop a UV absorption-based side illuminated nitrate sensor using the expertise of our visiting research Dr. Claudio Oliveira Egalon. This is a device that can be used "in the loop" of a dosing system to determine nitrate concentration in real time, its ideal concentration for different plants and prevent it from being discarded into the environment by helping recycle fertilizer solution in an automated system. Due to its multipoint sensing capability, the sensor can perform many independent measurements at different wavelengths to increase its specificity towards nitrate by measuring the presence of multiple chemical species. Preliminary results by the PI demonstrated this sensing concept in highly concentrated nitrate solutions and, during this grant, this device will be fine-tuned to detect nitrate at concentrations found in hydroponic solutions. Using low cost, commercially available components, it is anticipated that this sensor will be sensitive, selective and cost effective (less than $200 a unit). (AU)