Laser Nitrate Sensor

April 2018

The science behind the development of a new nitrate detection tool

Fundamental science is being combined with new technologies to help solve real-world problems at the University of Canterbury. A promising tool is being developed to help farmers pinpoint nitrate and phosphate problem areas and plan better strategies to minimise the environmental impacts of food production.

High levels of nitrates and phosphates in water and soil are harmful to the environment and human health. Some farming practices in certain environments are more at risk of creating an excess of these compounds entering the ecosystem. Algal blooms, and water unfit for drinking or swimming in are just some of the negative impacts of excess nutrients.

There is a significant amount of research and development being done all around New Zealand on ways to improve our water and soil health.

Dr Deborah Crittenden is a senior lecturer in physical chemistry and an associate investigator in the Biomolecular Interaction Centre at the University of Canterbury. She is working with environmental chemist, Associate Professor Sally Gaw, to develop a new tool designed to detect and measure nitrate levels in the field.

Associate Professor Sally Gaw is a member of the Waterways Centre for Freshwater Management, a joint initiative between Lincoln University and the University of Canterbury. In conjunction with her work at the University, Sally provides advice to regional councils who are monitoring current water health conditions.

The tool, a portable laser sensor, is currently in development and work has progressed enough that the pair have won a $20,000 grant from UC’s annual Tech Jumpstart competition. It has attracted a further $35,000 in funding from business incubator, Astrolab. Astrolab will help the project progress to a commercial platform.

Dr Crittenden says the development brings together old ideas (such as the basic principles of chemistry) and new technologies (such as lasers and drones) to develop practical tools to solve real-world problems.

Deborah says while there a number of existing solutions, none of them are perfect – each has its downsides, and this work has approached the problem by turning it on its head – so rather than adding something to the solution to be tested, they are looking at extracting from the sample, to better detect the nitrate level.

Existing nitrate detection methods either detect the nitrate within the sample directly or rely on expensive, sophisticated and non-portable lab instrumentation to perform the separation.

The key novelty in Deborah and Sally's work is using cheap (but efficient) processes to first separate the nitrate from its surrounding environment (in either water or soil) and then using a different (cheap but effective) process to do the detection.

There is also the potential to integrate the detection device into a number of different technologies. Deb says, “the next science challenge is to pull those together in a real working device, and that’s what we’re really excited about getting our teeth into”.

Deborah says there are three “pillars” that need to align to support this kind of work and allow it to progress successfully – they are:

  1. End-user demand - recognition of the practical problem to be solved. This is in fact the first and foremost consideration.
  1. Scientific capability - recognition of the scientific obstacles within existing technologies, and the ability to find new solutions with available scientific tools and technologies.
  1. Commercial support - funding and in-kind support to provide the time and resources to get the job done in a timely fashion.

Deborah and Sally have been working on the project (part-time) for about a year. The current work is focused on providing proof of principle and will take about a year. A further 1 – 2 years of refining the design will almost certainly be required before it can be commercialised. They are in talks with Ravensdown about working together to develop this technology.

Currently a research intern is being recruited to progress the work as quickly as possible but this will likely depend on the outcome of talks with potential commercial partners.

Effective environmental protection and cost-efficient farm management both require the right tools to properly monitor the environment. This marrying of science and technologies may yet provide a critical tool in making that a reality.