A High-Performance Optoelectronic Sensor Device for Nitrate Nitrogen in Recirculating Aquaculture Systems

Abstract

The determination of nitrate nitrogen (NO3-N) in recirculating aquaculture systems is of great significance for the health assessment of the living environment of aquatic animals. Unfortunately, the commonly used spectrophotometric methods often yield unstable results, especially when the ambient temperature varies greatly in the field measurement. Here, we have developed a novel handheld absorbance measurement sensor based on the thymol-NO3-N chromogenic rearrangement reaction. In terms of hardware, the sensor adopts a dual channel/dual wavelength colorimeter structure that features a modulated light source transmitter and a synchronous detector receiver. The circuit measures the ratio of light absorbed by the sample and reference containers at two LEDs with peak wavelengths at 420 nm and 450 nm. Using the modulated source and synchronous detector rather than a constant (DC) source eliminates measurement errors due to ambient light and low frequency noise and provides higher accuracy. In terms of software, we design a new quantitative analysis algorithm for absorbance by studying colloid absorbing behavior. The application of a buffer operator embedded in the algorithm makes the sensor get the environmental correction function. The results have shown that the sensitivity, repeatability, precision and environmental stability are higher than that by ordinary spectrophotometry. Lastly, we have a brief overview of future work.

Application of Graphene-Based Materials for Detection of Nitrate and Nitrite in Water—A Review

“…The concentration of nitrate and nitrite in water has become one of the indexes for evaluating water quality. Therefore, the detection of nitrate and nitrite in water samples at low concentrations has been the focus of research [11].So far, many methods have been used to detect nitrate and nitrite, such as spectrophotometry [12][13][14], chemiluminescence [15,16], chromatography [17], fluorescence [18,19] and electrochemical methods [20][21][22]. Among them, the electrochemical method is one of the most commonly used detection methods because of its advantages of being low cost, fast, direct and high efficiency [23].…”

Monolithic Integrated OLED–OPD Unit for Point-of-Need Nitrite Sensing

“…The results can be processed with a microcontroller and transmitted to a monitor. Wang et al recently reported a comprehensive design of a hardware circuit for an optoelectronic sensor [41].…”

A Portable Measurement Device Based on Phenanthroline Complex for Iron Determination in Water

“…The first time the term paired emitter detector diode (PEDD) was used dates back to 1993 [ 33 ]. Since then, this methodology of paring a diode and photodiode has been successfully used for determining water quality parameters (nitrate, nitrogen [ 34 , 35 ], turbidity [ 36 ], phosphate [ 37 ], phosphorous [ 38 ], paraquat and diquat [ 39 ], fluoxetine and citalopram [ 40 ], and chromium [ 41 ]). Use of novel signal processing algorithms that can replace some hardware leads to better instrument performance at a lower cost.…”