Development Of Optical Based Integrated Measurement System For Nitrate And Nitrite In Water
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Date
2015-10
Authors
Moo, Yow Chong
Journal Title
Journal ISSN
Volume Title
Publisher
Universiti Sains Malaysia
Abstract
Nitrate (NO3) and nitrite (NO2) are nitrogen compounds which mostly can be
found in wastewater, underground water, and landfill leachate water. In the initial
study, spectral response for nitrate and nitrite were investigated by Jaz spectrometer
for getting optimum results to determine its concentration in water. Calibration
equations for nitrate at wavelength 302 nm and nitrite at wavelength 356 nm by
using Jaz spectrometer were generated through Minitab software. Predicted and
residuals analysis were conducted to verify the reliability of regression model. All
calibration and validation analyses showed stable, high precision and acceptable
results for determining the concentrations of nitrate and nitrite in water. New novelty
of optical fibre sensor was developed which provided simple and effective approach
to determine the concentration of nitrate and nitrite in water. In the optical fibre
sensor method, monochromatic wavelengths for nitrate at 302 nm and nitrite at 356
nm were selected respectively for further analysis and generating of calibration
equations. New program was developed by added calibration equations for nitrate
and nitrite respectively and uploaded to microcontroller which was constructed in the
sensor. All calculations for concentrations of nitrate and nitrite analysis were done by
microcontroller in the sensor. Analysis of analytical detection limit and effects of
diverse ions were measured to ensure consistency of the optical fibre sensor. These
results were useful for further study on real water samples. Recovery (%) for added
values were analyzed and compared between Jaz spectrometer method with optical
fibre sensor method as well as standard chemistry method with optical fibre sensor
method. The optical fibre sensor method was given high precision in recovery results
for determination of nitrate and nitrite. T-test was carried out to analyze null
hypothesis between the methods. From the result, there were no significant
differences in accuracy and precision of optical fibre sensor method with Jaz
spectrometer method or standard chemical method. The results showed that new
development of optical fibre sensor method was successfully applied to determine
the concentrations of nitrate and nitrite in real water samples in this research.
Description
Keywords
Optical fibre sensor method , to determine the concentrations of nitrate and nitrite.