A New Analytical Method to Quantify Ammonia in Freshwater with a Bulk Acoustic Wave Sensor

A new method to analyse ammonia in freshwater, based on a piezoelectric quartz crystal coated with the metalloporphyrin chloro[5,10,15,20-tetrakis(pentafluorophenyl)porphyrinato] manganese(III) is presented. A 9 MHz quartz crystal coated on both faces with an amount of porphyrin produced a frequency...

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Main Authors: Vera Lúcia M. Antunes, Maria Teresa S. R. Gomes
Format: Article
Language:English
Published: MDPI AG 2022-02-01
Series:Sensors
Subjects:
Online Access:https://www.mdpi.com/1424-8220/22/4/1528
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author Vera Lúcia M. Antunes
Maria Teresa S. R. Gomes
author_facet Vera Lúcia M. Antunes
Maria Teresa S. R. Gomes
author_sort Vera Lúcia M. Antunes
collection DOAJ
description A new method to analyse ammonia in freshwater, based on a piezoelectric quartz crystal coated with the metalloporphyrin chloro[5,10,15,20-tetrakis(pentafluorophenyl)porphyrinato] manganese(III) is presented. A 9 MHz quartz crystal coated on both faces with an amount of porphyrin produced a frequency decrease of 21.4 kHz, which allowed ammonia in a 10.00 mL sample to be quantified in concentrations between 5 and 70 µg L<sup>−1</sup>, with a sensitivity of 0.60 Hz L µg<sup>−1</sup>, over a period of at least eight months. The proposed method has several advantages over the officially recommended indophenol spectrophotometric method: sample volume was reduced by a factor of 2.5, toxic reagents (phenol and sodium nitroprusside) were eliminated, analysing turbid samples presented no difficulty, and there was not only a significant time saving in solution preparation, but also in sample analysis time, which was reduced from 1 h to 2 min. No statistically significant differences (α = 0.05) were found both in the mean and precision of the results obtained for ammonia in water samples collected from domestic wells, analysed by this new method and by the indophenol spectrophotometric method. Furthermore, the proposed method would allow the individual quantification, with similar sensitivity, of amines and ammonia within a single analytical run.
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spelling doaj.art-879627a767b64fe49c650d4ff21153272023-11-23T22:01:02ZengMDPI AGSensors1424-82202022-02-01224152810.3390/s22041528A New Analytical Method to Quantify Ammonia in Freshwater with a Bulk Acoustic Wave SensorVera Lúcia M. Antunes0Maria Teresa S. R. Gomes1CESAM, Department of Chemistry, University of Aveiro, 3810-193 Aveiro, PortugalCESAM, Department of Chemistry, University of Aveiro, 3810-193 Aveiro, PortugalA new method to analyse ammonia in freshwater, based on a piezoelectric quartz crystal coated with the metalloporphyrin chloro[5,10,15,20-tetrakis(pentafluorophenyl)porphyrinato] manganese(III) is presented. A 9 MHz quartz crystal coated on both faces with an amount of porphyrin produced a frequency decrease of 21.4 kHz, which allowed ammonia in a 10.00 mL sample to be quantified in concentrations between 5 and 70 µg L<sup>−1</sup>, with a sensitivity of 0.60 Hz L µg<sup>−1</sup>, over a period of at least eight months. The proposed method has several advantages over the officially recommended indophenol spectrophotometric method: sample volume was reduced by a factor of 2.5, toxic reagents (phenol and sodium nitroprusside) were eliminated, analysing turbid samples presented no difficulty, and there was not only a significant time saving in solution preparation, but also in sample analysis time, which was reduced from 1 h to 2 min. No statistically significant differences (α = 0.05) were found both in the mean and precision of the results obtained for ammonia in water samples collected from domestic wells, analysed by this new method and by the indophenol spectrophotometric method. Furthermore, the proposed method would allow the individual quantification, with similar sensitivity, of amines and ammonia within a single analytical run.https://www.mdpi.com/1424-8220/22/4/1528ammoniapiezoelectric quartz crystalacoustic wave sensorfreshwateramines
spellingShingle Vera Lúcia M. Antunes
Maria Teresa S. R. Gomes
A New Analytical Method to Quantify Ammonia in Freshwater with a Bulk Acoustic Wave Sensor
Sensors
ammonia
piezoelectric quartz crystal
acoustic wave sensor
freshwater
amines
title A New Analytical Method to Quantify Ammonia in Freshwater with a Bulk Acoustic Wave Sensor
title_full A New Analytical Method to Quantify Ammonia in Freshwater with a Bulk Acoustic Wave Sensor
title_fullStr A New Analytical Method to Quantify Ammonia in Freshwater with a Bulk Acoustic Wave Sensor
title_full_unstemmed A New Analytical Method to Quantify Ammonia in Freshwater with a Bulk Acoustic Wave Sensor
title_short A New Analytical Method to Quantify Ammonia in Freshwater with a Bulk Acoustic Wave Sensor
title_sort new analytical method to quantify ammonia in freshwater with a bulk acoustic wave sensor
topic ammonia
piezoelectric quartz crystal
acoustic wave sensor
freshwater
amines
url https://www.mdpi.com/1424-8220/22/4/1528
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