Determination Of Ammonium In Waters Research Articles

Accurate and Rapid Determination of Ammonium in Water by Voltametric Analysis on a Novel Modified Electrode

The development of efficient and sensitive electrochemical sensors is of crucial for a wide range of applications, including environmental monitoring, chemical analysis, and biomedical diagnostics. In this study, we present on the development and characterization of a novel of electrochemical sensor, based on a silver/poly 1-aminoanthraquinone/glassy carbon modified electrode (Ag/PAAQ/GC), with high sensitivity and selectivity for the detection of ammonium ions (NH4 +) in water. The Ag/PAAQ/GC electrode was prepared by a simple and low- cost electrochemical co-deposition method, which enabled for a uniform and stable deposition of PAAQ and Ag ions on the surface of the GC electrode. The resulting electrode exhibited excellent electrocatalytic activity in the oxidation of NH4 + ions. The performance of the Ag/PAAQ/GC electrode as an electrochemical sensor for NH4 + was evaluated using square wave voltammetry (SWV) in aqueous solutions. The results showed that the Ag/PAAQ/GC electrode exhibited a linear response to NH4 + in a concentration range of 0.01 to 9 mgL−1, with a detection limit of 3 μgL−1 and a sensitivity of 0.0413 μA.Lmg−1. In addition, the Ag/PAAQ/GC electrode showed excellent selectivity for NH4 + over interfering ions such as K+, Na+, Ca2+, and Mg2+. Overall, our results show that the Ag/PAAQ/GC electrode is a promising platform for the development of advanced electrochemical sensors for the detection of NH4 + in water. Due to its high sensitivity, selectivity and stability, the Ag/PAAQ/GC electrode is suitable for a wide range of environmental and analytical applications, e.g., water quality monitoring, wastewater treatment and fertiliser analysis. The precision of the method was tested by analysing sixteen measurements of the same NH4 + concentration, yielding standard deviation (RSD) of 1.78%. Good recovery values were obtained when measuring spiked tap water samples analysed by the classical Colorimetric Nessler reagent methods and measuring natural water by the ion-selective electrode.

Modified electrode decorated with silver as a novel non-enzymatic sensor for the determination of ammonium in water

Ammonium is an essential component of the nitrogen cycle, which is essential for nitrogen cycling in ecosystems. On the other hand, ammonium pollution in water poses a great threat to the ecosystem and human health. Accurate and timely determination of ammonium content is of great importance for environmental management and ensuring the safety of water supply. Here we report a highly sensitive electrochemical sensor for ammonium in water samples. The modified electrode is based on the incorporation of silver nitrate (AgNO3) into a carbon paste embedded with 1-aminoanthraquinone and supported by multi-walled carbon nanotubes, which are commercially available. A potential of 0.75 V is applied to the modified electrode, followed by activation in hydrochloric acid. The modified electrode was used for square wave voltammetry of ammonium in water in the potential range of − 0.4–0.2 V. The performance of ammonium analysis was determined in terms of square wave frequency, square wave amplitude and concentration of electrolyte solution (sodium sulphate). The calculation of the surface area according to the Randles–Sevcik equation resulted in the largest surface area for the Ag/pAAQ/MWCNTs/CPE. The modified electrode exhibited a linear range of 5–100 µM NH4+ in 0.1 M Na2SO4 with a detection limit of 0.03 µM NH4+ (3σ). In addition, the modified electrode showed high precision with an RSD value of 9.93% for 10 repeated measurements. No interfering effect was observed at twofold and tenfold additive concentrations of foreign ions. Good recoveries were obtained in the analysis of tap and mineral water after spiking with a concentration of ammonium ions.

Recent Progress and Applications of Thermal Lens Spectrometry and Photothermal Beam Deflection Techniques in Environmental Sensing.

This paper presents recent development and applications of thermal lens microscopy (TLM) and beam deflection spectrometry (BDS) for the analysis of water samples and sea ice. Coupling of TLM detection to a microfluidic system for flow injection analysis (μFIA) enables the detection of microcystin-LR in waters with a four samples/min throughput (in triplicate injections) and provides an LOD of 0.08 µg/L which is 12-times lower than the MCL for microcystin-LR in water. μFIA-TLM was also applied for the determination of total Fe and Fe(II) in 3 µL samples of synthetic cloudwater. The LODs were found to be 100 nM for Fe(II) and 70 nM for total Fe. The application of µFIA-TLM for the determination of ammonium in water resulted in an LOD of 2.3 µM for injection of a 5 µL sample and TLM detection in a 100 µm deep microfluidic channel. For the determination of iron species in sea ice, the BDS was coupled to a diffusive gradient in the thin film technique (DGT). The 2D distribution of Fe(II) and total Fe on DGT gels provided by the BDS (LOD of 50 nM) reflected the distribution of Fe species in sea ice put in contact with DGT gels.

Advances in the Measurement of Polymeric Colorimetric Sensors Using Portable Instrumentation: Testing the Light Influence.

Sustainable and green sensors based on polydimethyl siloxane (PDMS) or cellulose polymers, as a case of study of the use of portable instrumentation joined to a smartphone, have been tested. A smartphone camera was used to obtain images and was also coupled to a minispectrometer, without and with an optical fiber probe to register spectra. To study light influence on the analytical signal, light-emitting diode (LED), halogen light and daylight have been assayed. A corrective palette of 24 colors and a set with 45 colors from different color ranges were used as the validation set. The results indicated that halogen light was the best option to obtain the spectra. However, for digital image analysis, it was the LED light that gave a greater approximation of the RGB values of the real colors. Based on these results, the spectra and the RGB components of PDMS solid sensors doped with 1,2-naphtoquinone-4-sulfonate (NQS) for the determination of ammonium in water or urea in urine, PDMS doped with Griess reagent for developing the assay of nitrite in waters and cellulose sensors for the determination of hydrogen sulfide in the atmospheres have been obtained. The results achieved were good in terms of sensitivity and linearity and were comparable to those obtained using a laboratory benchtop instrument. Several rules for selecting the most suitable light source to obtain the spectra and/or images have been established and an image correction method has been introduced.

Determination of Ammonium Concentration in Post-Process Waters from Underground Coal Gasification

Abstract A flow injection analysis method for spectrophotometric determination of ammonium in waters produced during underground coal gasification (UCG) of lignite and hard coal was described. The analysis of UCG water samples is very difficult because of their very complicated matrix and colour. Due to a huge content of organic and inorganic substances and intensive colour of samples (sometimes yellow, quite often dark brown or even black), most analytical methods are not suitable for practical application. Flow injection analysis (FIA) is based on diffusion of ammonia through a hydrophobic gas permeable membrane from an alkaline solution stream into an acid-base indicator solution stream. Diffused ammonia causes a colour change of indicator solution, and ammonia is subsequently quantified spectrophotometrically at 590 nm wavelength. The reliability of the results provided by applied method was evaluated by checking validation parameters like accuracy and precision. Accuracy was evaluated by recovery studies using multiple standard addition method. Precision as repeatability was expressed as a coefficient of variation (CV).

Selective determination of ammonium in water based on HPLC and chemiluminescence detection

A selective and sensitive method has been developed for liquid chromatographic determination of ammonium in water samples. The analyte is derivatized with Dansyl Chloride prior to injection into HPLC. Optimal solution derivatization conditions have been established. The dansyl derivative is separated with the aid of a chromatographic column and post-column mixed with peroxyoxalate (TCPO) and H 2O 2 in order to perform chemiluminescence detection. The detection limit achieved is 8 μg/L and linear response from 0.027 to 0.750 mg/L of ammonium was obtained. Ammonium ion was determined within 2.4 min under optimum chromatographic conditions. The method is fast, and near 10 derivatized samples can be measured per hour. No interference of amines has been obtained. Accuracy studies gave % relative error below 9.8%, and precision studies gave %RSD between 2 and 8%. The method can be applied for amine and ammonium screening and quantification of ammonium in different kind of water samples: bottled, tap, lake, fountain, irrigation, waste and sea. Matrix effect was only found in seawater samples. The method was also applied to several samples after applying Kjeldahl treatment in order to obtain values of total Kjeldahl nitrogen.

Determination of Ammonium by Using a Flow System with a Diffusion Cell Coupled to an Ammonium Ion-Selective Sensor

This paper describes a flow potentiometric method for determination of ammonium at low levels. A new diffusion cell coupled to an ammonium ion electrode was used as the potentiometric detector. This method eliminates interference to the ammonium ion electrode. When the stopped-flow method is employed for the acceptor stream, ammonium ions can be accumulated in the acceptor solution in the diffusion cell, giving high selectivity and sensitivity. The lower linear value of the proposed method can reach 1 × 10−6 mol L−1 with an accumulation time of 5 min. The method is simple, sensitive and suitable for online determination of ammonium in water samples. It has been applied to the determination of ammonium in rain water and river water, and recoveries of 95 – 104% were obtained. The relative standard deviation of seven replicate analyses for all samples was 1.1 – 2.7%.

Liquid chromatographic determination of ammonium in water

Liquid chromatographic determination of ammonium in water