Determination Of Nitrite In Water Research Articles

Selective determination of nitrite in water and food samples using zirconium oxide (ZrO2)@MWCNTs modified screen printed electrode.

Nitrite ions are being used in different forms as food preservatives acting as flavor enhancers or coloring agents for food products. However, continuous ingestion of nitrite may have severe health implications due to its mutagenic and carcinogenic effects. Thus, this study constructed an electrochemical assay using disposable nano-sensor chip ZrO2@MWCNTs screen printed electrodes (SPE) for the rapid, selective, and sensitive determination of nitrite in food and water samples. As a sensing platform, the use of nanomaterials, including metal oxide nanostructures and carbon nanotubes, exhibited a superior electrocatalytic activity and conductivity. Morphological, structural, and electrochemical analyses were performed using electron microscopy (SEM and TEM), Fourier-transform infrared (FTIR) spectroscopy, electrochemical impedance spectroscopy (EIS), cyclic voltammetry (CV) and chronoamperometry (CA). Accordingly, a wide dynamic linear range (5.0 μM to 100 μM) was obtained with a limit of detection of 0.94 μM by the chronoamperometric technique. In addition, the sensor's selectivity was tested when several non-target species were exposed to the sensor chips while no obvious electrochemical signals were generated when the nitrite ions were not present. Eventually, real food and water sample analysis was conducted, and a high recovery was achieved.

A palm-sized wireless device for colorimetric nitrite determination in water

In this work a palm-sized, affordable, and wireless device is presented for colorimetric determination of nitrite in water, based on the Griess method. A RGB sensor APDS 9960 was used, as a detector, to determine the amount of nitrite in water and the color intensity of the dye produced by the reaction between nitrite and Griess reagent was detected. The detection system consisted of a green LED (λmax = 530 nm) used as light source and the signals were monitored by selecting the green channel. An ESP32 board was used for signal processing and this ESP board includes a housing having space for receiving a lithium-ion battery, used for the power source of the circuit. Also, this boards act like a router which was employed to transfer data between the devices. A detection limit of 2 μgL−1 (3σ) was achieved by the proposed procedure with a relative standard deviation value varied from 1.6 to 2.5 for intra-day (and from 2.4 to 2.7 for inter-day precision, when a Green and White LEDs were used, respectively. With a low reagent demand of 20 μL, the proposed device is environmentally friendly, ideal for in situ determination and the resulting battery life of a 7-hours is feasibly for nitrite monitoring in different water samples. A comparison between the presented procedure employing a white and a green LEDs, used as light source, was conducted for nitrite determination and the results were compared with those obtained by UV–vis. The proposed procedure employing the green LED was more sensitive and provides greater accuracy.

Development of a simple analytical method for the determination of nitrite in waters using redox reaction and smartphone.

In this study, it was aimed to perform the colorimetric determination of nitrite in waters using the redox reaction of iodide in acidic conditions with smartphone. The simple redox reaction of iodide and nitrite in an acidic medium was used instead of the conventional nitrite methods based on the formation of azo dye. The quantitative relationship between the yellow-colored iodine formed because of the reaction and nitrite was determined by the digital image-based colorimetric method (DIC). In the optimal experimental conditions, detection limit and R2 values were determined as 0.02mg/L and 0.9925, respectively. New method (Redox-DIC method) was validated by the standard Griess Method for nitrite in lake waters. The perfect recovery results (94-112%) were calculated for lake, river, tap, and spring waters spiked at different concentrations, and very good (< 5.0%) percent relative standard deviation values were recorded. Unlike conventional nitrite methods, organic reagents and solvents were not used in this method. The method is fast, simple, and low cost.

Fast and Eco‐Friendly Determination of Nitrite in Water Using Deep Eutectic Solvent‐Based Magnetic Bucky Gels

In this study, a novel magnetic bucky gel (MBG) was synthesized and coupled with dispersive magnetic solid-phase extraction for preconcentration and determination of trace levels of nitrite in various water samples. The MBG was prepared by dispersing magnetic graphitic carbon nitride nanocomposite (g-C3N4@Fe3O4) in a choline chloride-urea deep eutectic solvent (1:2, molar ratio). The deep eutectic solvent (DES) acts as a disperser and surface modifier for g-C3N4/Fe3O4 nanocomposites simultaneously and led to superior uptake of the analyte in a shorter time. The sorbent was characterized by Fourier transform infrared (FT-IR) spectroscopy, X-ray diffraction (XRD), and field emission scanning electron microscopy (FESEM). The NO2− determination was carried out by UV-vis spectrophotometry. Variable factors on preconcentration of NO2− including pH, composition of MBG, contact time, sample volume, eluent type, eluent volume, and elution time were optimized. Under optimum condition, the limit of detection (LOD) was 1.56 μg L−1, the linear dynamic range extended from 5.14 to 900.00 μg L−1, the relative standard deviation (n = 5) and the preconcentration factor were 2.7% and 100, respectively. The method was successfully used for the preconcentration of NO2− ions in different water samples and gave recoveries between 89 and 103%. This article is protected by copyright. All rights reserved

Development of portable colorimeter for on-site determination of water quality in aquaculture

PurposeThis study aims to describe the development of a battery-operated portable colorimeter for on-site determination of water quality in aquaculture.Design/methodology/approachA simple and economical colorimeter is built using light sources of different wavelength and a light-dependent resistor combined with an electrical circuit. The whole system was fabricated as to fit into the pocket or palm for easy handling. The developed portable colorimeter was calibrated for estimation of nitrite. Further, the performance of developed portable colorimeters was compared with the commercially available colorimeter.FindingsThree colorimeters with different light sources were developed and calibrated for determination of nitrite in water. Among them, colorimeter with yellow light source exhibited higher potential for determination of nitrite in the range of 0.5–3.5 ppm. Further, the results of the developed colorimeter are comparable with the commercial colorimeter.Originality/valueThe portable colorimeter developed in this study exhibits potential for determination of nitrite in aquaculture. Determination of nitrite at low concentrations is important for assessing the quality of culture as well as wastewater in aquaculture industry. The accuracy, portable nature, economy and simple operation of these portable colorimeters offer opportunity for on-site determination of water quality parameters in aquaculture.

A Novel Method for the Polarographic Determination of Trace Nitrite in Water

A Novel Method for the Polarographic Determination of Trace Nitrite in Water

Silver-miang nanocomposites: A green, rapid and simple approach for selective determination of nitrite in water and meat samples

A green, rapid, simple and reliable procedure was developed for nitrite determination using silver-miang nanocomposites as colorimetric agents and camera phone as a detector. The crude water extracts of miang (Camellia sinensis var. assamica) were adopted as natural reagents in a rapid one-pot microwave synthesis of the nanocomposites. The extracts’ phytochemical contents were studied and the synthesis conditions were optimized. The yielded nanocomposites were characterized by UV–vis and FT-IR spectroscopies, powder X-ray diffraction, transmission electron microscopy, selected area electron diffraction and thermogravimetry, and proved to be reliable colorimetric agents and selective for nitrite. The underlying reactions were investigated. The linear calibration plots could be established based on the ratiometric R/G parameters over 2.0–10 mg∙L−1 nitrite concentration range with satisfying detection limits (0.12–0.62 mg∙L−1). In practice, the procedure was validated and applied with water and commercialized meat samples. The long storage time of miang (>5 years) was also evaluated, manifesting viability and reliability in views of both the nanocomposites synthesis and the nitrite determination performance.

A novel colorimetric sensor based onmodified mesoporous silica nanoparticles for rapid on-site detection of nitrite.

A novel colorimetric sheet based on Griess reagent-doped mesoporous silica nanoparticles was developed for nitrite detection. Griess reagent was adsorbed on long-range ordered hexagonal mesoporous silica nanoparticles and developed ink-bottle pores with some disorder. When the modified nanoparticles were bound using starch to fabricate a thin (~ 313μm) colorimetric sheet, spherical particles with a rougher surface and some distortion of their mesoporosity were observed. The sheet was used in conjunction with digital image colorimetry (DIC) andprovides a wide linear range of0.05 to 2.50mgL-1 with a low detection limit (15.0μgL-1-NO2-, equal to 4.5μgL-1 NO2--N), good inter-day precision (1.93%RSD), and excellent precision (2.67% relative error). The colorimetric sensors produced from the sheet costs only 0.04 USD each, while the DIC uses a standard smartphone for photographic detection. The method developed offers an easier and cheaper means of conducting rapid on-site determinationof nitrite in water with reliable quantitative results. Graphical abstract.

Terbium metal organic framework: Microwave synthesis and selective sensing of nitrite

The rapid and facile microwave method has been employed to synthesize [Tb2(TTHA)(H2O)4]·9H2O (I; H6TTHA = 1,3,5-triazine-2,4,6-triaminehexaacetic acid) microcrystals. Based on the photoluminescent emission of I, which can be selectively turned off upon the coordination of nitrite, the selective determination of nitrite in water was developed without the use of Griess reagents. With the use of smartphone camera as a detector, the quantitative analysis of nitrite was conducted within the CIELAB colorimetric space, revealing the relative standard deviation of less than 5% for the working range of 3–12 μg. Sensitivity, detection limit and quantification limit of the measurements were evaluated, providing the values of 0.732 (Lcontrol/Lsample)·μg−1, 1 μg and 3 μg, respectively.

Making and Testing Sample Control on Determination of Nitrite Content in Water and Wastewater by Using UV-Visible Spectrophotometer

&lt;p&gt;This study&lt;strong&gt; &lt;/strong&gt;focused on Making and Testing sample control as reference material on determination of nitrite content in water and waste water by using UV-Visible Spectrophotometer. Sample control has been made to replaced Certified Reference Materials (CRM) for determination of Nitrite content in water and waste water by using UV -Visible Spectrophotometer. Substitute materials for CRM should be homogeneous and stable, so the homogenity and stability control sample that has been made in this study is tested by using standard referring to ISO Guide 35 , 2006. The result of this experiments shows that the values of F&lt;sub&gt;stat&lt;/sub&gt; and F&lt;sub&gt;table&lt;/sub&gt; on homogenity test are 0.796 and 3.179 (F&lt;sub&gt;stat&lt;/sub&gt; &amp;lt; F&lt;sub&gt;tabl&lt;/sub&gt;&lt;sub&gt;e&lt;/sub&gt;); while the values of t&lt;sub&gt;stat&lt;/sub&gt; and table&lt;sub&gt; &lt;/sub&gt;on the stability test are 0.431 and 2.101 (t&lt;sub&gt;stat&lt;/sub&gt; &amp;lt; table), the mean of control sample concentration is 0,0435 mg / L. All test parameters have been qualified in accordance with ISO Guide 35 , 2006. The result of this research shows that the control of samples on the determination of Nitrite in water and waste water by using UV-Visible Spectrophotometer can be used as substitute for CRM and reference material.&lt;/p&gt;

An electro-active amphiphilic copolymer to functionalize carbon nanotubes for highly sensitive determination of nitrite in water

Carbon nanotubules (CNTs) are an attractive material to enhance the properties of electrochemical sensors because of their excellent conductivity. However, their poor dispersibility limits their application. In this paper, CNTs were successfully dispersed and stabilized through co-assembly with the copolymer poly(VMc-co-VCz-co-AA) (PCMA). The resulting PCMA/CNT sensor was able to rapidly measure nitrite with a low detection limit (0.067 μM), and a wide linear range of 1 μm - 4 mM. It also exhibited high sensitivity, good selectivity and long-term stability.

Gries – Ilosvay Spectrophotometry for Determination of Nitrite in Water and Vegetables in Vietnam

Gries – Ilosvay Spectrophotometry for Determination of Nitrite in Water and Vegetables in Vietnam

A hydrophobic deep eutectic solvent-based vortex-assisted dispersive liquid-liquid microextraction combined with HPLC for the determination of nitrite in water and biological samples.

In recent years, hydrophobic deep eutectic solvents as new generation of green solvents have attracted wide attention in liquid microextraction technique. In this article, four hydrophobic deep eutectic solvents composed of trioctylmethylammonium chloride and oleic acid were designed and prepared firstly. Combined with high-performance liquid chromatography, these deep eutectic solvents were used as an extraction solvent in vortex-assisted dispersive liquid-liquid microextraction for the selective enrichment and indirect determination of trace nitrite from real water and biological samples. This method is based on the diazotization-coupling reaction of nitrite with p-nitroaniline and diphenylamine in acidic water, and then the nitrite is quantified indirectly by measuring the obtained azo compounds. Some factors influencing the extraction efficiency, including the reaction and extraction conditions, were investigated. Under the optimized conditions, the method has a linear range of 1-300 μg/L with a correlation coefficient of 0.9924, limit of detection of 0.2 μg/L, limit of quantitation of 1 μg/L, intraday and interday relative standard deviations of 4.0 and 6.0%. This method was successfully applied in determination of nitrite from three environmental water and two biological samples with the recovery in the range of 90.5-115.2%. In addition, these results were well agreement with those obtained by the conventional Griess method.

Fluorimetric determination of nitrite in water using a novel fluorescent dye

A simple, sensitive and selective fluorimetric method for the determination of trace amounts of nitrite in different water samples (e.g., underground water, geothermal waste water, domestic waste water and drinking water) was proposed. The fluorimetric determination is based on the diazotization reaction of nitrite with a fluorescent dye, tetraamino zinc (II) phthalocyanine in an acidic medium. Under the optimum experimental conditions, nitrite can be determined in the range 10−6–10−4mol·L−1 with the detection limit 2.04×10−8mol·L−1. The proposed method has been successfully applied to the determination of nitrite in various water samples. The results compared favorably with the results from a standard isocertified method.

Fluorescence Determination of Nitrite in Water Using Prawn-Shell Derived Nitrogen-Doped Carbon Nanodots as Fluorophores

In this work, we report the synthesis of nitrogen (N)-doped carbon nanodots (N-CNDs) with an N doping level of 3.6 at. % by hydrothermal treatment of prawn shell and their application as fluorophores for selective and sensitive fluorescence detection of NO2– in water. The results demonstrate that NO2– detection by directly fluorescent quenching at N-CNDs fluorophores can achieve an analytical detection linear range up to 1.0 mM with a detection limit of 1.0 μM. The obtained detection limit of NO2– using N-CNDs fluorophores is dramatically lower than the maximum limit value of 3.0 mg L–1 (namely, 65 μM) for NO2– in drinking water ruled by the World Health Organization (WHO), which is very important for a practical application of the developed analytical method. The interference experiments indicate that only I– ions among all common anions and cations investigated show very adverse influence on selective detection of NO2– by this developed N-CNDs based fluorescent determination method. Further, the fluores...

Standard addition/absorption detection microfluidic system for salt error-free nitrite determination

A continuous-flow microfluidic chip-based standard addition/absorption detection system has been developed for accurate determination of nitrite in water of varying salinity. The absorption detection of nitrite is made via color development using the Griess reaction. We have found the yield of the reaction is significantly affected by salinity (e.g., −12% error for 30‰ NaCl, 50.0 μg L−1N-NO2− solution). The microchip has been designed to perform standard addition, color development, and absorbance detection in sequence. To effectively block stray light, the microchip made from black poly(dimethylsiloxane) is placed on the top of a compact housing that accommodates a light-emitting diode, a photomultiplier tube, and an interference filter, where the light source and the detector are optically isolated. An 80-mm liquid-core waveguide mounted on the chip externally has been employed as the absorption detection flow cell. These designs for optics secure a wide linear response range (up to 500 μg L−1N-NO2−) and a low detection limit (0.12 μg L−1N-NO2− = 8.6 nM N-NO2−, S/N = 3). From determination of nitrite in standard samples and real samples collected from an estuary, it has been demonstrated that our microfluidic system is highly accurate (<1% RSD, n = 3) and precise (<1% RSD, n = 3).

Determination of nitrites in water by in-electrode coulometric titration in reticulated vitreous carbon electrode.

Nitrite in water samples was determined by in-electrode coulometric titration in a reticulated vitreous carbon (RVC) electrode of 100 ppi porosity. The sample was mixed with dilute sulphuric acid and sodium sulphate, filled into a flow cell with the porous electrode and nitrite was oxidised to nitrate by constant current of 5 µA at which the potential of the electrode was monitored. The limits of detection and quantification were found to be 0.4 and 1.2 µg/L, respectively. The repeatability and reproducibility were 2.2 % and 2.6 %, respectively. The bias at 100 µg/L were found to be 0.3 %. The duration of the measurement is 2-3 min depending on the nitrite concentration. There were few interferences only, neutral and cationic surfactants decreased and increased slightly the signal, respectively. Humic acids above 30 mg/L increased the signal by 10 %. Drinking and surface water samples were analysed and the results matched well those from the photometric method.

Determination of Nitrite in Water by an Optical and Electrochemical Lanthanide Sensor

Determination of Nitrite in Water by an Optical and Electrochemical Lanthanide Sensor

Electrochemical sensors using modified electrodes based on copper complexes formed with Algerian humic acid modified with ethylenediamine or triethylenetetramine for determination of nitrite in water

The response and efficiency of new sensors for nitrite ions analysis have been studied electrochemically. These sensors were developed by modifying a carbon paste electrode (CPE) with copper (II) complexes formed with commercial (PFHA) and Algerian (YHA) humic acids and their modified compounds with ethylenediamine (EDA) or triethylenetetramine (TETA). The developed mechanism is based on the electrochemical oxidation of NO2(-) on the modified CPE for different nitrite concentrations. The obtained results showed that the carbon paste electrode modified with copper (II)-modified humic acids complexes (Cu-MHA) exhibited substantial electrocatalytic effect on the oxidation of nitrite anions compared with carbon paste electrode. The sensitivity of the modified CPE towards nitrite concentrations depends on the nature of the humic acid and its modified compounds. The measurements performed by using CPE/Cu-YHA-EDA and CPE/Cu-YHA-TETA gave the best sensitivity and a good linear response of current versus nitrite concentrations. The oxidation peak current of nitrite at CPE/Cu-YHA-TETA and CPE/Cu-YHA-EDA electrodes in weak acid solution is proportional to the concentration of nitrite over the range 0-1.38 × 10(-2) mol L(-1) with a limit of detection (LOD) of 1.46 μmol L(-1) (Sensitivity=41.06 μA(mmol L(-1))(-1) and 2.17 μmol L(-1) (Sensitivity=27.63μA(mmol L(-1))(-1), respectively. Compared to the sensors published in the literature, our CPE/Cu-YHA-TETA and CPE/Cu-YHA-EDA electrodes exhibit a good catalytic activity towards nitrite oxidation and a low limit of detection over a wide nitrite concentrations range.

Indirect cloud point extraction and spectrophotometric determination of nitrite in water and meat products

A new indirect micelle mediated cloud point extraction method has been developed for sensitive determination of trace amounts of nitrite by spectrophotometry. The method is based on the well known oxidation–reduction reaction of nitrite by iodide ion in acidic medium and cloud point extraction of I3− formed from aqueous solution using Triton X-100. The extracted surfactant rich phase is diluted with water and its absorbance is measured at 365nm. The effects of different operating parameters such as concentration of surfactant, KI concentration, temperature, incubation time and acid concentration on the cloud point extraction were studied in details and a set of optimum conditions was obtained. A linear calibration graph was obtained in the range of 8–120ngmL−1. The limit of detection (LOD) based on three times the standard deviation of the blank (3Sb) was 6.0ngmL−1 (n=10) and the relative standard deviation (RSD) for determination of 60ngmL−1 of nitrite was 3.40% (n=10). The method was applied to the determination of nitrite in meat products and water samples.