Determination Of Nitrite In Foods Research Articles

Density functional theory–guided electrochemical determination of nitrite in foods based on 2D metal-organic frameworks

This paper presents results for four types of morphology-controlled two-dimensional cobalt based tetrakis (4-carboxyphenyl) porphyrin metal-organic frameworks (2D Co-TCPP MOFs) with different catalytic properties for nitrite, and an electrochemical sensor was fabricated by the Co-TCPP MOF with superior catalytic properties. The sensor exhibited a high sensitivity of 311.3 μg/g, an extra low detection limit (LOD) of 0.03 μM, and a wide linear range of 0.1–375 μM, which was applied successfully for nitrite detection in water, milk and sausage. Moreover, density functional theory (DFT) calculations were used to establish the sensing method, the adsorption structures of nitrite on the surface of Co-TCPP MOF were built and the electrocatalytic mechanism was confirmed. The results explained why the sensor fabricated by a single Co-TCPP MOF exhibited equal or better performance than reported sensors fabricated by composite materials based on a combination of theory and experiment. This work reported a universal electrochemical sensing method for nitrite detection in food based on a single morphology-controlled 2D TCPP MOF, which provided a new and valuable strategy for establishing an efficient food safety determination method guided by theoretical calculations.

Fabrication of a Disposable Amperometric Sensor for the Determination of Nitrite in Food.

Silver nanoparticles (AgNPs) were synthesized through an environmentally friendly method with tea extract as a reduction agent. By immobilizing them on the surface of a low-cost pencil graphite electrode (PGE) with the aid of a simple and well-controlled in-situ electropolymerization method, a novel nanosensing interface for nitrite was constructed. The film-modified PGE showed good electrocatalytic effects on the oxidation of nitrite and was characterized through scanning electron microscopy, X-ray photoelectron spectroscopy, and electrochemical techniques. Characterization results clearly show that the successful modification of AgNPs improved the surface area and conductivity of PGEs, which is beneficial to the high sensitivity and short response time of the nitrite sensor. Under the optimal detection conditions, the oxidation peak current of nitrite had a good linear relationship with its concentration in the range of 0.02-1160 μmol/L with a detection limit of 4 nmol/L and a response time of 2 s. Moreover, the sensor had high sensitivity, a wide linear range, a good anti-interference capability, and stability and reproducibility. Additionally, it can be used for the determination of nitrite in food.

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.

Research Progress on the Determination of Nitrite in Food

Research Progress on the Determination of Nitrite in Food

Determination of nitrite in food based on its sensitizing effect on cathodic electrochemiluminescence of conductive PTH-DPP films

Herein, a novel strategy for electrochemiluminescence (ECL) detection of nitrite based on its sensitization effect on cathode ECL emission of 3,6-di(2-thienyl)-2,5-dihydropyrrolo [3,4-c] pyrrole-1,4-dione (TH-DPP) polymeric films (PTH-DPP) was formulated, by means of a one-step electropolymerization of TH-DPP with a short time on the glassy carbon electrode (GCE). It was shown that the PTH-DPP film-modified GCE exhibited a strong ECL response when S2O82− was used as a co-reactant. The ECL emission could be greatly enhanced by PTH-DPP with nitrite in a K2S2O8/PBS solution system and occurred at a relatively lower potential in comparison with traditional cathode ECL emitter, leading to high sensitivity and good selectivity. The ECL sensor exhibits excellent linear relationship in the ranges of 0.3 to 100 μM and 100 to 1000 μM for nitrite detection, with an outstanding detection limit of 0.08 μM (S/N = 3). The ECL sensor provides an impressive outcome for the detection of practical samples.

Voltammetric sensor based on glassy carbon electrode modified with hierarchical porous carbon, silver sulfide nanoparticles and fullerene for electrochemical monitoring of nitrite in food samples

This paper reports the development of a voltammetric sensor using glassy carbon electrode based on hierarchical porous carbon (HPC) with silver sulfide nanoparticles (Ag2SNP), Nafion and fullerene (C60) for the determination of nitrite in foods. Raman spectroscopy, scanning electron microscopy, transmission electron microscopy and energy-dispersive X-ray were used to characterize the morphology and composition of the materials. The use of HPC and C60 in the construction of the electrode contributed toward the enlargement of the specific surface area and the improvement of the electrochemical performance of the device. The electrochemical behavior of nitrite in different electrodes was evaluated by cyclic voltammetry in the potential range of 0.4 – 1 V. Using the optimal conditions, a linear response ranges of 4.0– 148 μmol L−1, a limit of detection of 0.09 μmol L−1 and a sensitivity of 0.05 μAμmol L−1 cm−2 were obtained. The results showed that the proposed method can selectively detect nitrite in the presence of other compounds without interference and with good stability. The proposed method was successfully applied for the detection of nitrite in food samples where it demonstrated a good degree of accuracy and satisfactory efficiency.

Fabrication of gold nanoparticles/l-cysteine functionalized graphene oxide nanocomposites and application for nitrite detection

In this paper, the gold nanoparticles/l-cysteine functionalized graphene oxide (AuNPs/GO-SH) nanocomposites was synthetized with a simple approach for nitrite determination. The prepared nanocomposites were characterized by scanning electron microscopy, transmission electron microscopy, X-ray diffraction and Raman spectroscopy, etc. A pair of well-defined redox peaks was founded for AuNPs/GO-SH hybrids with a formal potential of 0.90 V in 0.1 M phosphate buffered solution by cyclic voltammetry. Under optimal conditions, the sensor could detect nitrite as low as 0.25 μM with a wide linear response range from 5 to 1000 μM, high sensitivity and excellent selectivity. The superior results of nitrite determination in pickled radish showed a promising application for determination of nitrite in food.

Rapid determination of nitrite in foods in acidic conditions by high-performance liquid chromatography with fluorescence detection.

In this study, a simple, rapid, and sensitive method for the determination of nitrite (NO2 (-) ) in food samples by high-performance liquid chromatography with fluorescence detection in acidic conditions had been developed. The derivatization of the nitrite with 2,3-diaminonaphthalene was performed in acidic conditions to yield the highly fluorescent 2,3-naphthotriazole, which was directly analyzed by high-performance liquid chromatography with fluorescence detection without adjusting the solution to alkaline. The analysis column was reversed-phase C8 column. A constant flow rate of 1.0 mL/min was employed using water/acetonitrile as the mobile phase in isocratic mode (70:30, v/v). Fluorescence was monitored with excitation at 375 nm and emission at 415 nm. The standard calibration curves were linear for nitrite in different matrixes in the concentration range of 0-100 μg/L, and the correlation coefficients ranged from 0.9978 to 0.9998. The limits of detection and quantification were in the ranges of 0.012-0.060 and 0.040-0.20 mg/kg, respectively. The recoveries of nitrite from samples spiked at three different concentrations were 74.0-113.2%, and the relative standard deviations of the recovery results (n = 6) were 1.67-10.8%. The proposed method has good repeatability and is very sensitive and simple. It has been successfully used to determine nitrite in foods.

Electrocatalytic oxidation of nitrite using metal-free nitrogen-doped reduced graphene oxide nanosheets for sensitive detection

Nitrite can become poisonous to animals and human beings as it can lead to generation of carcinogenic N-nitrosamines. Metal-free nitrogen-doped reduced graphene oxide (NrGO) exhibited a good electrocatalytic activity toward oxidation of nitrite with the relatively low oxidation potential of 0.68V (v.s. saturated calomel electrode), thus, a facile electrochemical sensor based on metal-free NrGO was fabricated for sensitive detection of nitrite for the first time. The novel sensor showed a wide linear concentration range from 0.5 to 5000μM and a low detection limit of 0.2μM at the signal-to-noise ratio of 3 with good selectivity, stability, and reproducibility. This fabricated sensor was used for the determination of nitrite in pickled garlic and river water. These results demonstrate that the facile metal-free NrGO-modified electrochemical sensor has promising applications for the determination of nitrite in food and environment.

Development and Optimization of a SERS Method for On-site Determination of Nitrite in Foods and Water

A rapid, sensitive, and selective detection method of nitrite in foods and water was established by surface-enhanced Raman spectroscopy (SERS) based on the diazo reaction of nitrite with p-nitroaniline and 1-naphthylamine in acidic solution. The azo dye (4-(4-nitrophenyldiazenyl)naphthalene-1-aminium, NNA), which was derived from the diazo reaction, was determined by SERS using citrate-coated silver nanoparticles (AgNPs) as SERS substrates. The concentrations of nitrite in samples were finally calculated from the intensities of SERS signals generated by NNA in the testing solutions. By using the present method combined with a portable miniature Raman spectrometer, on-site determination of nitrite could be performed easily and efficiently. The effects of several experimental parameters on the intensity of SERS signals, such as the volume of AgNP solution and the mixing time of AgNPs and NNA, were investigated. The linear range of the method was 0.1–10.0 mg L−1. The limits of detection (LODs) were 0.01, 0.03, and 0.05 mg L−1 at 720, 1,459, and 1,609 cm−1, respectively. The method was applied to the determination of nitrite in real food and water samples, with recoveries in the range of 86.9–103.4 % and relative standard deviations (RSDs) less than 9.64 %.

Nitrite electrochemical biosensing based on coupled graphene and gold nanoparticles

Biofunctionalized graphene-gold nanoparticle (AuNP) hybrids were prepared using a facile approach of in situ growth, with homogeneous distribution of AuNPs on the graphene nanosheets. Hemoglobin (Hb) was immobilized on the graphene-AuNP composites to fabricate biosensors for determination of nitrite (NO2−). A pair of well-defined redox peaks was observed for Hb immobilized on the graphene-AuNP hybrids with a formal potential (E0′) of −0.314V in 0.1M phosphate buffered saline (0.15M NaCl, pH 7.0). The novel biosensors exhibited many advantages, such as wide linear response range (from 0.05 to 1000µM, R2=0.997), low detection limit (0.01µM, a signal to noise ratio of 3), high sensitivity (0.15μAμM−1cm−2), and excellent selectivity. These constructed biosensors were further used for determination of nitrite in pickled radish. The results obtained were in good agreement with those using spectrophotometry based on the National Food Safety Standard (GB 5009.33-2010), which indicates that these novel and sensitive biosensors have promising application for determination of nitrite in food.

Fast Detection of Nitrite with a Test Paper Tape

A test paper tape on the determination of nitrite in food was designed, which is based on the diazotization of nitrite with sulfanilic acid under weakly acidic conditions then coupled with N-(1-Naphthyl)-ethylenediamine dihydrochloride in forming the colour-producing response. Then the reaction membrane turned to purple-red. The deeper purple-red film was obtained in an increased nitrite concentration-dependent manner. Experimental results showed that nitrite concentrations were proportional to a values of the L a b color system. A favorable linearity was presented in the range of 25 to 5000 μg/mL. The correlation coefficient(r) was 0.984 and the whole testing time needed was about 1.5 min at room temperature.

Development of an optical redox chemical sensor for nitrite determination

An optical chemical sensor for the determination of nitrite based on incorporating methyltrioctylammonium chloride as an anionic exchanger on the triacetylcellulose polymer has been reported. The response of the sensor is based on the redox reaction between nitrite in aqueous solution and iodide adsorbed on sensing membrane using anion exchange phenomena. The sensing membrane reversibly responses to nitrite ion over the range of 6.52×10-6 - 8.70×10-5 mol L-1 with a detection limit of 6.05×10-7 mol L-1 (0.03 µg mL-1) and response time of 6 min. The relative standard deviation for eight replicate measurements of 8.70×10-6 and 4.34×10-5 mol L-1 of nitrite was 4.4 and 2.5 %, respectively. The sensor was successfully applied for determination of nitrite in food, saliva and water samples.

Nitrite as undesirable substances in animal feed ‐ Scientific Opinion of the Panel on Contaminants in the Food Chain

Nitrite as undesirable substances in animal feed ‐ Scientific Opinion of the Panel on Contaminants in the Food Chain

Flow injection kinetic spectrophotometric method for the determination of trace amounts of nitrite

In this work, a new, simple and sensitive flow injection catalytic kinetic spectrophotometric determination of nitrite is reported based on catalytic effect of nitrite on the redox reaction between sulfonazo III and potassium bromate in acidic media. The reaction was monitored by measuring the decrease in the absorbance of sulfunazo III at 570 nm. Various chemical (such as the effect of acidity, reagents concentrations) and instrumental parameters (flow rate, reaction coil length, injection volume and temperature) were studied and were optimized. Under the optimum conditions calibration graph was linear in the nitrite concentration ranges of 8.00 × 10 −3–3.00 × 10 −1 μg/ml (with slope of 2.40) and 3.50 × 10 −1–1.80 μg/ml (with slope of 0.42). The detection limit was 6.00 × 10 −3 μg/ml of nitrite, the relative standard deviation ( n = 10) was 1.25% and 0.88% for 5.00 × 10 −2 and 2.00 × 10 −1 μg/ml of nitrite respectively. About 60 samples in 1 h can be analyzed. The interfering effects of various chemical species were studied. The method was successfully applied in the determination of nitrite in food and environmental samples.

Chemiluminescence microflow injection analysis system on a chip for the determination of nitrite in food

A new microflow injection analysis (μFIA) system on a chip for the determination of nitrite is described. The chip is produced by using two transparent poly(methylmethacrylate) (PMMA) slices measured 50 × 40 × 5 mm, and the microchannels etched by CO 2 laser are 200 μm wide and 100 μm deep with the volume of reaction area about 1.8 μL. Nitrite is sensed by the chemiluminescence (CL) reaction of luminol with ferricyanide that is the product of the reaction of ferrocyanide with nitrite in acidic medium. The syringe pump with an accurate timer controls all reagents, including the sample. The linear range of the nitrite concentration is 8–100 μg L −1 and the detection limit is 4 μg L −1 ( S/ N = 3). The proposed method has good reproducibility with the relative standard deviation 4.1% for 50 μg L −1 of nitrite ( n = 9) and is very sensitive and simple. It has been successfully applied to the determination of nitrite in food.

Determination of Nitrite in Foods by Single-Sweep Polarography

In an acid medium, nitrite diazotized with p-rosaniline and then coupled with 8-hydroxyquinoline in a weak alkaline medium produces azo compounds. The azo compounds produce a very sensitive polarographic wave at -0.70 V (versus the saturated calomel electrode). The height of the peak is linear with the concentration of nitrite in the range of 5 x 10(-9) to 5 x 10(-7) g/mL. The detection limit is 3 x 10(-9) g/mL. The electrochemical characteristics of the polarographic wave are also discussed. The method was used to determine nitrite in sausage. The results agree well with those obtained by spectrophotometry.

Studies on the Preparation of Sample Solution for Colorimetric Determination of Nitrite in Foods.

The preparation of a sample solution for the colorimetric determination of nitrite in processed foods has been studied in detail focusing on the deproteinizing procedure. A simple and rapid deproteinizing procedure was obtained by precipitation of colloid zinc hydroxide which was formed by adding constant amounts of zinc acetate and sodium hydroxide to the alkaline extracts from salted salmon roe. The amounts of nitrite isolated from the samples of salted roe of salmon, pollack, sausage and ham fortified at 5, 50 or 70 μg/g of nitrite were determined using this procedure and the recoveries of nitrite were found to be not less than 84.8%. This preparation of sample solution is applied for the determination of residual nitrite in various foods by diazotaiztion-coupling colorimetry.

Rapid and sensitive determination of nitrite in foods and biological materials by flow injection or high-performance liquid chromatography with chemiluminescence detection

A method is described for the determination of nitrite that is based on reduction of nitrite with potassium iodide followed by chemiluminescence detection of the liberated NO using a thermal energy analyzer. The method worked well both in the flow injection mode and upon interfacing with a reversed-phase high-performance liquid chromatography system. Limited data available indicated a good agreement between results obtained by the chemiluminescence method and those obtained by using a well established colorimetric procedure when they were applied for the determination of nitrite in a number of cured meats, human saliva, and baby foods. The chemiluminescence method is, however, much superior to the colorimetric one in its speed, versatility, as well as sensitivity (200 times more), and requires only a minimum of sample preparation. The detection limit of the new method is about 0.1 ng NaNO 2 per injection or 5 μg/kg in cured meats and other substrates analyzed.

Selective Kinetic Spectrophotometric Determination of Nitrite in Food and Water

Abstract A highly selective and sensitive method for the kinetic spectrophothometric determination of sub-microgram amounts of nitrite has been development based on its reaction with Nile blue 2B in acidic medium. The reaction is monitored spectrophotometrically at 595 nm at a fixed time of 4.5 min. The change in absorbance at 595 nm is related to the concentration of nitrite in the range 0.005 - 1.100 μg.ml−1 The detection limit is 0.001 μg.ml−1. The relation standard deviation is 1% for 0.020 μg.ml−1 of nitrite for ten replicate measurements. Most common anions and cations do not interfere. The procedure was applied to the determination of trace amounts of nitrite in sausage and water.