Determination Of Nitrite Ions Research Articles

Evaluation of human macrophage functional state by voltammetric monitoring of nitrite ions.

The method for assessing the level of nitric oxide (II) (NO) by voltammetric monitoring of nitrite ions was carried out on models M1 and M2 of polarized macrophages induced from monocytes of human peripheral blood with the addition of lipopolysaccharide (LPS) and interleukin-4 (IL-4), respectively. The model of induction of M1 and M2 macrophages was used in the work to achieve the corresponding shifts in the functional status of studied cells. Ethyl nitrite (EtONO) was used as a standard compound of nitrite ions for electrochemical measurements. Electrochemical determination of nitrite ions was performed by anodic linear sweep voltammetry in the first-order derivative mode (ALSV FOD) in Britton-Robinson (BR) buffer with pH4.02 on carbon ink modified graphite electrode. EtONO calibrations were linear over a concentration range from 2 to 9μmolL-1 with corresponding regression equation y = 0.768c - 0.048. Limit of detection (LOD) (S/N = 3) was 0.38μmolL-1. The results of the study showed the fundamental possibility of using voltammetry to assess indirectly the production of nitric oxide by cells in supernatants of the monocytic macrophage lineage. The level of nitric oxide metabolites (nitrite ions) in supernatants was associated with the functional state of macrophages.

Diazo-reaction-based SERS substrates for detection of nitrite in saliva

Nitrite is a biomarker to diagnosis oral disease such as nasopharynx cancer, and obstructive lipoprotein. As an important biomarker of human oral disease, determination of nitrite ions is a demand task. Herein, we demonstrate a novel and pragmatic approach based on surface enhanced Raman scattering (SERS) spectroscopy to detect the concentration of nitrite. Firstly, we functionalize the cleaned glasses by (3-aminopropyl) trimethoxysilane for self-assembling Au nanoparticles and then modify the resultant Au array with urea for synthesizing SERS substrate. On the basis of specific diazo reaction between nitrite and urea in acidic media, resulting that intensity of urea SERS band at 1003 cm−1 suppress, a good linear relationship ranging from 20 to 120 μM is obtained. This specific SERS substrate can be used to detect nitrite in human saliva without pretreatment process, exhibiting its advantages of rapidness, sensitivity and selectivity.

The analysis of adhesive-dysfunctional endothely at resistant arterial hypertension

Aim: To examine the antihypertensive activity of Telmisartan and Bisoprolol at resistant hypertension.To evaluate the features of resistant hypertension and endothelial vasomotor and adhesive dysfunction.Methods: The level of adhesion molecules s-ICAM-1, L-selectin and matrix metalloproteinase-9 was determined by ELISA with regard to vasoactive function of the brachial artery, which is determined through the flow-dependent vascular dilatation sample. Determination of Nitrogen oxide was conducted on data metabolites of total Nitrogen (NOx) by determination of Nitrite ion after colorimetric reaction with Griess reagent using SF-46 spectrometer (Russia).Results. The studies have shown that six-month treatment by Telmisartan and Bisoprolol in most patients (22 patients) was accompanied by target levels of blood pressure achievement, and was observed in 14 patients resistant to the treatment. The additional inclusion in complex treatment Aliskiren 150-300 mg per day was also accompanied by normalization of blood pressure.Conclusion.1. The function of endothelial adhesion and appearance of endothelial dysfunction occur prior to hypertension clinical and morphological signs.2. Induced hypertension increase of sICAM-1 and L-selectin and matrix metalloproteinase-9 is a marker of hypertension severity and the treatment efficiency.3. Telmisartan and Bisoprolol significantly reduce the adhesive endothelial dysfunction and contribute to the achievement of target blood pressure levels

Chemiluminescence detection in urethane-acrylate microfluidic devices

This work reports on the use of a urethane-acrylate (UA)-based resin in the construction of micro-flow injection analyzers (μFIA) with integrated chemiluminescence (CL) cells for application in ordinary analytical determinations. The proposed devices, manufactured by a rapid and low-cost prototyping procedure, offered suitable transparency to visible electromagnetic radiation and supported flow rates over 2.0mLmin−1 without leakages or damages to the structures of the CL cell. By using a pair of photodiodes as detectors, the determination of hypochlorite ions (2.0–20mgL−1) based on its reaction with 3-aminophthalhydrazide (luminol) provided a linear response (R2=0.998) with a limit of detection (LOD) of 0.5mgL−1 and repeatability of 0.4% for successive injections (n=4) of a 2.0mgL−1 standard solution. The determination of nitrite ions (10–80μgL−1), carried out using a photomultiplier to detect the quenching of luminescence for the hypochlorite (ClO−)/luminol reaction in the presence of the analyte, demonstrated an adequate linearity (R2=0.998), LOD of 5.0μgL−1 and precision of 0.6% for successive injections (n=4) of a 10μgL−1 solution. The results obtained for the determination of hypochlorite in household bleaches and of nitrite in commercial pâtés did not differ significantly from the reference methods at a confidence level of 95%, demonstrating a suitable accuracy for the miniaturized methods. In addition, only 24mL of residues were produced per hour in both procedures, so that the proposed analyzer fits one of the green chemistry requirements.

Hybrid silica-organic material with immobilized amino groups: surface probing and use for electrochemical determination of nitrite ions

Hybrid silica-organic material with fixed n-propylamine groups was prepared by a sol-gel route and characterized by several techniques. Specific surface area of the material was 110 ± 2m 2 g -1 , specific pore volume was 0.90 ± 0.01 cm 3 g -1 , and average pore size was 25 ± 3 nm. The specific concentration of attached amino groups was 3.28 ± 0.05 mmol g -1 , the amount of residual silanol groups being comparable with that of amino groups. The maximum attainable adsorption of H ? ions was 2.34 ± 0.10 mmol g -1 . The Dimroth-Reichardt normal- ized polarity parameter of the near-surface layer was 0.64 that points to the closeness of properties of the near-surface layer to those of water-organic mixtures and polar organic solvents rather than aqueous solutions. Surface probing with H ? ions has revealed that due to interactions between surface amino groups and weakly acidic silanol groups the protonization constants of fixed amino groups are consid- erably smaller than the protonization constants of aliphatic amines in aqueous solutions. The equimolecular composi- tion of Cu (II) complexes with immobilized amino groups was concluded from the results of surface probing with Cu 2? ions and UV-vis diffuse reflectance spectroscopy. The stability constants of Cu (II) complexes were deter- mined with the aid of the model of polydentate binding, and the influence of strong negative cooperativity effects on the adsorption equilibria was detected. The material with sorbed Cu (II) ions was used to prepare a working electrode for the electrochemical determination of nitrite ions. The electrocatalytic determination of nitrite ions in aqueous media may be performed by means of cyclic voltammetry, differential pulse voltammetry and chrono- amperometry with the limits of detection 1.3, 4.6, and 3.1 lmol l -1 , correspondingly.

Effective indirect enrichment and determination of nitrite ion in water and biological samples using ionic liquid-dispersive liquid–liquid microextraction combined with high-performance liquid chromatography

An ionic liquid dispersive liquid–liquid microextraction high-performance liquid chromatography (IL-DLLME-HPLC) method for effective enrichment and determination of nitrite ion in water and biological samples was developed. The method was based on the reaction of nitrite ion with p-nitroaniline in the presence of diphenylamine in acid media and IL-DLLME of azo product. The optimization of reaction and extraction conditions, such as kind and concentration of acid, reaction time, volume of reaction solvent, temperature, kind of extraction and dispersive solvent, volume of extraction and dispersive solvent, addition of salt, extraction and centrifugal time were studied. Under the optimal conditions, 1-octyl-3-methylimidazolium bis[(trifluoromethyl)sulfonyl]imide IL-DLLME procedure provided high enrichment factor of 430 and good extraction recovery of 91.7% for nitrite ion. The linearity was observed in the range of 0.4–500.0 μg L −1 with good correlation coefficient ( r 2 = 0.9996). The relative standard deviations (RSDs) for five replicate measurements varied between 1.5% and 4.8%. The limit of detection of the method (S/N = 3) was 0.05 μg L −1. The interference effect of some anions and cations was also tested. The developed method allowed achieving an excellent enrichment factor, yielding a lower LOD in comparison with other methods. Moreover, the proposed method was able to analyze nitrite ion in water and biological samples with satisfactory recovery ranged from 96.5% to 107.3%.

Silver nanoparticles embedded three dimensional silicate sol-gel matrix modified electrode for nitrite sensor application

A simple amperometric sensor was fabricated by using silver nanoparticles (Agnps) embedded three dimensional silicate sol–gel (SG) matrix (SG–Agnps). The silver nanoparticles stabilised by SH functionalised 3–D silicate sol–gel network was coated on the glassy carbon electrode and used for the determination of nitrite ion in 0.1 M PBS (pH 7.2). The prepared silver nanoparticles–silicate sol–gel (SG–Agnps) modified electrode was characterised by UV–visible absorption spectroscopy, scanning electron microscopy (SEM) and electrochemical method. The electrochemical behaviour of SG–Agnps modified electrode was studied by using potassium ferricyanide as a redox marker to probe the tunable kinetic barrier of the dispersed silver nanoparticles in silicate sol–gel matrix. The SG–Agnps film was used as nanomaterials comprised electrochemical device for direct electrocatalysis and amperometric sensing of nitrite ion. The silver nanoparticles embedded silicate sol–gel film showed good stability and sensitivity with an experimental amperometric detection limit of 4 M. The fabrication of SG–Agnps modified electrode was very simple and it showed fast amperometric response and reproducible results for nitrite sensing.

Determination of nitrite ions using test strips based on 3-hydroxy-7,8-benzo-1,2,3,4-terahydroquinoline

RIB-Nitrite-Test and Sorbfil-Nitrite-Test strips were developed for determining nitrite ions in water samples and foodstuffs by a reaction similar to the Griess reaction. Stable and noncarcinogenic 3-hydroxy-7,8-benzo-1,2,3,4-tetrahydroquinoline was used as an azo component adsorbed in the reagent paper zone on a polymeric support or on a Sorbfil plate sealed in a transparent polymeric film. Performance characteristics were evaluated by a statistical method for visual test procedures for the detection and determination of NO2− using two different test strips. The determination limit was 0.54 and 0.09 mg/L, and the detection limit was 0.50 and 0.08 mg/L, respectively.

The Use of Ultrasound for the Analytical Determination of Nitrite on Diamond Electrodes by Square Wave Voltammetry

This work describes an analytical methodology for the determination of nitrite ions in aqueous solutions using boron‐doped diamond electrodes and square wave voltammetry associated with ultrasound radiation. The nitrite ions were oxidized to nitrate ions in Britton‐Robinson buffer solutions 0.1 M, pH 2.0 at 1.0 V versus Ag/AgCl. The voltammetric response of nitrite in the presence of ultrasound showed a peak current five times higher than the obtained in silent conditions. Thus, the detection limit obtained in the presence of radiation was 17 nM (0.782 µg l−1), a small value if compared with that obtained in the absence of ultrasound: 140 nM (6.44 µg l−1).

Sorption–Optical Determination of Nitrite Ions in Sea Water with Chromotrope 2B

The Chromotrope 2B reagent was used as an analytical reagent for the direct determination of nitrite ions by sorption chromaticity measurements, diffuse reflectance spectrometry, and solid-phase spectrophotometry. The silochrom C-120 silica gel and the AV-17 anion exchanger were used as supports. Optimum conditions were found for the formation and sorption of Chromotrope 2B. The dependence of the chromaticity characteristics (chromaticity coordinates, lightness, color saturation, yellowness, and whiteness) on the concentration of nitrite ions was examined. The advantages of the use of chromaticity characteristics over the diffuse reflection coefficient were demonstrated. A procedure was developed for the test and sorption–optical determination of nitrite ions in sea water.

Determination of nitrite ions in well water by biamperometric standard addition

AbstractA new modified biamperometric method of analysis is proposed which has the advantage of producing straight lines as plots. Nitrite ions in well water have been determined by biamperometry and standard addition of solutions containing nitrite or iodate ions. Two platinum foils are immersed in the solution and 100 mV potential is applied between the electrodes; the resulting current is measured. The standard nitrite or iodate ions react with excess of iodide ions, producing triiodide. The reversible redox pair I/I− is responsible for a change in current, allowing the biamperometric measurement. The concentration of triiodide formed depends on the nitrite concentration. Twenty ppb of nitrite ions have been determined with good accuracy and precision. EDTA was added to eliminate interference from Fe(III), Cu(II), and other metal ions.

Determination of nitrite ion by differential-pulse polarography using N-(1-naphthyl)ethylenediamine

A highly sensitive differential-pulse polarographic method has been developed for the determination of sub-micromolar concentrations of nitrite ion after diazotisation with sulphanilic acid at low pH and coupling with N-(1-naphthyl)ethylenediamine dihydrochloride. At pH 2.0 and with 0.01 M potassium dihydrogen phosphate as the base electrolyte, the peak current at +0.020 V versus a saturated calomel electrode increases linearly in the concentration range 5 × 10–8–2.12 × 10–6M in simple aqueous solutions. The relative standard deviation is 3.3% for the determination of 1 × 10–7M nitrite.

Separation and determination of nitrite ion by affinity chromatography with cyano(pheophytinato a)cobalt(III) charged column

The separation and determination of the nitrite ion by affinity chromatography is described. The good separation of the nitrite ion was obtained by using cyano-(pheophytinato a)cobalt(III) bonded octadecylsilica as the stationary phase and water of pH 4.3 adjusted by acetic acid as the mobile phase. Conventional ion chromatograph was also used for the analysis of the nitrite ion. For the synthetic samples prepared by mixing the nitrite and nitrate ions, analytical values obtained by affinity chromatography were in agreement with calculated values and close to the analytical values obtained by ion chromatography. In the proposed affinity chromatography, the nitrite and nitrate ions could be determined in the concentration range of 0.15–1.0ppm and 0.1–1.0ppm with relative standard deviations (n=10) of 5.3% and 4.7%, respectively.

Spectrophotometric Determination of Nitrite Ion or Chloramine T with Gallein-Molybdenum Complex and Cobalt (II) with Gallin and Hydrogen Peroxide in a Micellar Media

Abstract A simple and sensitive spectrophotometric method for the determination of nitrite ion or chloramine T is proposed utilizing a gallein-molybdenum complex in the presence of N-hexadecyltrimethylammonium chloride in acidic media. Also, a sensitive catalytic spectrophotometric procedure for determi

Determination of nitrite ion and sulfanilic and orthanilic acids by differential pulse polarography.

On peut doser les ions nitrite grâce a la reaction rapide et quantitative de diazotation par l'acide sulfanilique ou orthanilique avec formation de sels diazonium a pH=1,5. Limite de detection 8,6•10 −8 M NO 2 − en solution aqueuse. On peut aussi utiliser la methode pour doser l'acide sulfanilique jusqu'a 4•10 −7 M et l'acide orthanilique jusqu'a 1,6•10 −6 M

Spectrofluorimetric method for determining trace quantities of nitrite ion

A sensitive fluorimetric method for the determination of nitrite ion is described. The procedure consists of diazotization ofo-amino-phenols followed by coupling with resorcinol, and reaction of the resulting azo compound with gallium sulfate. The intensity of the fluorescence is linearly dependent upon the nitrite concentration. The procedure permits the determination of 3·10−10–10−5g/ml nitrite ion. The method was applied for determining trace quantities of nitrite ion in meat products.

The Determination of Nitrite Ion in Copper Pyrophosphate Plating Solution

not Available.

環境中亜硝酸イオンの定量法に関する最近の進歩

環境中における亜硝酸イオンは, 1）そのままの形でか, あるいは2）種々の誘導体－アゾ色素, べンゾトリアゾール体, テトラゾ口フタラジン（Tetra-P）, 芳香族ハロゲン化合物, 芳香族ニトロおよびニトロソ誘導体-に導いたあと, 比色法, ガスクロマトグラフ法（GC）, 高速液体クロマトグラフ法（HPLC）, 化学発光検出法あるいはイオン選択電極を用いる電位差測定法などの手段で定量されている. 本総説において, 各種定量法をルーチン操作法としての観点からまとめ, それぞれの特長と欠点について評価した. また環境試料を測定サンプルヘ調製する方法についても述べた.

Determination of nitrite ion in waste and treated waters by resonance Raman spectrometry

The determination of NO 2 − ion in aqueous solutions by resonance Raman spectrometry has been examined in view of the application of the method to an optimum control of waste water treatment. In order to induce the resonance Raman effect, NO 2 − has been transformed into a colored product (azo dye) by a chemical reaction. From the resonance Raman spectra of the resultant colored product, it has been clarified that the detection limit of NO 2 − by this method is about 0.5 ppb, an order of magnitude lower than that of usual colorimetry, and that the analytical curve can be fitted well enough to a straight line in the concentration range below 140 ppb. The sensitivity of this method is regulated by the background intensities of sample solutions, and it has been shown that in the present case, the addition of sodium thiocyanate brings about a marked decrease of background intensities. Moreover, it has been proved that the application of the method developed here to practical waste and treated water samples produces appropriate results. Finally, the excellent selectivity of this method has been demonstrated, and the process of simultaneous determination of NO 2 − and NO 3 − has been proposed.

Determination of nitrite ion in unused cutting fluids and cutting oils using a gas-sensing electrode method

Modifications of the Orion NOx gas-sensing electrode method that were made to determine nitrite ion in unused cutting fluids and cutting oils are described. Detection limits for both types of lubricants of the order of 15 µg g–1 of NO2– ion were obtained. Previous analysis of six cutting fluids, collected in the Ottawa region and analysed by spectrophotometry, confirmed the presence of high levels of nitrite ion and showed fair agreement between results. Analysis of six other cutting fluids and 20 cutting oils collected in the same region showed the presence of nitrite ion in only three instances. The operation of the electrode, interferences, the use of standard-addition and -subtraction methods and the possibility of applying this method to used cutting lubricants are discussed.