Nitrite Salts Research Articles

ASSESSMENT OF NITRITE AND SORBIC ACID SALTS LEVEL IN SOME MEAT PRODUCTS AND THEIR PUBLIC HEALTH SIGNIFICANCE

One hundred twenty samples of some meat products (30 each of sausage, pastrami, corned beef and canned luncheon beef) were randomly purchased from Port-Said markets. The samples were examined for assessment the levels of nitrite, nitrate and sorbic acid salts. The obtained results revealed that the mean values of nitrite level in the examined meat products were 120.40 ± 7.03, 142.15 ± 9.13, 186.27 ± 4.42 and 159.96 ± 6.73 ppm for sausage, pastrami, corned beef and canned luncheon beef respectively. While that of nitrate and sorbic acid salts were 73.49 ± 6.46, 62.54 ±19.44, 39.82 ± 9.96 and 28.52 ±10.86 ppm and 0.92 ±0.11, 1.25 ±0.12, 0.00 and 0.00 g/kg for sausage, pastrami, corned beef and canned luncheon beef respectively. For all samples nitrite was detected in 100% of the examined samples, while nitrate was detected in 100, 3.33, 43.33 and 26.67% of the sausage, pastrami, corned beef and canned luncheon beef samples respectively. On the other hand sorbic acid salts was detected in 100% of sausage and pastrami samples and could not be detected in the corned beef and canned luncheon beef samples. For all specimens 3 (10%), 7 (23.33%) and 4 (13.33%) of pastrami, corned beef and canned luncheon beef samples exceeded the permissible limits of nitrite established by JECFA FAO/WHO (1974) respectively, while nitrate not exceed the permissible limits. In case of sorbic acid salts 2 (6.67%) of sausage and 5 (16.67%) of pastrami exceeded the permissible limits of sorbic acid salts.The effects of nitrite, nitrate and sorbic acid salts levels on public health significance were discussed.

Physico-Chemical Environment of Coastal Areas in the Vicinity of Lbod And Tidal Link Drain in Sindh, Pakistan after Cyclone 2a

This paper presents the results of preliminary assessment of water quality along the coastal areas in the vicinity of Left Bank Outfall Drainage (LBOD) and Tidal Link Drain (TLD) in Sindh province after the cyclone 2A occurred in 1999. The water samples were collected from various RDs of Tidal Link Drain and lakes during September 2001 to April 2002 and were analysed for salinity, nitrite, phosphate, ammonia, silicate and suspended material in water. The results of the study showed considerable variations in water quality depending upon the location along the coast in the vicinity of LBOD and RDs. The salinity ranged between 4.39-65.25 ppt in Tidal Link Drain samples whereas 2.4-38.05 ppt in samples collected from lakes. The values of suspended material at various RDs of Tidal Link Drain ranged between 56.6-2134 ppm and at the lakes between 68-297 ppm. The data of continuous monitoring at RD-93 showed the range of PO4 (8.6-25.2 µg/l), SiO3 (554.96-1462 µg/l), NO2 (0.557.2-25.2 µg/l) and NH3 (9.38-23.62 µg/l). The concentration of nutrients in water samples collected from different RDs was found in the range of PO4 (10.85 to 11.47 µg/l), SiO3 (1624 to 2635.08 µg/l), NO2 (20.38 to 44.8 µg/l) and NH3 (24.08 to 26.6 µg/l). Sindh coastal areas which situated at the north-western boundary the Arabian Sea are highly vulnerable to flood damages due to flash floods during SW monsoon or impact of sea level rise and storm surges coupled with cyclones passing through Arabian Sea along Pakistan coast. It is hoped that the obtained data in this study would act as a database for future investigations and monitoring of LBOD and Tidal Link Drain coastal waters. Keywords—Tidal Link Drain, Salinity, Nutrients, Nitrite salts, Coastal areas.

Corrosion Inhibition of the Galvanic Couple Copper-Carbon Steel in Reverse Osmosis Water

The purpose of this paper is to evaluate the electrochemical behaviour of corrosion inhibition of the copper-carbon steel galvanic couple (Cu-CS), exposed to reverse osmosis water (RO) used for rinsing of heat exchangers for heavy duty machinery, during manufacture. Molybdate and nitrite salts were utilized to evaluate the inhibition behaviour under galvanic couple conditions. Cu-CS couple was used as working electrodes to measure open circuit potential (OCP), potentiodynamic polarization (PP), and electrochemical impedance spectroscopy (EIS). The surface conditions were characterized by scanning electron microscopy (SEM) and electron dispersive X-ray spectroscopy (EDS). The most effective concentration ratio between molybdate and nitrite corrosion inhibitors was determined. The morphological study indicated molybdate deposition on the anodic sites of the galvanic couple. The design of molybdate-based corrosion inhibitor developed in the present work should be applied to control galvanic corrosion of the Cu-CS couple during cleaning in the manufacture of heat exchangers.

Synthesis of Ag-Au Nanoparticles by Galvanic Replacement and Their Morphological Studies by HRTEM and Computational Modeling

Bimetallic nanoparticles are important because they possess catalytic and electronic properties with potential applications in medicine, electronics, and chemical industries. A galvanic replacement reaction synthesis has been used in this research to form bimetallic nanoparticles. The complete description of the synthesis consists of using the chemical reduction of metallic silver nitrite (AgNO3) and gold-III chloride hydrate (HAuCl) salt precursors. The nanoparticles display round shapes, as revealed by high-resolution transmission electron microscope (HRTEM). In order to better understand the colloidal structure, it was necessary to employ computational models which involved the simulations of HRTEM images.

ChemInform Abstract: Copper‐Catalyzed Aerobic Oxidative Dehydrogenative Coupling of Anilines Leading to Aromatic Azo Compounds Using Dioxygen as an Oxidant.

Aromatic azo compounds are ubiquitous motifs and are widely used in industry as organic dyes, indicators, pigments, food additives, radical reaction initiators, and therapeutic agents. Despite numerous efforts towards the synthesis of azo derivatives, big challenges still remain because: 1) the catalytic procedures that have been reported to afford high yields have been less widely explored; 2) stoichiometric and environmentally unfriendly oxidants, such as manganese salts, lead salts, mercury salts, or ferrates were previously employed for their preparation form aromatic amines; 3) unsymmetric aromatic azo compounds are not easy to prepare. Usually, two step syntheses are used, proceeding from anilines via diazonium salt or nitrosobenzene intermediates, using stoichiometric amounts of nitrite salts or other oxidants, to produce unsymmetric aromatic azo compounds, with inorganic salts as the by-products [Eq. (1)].

Compatibility of a polycarboxylate-based superplasticiser with different set-controlling admixtures

The compatibility of specific combinations of chemical admixtures for cement pastes and mortars have been investigated. The consistency, setting time and compressive strength of cement pastes and mortars incorporating a polycarboxylate-based plasticizing admixture (PCA) with four different set-controlling admixtures (SCA); calcium formate (CF), tri-ethanolamine (TEA), mixture of calcium nitrite and nitrate salts (CNN blend) and sodium aluminate (SA) have been determined within the scope of this study. Fifty-two mortar and paste specimens with different amounts of PCA and SCA combinations have been prepared. Water/cement ratios of cement paste and mortar mixtures were 0.24 and 0.50, respectively. The paste mixtures have been prepared to determine the setting time data and the mortar mixtures have been used to determine the consistency and compressive strength values. Test results indicated that the PCA employed in this study, retards the setting time, improves consistency and reduces the early strength development of all paste and mortar mixtures at dosages greater than 0.4% by mass of cement. However, the use of different set-controlling admixtures in combination with PCA caused drastic changes in the performances of the mixtures depending on the type and amount of SCAs. It was concluded that, in order to reduce the setting time and increase the early strength of PCA incorporated mortars without causing consistency loss, the combination of PCA, and SCA should be optimized according to their types. A new 3D box-plot method has been used to determine the optimum admixture combinations for the desired properties. Maximum flow, shortest setting time and highest early strength criterion were the targets of the optimization. The most effective combination to obtain desired set acceleration and high early strength values was 1.8% PCA with 1.6% nitrite and nitrate salts based SCA by mass of cement. If consistency lost is in secondary importance, 1.8% PCA based plasticiser with 1% sodium aluminate based SCA may be an alternative combination. The proposed method can be used to optimize the targeted properties for a specific combination of cement, PCA and SCA.

Nitrite pickling salt as an alternative to formaldehyde for embalming in veterinary anatomy—A study based on histo- and microbiological analyses

Formaldehyde, the traditional embalming agent has negative health effects. Nitrite pickling salt has been reported to be a good and inexpensive alternative when supplemented with antioxidants, but the antioxidants caused yellowish colouration of cadavers, and damaged corrosion-resistant steel tables and stone floors. Here, nitrite pickling salt was supplemented with ethanol and Pluriol(®) and tested for effectiveness as an embalming agent of twenty dog cadavers: 10 with open, and 10 with closed abdominal cavity. The texture of the tissue was monitored intermittently for 12 months throughout the course of an anatomical dissection class. Histological and microbiological analysis of samples from muscles, lungs, duodenum and colon were performed. Dogs with an open abdomen remained suitable for dissection purposes during the entire course. The abdominal organs of the closed cadavers lost their natural features, without histological signs of autolysis. Enterococcus spp., Staphylococcus spp., Micrococcus spp., Bacillus spp. and Clostridium perfringens were recorded after 24 weeks. The open cadavers underwent additional maintenance via renewed treatment with ethanol and Pluriol(®) after each dissection. After 30 weeks, C. perfringens was massively reduced in the colon of the open cadavers. The tested solution successfully embalms open bodies, carries no health risks and is environmentally friendly and cost effective.

Copper‐Catalyzed Aerobic Oxidative Dehydrogenative Coupling of Anilines Leading to Aromatic Azo Compounds using Dioxygen as an Oxidant

Aromatic azo compounds are ubiquitous motifs and are widely used in industry as organic dyes, indicators, pigments, food additives, radical reaction initiators, and therapeutic agents. Despite numerous efforts towards the synthesis of azo derivatives, big challenges still remain because: 1) the catalytic procedures that have been reported to afford high yields have been less widely explored; 2) stoichiometric and environmentally unfriendly oxidants, such as manganese salts, lead salts, mercury salts, or ferrates were previously employed for their preparation form aromatic amines; 3) unsymmetric aromatic azo compounds are not easy to prepare. Usually, two step syntheses are used, proceeding from anilines via diazonium salt or nitrosobenzene intermediates, using stoichiometric amounts of nitrite salts or other oxidants, to produce unsymmetric aromatic azo compounds, with inorganic salts as the by-products [Eq. (1)].

Use of sodium nitrite in salt-curing of Atlantic salmon ( Salmo salar L.) – Impact on product quality

Quality changes during processing and quality differences in smoked fillets of Atlantic salmon (4–5 kg) salted with nitrite salt compared to table salted fillets were measured. Quality parameters from right-side fillets dry salted with nitrite salt were compared with the respective left-side fillets treated the same way with table salt. Ten raw right-side fillets were analysed and used as raw material reference. Use of nitrite salt in salt-curing of smoked salmon affected colour to a more reddish hue, tended to increase carotenoid stability and displayed positive effects on NaCl diffusivity. Only slight weight changes and change in texture properties were revealed. The use of nitrite salt displayed no adverse effects like increased content of N-nitrosoamines in smoked products. In fact, significant lower contents of N-nitrosoamines were found in nitrite salted smoked fillets compared to smoked fillets salted with table salt. Relatively high amounts of residual nitrite in nitrite-treated fillets seem to be the most prominent adverse effect caused by the use of nitrite salt in salt-curing of smoked Atlantic salmon.

A novel nitric oxide producing probiotic patch and its antimicrobial efficacy: preparation and in vitro analysis

Microbial and fungal infections are a significant consideration in the etiology of all wounds. Numerous antimicrobial and antifungal formulations have been developed with varying degrees of efficacy and stability. Here, we report a nitric oxide producing probiotic adhesive patch device and investigate its antimicrobial and antifungal efficacy in vitro. This probiotic patch utilizes the metabolic activity of immobilized lactic acid bacteria, glucose, and nitrite salts for the production of gaseous nitric oxide (gNO), which is used as an antimicrobial agent against bacterial and fungal pathogens. Results show that application of gNO-producing probiotic patches to cultures of E. coli, S. aureus, P. aeruginosa, MRSA, T. mentagrophytes, and T. rubrum resulted in complete cell death at between 4 and 8 h, and application to cultures of A. baumannii, resulted in fewer than ten colonies detected per milliliter at 6 h. These results demonstrate that a gNO-producing probiotic patch device containing bacteria, glucose, and nitrite salts can produce sufficient levels of gNO over a therapeutically relevant duration to kill common bacterial and fungal wound pathogens in humans.

Lactoperoxidase catalyzes in vitro activation of acrylonitrile to cyanide

Acrylonitrile (ACN) is a widely used industrial chemical. Although it is a well reported animal carcinogen, its current designation to humans is “possibly carcinogenic”. The present study aimed at investigating the ability of LPO enzyme system to oxidize ACN to cyanide (CN−) in vitro. Detection of CN− served as a marker for the possible generation of free radical intermediates implicated in ACN induced toxicity in the activation process. Optimum conditions for the oxidation of ACN to CN− were characterized with respect to pH, temperature and time of incubation as well as ACN, LPO and H2O2 concentrations in incubation mixtures. Maximum reaction velocity (Vmax) and Michaelis–Menten constant (Km) were assessed. Addition of nitrite (NO2−) salts to the reaction mixtures significantly enhanced the rate of the reaction. Free radical scavengers (quercetin and trolox C), LPO enzyme inhibitor (resorcinol) and competitors for LPO binding (sodium azide and indomethacin) were found to reduce the rate of CN− production. Inclusion of the sulfhydryl compounds glutathione (GSH), NAC (N-acetylcysteine), d-penicillamine or l-cysteine enhanced the rate of ACN oxidation. The present results demonstrate the ability of LPO enzyme system to oxidize ACN to CN− and provide insight for the elucidation of ACN chronic toxicity.

Photooxidation of Halides by Chlorophyll at the Air−Salt Water Interface

Glancing angle laser-induced fluorescence was used to follow the kinetics of chlorophyll loss at the air-salt water interface under the influence of visible radiation. Aqueous solutions of NaCl, NaBr, NaI, KNO(3), and NaNO(2) in a range of concentrations up to approximately 1 M were used as substrates. The first-order reaction rate depends linearly on salt concentration for the halide salts but does not vary with concentration for nitrate or nitrite salts. At the same salt concentration, the chlorophyll loss rate is greatest for the bromide-containing solutions, followed by those containing chloride and then iodide. The results are consistent with a mechanism in which photoproduced chlorophyll cations are reduced by halide anions and subsequently react with the halogen atoms thus produced. This mechanism gives a novel route for gas-phase halogenated species, and possibly nitrogen oxides, to be released to the marine boundary layer.

Investigação do Teor de Nitrito em Linguiças do Tipo Toscana, Comercializadas na Região de Franca-SP

Os sais de nitrito e nitrato em excesso são prejudiciais à saúde. O presente trabalho teve como objetivo avaliar a qualidade das linguiças do tipo toscana de vários fabricantes comercializadas na região de Franca-SP, por meio do método analítico quantitativo por espectrofotometria. Em paralelo, realizou-se uma avaliação do nível de conhecimento dos fabricantes sobre os riscos quanto ao uso abusivo desse aditivo. Os níveis de nitrito foram analisados em seis amostras de linguiça toscana, classificadas numericamente em: I, II, III, IV, V e VI, coletadas em supermercados distintos. O método foi baseado na reação do nitrito com o ácido sulfanílico e - naftol com formação de um azo composto. Constatou-se que as amostras I, II e III apresentaram concentração de nitrito muito superior ao permitido pela legislação (150 mg/kg). O questionário aplicado a três dos seis fabricantes revelou que dois deles desconhecem a legislação e não fazem análise da concentração do nitrito; somente um fabricante declarou não saber dos malefícios que esse aditivo poderia causar se usado indiscriminadamente. Os resultados permitiram indicar que 50% das amostras estavam em desacordo com a legislação, portanto, medidas preventivas devem continuar sendo tomadas, como o controle de qualidade pelas indústrias e pela vigilância sanitária.

Identification of animal species in heat treated muscle homogenates using the polymerase chain reaction

The possibility of identification of animal species in pasteurized and sterilized muscle homogenates was studied. Homogenates consisted of beef, pork and chicken meat, mixed in equal amounts. Nitrite salt and polyphosphates were also added. Heat treatment included pasteurization at temperatures of 80oC, 90oC and 100oC, while sterilization was performed at temperatures of 110oC and 121oC, respectively. Animal mitochondrial DNA was isolated from the samples and the target gene was subsequently amplified by PCR. The presence of species-specific bands indicated respective animal species in homogenates. The results showed that it was possible to identify the most common domestic animal species in heat treated muscle homogenates.

Synthesis of a nitro complex of RuIII(salen): Unexpected aromatic ring nitration by a nitrite salt

Reaction of silver nitrite with Ru(salen)(PPh(3))(Cl) (salen(2-)=N,N'-ethylenebis(salicylideneiminato dianion) using [NEt(4)]OH as a phase transfer agent led to the formation of a stable, N-coordinated nitrite ion complex (Ru(III)-NO(2)) that was characterized by single crystal X-ray diffraction. This reaction also resulted in nitration of the two phenolic rings of the salen ligand, which was unexpected given the basic conditions. With sodium nitrite, the Ru(III)-nitro complex was formed, but no ring nitration was observed. Thus, in a non-acidic medium, the combination of nitrite with redox active metal centers may provide a route to the nitration of phenolic derivatives. Possible mechanisms of this unusual reaction having potential relevance to aromatic nitrations in biological systems are discussed. This is also the first report of the crystal structure of a Ru(III)-nitro complex, a species that has been suggested to be unstable and prone to rapid disproportionation.

Control of H 2S emission from swine manure using Na-nitrite and Na-molybdate

Biogenic production of hydrogen sulphide (H 2S) in oil reservoirs (souring) has been shown to be controlled effectively using nitrite and molybdate salts. In the present work the effects of addition of nitrite and molybdate on reducing the emission of H 2S from swine manure slurry was investigated in the laboratory and semi-pilot scale systems. Addition of 80 mM nitrite or 2 mM molybdate (final concentration in the manure slurry) to fresh manure in the laboratory scale closed systems (125 mL and 4 L) reduced the concentration of H 2S in the headspace gas from 1500 μL L −1 to 10 μL L −1 which maintained during the remaining period of trials (40–60 days). With aged manure, similar results were achieved with a lower level of nitrite (10 mM). Simultaneous or sequential additions of nitrite and molybdate to fresh manure had similar effects. Contrary to the systems simulating biological conditions in oil reservoirs in which simultaneous addition of nitrite and molybdate has been reported to have a synergistic effect, no synergism was observed when nitrite and molybdate were added to the manure simultaneously. Experiments with fresh manure slurry in the semi-pilot scale systems (200 L) confirmed the effectiveness of this approach in which addition of 80 mM nitrite or 2 mM molybdate or a combination of 80 mM nitrite and 2 mM molybdate decreased the concentration of the H 2S in the headspace gas from an initial value of 500 μL L −1 to a low level in the range 2–25 μL L −1 and maintained these low levels during the remaining period of trials (16 days). The concentration of ammonia (NH 3) in the headspace gas of the treated systems was similar to that observed in the control system (untreated), indicating that the treatment did not have an effect on the level of present NH 3. Although the addition of nitrite or molybdate reduced emissions of H 2S from swine manure and the associated health and safety concerns, it had little impact on the intensity of odour in the headspace gas samples from the semi-pilot scale system.

Influence of ammonium, nitrate and nitrite on the performance of the pure culture of Acinetobacter junii

The influence of different concentration ranges (0-500 mg/L) of ammonium, nitrate and nitrite presence in the wastewater, on the performance of the pure culture of phosphate-accumulating bacterium Acinetobacter junii in the anaerobic and aerobic conditions, was investigated. A. junii was able to use ammonium and nitrate salts as the source of nitrogen, unlike in the case of nitrite salt. Comparing to the control reactors with the peptone and yeast extract as the sources of nitrogen, at the lowest tested concentration of ammonium and nitrate the performance of the system was inhibited due to the nitrogen deficit in the wastewater, while at the highest concentration it was positively influenced. Nitrite in all concentrations detrimentally affected the phosphate release and uptake rates, chemical oxygen demand uptake rates, nitrogen uptake rates, as well as multiplication of A. junii. The higher the nitrite concentration, the more pronounced was the effect. At the highest nitrite concentration tested a complete failure of the system was observed.

Effects of atmospheric NO x on biocalcarenite coated with different conservation products

One of the most important factors of calcareous stone decay is the chemical attack caused by atmospheric pollutants dissolved in water, in particular acidic gases such as SO x , NO x and CO 2. The treatment of stone artefacts with hydrophobic products reduces the water uptake of the rock and is, therefore, considered a “protective treatment”. The aims of the present study were the observation of the effects of NO x on a biocalcarenite (Lecce stone) and the evaluation of the performance of protective products (Paraloid B72 and a fluoroelastomer) normally used in stone conservation. A system for the simulation of accelerated ageing has been assembled and the Lecce stone samples, treated with polymeric products, have been exposed to NO 2 (nearly 1 ppm) during thermo hygrometric cycles. The nitrite and nitrate salts formed on the specimens have been determined by ion chromatography. Both the polymeric products tested have given high hydrophobic properties to the stone, even if they do not assure satisfactory protection toward NO 2 exposure. Actually, their protective efficacy, or ability to reduce the acidic attack of NO 2, quickly decreases when the ageing period increases. Paraloid B72 seems more effective than fluoroelastomer because, on the samples treated with the latter, higher amounts of nitrites and nitrates have always been detected. In contrast, non-treated samples – used as reference – have shown a constant increase in the amount of nitrates and nitrites during ageing. However, the surface analyses of the stone samples, by environmental SEM and μ-laser profilometry, did not show any change in superficial morphology after the ageing, suggesting that NO 2 acts inside the pores.

Oxygen Isotopes in Nitrite: Analysis, Calibration, and Equilibration

Nitrite is a central intermediate in the nitrogen cycle and can persist in significant concentrations in ocean waters, sediment pore waters, and terrestrial groundwaters. To fully interpret the effect of microbial processes on nitrate (NO3-), nitrite (NO2-), and nitrous oxide (N2O) cycling in these systems, the nitrite pool must be accessible to isotopic analysis. Furthermore, because nitrite interferes with most methods of nitrate isotopic analysis, accurate isotopic analysis of nitrite is essential for correct measurement of nitrate isotopes in a sample that contains nitrite. In this study, nitrite salts with varying oxygen isotopic compositions were prepared and calibrated and then used to test the denitrifier method for nitrite oxygen isotopic analysis. The oxygen isotopic fractionation during nitrite reduction to N2O by Pseudomonas aureofaciens was lower than for nitrate conversion to N2O, while oxygen isotopic exchange between nitrite and water during the reaction was similar. These results enable the extension of the denitrifier method to oxygen isotopic analysis of nitrite (in the absence of nitrate) and correction of nitrate isotopes for the presence of nitrite in "mixed" samples. We tested storage conditions for seawater and freshwater samples that contain nitrite and provide recommendations for accurate oxygen isotopic analysis of nitrite by any method. Finally, we report preliminary results on the equilibrium isotope effect between nitrite and water, which can play an important role in determining the oxygen isotopic value of nitrite where equilibration with water is significant.

Optical Properties of the Me NO2 Ferroelectrics and Me NO3- NO 2 − Compounds

The lowest singlet-singlet and singlet-triplet electronic transitions of the nitrite molecular ion, responsible for the ferroelectricity of the nitrite crystal salts, have been investigated in a temperature range of 1.6–300 K. Polarized well-resolved spectra enabled dealing with separate spin substates of the excited triplet level, and for the nitrite-ion impurity incorporated in the nitrate crystals, to elucidate the effect of the symmetry correlations on the imbedding features of the impurity center. Parameters of the spin-orbit and electron-phonon interactions have been derived, and the microscopic characteristics of the crystal, mostly affecting the electron-phonon coupling, are deduced.