Addition Of Bromate Research Articles

الآثار الضارة للتعرض لبرومات الصوديوم على بعض أنسجة إناث الفئران

البرومات عبارة عن أنيون لعنصر البروم له صيغة Bro3- يوجد بطريقتين الأولى أثناء تعقيم الماء بالأوزون والثانية إضافة مادة برومات أثناء التصنيع فحاولنا من خلال هذا البحث القاء الضوء على مادة البرومات وخطرها على صحة الإنسان بدراسة التغيرات التي تطرأ على بعض أنسجة الفئران نتيجة التعرض لمادة البرومات عن طريق مياه الشرب واستخدم في هذا البحث (٣٠) من إناث الفئران البيضاء albino mice وقد تم توزيع الحيوانات في أقفاص خاصة مزودة برضاعات لشرب الماء في غرفة متجددة التهوية تخضع للعوامل الطبيعية وقٌدم للحيوان الغذاء المناسب أما الماء حسب الحاجة وقد اختيرت حيوانات هذا البحث بمتوسط أعمار ١٢-١٥ أسبوع ومتوسط وزن الفأرة50-60 جرام أما البرومات تم الحصول عليها من شركة ساتك وتم تقسيم الحيوانات إلى مجاميع المجموعة التجريبية الضابطة وتضم ٥ من إناث الفئران تم إعطائها مياه شرب عادية والمجموعة المعاملة وتضم ١٥ من إناث الفئران تم إعطائها برومات الصوديوم بجرعة مقدارها ٢٠٠ ملجم/كجم من وزن الجسم في مياه الشرب لمدة أسبوعين وبعد ذلك تم تخدير الفئران وتشريحها وأخذ عينات الكبد والكلية من إناث الفئران وحفظت في محلول فورمالين متعادل ١٠% لعمل قطاعات نسيجية. أظهرت النتائج حدوث العديد من التغيرات المرضية النسيجية للكبد متمثلة في احتقان الوريد المركزي واتساع الجيوب الدموية وظهور علامات الموت لمعظم الخلايا الكبدية مثل الانتفاخ السحابي وتكثف كروماتين بعض الأنوية وارتشاح في الوريد المركزي وغزو للخلايا الالتهابية حول الوريد المركزي، أما الكلى يلاحظ اختفاء لعدد كبير من الكريات الكلوية مع موت وتحلل لمعظم الخلايا الأنيبيبات مع ضيق في تجويف هذه الأنيبيبات وانغلاق بعضها وتوسع وارتشاح في البعض الآخر ونزف داخل النسيج مع ظهور موت وتحلل لمعظم خلايا الأنيبيبات. نستنتج من هذه الدراسة أن التعرض للبرومات أدى إلى حدوث العديد من الأضرار في نسيج الكبد والكلية، وكانت الكلية أكثر تأثيراً من الكبد نظراً لأن البرومات تمر على الكلى من خلال الدم مما يؤدي إلى تلف خلايا الكلى "النيفرونات" وهذا يثبت سمية البرومات للكلية وقدرتها على إحداث الفشل الكلوي.

Termination of nanoscale zero-valent iron reactivity by addition of bromate as a reducing reactivity competitor

Remediation of contaminated groundwater by nanoscale zero-valent iron (nZVI) is widely becoming a leading environmentally friendly solution throughout the globe. Since a wide range of various nZVI-containing materials have been developed for effective remediation, it is necessary to determine an appropriate way to terminate the reactivity of any nZVI-containing material for a practical experimental procedure. In this study, bimetallic Ni/Fe-NPs were prepared to enhance overall reduction kinetics owing to the catalytic reactivity of nickel on the surface of nZVI. We have tested several chemical strategies in order to terminate nZVI reactivity without altering the concentration of volatile compounds in the solution. The strategies include surface passivation in alkaline conditions by addition of carbonate, and consumption of nZVI by a reaction competitor. Four halogenated chemicals, trichloroethylene, 1,1,1-trichloroethane, atrazine, and 4-chlorophenol, were selected and tested as model groundwater contaminants. Addition of carbonate to passivate the nZVI surface was not effective for trichloroethylene. Nitrate and then bromate were applied to competitively consume nZVI by their faster reduction kinetics. Bromate proved to be more effective than nitrate, subsequently terminating nZVI reactivity for all four of the tested halogenated compounds. Furthermore, the suggested termination method using bromate was successfully applied to obtain trichloroethylene reduction kinetics. Herein, we report the simple and effective method to terminate the reactivity of nZVI by addition of a reducing reactivity competitor.

KINETIC DETERMINATION OF VANADIUM USING THE BROMATE OXIDATIVE COUPLING REACTION OF 4-(METHYLAMINO)PHENOL WITH 2,3,4-TRIHYDROXYBENZOIC ACID AND TARTRATE ACTIVATOR

ABSTRACT A new, simple, sensitive and selective kinetic method is developed for the spectrophotometric determination of VV and/or VIV based on its catalytic effect on the bromate oxidative coupling reaction of 4-(methylamino)phenol (MAP) with 2,3,4-trihydroxybenzoic acid (THBA) in the presence of tartrate as an activator. The reagents: 6.4 mmol l−1 MAP, 2.0 mmol l−1 THBA and 160 mmol l−1 bromate were mixed in the presence of an activator-buffer solution of 10 mmol l−1 tartrate (pH = 3.10) and at 35°C. The rate of formation of the oxidative coupling product was followed at 380 and/or 570 nm for 3 min from the addition of bromate. Linear calibration graphs up to 0.75 ng ml−1 of vanadium were obtained with detection limits, based on the 3S b criterion, of 0.019 and 0.026 ng ml−1 at 380 and 570 nm, respectively. The developed method was conveniently applied to the determination of vanadium in tap and ground waters and in human plasma, serum, and urine. Moreover, the nature of the oxidative coupling product wa...

Square wave catalytic stripping voltammetry of molybdenum complexed with dihydroxynaphthalene

Abstract A procedure is described for the determination of molybdenum using square wave catalytic stripping voltammetry in the presence of 2,3-dihydroxynaphthalene (DHN) and bromate. Linear scan voltammetry revealed that Mo(VI) forms a 1:2 complex with DHN and undergoes a one-electron reduction at the hanging mercury drop electrode. This reduction is reversible and especially suitable for square wave voltage modulation. A large enhancement of the peak current (500 ×) is observed upon the addition of bromate. The optimum conditions were 1 × 10 −3 M DHN, 3 × 10 −2 M bromate, pH 4.7, and an adsorption potential of −0.05 V. For an adsorption time of 1 min, the relative standard deviation for the measurement of 5 × 10 −12 M Mo(VI) was ±4% ( n = 7), and the detection limit was determined as 6 × 10 −12 M. The peak current was linear with the concentration of Mo(VI) from 1 × 10 −11 to 1 × 10 −9 M. The linear range could be extended with shorter adsorption times or a non-stirring adsorption mode.

Photocatalytic degradation of organic compounds: accelerating the process efficiency

The photocatalytic activites of several TiO2 materials have been compared studying the degradation of an aliphatic and an aromatic model compound under optimized experimental conditions (e.g., c(TiO2), pH of the solution). For dichloroacetic acid (DCA) a new anatase catalyst, i.e., Hombikat UV100, yielded significantly higher photonic efficiencies (ζ=15%) than almost all the other materials, especially in comparison to rutiles. For 4-chlorophenol (4-CP) the discrepancies were relatively small and the degradation was generally slower (ζ<1%); in this case the formation of intermediates has to be considered, too. While for DCA the addition of CuNO3 (1–10mM) or a platinization of the catalyst lead to a significant raise in ζ, this had almost no effect on the degradation of 4-CP. For this model compound ζ could be accelerated strongly by the addition of bromate (3mM KBrO3); the photocatalytic nature of the process could be demonstrated. The addition of other oxidants had no beneficial effect, in some cases an inhibition was observed. The stability and long time activity of standard and platinized TiO2 materials could be demonstrated.

Photocatalytic degradation of organic compounds: accelerating the process efficiency

The photocatalytic activities of several TiO2 materials have been compared studying the degradation of an aliphatic and an aromatic model compound under optimized experimental conditions (e.g., c(TiO2), pH of the solution). For dichloroacetic acid (DCA) a new anatase catalyst, i.e., Hombikat UVlOO, yielded significantly higher photonic efficiencies (ζ=15%) than almost all the other materials, especially in comparison to rutiles. For 4-chlorophenol (4-CP) the discrepancies were relatively small and the degradation was generally slower (ζ<1 %); in this case the formation of intermediates has to be considered, too. While for DCA the addition of CuNO3 (1-1OmM) or a platinization of the catalyst lead to a significant raise in ζ, this had almost no effect on the degradation of 4-CP. For this model compound ζ could be accelerated strongly by the addition of bromate (3mM KBrO3); the photocatalytic nature of the process could be demonstrated. The addition of other oxidants had no beneficial effect, in some cases an inhibition was observed. The stability and long time activity of standard and platinized TiO2 materials could be demonstrated.

Determination of vanadium in sea water by catalytic adsorptive cathodic stripping voltammetry

The sensitivity of adsorptive cathodic stripping voltammetry (CSV) to vanadium is much improved by inclusion of a catalytic effect. The deposition step is based on the adsorptive accumulation of complex species with catechol on a hanging mercury drop electrode. The reduction current of the adsorbed complex is catalytically enhanced by addition of bromate. This effect is utilised to develop a sensitive method to determine vanadium in natural waters including sea water. Optimum response was obtained at pH 6.6 in the presence of 20 mM bromate and 0.1 mM catechol; the deposition potential was −0.1 V and the square-wave modulation (50 Hz) was used. The limit of detection was 0.07 nM vanadium using a deposition time of 120 s and 0.6 nM at a deposition time of 15 s.

水産ねり製品の足に対する酸化剤の増強効果

Kamaboko, a traditional fisheries product in Japan, is an elastic jelly with high jelly strength made from fish meat. Its elasticity and jelly strength depend on the kinds of fish used and the manufacturing process. It is accepted that both hydration of muscle protein and formation of network of hydrated protein are two important factors for elastic jelly and hence for elastic Kamaboko. Objective of this investigation was to find a new method of strengthening Kamaboko by use of oxidants which would promote cross linking of protein molecules by the following reaction, 2SH→S-S Addition of oxidants such as potassium bromate was shown to make an elastic jelly out of fish meat with low ability of jelly formation such as horse mackerel, from which only a brittle, easily crushable and synerizing jelly can be made. Simulataneous measurement of sulfhydryl groups of cooked meat clearly demonstrated that an elastic jelly was formed (as shown by decrease in the amount of expressible water in Fig. 1), when sulfhydryl groups were diminished by the addition of more than one-tenth percent of bromate. A small decrease in solubility of meat protein in 3% NaCl soln. was observed after the addition of bromate even when Na-tripolyphosphate was added to the mixture (Table 4). It was, therefore, supposed that the effectiveness of oxidants was primarily due to its action on strengthening the network of Kamaboko by cross linking protein molecules with disulfide bonds.

CHEMICAL AND PHYSICO-CHEMICAL CHANGES IN WHEAT AND WHEAT PRODUCTS INDUCED BY ELEVATED TEMPERATURES: III. THE INFLUENCE OF GERM CONSTITUENTS ON BAKING QUALITY AND THEIR RELATION TO IMPROVEMENT IN FLOUR INDUCED BY HEAT AND CHEMICAL IMPROVERS

Experiments were conducted in an effort to determine the cause of enhancement in baking quality previously observed on heat treatment of straight-grade flour not aged nor bleached. Heat treatment of straight-grade flour matured with agene (nitrogen trichloride), or of unaged fifth middlings flour (highly refined mill stream) did not result in any essential improvement in baking quality, and the unheated flours gave only a slight positive response to bromate. Similarly, ether extracted straight-grade flour gave no appreciable response to bromate and no significant improvement due to heat treatment. Germ added to fifth middlings flour markedly reduced its baking quality when determined by the basic procedure, as reflected in poorer handling qualities of the dough, and in the baked loaf by a decrease in loaf volume, underfermented characteristics, and coarse open texture. Increasing the fermentation time, addition of bromate, or heating the germ before admixture reduced the deleterious effects of the germ. The experiments indicate that response to bromate, and improvement of natural flour induced by proper heat treatment is associated with the presence of germ in the flour. Oxidation of certain germ constituents—presumably the phosphatides—is suggested as the primary change involved in such improvement. Addition of lecithin to middlings flour caused a marked response in loaf volume to the addition of bromate which is considered as indirect evidence that the phosphatides are involved. Heat treatment of germ induced a marked increase in the hydrogen ion concentration of aqueous extracts and a decrease in the iodine number of the ether extract. It is concluded from this series of investigations that heat treatment of flour is detrimental to gluten quality, but decreases the deleterious effect of germ present in the flour. Unaged flours containing low grade mill streams may show an enhancement in baking quality by heat treatment, but the improvement will not equal that induced by chemical improvers which apparently act primarily on the germ constituents.