• Corrosion Science and Technology
• /
• v.14 no.2
• /
• pp.85-92
• /
• 2015

An on-line corrosion rate measurement system was developed using a personal computer, a data acquisition board and program, and a 2-electrode corrosion probe. Reliability of the developed system was confirmed with through comparison test. With this system, the effect of sodium nitrite ($NaNO_2$) as a corrosion inhibitor were studied on iron and aluminum brass that were immersed in sodium chloride (NaCl) solution. Corrosion rate was measured based on the linear polarization resistance method. The corrosion rates of aluminum brass and iron in 1% NaCl solutions were measured to be 0.290 mm per year (mmpy) and 0.2134 mmpy, respectively. With the addition of 200 ppm of $NO{_2}^-$, the corrosion rates decreased to 0.0470 mmpy and 0.0254 mmpy. The addition of $NO{_2}^-$ caused a decrease in corrosion rates of both aluminum brass and iron, yet the $NO{_2}^-$ acted as a more effective corrosion inhibitor for iron. than aluminum brass.

• Journal of Food Hygiene and Safety
• /
• v.17 no.2
• /
• pp.94-100
• /
• 2002

This work was performed in order to examine the effect of nitrite, thiocyanate and ascorbic acid on formation of N-nitrosamine(NA) in kimchi, fermented anchovy and shrimp under simulated gastric digestion, in vitro. The contents of nitrate were 10.7~24.5 mg/kg in kimchi, 1.5~5.6 mg/kg in fermented anchovy, 1.0~2.0 mg/kg in fermented shrimp and those of nitrite were average 0.3 mg/kg in all analyzed samples. Dimethylamine and trirmethylarnine contents were 4.9~l5.4 mg/kg, 0.6~0.8 mg/kg in kimchi, 3.3~4.0 mg/kg, 1.9~2.8 mg/kg in fermented anchovy, 30.3~177.9 mg/kg, 4.4~21.3 mg/kg in fermented shrimp, respectively. The contents of N-nitrosodime -thylamine(NDMA) were in the range of 0.8~6.9 $\mu\textrm{g}$/kg in kimchi, 0~l.2 $\mu\textrm{g}$/kg in fermented anchovy and 0~0.9 $\mu\textrm{g}$/kg in fermented shrimp. After simulated gastric digestion, NDMA was increased about 1.5 times in all sample. In every nitrite added samples, the contents of NDMA were increased by 183.1 times in fermented shrimp and were detected 192.4 $\mu\textrm{g}$/kg and 220.9 $\mu\textrm{g}$/kg when it was treated with 4 mM and 8 mM of nitrite, respectively. NDMA, when above samples were added 8 mM nitrite and 6.4 mM thiocyanate, was increased about 1.5 times than control samples. The formation of NDMA was inhibited by 49.9~92.4% in all samples added 12.8 mM ascorbic acid compared with the control sample.

• Journal of Food Hygiene and Safety
• /
• v.13 no.3
• /
• pp.274-277
• /
• 1998

The study was focused to investigate the effect of nitrosodimethylamine (NDMA) formation due to nitrosamine (NA) precursor and/or inhibitor addition to Kimchi during the fermentation of Kimchi at room temperature ($16{\pm}2^{\circ}C$). The addition of nitrite and dimethylamine (DMA) to Kimchi showed the average 32-fold ($21.3{\sim}113.9\;\mu\textrm{g}/kg$) and 9-fold ($1.3{\sim}40.3\;\mu\textrm{g}/kg$) higher NDMA formation than control ($O{\sim}5.6\;\mu\textrm{g}/kg$), respectively. Also, the addition of both nitrite and DMA resulted in the increase of NDMA formation to average 42-fold ($39.4{\sim}155.7\;\mu\textrm{g}/kg$) higher than control. On the other hand, the addition of 4 ruM ascorbic acid to Kimchi with nitrite and DMA inhibited the formation of NDMA down to 71.3% of control. However, the addition of cysteine and erythorbic acid affected no inhibition to NDMA formation during the test. The addition of sodium sulfite increased NDMA formation. Accordingly, this showed that the amount of ascorbic acid generated during Kimchi fermentation played an important inhibition role for NA formation.

• Bulletin of the Korean Chemical Society
• /
• v.33 no.2
• /
• pp.415-419
• /
• 2012

Electrochemical characteristics of nitrite ion were investigated at a poly(methylene blue)-modified glassy carbon electrode by cyclic voltammetry and differential pulse voltammetry. The poly(methylene blue)-modified glassy carbon electrode exhibited enhanced anodic signals for nitrite. The effects of key parameters on the detection of nitrite were evaluated at the modified electrode, such as pH, accumulation time, and scan rate. Under optimum condition, the chemically modified electrode can detect nitrite in the concentration range $2.0{\times}10^{-6}$ to $5.0{\times}10^{-4}$ M with the detection limit of $2.0{\times}10^{-6}$ M and a correlation coefficient of 0.999. The detection of nitrite using the chemically modified electrode was not affected by common ions such as $Na^+$, $K^+$, $Ca^{2+}$, $Cl^-$, $HPO_4^{2-}$ and $H_2PO_4^- $. The modified electrode showed good stability and reproducibility. The practical application of the present method was successfully applied to the determination of nitrite ion in cabbage samples.

• Journal of the Korean Society of Food Science and Nutrition
• /
• v.19 no.1
• /
• pp.35.2-72
• /
• 1990

N-Nitrosamines have been known to be strong carcinogens and are formed by the reaction of nitrous acid with amines. In this experiment the changes in the contents of nitrate nitrite trimethylaminoxide(TMAO) trimethylamine(TMA) and dimethylamine(DMA) during femen-tation of damsel fish were analyzed periodically and N-nitrosamines in a commercial products. N-Nitrosamines were determined by mineral oil distillation methods using gas chromatography-thermal energy anlyzer(GC-TEA) in a commerical product. Nitrate nitrite and amines were quantitate by colorimetric methods. Level of nitrate-N were gradually decreased but nitrite-n was not detected or trace. Contents of dimethlamine(DMA) and trimethlamine were mar-kedly increased while trimethylaminoxide nitrogen was decreased during the fermentation of damsel fish. The change of pH was in the ranges of 5,5-7.0 during fermentation of salted damsel fish. It was out of the optimum pH(3.0-3.4) for the formation of nitrosamine. N-Nitrosamines were not detected in salt-fermented damsel fist but much N-nitrosodimethyla-mine(NDMA) could be detected in salt-fermented damsel fish after adding 0.05M NaNo2 in the acidic condition. The identifaction of NDMA in it was confirmed by mass spectrophotometry. Nitrate decrea-sed during the fermentation of damsel fish. however nitrite was trace level and nitrosamines were not formed in its. This could be supposed that it was due to the rapid consumption of nitrite by amino acid and bacteria.

• Proceedings of the Korea Concrete Institute Conference
• /
• 2001.05a
• /
• pp.359-364
• /
• 2001

The purpose of this study is to develop the repair system for RC members with damaged by rebar corrosion using new corrosion inhibitor which was high nitrite content. In the experiments, the acceleration corrosion test of rebar was conducted using the specimen which was applied by various repair system. As a result, it was confirmed that the new repair system without concrete patching had high anti-corrosion property compared with other repair systems and was very effective as a spray type corrosion inhibitor in concrete containing chloride (0.1% of NaCl).

• Journal of the Korean Chemical Society
• /
• v.21 no.2
• /
• pp.149-151
• /
• 1977

• Journal of Food Hygiene and Safety
• /
• v.12 no.4
• /
• pp.333-339
• /
• 1997

The effects of kind of vegetables and of the kind and amounts of fermented fish sauce on the formation of nitrosamine (NA) during kimchi fermentation were investigated. Kimchies made of Chinese cabbage, cucumber, and radish with fermented shrimp, anchovy and liquid sauces were fermented at 4$^{\circ}C$ for 6 weeks and the changes in the content of nitrate, nitrite, trimethylamine (TMA), dimethylamine (DMA) and NA were studied. Nitrate content in kimchies made of Chinese cabbage, cucumber, and radish increased at the initial period of fermentation, but it decreased at the later period. Nitrite was not detected at the later period of kimchi fermentation. Overall, there have not been great changes in the contents of nitrite and nitrate. However, there have been considrable changes in the contents of TMA and DMA as fermentation progressed. Only nitrosodimethylamine (NDMA) at the level of 0.5~10.3 $\mu\textrm{g}$/kg was formed in three kinds of kimchies. More NDMA was formed in radish and cucumber kimchies than in Chinese cabbage kimchi. The pH was lowered faster in radish and cucumber kimchies than in Chinese cabbage kimchi. More NDMA was formed in Chinese cabbage kimchi made with fermented shrimp sauce than those with anchovy or liquid sauces. Shrimp sauce contained higher amount of DAM than anchovy and liquid sauces. The contents of NDMA tended to increase as the amount of shrimp sauce increased. The kind and amount of fermented fish sauce used for kimchi preparation may be an important factor affecting the formation of NDMA.

• Korean Journal of Food Science and Technology
• /
• v.19 no.3
• /
• pp.250-256
• /
• 1987

An attempt was made to establish a simple and rapid method for the evaluation of Kimchi quality. Four kinds of Kimchi included one home made traditional Kimchi were stored at $4^{\circ}C$ and$25^{\circ}C$ and biochemical changes, including pH, total acidity, volatile acidity, volatile basic nitrogen, vitamin C, NaCl, glucose, nitrite and resazurin value were determined and tested for the relationship with sensory evaluation. The change in pH, total acidity and resazurin value were highly correlated with the sensory maturity of Kimchi-Resazurin value was strongly influenced by the sample dilution and fermentation temperatures. It was concluded that resazurin test with sample solution of $2{\sim}4%$ could be used as a rapid method for the estimation of the maturity of Kimchi.

• Journal of fish pathology
• /
• v.5 no.2
• /
• pp.93-118
• /
• 1992

The research was carried out to examine the chronic toxic effects of nitrite on the Japanese eel, Anguilla japonica by neans of histological observations. Young eel, 10.8g mean body weight. were exposed to 6 different concentrations of nitrite(1, 5, 10, 20, 30 and 40ppm) for 10 weeks. Each concentration was treated under 5 different levels of pH(5.5, 6.0, 6.5, 7.0 and 7.5) and each of these treatment was tested at 2 different temperature regimes($25^{\circ}C$ and $30^{\circ}C$). Proper concentration of nitrite was made by $NaNO_2$ and proper pH levels were made by the combinations of 0.1M $KH_2PO_4$ and 0.1M $NaHCO_3$. Histopathological test of gill tissues were made along with the test of the formation of thrombocystes and chloride cells on the gill filaments. At the lower pH levels, mucus secretion from the gill was incrased as the nitrite concentration increased. As the level of nitrite increased the number of chloride cells on the gill filament were decreased. Most of the remained chloride cells were observed only at the terminar part of the gill filament at 40ppm of nitrite. Degeneration of gill tissues were observed when nitrite levels were over 10ppm along with detachement and sweption of the epithelial cells of the gill lamellae. Shrunken gill lamellae and formation of thrombosis in the capillaries of gill lamellae were also observed. When temperature goes higher at the higher level of nitrite, necroses in the gill lamellae was increased. At the lower than 10ppm of nitrite, degeneration of gill lamellae was occured at the beginning of the test period but regenerated later. Negative effects of nitrite on the growth of young eel was started between 5~10ppm at the pH level of 7.0 and 7.5. Thrombosis formation were also started at this level. The safety concentration of nitrite at the pH levels of 7.0 and 7.5 on the small eel seems to be 1ppm. Thrombosis and gill lamella detachment and necrosis in the gill capillaries were not observed at this level. Chloride cells were appeared the whole part of the gill filament.