• Journal of the Korean Society of Food Science and Nutrition
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• v.26 no.4
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• pp.614-619
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• 1997

To examine effects of drying methods on the formation of N-nitrosamine(NA) in squid during its drying. Three different types of dried products, which were made by sun, hot-air and traditional drying of squid after removal of intestines, were utilized. NA was analyzed by a gas chromatography-thermal energy analyzer. The contents of nitrate and nitrite nitrogen in dried products were in the range of 0 to 5.2mg/kg and 0 to 2.7mg/kg, respectively. The contents of TMAO and betain nitrogen in squid during its drying decreased, while those of TMA and DMA nitrogen increased. The contents in dried products were 27.8~29.2mg% and 10.4~12.3mg/kg, respectively. N-Nitrosodimethylamine (NDMA) was only detected in squid during its drying, recovery from raw sample and its dried pro- ducts spiked with 10$\mu\textrm{g}$/kg for NDPA was 81.0~ 100.0%. NDMA in raw samples was found to be below 0.05$\mu\textrm{g}$/kg. The levels of NDMA in squid increased remarkably during its drying and those in dried products were ranged from 2.7 to 42.7$\mu\textrm{g}$/kg. The effects of drying methods in squid were found to be quite different. the levels of NDMA in traditionally dried products were 11~16 and 3~4 times higher than those in sun dried and hot-air dried products, respectively It is believed that high levels of NDMA were detected in traditionally dried products because NDMA was formed from reaction between various amines and nitrogen oxide produced by combustion of briquet during drying of squid.

• Environmental Analysis Health and Toxicology
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• v.26
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• pp.2.1-2.7
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• 2011

Objectives: N-Nitrosodimethylamine (NDMA) is classified as a probable human carcinogen by the United States Environmental Protection Agency (US EPA) and is formed during the chlorination of municipal drinking water. In this study, selected nitrosamines were measured in chlorinated drinking water collected from Chuncheon, Kangwon-do, Republic of Korea, and a risk assessment for NDMA was conducted. Methods: Twelve water samples were collected from 2 treatment plants and 10 household taps. Samples were analyzed for 6 nitrosamines via solid-phase extraction cleanup followed by conversion to dansyl derivatives and high-performance liquid chromatography-fluorescence detection (HPLC-FLD). Considering the dietary patterns of Korean people and the concentration change of NDMA by boiling, a carcinogenic risk assessment from ingestion exposure was conducted following the US EPA guidelines. Results: NDMA concentrations ranged between 26.1 and 112.0 ng/L. NDMA in water was found to be thermally stable, and thus its concentration at the end of boiling was greater than before thermal treatment owing to the decrease in water volume. The estimated excess lifetime carcinogenic risk exceeded the regulatory baseline risk of $10^{-5}$. Conclusions: This result suggests that more extensive studies need to be conducted on nitrosamine concentration distributions over the country and the source of relatively high nitrosamine concentrations.

• Mass Spectrometry Letters
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• v.12 no.2
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• pp.31-40
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• 2021

Probable human carcinogenic compounds nitrosamines, have been detected as by-product impurities in sartan pharmaceuticals in recent years which has drawn worries for medication safety. To provide a sensitive and effective method for the quality control of sartan pharmaceuticals, this study established a feasible gas chromatography-tandem mass spectrometry (GC-MS/MS) method for simultaneous determination of 13 nitrosamines. The target analytes were separated on a DB-WAX Ultra Inert column (30 m × 0.25 mm; i.d., 0.25 ㎛) and were then subjected to electron impact ionization in multiple reaction monitoring mode. The established method was validated and further employed to analyze authentic samples. Limits of detection (LODs) and limits of quantification (LOQs) of the 13 nitrosamines were 15-250 ng/g and 50-250 ng/g, respectively, which also exhibited intra-day and inter-day accuracies of 91.4-104.8%, thereby satisfying validation criteria. Five nitrosamines, viz., N-nitrosodiethylamine, N-nitrosodimethylamine, N-nitrosodiphenylamine, N-nitrosomorpholine, and N-nitrosopiperidine were detected at concentrations above their LODs in 68 positive samples out of 594 authentic samples from seven sartans.

• Culinary science and hospitality research
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• v.11 no.4 s.27
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• pp.1-13
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• 2005

This study analyzed the levels of N-nitrosamine(NA) and its precursors such as nitrite, nitrate, dimethylamine and trimethylamine in 10 samples of mollusk fish, 4 samples of crustacea fish and 11 samples of shellfish from fish distributed in a local markets. Mollusk fishes had nitrite concentrations ranging from non-detectable(ND) to 9.4 mg/kg, crustacea fishes ND to 8.8 mg/kg, and shellfishes ND to 4.3 mg/kg. Nitrates in mollusk fishes ranged from ND to 19.3 mg/kg, crustacea fishes 4.1 to 79.9 mg/kg, and shellfishes 1.5 to 61.9 mg/kg. DMK concentrations were 11.2 to 551.4 mg/100g in mollusk fishes, 44.4 to 79.9 mg/100g in crustacea fishes, and 1.3 to 5.9 mg/100g in shellfishes. TMA concentrations in mollusk fishes, crustacea fishes, and shellfishes were 10.3${\sim}$292.4 mg/100g, 35.5${\sim}$90.3 mg/100g, and 2.3${\sim}$17.1 mg/100g respectively. Only N-nitrosodimethylamine (NDMA) was detected for NA in fish distributed in local markets. NDMA contentrations ranged from ND to 41.4 ${\mu}g/kg$ in mollusk fishes, 3.0 to 47.3 ${\mu}g/kg$ in crustacea fishes, and 1.7 to 12.1 ${\mu}g/kg$ in shellfishes.

• Parasites, Hosts and Diseases
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• v.55 no.1
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• pp.21-29
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• 2017

Schistosoma haematobium is a biocarcinogen of human urinary bladder (UB). The present study investigated developing UB cancer mouse model by injecting S. haematobium eggs into the bladder wall and introduction of chemical carcinogens. Histopathological findings showed mild hyperplasia to epithelial vacuolar change, and high grade dysplasia. Squamous metaplasia was observed in the S. haematobium eggs+NDMA group at week 12 but not in other groups. Immunohistochemistry revealed significantly high expression of Ki-67 in urothelial epithelial cells of the S. haematobium eggs+BBN group at week 20. The qRT-PCR showed high expression of p53 gene in S. haematobium eggs group at week 4 and S. haematobium eggs+BBN group at week 20. E-cadherin and vimentin showed contrasting expression in S. haematobium eggs+BBN group. Such inverse expression of E-cadherin and vimentin may indicate epithelial mesenchymal transition in the UB tissue. In conclusion, S. haematobium eggs and nitrosamines may transform UB cells into squamous metaplasia and dysplasia in correlation with increased expression of Ki-67. Marked decrease in E-cadherin and increase in p53 and vimentin expressions may support the transformation. The present study introduces a promising modified animal model for UB cancer study using S. haematobium eggs.

• The Korean Journal of Food And Nutrition
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• v.11 no.4
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• pp.452-459
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• 1998

In 7 kinds of Gulbi purchansed from Yosu, Sunchon and Chinju, N-nitrosamine (NA) such as N-nitrosodimethylamine (NDMA), N-nitrosodiethylamine (NDEA) and N-nitrosodipropylamine(NDPA), were detected and their content was 2.8∼78.3$\mu\textrm{g}$/kg, trace and 0∼1.4$\mu\textrm{g}$/kg, respectively. This experiment was conducted to study the effect of processing conditions on NA formation in the salted and dried yellow corvenia(Guibi), prepared by using the different salting method like dry and brine salting by pure and crude salt. NDMA, NDEA and NDPA were not detected in raw sample, but NDMA content increased in yellow corvenia during its salting (27.6∼37.4$\mu\textrm{g}$/kg), and then drastically decreased in Gulbi stored for 40 days, ranging from 2.8 to 4.3$\mu\textrm{g}$/kg. Content of above NA was inhibited more effectively in the samples prepare with brine salting method than with the dry salting method during its processing and storage. Especially, NA in the sample prepared with brine salted and dried yellow corvenia using the pure salt was detected in the lower concentrations, and that of NDMA, NDEA and NDPA was 2.8∼27.6, trance and ND-2.7$\mu\textrm{g}$/kg, respectively.

• Journal of Korean Society of Environmental Engineers
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• v.30 no.9
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• pp.913-917
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• 2008

Since the difficulty of analysis at low concentration and the uncertainty of the removal mechanism for Nitrosodimethylamine (NDMA) have been reported, this study has detected extremely low concentration $^{14}$C-NDMA using the LSC(Liquid Scintillation Counter) and tested NDMA removal by Powdered Activated Carbon(PAC). The results showed the highest correlation over 99% when samples were measured with the mixture ratio of sample to scintillation liquid of 10 : 10 and at the detection time of 10 min. For $^{14}$C-NDMA removal by the PACs(S-A(Sigma-Aldrich co.) and Dj(Daejung co.)) raging from 50$\sim$10,000 mg/L, $^{14}$C-NDMA was removed over 90% by adsorption treatment. In addition, S-A showed twice greater adsorption capacity than that of Dj. However, the required PAC amount for $^{14}$C-NDMA removal was higher than that of other amine compounds.

• Journal of Korean Society on Water Environment
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• v.26 no.3
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• pp.446-453
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• 2010

This study was investigated nine nitrosamines in small tributary rivers, sewage treatment plants (STPs) and drinking water treatment plants. They are N-nitrosodimethylamine (NDMA), N-nitrosomethylethylamine (NMEA), N-nitrosodiethylamine (NDEA), N-nitrosopyrrolidine (NPYR), N-nitrosodi-n-propylamine (NDPA), N-nitrosomorpholine (NMOR), N-nitrosopiperidine (NPIP), N-nitrosodi-n-butylamine (NDBA) and N-nitrosodiphenylamine (NDPHA). The nine nitrosamines were analyzed by gas chromatography mass spectrometry (GC/MS) using solid phase extraction (SPE) with a coconut charcoal cartridge. Among the nine nitrosamines, NDMA, NMEA, NDEA, NDPA NDBA and NDPHA were detected in small tributary rivers and sewage tretment plants. In small tributary rivers, NDMA, NMEA, NDEA, NDPA, NDBA and NDPHA were obtained as ND~16.4 ng/L, ND~17.7 ng/L, ND~102.4 ng/L, ND~455.4 ng/L, ND~330.1 ng/L and ND~161.0 ng/L, respectively. Also NDMA, NMEA, NDEA, NDPA and NDBA were investigated ND~821.4 ng/L, 22.5~55.4 ng/L, 53.2~588.5 ng/L, ND~56.6 ng/L and ND~527.9 ng/L in STPs, respectively. In drinking water treatment plants, NMEA and NDEA concentration were increased to as high as 38.8 ng/L after ozonation process. However nitrosamines were decreased subsequent biological activated carbon (BAC) treatment process. It was supposed that nitrosamines were formed by $O_3$ oxidation and were removed by biodegradation of BAC.

• Journal of Korean Society of Water and Wastewater
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• v.32 no.5
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• pp.389-398
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• 2018

A nationwide survey of 8 N-nitrosamines in finished water samples from drinking water treatment plants (DWTPs) in Korea was conducted. The samples were pre-treated by solid-phase extraction (SPE) and analyzed using a gas chromatography coupled with tandem mass spectrometry (GC-MS/MS). According to the study results, four N-nitrosamines (NDMA, NDEA, NMOR, NDBA) were detected for three consecutive years, NMEA and NPYR were only found in samples collected in 2013. Two of these N-nitrosamines, N-nitrosodimethylamine (NDMA) and N-nitrosodiethylamine (NDEA), have received attention and were the most commonly detected. The concentration of NDMA and NDEA in this study ranged from $0.002{\mu}g/L$ to $0.013{\mu}g/L$ and in $0.001{\mu}g/L$ to $0.008{\mu}g/L$, respectively. In comparison to studies performed in EPA(UCMR2), the concentrations of NDMA (from $0.002{\mu}g/L$ to $0.630{\mu}g/L$) and NDEA (from $0.005{\mu}g/L$ to $0.100{\mu}g/L$) observed in the this study were low.

• Journal of Food Hygiene and Safety
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• v.13 no.4
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• pp.400-405
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• 1998

This experiment was conducted to study occurrence of N-nitrosamine (NA) and its precursors such as nitrate and nitrite. For the experimental samples, 26 kinds of commercial hams and 30 kinds of sausages produced in Korea were purchased. The nitrate and nitrite were positive in all of the collected samples; nitrate levels were by average 4.4~9.2 mg/kg and nitrite ones were by average 1.3~3.6 mg/kg. The contents of nitrate and nitrite were detected higher in sausage than in ham. Especially, nitrate contents were contained higher in lyoner sausage prepared with the mixture of meat and fish, while nitrite contents were contained higher in the meat only mixture. N-nitrosodimethylamine (NDMA) among the analyzed 7 kinds of NA was detected only in ham and sausage; its contents were outstanding in lyoner sausage which was prepared with only meat and pork sausage, and then regular ham was the next one in its order, but its contants were detected by average $<0.5\;\mu\textrm{g}/kg$ in press hams added vegetable.