ENVIRONMENTAL SCIENCE & TECHNOLOGY
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2024
·
IF 10.8
Yi-Hsueh Chuang,Chia-Shun Chou,Yi-Lin Chu
Chlorination of ammonia or chloramine-containing waters induces breakpoint chlorination reactions, producing a hydroxyl radical (•OH), but enhances the formation of undesirable N-nitrosamines. The prevailing view attributes •OH formation to a nitrosyl intermediate derived from the hydrolysis of dichloramine, but this pathway is unlikely at neutral or acidic pH. This study reveals a novel mechanism where •OH is generated via interactions between trichloramine (NCl3) and dichloramine (NHCl2), which also form nitrosation agents. Our experiments demonstrated that the NCl3–NHCl2 interaction degrades micropollutants with kinetics 2–3 times faster than breakpoint chlorination. Using electron paramagnetic resonance, we detected •OH in the NCl3–NHCl2 reaction. Micropollutant removal was unimpaired under low dissolved oxygen (O2(aq)) conditions, aligning with negligible O2(aq) changes during the NCl3–NHCl2 reaction and suggesting O2(aq) does not participate in •OH formation. Using benzene as a probe in 18O-labeled H2O, we confirmed water contributes to the oxygen source of •OH in NCl3–NHCl2 interactions, through which parallel reactions occur, leading to the formation of one mole of •OH alongside 1.92 mol of N2. A kinetic model developed in this study accurately predicted •OH and N2 and demonstrated the NCl3–NHCl2 interaction as the primary pathway for •OH formation in breakpoint chlorination, providing new insights into breakpoint chemistry.
研究领域:
环境科学
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化学工程
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DOI
PubMed
高影响因子
Natural Product Communications
·
2020
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IF 0.468
YanHua Tian,HuiZhi Du,Li Wang,ShiFei Li,Lu Zhang,LiWei Zhang
Diospyros lotus L. leaves are used as a functional tea and folk medicine in several Asian countries. This study aimed to evaluate the effects of phenolic extracts of the leaves on scavenging nitrite and inhibiting N-nitrosamines (NAs) formation and to determine the active ingredients responsible for these effects. Of the 7 fractions (Fr1-Fr7) prepared from the extract of D. lotus leaves, Fr5 contained the highest phenolic content and exhibited the strongest activity. Five active ingredients of Fr5 were discovered, and 4 of them were identified as myricitrin (Mytr), myricetin (Myt), myricetin-3-O-β-d-glucoside (Myt-Glc), and myricetin-3-O-β-d-galactoside (Myt-Gal). The content of Mytr was much higher than those of the other 3 ingredients, both in Fr5 and extracts of D. lotus leaves. Finally, Mytr and Myt were proved to have stronger activities by the 1,1-diphenyl-2-trinitrophenyl hydrazine scavenging, nitrite scavenging, and inhibition of NAs formation assays. These results indicated that Mytr was the main active ingredient of D. lotus leaves. Myt, Mytr, and Fr5 from the leaves could be used as natural agents for antioxidant, nitrite scavenging, and inhibition of NAs formation in food and the human body.
研究领域:
食品科学
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植物化学
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药理学
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DOI
高影响因子
INTERNATIONAL JOURNAL OF FOOD PROPERTIES
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2019
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IF 1.398
Ling Li,Hui Ji
The present study investigated the protective effects of the polyphenol epicatechin on the protein structural changes, gel properties and N-nitrosodiethylamine (NDEA) formation of oxidatively stressed myofibrillar protein (MP). Results showed that oxidation treatments to MP significantly increased their carbonyl content and surface hydrophobicity as compared to the control groups (p < 0.05). Epicatechin inhibited protein carbonyl content and surface hydrophobicity, especially treated with 2 mM epicatechin. Under oxidative conditions, the fluorescence intensity of tryptophan gradually decreased with the increase of epicatechin concentrations from 0 to 2 mM. The storage modulus (G’) was increased gradually after oxidation and epicatechin treatment. Epicatechin reduced the loss of P22 and water holding capacity (WHC), promoted the hydration of the proteins. Under oxidative conditions, epicatechin had a concentration dependent effect on the formation of NDEA; low concentrations of epicatechin promoted NDEA formation, while high concentrations inhibited NDEA production. In conclusion, an appropriate quantity of polyphenols can inhibit the oxidation of MP and formation of N-nitrosamines.
研究领域:
食品科学
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生物化学
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DOI
高影响因子
Foods
·
2023
·Vol. 12
·期 4
·724
·
IF 5.2
Wenjing Wang,Yafei Kou,Yanli Du,Mingyu Li,Jian Zhang,Aiping Yan,Jianhua Xie,Mingyue Shen
Sausages are among the most popular meat products worldwide. However, some harmful products, such as advanced glycation end-products (AGEs) and N-nitrosamines (NAs), can be formed simultaneously during sausage processing. In this study, the contents of AGEs, NAs, α-dicarbonyls and the proximate composition were investigated in two kinds of commercial sausages (fermented sausages and cooked sausages) in the Chinese market. The correlations among them were further analyzed. The results showed that the fermented and cooked sausages had different in protein/fat contents and pH/thiobarbituric acid reactive substance values due to their different processing technologies and added ingredients. The Nε-carboxymethyllysine (CML) and Nε-carboxyethyllysine (CEL) concentrations varied from 3.67 to 46.11 mg/kg and from 5.89 to 52.32 mg/kg, respectively, and the NAs concentrations ranged from 1.35 to 15.88 µg/kg. The contents of some hazardous compounds, such as CML, N-nitrosodimethylamine, and N-nitrosopiperidine, were observed to be higher in the fermented sausages than in the cooked sausages. Moreover, levels of NAs in some sausage samples exceeded the limit of 10 µg/kg issued by the United States Department of Agriculture, suggesting that particular attention should be paid to mitigating NAs, especially in fermented sausages. The correlation analysis suggested that the levels of AGEs and NAs were not significantly correlated in both kinds of sausages.Keywords:sausages;advanced glycation end-products;N-nitrosamines;α-Dicarbonyls
研究领域:
食品科学
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公共卫生
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DOI
PubMed
高影响因子
Journal of Environmental Chemical Engineering
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2024
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IF 7.4
Xue Bai,Fengyi Sun,Liyan Ma,Zhuwu Jiang,Hongcheng Di,Chuntao Pan,Fengying Zhang,Jiahan Yang,Hongyu Zhang
A green and sustainable three-dimensional particle electrodes system with nickel-iron layered double hydroxide mixing activated carbon particles (NiFe-LDH/AC) as particle electrodes is used in this work. Its employment in degradation of N-Nitrosodiethylamine (NDEA), A type of nitrosamines disinfection byproducts (NAs) widely present in water bodies, exhibiting significant degradation efficiency at close to neutral pH. Response surface methodology (RSM) is used to analyze the interaction effects and predict optimal conditions of four operating parameters (influent water flow, electrolyte concentration, current density and initial concentration) on the NDEA degradation efficiency. Calculated coefficients of determination (R 2 ) are higher than 0.997 for all responses according to analysis of variance. At optimum conditions, a maximum degradation efficiency of 71.88% is achieved for NDEA. The results of electron paramagnetic resonance (EPR) and free radical quenching experiments indicate that the degradation of NDEA in the 3D AER system is dominated by •OH. Furthermore, based on the recognition of main reaction intermediates by GC-MS and density functional theory (DFT), possible degradation pathway is proposed and toxicological evaluation of degradation products is made. Our research provides a promising alternative method for the efficient and environmentally friendly removal of NAs from water.
研究领域:
环境科学
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化学工程
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DOI
高影响因子
CHEMICAL ENGINEERING JOURNAL
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2021
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IF 13.273
Chenglin Liu,Zhijie Liang,Chun Yang,Fuyi Cui,Zhiwei Zhao
N-nitrosamines (NAs), a class of emerging nitrogenous disinfection byproducts , have been detected remarkably in drinking/reclaimed water. There is a significant risk of excessive levels of NAs in the chlorination of the polluted source water, especially in the direct chlorination of nitrite-enriched groundwater. Considering the co-pollution of nitrite and micro-organic pollutants on groundwater, experiments were conducted on chlorination of nitrite-enriched water with precursor of antibiotics, and it was confirmed that the Cl 2 : N (molar ratio of chlorine to nitrite), contacting time, pH, and DO appreciably influenced the NAs formation potential. The molecular electric potential revealed that different dissociation status of precursors has a specific correlation with NAs formation potential (FP). The nitrite significantly increased the NAs FP because the reactive nitrogen species (RNS) formed in the oxidation process from nitrite to nitrate. Sequences of transformation products are determined to support the RNS promoted hypothesis of N-nitrosodimethylamine (NDMA) formation mechanism; furthermore, theoretical investigation in the reaction of dimethylamine (DMA) with different RNS verified the above hypothesis.
研究领域:
环境科学
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化学
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DOI
高影响因子
RSC Advances
·
2019
·Vol. 9
·期 41
·23579-23588
·
IF 3.049
Pingfeng Fu,Yanhong Ma,Huifen Yang,Gen Li,Xiaofeng Lin
The diethyl dithiocarbamate (DDC) collector, a precursor of toxic N-nitrosamines, is detected in flotation wastewaters usually at the ppm level. In this study, the O3 and O3/Vacuum-UV (O3/VUV) processes were compared to investigate the efficient removal of DDC with a low risk of N-nitrosamine formation. The results showed that 99.55% of DDC was removed at 20 min by O3/VUV, and the degradation rate constant was 3.99 times higher than that using O3-alone. The C, S and N mineralization extents of DDC using O3/VUV reached 36.36%, 62.69% and 79.76% at 90 min, respectively. O3/VUV achieved a much higher mineralization extent of DDC than O3-alone. After 90 min of degradation, O3/VUV achieved lower residual concentrations of CS2 and H2S, and released lower amounts of gaseous sulfur byproducts compared to O3-alone. The solid phase extraction and gas chromatography-mass spectrometry (SPE/GC–MS) analysis indicated that the main byproducts in O3/VUV degradation of DDC were amide compounds without the detection of N-nitrosamines. The avoidance of N-nitrosamine formation might be attributed to exposure of UV irradiation and enhanced formation of ˙OH radicals in the O3/VUV system. The degradation pathways of DDC were proposed. This work indicated that O3/VUV was an efficient alternative treatment technique for the removal of DDC flotation collector with low risk of N-nitrosamine formation.
研究领域:
环境科学
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化学工程
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DOI
PubMed
高影响因子
ANALYTICAL AND BIOANALYTICAL CHEMISTRY
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2024
·
IF 3.8
Duan Lian,Wang Cheng,Li Yuwei,Yang Binwang,Zheng Xiuqing,Liu Jiaxu,Jing Guoxing,Liu Wenjie,Yu Jianna
In recent years, the control of volatile N -nitrosamines (NAs) has been of interest in the pharmaceutical and food industries, as many of these compounds are probable human carcinogens. Thus, rapid and trace-level quantitative determination methods are in urgent demand. In this work, ambient pressure ammonium-adduct ionization mass spectrometry was proposed for the sensitive detection of volatile nitrosamines in various pharmaceutical headspaces. The ammonium ions produced through electrospray ionization acted as reactant ions for NAs to generate ammonium–NA adduct ions and underwent in-source collision-induced dissociation to produce protonated NAs, which were detected by mass spectrometry. The ionization selectivity and sensitivity for various volatile NAs were improved significantly using the developed method, which was demonstrated by the limit of quantification (LOQ) below 52 ng L −1 for all NAs, and the quantitative performance was consequently improved. Different NAs exhibited almost equimolar response using NH 4 + as the reactant ion, with at least a twofold enhancement in intensity for the individual compounds relative to when using H + as the reactant ion. The proposed method is a rapid, sensitive, and environmentally economical approach that uses few reagents.
研究领域:
分析化学
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药物分析
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环境科学
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产品关联
DOI
PubMed
高影响因子
FOOD CHEMISTRY
·
2025
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IF 9.8
Wenjing Wang,Zixiong Song,Ying Jing,Xiaoxiao Wei,Haizhen Li,Jianhua Xie,Mingyue Shen
Most research on the formation of advanced glycation end-products (AGEs) and N-nitrosamines (NAs) in meat products has focused on high-temperature processing. The effects of low-temperature processing on AGEs and NAs formation have rarely been studied. This study investigated the effects of salt addition (0 %, 2 %, and 4 %) and lean-to-fat ratio (10:0, 8:2, and 6:4) on the formation of AGEs and NAs in Salami. We found that the salt in Salami would inhibit CEL formation. And the Lean pork Salami showed the highest N ε -carboxyethyllysine (CEL) and lowest N ε -carboxymethyllysine (CML) contents. For NAs content, it was lowest in Salami with 40 % fat. Principal component analysis and correlation analysis revealed significant correlations between CEL and N -nitrosodiphenylamine (NDPhA) formation in Salami. Additionally, the production of CML was correlated with the extent of fat oxidation, while CEL formation was more strongly associated with protein-related reactions. Furthermore, NAs formation correlated with protein content and protein oxidation.
研究领域:
食品科学
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生物化学
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产品关联
DOI
PubMed
高影响因子
Journal of Environmental Chemical Engineering
·
2022
·
IF 7.968
Xin Lei,Yu Lei,Shuangshuang Cheng,Xin Yang
N -nitrosamines are great concern in potable water reuse. This study investigated the reaction kinetics of chlorine radicals (Cl • and Cl 2 •− ) with N -nitrosamines. The second-order reaction rate constants of Cl • ( k Cl • ) and Cl 2 •− ( k Cl2 •− ) with eight N -nitrosamines at pH 7.0 varied in the range of (5.02 ± 0.41)–(57.1 ± 4.25) × 10 8 M −1 s −1 and (0.46 ± 0.04)–(10.6 ± 0.73) × 10 8 M −1 s −1 , respectively. The numbers of methylene groups (#−CH 2 −) showed a good positive correlation with k Cl • (R 2 = 0.71), but not with k Cl2 •− . The degradation of eight N -nitrosamines under UV/chlorine advanced oxidation process (AOP) slightly increased by 1–18% in contrast to UV irradiation alone, and Cl − in the AOPs cannot inhibit their removal. The results improved the understanding of the fate of N -nitrosamines in chlorine radical-involved AOPs.
研究领域:
环境化学
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水处理
·
高级氧化过程
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DOI
高影响因子
Water
·
2022
·Vol. 14
·期 15
·2371
·
IF 3.53
Huili Tang,Ziru Li,Hanqing Chen,Yang Xu,Xu Jiang,Erdeng Du,Zhen Lyu,Lu Zheng,Mingguo Peng
N-nitrosamines have recently attracted attention as a class of disinfection byproducts and are also a hot spot in environmental studies. Current N-nitrosamine analytical methods typically involve manual solid phase extraction (SPE) of samples followed by quantitative analysis using liquid chromatography-mass spectrometry (LCMS), which is time-consuming and may also fail to eliminate complex matrix effects. Size exclusion chromatography (SEC) is a technique that can separate compounds according to their molecular size. For the first time, this study developed an Online-SPE/SEC/LCMS quantitative analysis method to detect and analyze nine common N-nitrosamine disinfection byproducts in wastewater plant tailwater, including N-dimethylnitrosamine (NDMA) and N-nitrosodiethylamine (NDEA), etc. The samples of 1.0 mL can be directly injected after the simple 0.22 μm membrane filtration. This method reports the combination of SPE, SEC, and RP C18 columns to achieve several functions in a processing time of 20 min, including online enrichment, desalination, and matrix separation for the first time. The method provides good linearity (R2> 0.999), recoveries ranging from 91.67% to 105.88%, relative standard deviation (RSD) lower than 4.17%, and the limits of detection (LOD) are 0.12–6.60 ng/L. This method alleviates tedious human labor and can effectively overcome the matrix effect (ME< 20%). This method allows for the accurate quantitative analysis of N-nitrosamines with high compatibility in wastewater plant tailwater, rivers, and lakes with a high background matrix. Interested researchers can also use this method as a reference in the online analysis of other specific pollutants after necessary optimization. It can also be utilized for non-targeted screening and targeted analysis of contaminants in water with a wide range of applications, giving valuable information for environmental monitoring.Keywords:N-nitrosamines;analysis method;online solid-phase extraction (Online-SPE);size exclusion chromatography (SEC);LCMS;column switching;wastewater plant tailwater
研究领域:
环境科学
·
分析化学
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DOI
高影响因子
TALANTA
·
2016
·
IF 4.035
Junwei Liu,Yong Wang,Weixia Li,Peimin Zhang,Nani Wang,Shuchao Wu,Yan Zhu
Poly (glycidylmethacrylate-divinylbenzene) (Poly (GMA-DVB)) microspheres were prepared by the two-staged swelling and polymerization method, and modified with octadecylamine (ODA) to obtain ODA-poly (GMA-DVB) stationary phase for HPLC. The new material was characterized by scanning electron microscope, nitrogen adsorption-desorption measurement, Fourier transform infrared spectrum , elemental analysis and thermogravimetric analysis . The results showed that poly (GMA-DVB) microspheres had good monodispersity, porosity and ball shapes. The diameters and specific surface area of the microspheres were about 6 µm and 396 m 2 g −1 , respectively. ODA-poly (GMA-DVB) stationary phase had good thermal stability. Furthermore, the chromatographic performance of the stationary phase was illustrated by separating n-alkylbenzenes, mono-substituted benzenes and N -nitrosamines. Auxiliary quantum chemistry calculation was also carried out to evaluate the interaction mechanism. According to the evaluation, ODA-poly (GMA-DVB) stationary phase exhibited good hydrophobicity and hydrophobic selectivity, strong stereo-selectivity, polar interaction and π-π interaction. The multi-interaction mechanisms could very likely guarantee its excellent chromatographic performance for the analysis of complex samples. Finally, the column was successfully applied in the determination of N -nitrosamines in pickles sample.
研究领域:
分析化学
·
材料科学
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产品关联
DOI
PubMed
高影响因子
危险品化学品经营许可证（带存储）