饮用水含氮消毒副产物NDMA的形成与去除研究进展

N-亚硝基二甲胺(NDMA)是一种强致痛物质,普遍存在于食品、工业制品和污染大气之中.作为一种新发现的饮用水消毒副产物,NDMA已逐渐成为水环境化学研究领域的一个热点.介绍了饮用水消毒副产物NDMA的相关背景,重点评述了NDMA在水中的形成机制,主要包括亚硝化和非对称二甲肼氧化两种途径,强调NDMA的前体物还有待进一步确认.对水中NDMA的去除方法进行了总结,包括物理方法、光解作用、生物降解和高级氧化技术.最后提出了饮用水含氮消毒副产物NDMA的若干研究方向.     

气球中N-亚硝胺及其前体物迁移量的测定与NDMA的儿童致癌暴露风险分析

用Sep-Pak AC2串联Dry cartridges固相萃取小柱对气球中的7种挥发性N-亚硝胺进行分离净化,并用气相色谱-串联质谱法对其进行定性与定量分析。方法对气球中N-亚硝胺及其前体物的检出限分别为1.25μg/kg和5.00μg/kg。对空白样品进行添加量为2.5μg/kg的加标回收实验,回收率为85%～103%,RSDs(n=3)≤4.6%。分析的气球样品中,N-亚硝基二甲胺(NDMA)及其前体物的检出频率最高;其次是N-亚硝基二乙胺(NDEA)及其前体物;N-亚硝基吗啉(NMOR)、N-亚硝基二丙胺(NDPA)和N-亚硝基哌啶(NPIP)及其前体物均未检出;7种N-亚硝胺及其前体物的总迁移量分别为0.036～0.964 mg/kg和0.259～8.436 mg/kg。6个月～4岁儿童通过口直接接触单个气球样品造成的NDMA的暴露量集中在0.010～0.030mg/kg体重,具有潜在的致癌暴露风险。     

欧盟EN12868方法与固相微萃取-气质联用法检测乳胶气球中亚硝胺模拟迁移量

利用欧盟EN12868方法对市售乳胶气球中的8种挥发性亚硝胺及其前体物的模拟迁移量进行了检测,包括N-亚硝基二甲胺(NDMA),N-亚硝基二乙胺(NDEA),N-亚硝基二丙胺(NDPA),N-亚硝基异丙胺(NDiPA),N-亚硝基二丁胺(NDBA),N-亚硝基哌啶(NPIP),N-亚硝基吡咯烷(NPYR),N-亚硝基吗啉(NMOR)。其中NDMA,NDEA和NDBA 3种亚硝胺及其前体物被检出,且均超标。建立了顶空-固相微萃取-气相色谱-质谱法(HS-SPMEGC-MS)快速测定乳胶气球中亚硝胺模拟迁移量的分析方法。样品置于人工唾液40℃浸提1h来模拟气球的使用情况,考察了不同的萃取条件对分离检测的影响,综合评价了4种检测系统的性能。8种亚硝胺的方法检出限为0.26~5.38μg/kg。利用所建方法检测9种市售乳胶气球中亚硝胺的模拟迁移总量为31.37~337.72μg/kg。     

利用溶液前体物组合化学方法研究固相体系相关系

利用溶液前体物组合化学方法研究了La-Ca-Mn-O的相关系。这种合成方法可以完全重现常规固相反应得到的相关系，表明溶液前体物组合化学是一种研究固态相关系的可靠方法。组合化学方法对于提高寻找新型化合物和研究相关系研究效率方面具有重要意义。     

紫外高级还原技术还原降解水中N-亚硝基二甲胺

采用2种高级还原技术(UV/Na2SO3和UV/Na2S2O4)还原降解N-亚硝基二甲胺(NDMA),考察pH值、光照强度、还原剂质量浓度和溶解氧等因素对NDMA还原降解效果的影响,计算还原降解反应过程中的表观反应动力学常数,推断NDMA的还原降解机理.研究结果表明,弱酸性条件下有利于2种高级还原技术对NDMA的还原降...     

N—亚硝基二甲胺化学电离的量子化学研究

用质谱化学电离和量子化学方法研究了致癌物质N-亚硝基二甲胺(NDMA)的结构及性质,优化了化学电离质谱中主要离子的构型;探讨了NDMA的质子化合物的形成途径,经NDMA及其质子化合物的静电势计算,阐述了NDMA的可能致癌机理。     

液相色谱-质谱联用法结合主成分分析考察食品中前体物质对杂环胺生成的影响

为了考察不同温度条件下前体物质及其含量对杂环胺生成的影响,采用超高效液相色谱串联质谱法定性定量分析了不同温度(200℃,230℃和270℃)、不同前体物质种类(葡萄糖、肌酸、肌酸酐、苯丙氨酸、色氨酸和苏氨酸)以及不同添加量(添加1倍和2倍原料牛肉中的含量)条件下,烤牛肉饼中的17种极性和非极性杂环胺,采用主成分分析考察了温度、前体物质种类及其添加量对杂环胺生成的影响,并筛选出了受到影响的关键杂环胺。结果表明,3种温度条件下杂环胺的生成具有较明显的差异;200℃条件下前体物质的种类对杂环胺生成的影响较小,而230℃和270℃条件下则有较大的影响;对于葡萄糖、肌酸、肌酸酐和苏氨酸,3种温度下添加量对杂环胺的生成均影响较小;而对于苯丙氨酸和色氨酸,200℃条件下添加量对杂环胺生成的影响较小,230℃和270℃条件下添加量对杂环胺生成的影响则较大。由主成分分析载荷图筛选出4种杂环胺(Harman、Norharman、MeIQ x和PhIP)为温度、前体物质及其添加量影响的关键杂环胺。本方法可用于各种因素对杂环胺生成的影响研究以及相关关键杂环胺的筛选。     

O_(3)/UV多相催化氧化法处理UDMH废水的研究北大核心CSCD

含偏二甲肼(UDMH)的废水在臭氧氧化过程中会显著生成高毒性且难降解的次级氧化产物亚硝基二甲胺(NDMA),采用臭氧/紫外(O_(3)/UV)联用技术仍不能有效抑制NDMA的生成和彻底氧化NDMA.我们以Fe_(2)O_(3)/γ-Al_(2)O_(3)为催化剂,采用多相催化氧化-O_(3)/UV联用技术对含UDMH的废水进行了氧化处理,详细对比了有无催化剂时UDMH的降解效率以及次级氧化产物NDMA生成、氧化消除的规律,结果表明,多相催化技术与O_(3)/UV联用能够显著提高对废水中UDMH的氧化分解效率,且能有效地抑制NDMA的生成和促进NDMA的氧化消除.通过反应参数的优化,确定了最佳的反应条件.在此基础上,对UDMH和NDMA的氧化降解反应动力学进行了对比研究,结果显示,多相催化技术有效提升了NDMA在O_(3)/UV中的氧化降解效率,使得反应所产生的NDMA可以及时分解.我们还对稳定性进行了研究,催化剂经8次循环仍保持较高的催化活性和稳定性.我们的研究结果表明多相催化-O_(3)/UV联用技术对含UDMH废水处理有优良的适用性,综合效能优于现用的O_(3)/UV处理技术.     

气相色谱-三重四极杆质谱法同时测定纺织品中11种挥发性全氟化合物前体物

以甲醇为提取溶剂,超声辅助提取纺织品中的全氟化合物前体物,建立了一种气相色谱-三重四极杆质谱(GC-MS/MS)法同时测定纺织品中11种挥发性全氟化合物前体物:4种氟调聚物醇(FTOHs)、3种氟调聚丙烯酸酯(FTAs)、2种全氟辛基磺酰胺(FOSAs)和2种全氟辛基磺酰胺乙醇(FOSEs)。考察了超声提取溶剂、提取温度和提取时间对提取效率的影响,最终确定用甲醇为提取溶剂,70 ℃下超声提取60 min,目标物经VF-WAXms毛细管柱(30 m×0.25 mm×0.25 μm)程序升温分离,GC-MS/MS多反应监测(MRM)模式检测,外标法定量。实验结果表明:11种挥发性全氟化合物前体物在10~500 μg/L范围内线性关系良好,相关系数(r)均不低于0.9984;以信噪比为3计算,检出限(LOD)为0.002~0.04 mg/kg;以信噪比为10计算,定量限(LOQ)为0.006~0.1 mg/kg;不同材质纺织品中,11种挥发性全氟化合物前体物在高、中、低3个添加水平下的回收率为73.2%~117.2%,相对标准偏差(RSD)为0.1%~9.4%(n=6)。该方法前处理简单,定性、定量准确,灵敏度高,重现性好,可有效用于纺织品中11种挥发性全氟化合物前体物的同时检测。实际样品分析发现,当前全氟化合物前体物已被应用于纺织品整理当中。该方法的建立对我国纺织品中全氟化合物前体物风险物质的管控和检测标准的制定具有一定的理论和现实意义。     

臭氧化对水厂水中消毒副产物生成势的影响

以某饮用水厂沿程工艺出水为研究对象,研究了臭氧化预处理对水体中消毒副产物(DBPs)氯化生成势的影响。结果表明,水厂生物处理单元产生的胞外聚合物(EPS)和溶解性微生物产物(SMP)等生物源有机物是非常有效的DBPs前体物,但其更易于氯化生成三卤甲烷(THMs)而非卤乙酸(HAAs)。水厂水中存在的THMs前体物主要是各类大分子量有机物,并且臭氧工艺对其有较好的氧化去除效果。水厂水中经臭氧氧化产生的小分子量有机物可能是更为有效的一氯乙酸(MCAA)和一溴乙酸(MBAA)前体物。此外,当水体中三氯乙酸(TCAA)前体物浓度较高时,臭氧工艺对TCAA生成势具有很好的去除效果。     

Simultaneous amperometric determination of lignin peroxidase and manganese peroxidase activities in compost bioremediation using artificial neural networks

High-performance liquid chromatography (HPLC) and fluorescence derivatization were applied for a nanogram-level N-nitrosodimethylamine (NDMA) analysis of water samples. For the analysis of N-nitrosodimethylamine, samples were first denitrosated by a mixed solution of hydrobromic acid and acetic acid to produce dimethylamine, which was derivatized with dansyl chloride for HPLC fluorescence detection. Fluorescence detection was optimized with excitation and emission wavelengths of 340 and 530 nm, respectively. pH adjustment after denitrosation was necessary to maximize fluorescence intensity with pHs in the range of 9-12. A dansyl chloride concentration of 500 mg l⁻¹ was found to be optimal for measuring a fluorescence signal. An instrumental detection limit of 0.1 ng of NDMA was possible with fluorescence derivatization. The NDMA in water samples was extracted by continuous solid-phase extraction using Ambersorb 572. Although the determination of NDMA was variable at lower concentrations (less than 200 ng l⁻¹), it was observed that the NDMA detection limit with this method could be lowered to a concentration of 10 ng l⁻¹. Another benefit of this method can be found in its selectivity for NDMA. Unlike gas chromatographic (GC) methods, this method generates a distinct peak for NDMA without interference even in the complex matrix of wastewater effluents. The HPLC with fluorescence derivatization method may be applicable for determining NDMA in water and wastewater samples for various research purposes and for screening environmental samples.     

Determination of N-nitrosodimethylamine in fish products using gas chromatography with nitrogen-phosphorus detection

A simple and rapid gas chromatographic method for the determination of N-nitrosodimethylamine (NDMA) in fish products is described. NDMA is extracted from a dried sample with methylene chloride, mixed with n-hexane and passed through a silica gel column. NDMA adsorbed on silica gel is eluted with methylene chloride-diethyl ether (7:3) and the eluate is passed through a Sep-Pak alumina A cartridge column, on which NDMA is adsorbed. NDMA is eluted from the cartridge with diethyl ether-methanol (2:1) and the solution is injected into a gas chromatograph with nitrogen-phosphorus detection. This method does not use solvent evaporation and concentration in the clean-up procedure, which eliminates the loss of volatile NDMA and artifactual formation of NDMA in the analytical procedure. The detection limit is 0.5-1 micrograms/kg and recoveries from salted pollack roe spiked at 40 and 4 micrograms/kg were 96.7% [relative standard deviation (R.S.D.) 3.6%] and 85.0% (R.S.D. 6.8%) respectively.     

顶空气相色谱质谱联用测定厄贝沙坦中遗传毒性杂质N-亚硝基二甲胺和N-亚硝基二乙胺

采用顶空进样气相色谱-质谱联用法,对厄贝沙坦原料药中的遗传毒性杂质N-亚硝基二甲胺(NDMA)和N-亚硝基二乙胺(NDEA)进行同时测定。采用岛津SH-Rtx-Wax气相色谱柱程序升温进行分离,电子轰击电离源(EI)电离,选择离子监测(SIM)模式检测。结果表明NDMA和NDEA在10~500 ng/mL浓度范围内线性关系良好,检出限(LOD)分别为1.7 ng/mL和4.5 ng/mL,峰面积相对标准偏差(RSD)均小于2.4%。阴性及阳性样品加标回收率为100.6%~108.7%。该方法能够有效地检测原料药厄贝沙坦中NDMA和NDEA的含量。     

Collision induced dissociation of protonated N-nitrosodimethylamine by ion trap mass spectrometry: Ultimate carcinogens in gas phase

Collision induced dissociation of protonated N-nitrosodimethylamine (NDMA) and isotopically labeled N-nitrosodimethyl-d6-amine (NDMA-d6) was investigated by sequential ion trap mass spectrometry to establish mechanisms of gas phase reactions leading to intriguing products of this potent carcinogen. The fragmentation of (NDMA + H⁺) occurs via two dissociation pathways. In the alkylation pathway, homolytic cleavage of the N–O bond of N-dimethyl, N′-hydroxydiazenium ion generates N-dimethyldiazenium distonic ion which reacts further by a CH₃ radical loss to form methanediazonium ion. Both methanediazonium ion and its precursor are involved in ion/molecule reactions. Methanediazonium ion showed to be capable of methylating water and methanol molecules in the gas phase of the ion trap and N-dimethyldiazenium distonic ion showed to abstract a hydrogen atom from a solvent molecule. In the denitrosation pathway, a tautomerization of N-dimethyl, N′-hydroxydiazenium ion to N-nitrosodimethylammonium intermediate ion results in radical cleavage of the N–N bond of the intermediate ion to form N-dimethylaminium radical cation which reacts further through α-cleavage to generate N-methylmethylenimmonium ion. Although the reactions of NDMA in the gas phase are different to those for enzymatic conversion of NDMA in biological systems, each activation method generates the same products. We will show that collision induced dissociation of N-nitrosodiethylamine (NDEA) and N-nitrosodipropylamine (NDPA) is also a feasible approach to gain information on formation, stability, and reactivity of alkylating agents originating from NDEA and NDPA. Investigating such biologically relevant, but highly reactive intermediates in the condensed phase is hampered by the short life-times of these transient species.     

N-Nitrosodimethylamine Contamination in the Metformin Finished Products

A GC–MS/MS method with EI ionization was developed and validated to detect and quantify N-nitrosodimethylamine (NDMA) and seven other nitrosamines in 105 samples of metformin tablets from 13 different manufactures. Good linearity for each compound was demonstrated over the calibration range of 0.5–9.5 ng/mL. The assay for all substances was accurate and precise. NDMA was not detected in the acquired active pharmaceutical ingredient (API); however, NDMA was detected in 64 (85.3%) and 22 (91.7%) of the finished product and prolonged finished product samples, respectively. European Medicines Agency recommends the maximum allowed limit of 0.032 ppm in the metformin products. Hence, 28 finished products and 7 pronged dosage products were found to exceed the acceptable limit of daily intake of NDMA contamination. The implications of our findings for the testing of pharmaceutical products are discussed.     

高效液相色谱-串联质谱法测定盐酸二甲双胍及其制剂中痕量N -亚硝基二甲胺

建立了高效液相色谱-串联质谱（HPLC-MS/MS）检测盐酸二甲双胍原料和制剂中N -亚硝基二甲胺（NDMA）含量的方法。样品以水为提取溶剂,经涡旋混匀、恒温振荡、高速离心、微孔过滤后进行HPLC-MS/MS分析。采用ACE EXCEL 3 C18-AR色谱柱（150 mm×4.6 mm,3 μm）分离,流动相为均含0.1%甲酸的水和甲醇溶液,梯度洗脱,流速0.8 mL/min,柱温40℃,自动进样器温度10℃。采用阀切换技术保护质谱仪,设置六通阀切换使保留时间2.85~7.00 min的流动相进入质谱,其余时间流动相进入废液。质谱部分采用大气压化学电离（APCI）源,在正离子、MRM模式下扫描,雾化器流量为3 L/min,加热器流量为10 L/min,接口温度为300℃,脱溶剂管温度为250℃,加热块温度为400℃,干燥器流量为10 L/min。NDMA定量离子对为m /z 75.0→43.1,碰撞能量（CE）为-17.0 eV,定性离子对为m /z 75.0→58.2,CE为-16.0 eV。采用外标法定量。对方法进行了详细的方法学验证,结果表明,该法专属性良好,溶剂和辅料对NDMA测定无干扰。NDMA峰面积与其质量浓度在1.00~100.00 ng/mL范围内呈现良好的线性关系,相关系数（r ）>0.9999;低、中、高3个水平下NDMA的回收率为94.55%~114.67%,RSD为4.73%~13.46%;检出限和定量限分别为0.20 ng/mL和1.00 ng/mL;NDMA在自动进样器放置0、8、24 h的峰面积RSD为2.08%。使用该方法对113批盐酸二甲双胍原料和制剂供试品中的NDMA进行测定,发现原料药中NDMA检出量不超限,但有8批二甲双胍制剂超过了限度。该法灵敏、准确,操作简便,可用于盐酸二甲双胍原料及制剂中的NDMA检测。     

地表水和饮用水中NDMA的降解方法*

NDMA（二甲基亚硝胺）是在地表水和消毒后的饮用水中新检测到的强致癌污染物,研究其去除方法对保护公众健康和发展安全的水工业具有重要的现实意义。本文综述了NDMA的去除方法,分析了挥发﹑汽提﹑吸附﹑反渗透﹑生物处理﹑金属催化还原﹑UV处理﹑自然光解和二氧化钛光催化方法的优缺点,并探讨了该领域的研究方向,旨在为解决地表水和饮用水中的亚硝胺污染问题开发高效、实用的方法和途径提供新的思路。     

Identification of radiolytic products from N-nitrosodimethylamine and N-nitrosopyrrolidine by gas chromatography and mass spectrometry

The radiolytic products of N-nitrosodimethylamine (NDMA) and N-nitrosopyrrolidine (NPYR) dissolved in dichloromethane (DCM) were identified after gamma irradiation. The UV spectra of NDMA and NPYR indicated that irradiation reduced the typical peak of NDMA at 258 nm and NPYR at 260 nm.The major radiolytic components identified in irradiated NDMA were ethyl acetate and 2-dimethyl propanol. The irradiated NPYR dissolved in DCM and produced 2-butanone and 2-methyl-6-propyl piperidine as the major radiolytic components. 2-Methyl-6-propyl piperidine was the component detected in the greatest concentration in irradiated NPYR.