摘要
【目的】在模拟胃液条件下研究重金属Cu^(2+)和Zn^(2+)对内源致癌性N-二甲基亚硝胺(NDMA)形成的影响,并进一步探讨其作用机理。【方法】分别用气相色谱-质谱联用法(GC-MS)和离子色谱法(IC)来测定NDMA、二甲胺(DMA)和亚硝酸根(NO_2^-)含量。【结果】在模拟胃液条件下,Cu^(2+)和Zn^(2+)浓度高于50mg/L时,可以促进NDMA的形成,且当浓度由50mg/L增大到200mg/L时,Cu^(2+)促进率由1.16%增大到94.56%,Zn^(2+)促进率由21.32%增大到45.86%。在重金属浓度为符合或接近符合水质基准值1.0mg/L时,Cu^(2+)和Zn^(2+)对NDMA的形成也分别有16.88%和13.42%的促进率;而当重金属浓度为10mg/L时,两种离子却均抑制NDMA的形成。机理研究表明Cu^(2+)、Zn^(2+)促进NDMA的形成主要是由于其与DMA发生相互作用,进而导致NDMA形成。【结论】高浓度的Cu^(2+)和Zn^(2+)通过与DMA相互作用,形成活性中间体从而促进NDMA的生成。
【Objective】The aim of this study was to investigate the effect of heavy metal irons Cu^(2+)and Zn^(2+)on the formation of N-nitrosodimethylamine(NDMA)in simulated gastric fluid(SGF)and further explore its mechanism.【Methods】The concentrations of NDMA and dimethylamine(DMA),nitrite(NO_2^-)were determined by gas chromatography-mass spectrometry(GC-MS)and ion chromatography(IC),respectively.【Results】Cu^(2+)and Zn^(2+)could promote the formation of NDMA when the concentrations of Cu^(2+)and Zn^(2+)were higher than 50mg/L in simulated gastric fluid(SGF).Meanwhile,the promotion rates were increased from 1.16%to 94.56% and 21.32% to 45.86% for Cu^(2+)and Zn^(2+),respectively,with their concentrations increasing from 50mg/L to 200mg/L.It is noteworthy that very low concentration of Cu^(2+)and Zn^(2+)at 1.0mg/L,which already or almost met their guideline values in drinking water,could still enhance NDMA formation with the promotion rates of 16.88% and 13.42%,respectively.Interestingly,both Cu^(2+)and Zn^(2+)could inhibit NDMA formation when their concentration was10 mg/L.Mechanism research showed that the promotion of the NDMA was mainly due to the interaction between the heavy metal ions and DMA.【Conclusion】Heavy metal ions Cu^(2+)and Zn^(2+)at relatively high concentrations can both promote NDMA formation in SGF through interacting with DMA.
出处
《广西科学》
CAS
2016年第1期67-71,共5页
Guangxi Sciences
基金
北京市自然科学基金项目(8132015)资助
