Wawryk Nicholas J P, Huang Guang, Craven Caley, Qiu Junlang, Jmaiff Blackstock Lindsay K, Li Xing-Fang
Division of Analytical and Environmental Toxicology, Department of Laboratory Medicine and Pathology, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, AB T6G 2G3, Canada.
Department of Hygiene Analysis and Detection, School of Public Health, Nanjing Medical University, 101 Longmian Avenue, Nanjing, Jiangsu 211166, P.R. China.
Environ Sci Technol. 2023 Jan 10;57(3):1332-41. doi: 10.1021/acs.est.2c07156.
Aspartame (APM), a dipeptide of aspartic acid (ASP) and phenylalanine (PHE), is a widely used artificial sweetener in beverages. It is unclear whether residual chlorine in tap water can react with APM to form disinfection byproducts (DBPs). Therefore, we investigated the formation of DBPs from the reaction of APM with residual chlorine in authentic tap water. APM and a commercial sweetener (CS) packet containing APM were studied under authentic and simulated tap water conditions. Eight chlorinated products of APM were detected using solid-phase extraction (SPE) and high performance liquid chromatography quadrupole time-of-flight mass spectrometry (HPLC-QTOF-MS). These new chloro-products were tentatively identified based on accurate masses, isotopic patterns of Cl, and MS/MS spectra. Furthermore, we identified APM as a precursor to 2,6-dichloro-1,4-benzoquinone (DCBQ). DCBQ significantly increased to 2.3-12 ng/L with the addition of APM or CS in tap waters collected from different locations compared to 1.4-1.8 ng/L in the same tap water samples without sweetener. DCBQ and two of the chlorinated transformation products were identified in cold prepared tea containing APM. DCBQ formation was eliminated when the residual chlorine in tap water was reduced by ascorbic acid or boiling prior to the addition of APM or CS. This study found that eight new DBPs and DCBQ were produced by the reactions of residual chlorine with APM and CS. These findings show an unintended exposure source of emerging DBPs via APM sweetened beverages.
阿斯巴甜（APM）是天冬氨酸（ASP）和苯丙氨酸（PHE）的二肽，是一种在饮料中广泛使用的人工甜味剂。尚不清楚自来水中的余氯是否会与APM反应形成消毒副产物（DBPs）。因此，我们研究了在真实自来水中APM与余氯反应形成DBPs的情况。在真实和模拟自来水条件下研究了APM以及含有APM的商业甜味剂（CS）包。使用固相萃取（SPE）和高效液相色谱四极杆飞行时间质谱（HPLC-QTOF-MS）检测到了APM的八种氯化产物。这些新的氯代产物根据精确质量、Cl的同位素模式和MS/MS光谱进行了初步鉴定。此外，我们确定APM是2,6-二氯-1,4-苯醌（DCBQ）的前体。与未添加甜味剂的相同自来水样品中1.4-1.8 ng/L相比，在从不同地点采集的自来水中添加APM或CS后，DCBQ显著增加至2.3-12 ng/L。在含有APM的冷泡茶中鉴定出了DCBQ和两种氯化转化产物。在添加APM或CS之前，通过用抗坏血酸或煮沸降低自来水中的余氯时，DCBQ的形成被消除。本研究发现，余氯与APM和CS反应产生了八种新的DBPs和DCBQ。这些发现表明通过含APM的甜味饮料存在新兴DBPs的意外暴露源。
