一种用于水中次氯酸根检测的高选择性裸眼比色探针

A Highly Selective Colorimetric Naked-Eye Probe for Hypochlorite Detection in Water

实时检测和监测水中的次氯酸根离子(ClO-)是极富挑战性的研究工作。报道了一种光学性能优异、“裸眼”可分辨的比色型探针分子(PAH)。首先利用高分辨质谱,核磁共振氢谱和核磁共振碳谱等方法对目标探针分子(PAH)的结构进行表征。随后,利用紫外-可见吸收光谱考察了不同pH缓冲溶液条件下探针PAH与次氯酸根离子的相互作用。结果显示,水溶性的探针分子PAH在pH值为2.0~5.0的磷酸盐缓冲液中为黄色溶液,其最大吸收峰在424 nm处;在pH值为6.0~12.0的磷酸盐缓冲液中PAH为紫色溶液,最大吸收峰在532 nm处;在不同pH缓冲液体系中分别加入次氯酸根离子,肉眼可观察PAH溶液颜色褪去,紫外-可见吸收光谱显示在424 nm处的特征吸收峰逐渐降低并在532 nm处出现新的吸收峰,溶液颜色从黄色到紫色然后到无色,特征峰明显消失。进一步优化了实验条件,发现在pH 5.0的磷酸盐缓冲液中,探针分子PAH对ClO-离子具有特定的选择性和灵敏度,并且具有较低检出限等优点;在优化的条件下,探究了常见的金属离子、阴离子等共存条件下,对探针分子PAH检测次氯酸根离子的干扰影响。实验发现,常见的金属离子(Li^(+),Co 2^(+),Cr 3^(+),K^(+),Cd 2^(+),Pb 2^(+),Ca 2^(+),Hg 2^(+),Ba 2^(+),Cu 2^(+),Mg 2^(+),Ni 2^(+),Zn^(2^(+)),Al 3^(+)和Fe 3^(+)),阴离子(NO-2,I-,AcO-,ClO-4,SO_(2)-4,CN-,Br-,CO_(2)-3和F-),活性氧(ROO·,·OH,H_(2)O_(2),·O-2,tBuOOH,tBuO·和^(1)O_(2)),和活性氮(ONOO-和NO·)等33种物质对探针分子检测ClO-离子的干扰较小。同时,探针PAH可以定量检测次氯酸根离子(y=1.58678-0.52451x,R^(2)=0.99852),检出限为5.39μmol·L^(-1)。此外,对水体系(84消毒剂和自来水)中的次氯酸根离子浓度进行分析,三次平行试验测得自来水中次氯酸根离子的平均浓度为7.96μmol·L^(-1),平均加标回收率高,表明探针PAH还可用于定量检测实际水体系中的次氯酸根离子。

The real-time detection and monitoring of hypochlorites(ClO-)in water is highly challenging.An excellent colorimetric“naked-eye”probe photoacid(PAH)was synthesized.PAH was comfirmed using High-Resolution Mass Spectrometry(HRMS),^(1)H NMR and ^(13)C NMR.The interaction between PAH and ClO-was investigated via UV-Vis absorption spectrophotometry under different pH conditions.The results indicated that PAH was completely soluble in water,PAH displayed a yellow solution in a phosphate buffer with a pH of 2.0 to 5.0,and the maximum absorption peak was at 424 nm.PAH displayed a purple solution in a phosphate buffer with a pH of 6.0~12.0,and the maximum absorption peak was at 532 nm.After adding ClO-to different pH systems,PAH discoloration and the UV-Vis absorption peak disappeared.The probe PAH exhibited specific selectivity and sensitivity for ClO-detection with a low detection limit in the pH 5.0 phosphate buffer.After PAH reacted with ClO-,the absorption peak of the probe at 424 nm gradually decreased,and a new absorption peak appeared at 532 nm.The probe displayed a vivid color-tunable process from yellow to purple then to colorless with a fast response time for ClO-detection.However,other common 33 substances such as metal ions(Li^(+),Co 2^(+),Cr 3^(+),K^(+),Cd 2^(+),Pb 2^(+),Ca 2^(+),Hg 2^(+),Ba 2^(+),Cu 2^(+),Mg 2^(+),Ni 2^(+),Zn^(2^(+)),Al 3^(+)and Fe 3^(+)),anions(NO-2,I-,AcO-,ClO-4,SO_(2)-4,CN-,Br-,CO_(2)-3 and F-),reactive oxygen species(ROO·,·OH,H_(2)O_(2),·O-2,t BuOOH,t BuO·and 1O_(2))and reactive nitrogen species(ONOO-and NO·),did not cause changes in the color of the probe solution and the UV-Vis absorption spectrum.The above species had only a limited effect on detecting the ClO-anion.When they coexisted with ClO-,the probe also showed a similar solution color change,and the absorption peak at 424 nm disappeared.Meanwhile,the probe PAH could quantitatively detect the content of ClO-with a detection limit of 5.39μmol·L^(-1)(y=1.58678-0.52451x,R^(2)=0.99852).Furthermore,ClO-concentration in the water system(84 disinfectant and tap water)was analyzed.The average concentration of ClO-ion in the tap water measured by three parallel tests was 7.96μmol·L^(-1) with high recoveries rate.It showed that PAH could also be utilized to detect ClO-quantitatively in real water systems.