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在pH 3.2~5.7的HAc-Na Ac缓冲溶液中,Ag+与Cl-反应形成Ag Cl.当Ag+适当过量时,Ag Cl与Ag+结合形成[Ag Cl·Ag]+阳离子,它能进一步借静电引力和疏水作用力与曙红B(二溴二硝基荧光素)、曙红Y(四溴荧光素)、乙基曙红(四溴荧光素乙酯)、荧光桃红(四氯四溴荧光素)和虎红(四氯四碘荧光素)等多取代荧光素阴离子(HL-)反应生成离子缔合物[(Ag Cl·Ag)HL].该疏水性离子缔合物可在水相的挤压作用和范德华力的作用下,进一步聚集形成平均粒径约为20 nm的纳米微粒.此时仅引起吸收光谱和荧光光谱的微小变化,但能导致共振瑞利散射(RRS)以及倍频散射(FDS)和二级散射(SOS)等共振非线性散射(RNLS)的显著增强,其中以曙红B体系最灵敏.曙红B体系的最大RRS、FDS和SOS波长分别位于315 nm、350 nm和560 nm处,3种散射增强(ΔIRRS、ΔIFDS和ΔISOS)在一定范围内均与氯离子浓度成正比,均可用于氯离子的测定.其中以FDS法最灵敏,RRS法次之.3种方法(RRS、FDS和SOS法)对于氯离子的检测,曙红B体系的线性范围分别是0.005~1.22μg/m L、0.004~2.92μg/m L和0.01~1.94μg/m L,检出限分别为1.50 ng/m L、1.20 ng/m L和3.90 ng/m L.本文研究了[(Ag Cl·Ag)HL]n纳米微粒的形成、散射强度的提高、适宜的反应条件及影响因素,考察了共存物质的影响,表明方法具有良好的选择性.据此利用上述反应,发展一种RRS、SOS和FDS技术高灵敏、高选择性和简便、快速测定环境空气和废气中HCl及环境水样中氯化物的新方法.文中还对反应机理和散射增强的原因进行了讨论.
In HAc-Na Ac buffer solution at pH 3.2-5.7, Ag + reacts with Cl- to form AgCl. When Ag + is in excess, AgCl and Ag + combine to form [AgCl.Ag] + cations, which can be further electrostatically attracted And hydrophobic interaction with Eosin B (dibromonitrophenyl fluorescein), Eosin Y (tetrabromofluorescein), ethyl eosin (tetrabromofluorescein ethyl ester), fluorescent pink (tetrachlorobrofluorescin ) And tiger red (tetrachlorotetraosine fluorescein) and other multi-substituted fluorescein anion (HL-) react to form ion association [(Ag Cl · Ag) HL] The hydrophobic ion association can be in the aqueous phase Squeezing and van der Waals forces, further aggregating to form nanoparticles with an average particle size of about 20 nm, at which point only minor changes in absorption and fluorescence spectra are caused, but results in Resonance Rayleigh Scattering (RRS) and frequency doubling (RDS), scattering (FDS) and secondary scattering (SOS). The maximum RRS, FDS and SOS wavelengths of eosin B system were at 315 nm and 350 respectively The three kinds of scattering enhancement (ΔIRRS, ΔIFDS and ΔISOS) at both nm and 560 nm are in direct proportion to the chloride ion concentration within a certain range and can be used for the determination of chloride ion The FDS method was the most sensitive and the RRS method was second.The three methods (RRS, FDS and SOS method) For the detection of chloride ion, the linear range of Eosin B system was 0.005 ~ 1.22μg / m L, 0.004 ~ 2.92μg / m L and 0.01-1.94μg / ml, the detection limits were 1.50 ng / m L, 1.20 ng / m L and 3.90 ng / m L. The formation of [(AgCl · Ag) HL] n nanoparticles , The improvement of the scattering intensity, the suitable reaction conditions and the influencing factors, and the influence of the coexisting substances were investigated, indicating that the method has good selectivity. Based on the above reaction, an RRS, SOS and FDS technique was developed to be highly sensitive and highly selective And a simple and rapid method for the determination of chloride in environmental air and exhaust HCl and environmental water samples.The reaction mechanism and the reasons for the enhanced scattering are also discussed.