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The pH value is a very commonly used in environmental monitoring, biological processes , biomedical measurement parameters . Fiber fluorescent nano- glass electrode pH sensor proved the advantages , but in recent years it has become a very popular analysis tools . Optical pH sensor is most important is posed by the pH - sensitive pH-sensitive probe . This article uses the inverting micro-emulsion synthesis of a new type of fluorescent silica nano - pH sensor in square acid as a pH - sensitive material through the carboxyl surface modification . In order to prevent the the mutual aggregation between the nanoparticles and enhance the water solubility of the pH sensor in the surface of the nanoparticles , a carboxyl group- modified processing . This pH sensor for pH good fluorescence response and a linear response between 3.01 ~ 5.72 , and the pH value . A variety of alkali metals, alkaline earth metals and transition metal ions ( Li , Na , K , Rb , Cs , Mg2 , Ca2 , SR2 Al3 , V5 , CR3 , CR6, Mn2 , Fe2 , Fe3 , Co2 , Ni3 , Cu2 , Zn2 , As3 , Se4 Mo6, Ag, Cd2, La3, Er3, Ir3, Hg, Hg2, Pb2) its interference will not occur . Moreover , the buffer system also has little affect on the pH sensor used herein, the deionized water, mixed acid ( boric acid, phosphoric acid , acetic acid ) - sodium hydroxide , Tris - HCl , phosphate ( KH2PO4 - Na2HPO4 ) four buffer system . It varies with temperature at 50 ° C or less is not stable and can be maintained in a long time . The analog sample testing also showed that this pH nanosensors good prospect of application in biology and biomedical . In addition, the pH nanosensors for enzymatic hydrolysis process monitoring , to obtain the desired results .
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