The Preparation Of Cyclodextrin Functionalized Glod Nanoparticles And The Detection Of Nitrite Ions

As an essential ingredient of fertilizer and food additives,nitrite widely exists in the environment.When inteacting with proteins,nitrite can produce the carcinogenic N-nitrosamines.Moreover,it is the atmospheric pollution for leading to photochemical smog,acid rain and ozone layer depletion.Therefore,the presence of nitrite in water will result in great harm to human,so the rapidly detection of the trace concentration of nitrite in water body is extremely essential.Fluorescence method becomes the effective method for the detection of nitrite ions?NO₂^-?due to high sensitivity,good selectivity,low detection limit and simple detection conditions.Thus,the design of the fluorescent sensor is of great significance.In this paper,two methods of the preparation of fluorescent probe NR-?-CD@AuNPs are discussed.In the first preparation method,the fluorescent probe NR-?-CD@AuNPs is preparated for three steps.?1?Under the condition of microwave,AuNPs with 10-nm diameters are prepared using citrate as reducing agent.?2?AuNPs are modified by per-6-mercapto-beta-cyclodextrin?SH-?-CD?for the fabrication of SH-?-CD functionalized AuNPs??-CD@AuNPs?.?3?The identification unit NR enter into the catives of?-CD@AuNPs forming fluorescent probe NR-?-CD@AuNPs.In the second preparation method,the fluorescent probe NR-?-CD@AuNPs is synthesized for two steps.?1?Under the condition of microwave,using citrate as reducing agent and stabilizer to fabricate?-CD@AuNPs with 10 nm diameters.?2?The identification unit NR enter into the catives of?-CD@AuNPs forming fluorescent probe NR-?-CD@AuNPs.Through the contrast,the second method is proved to be not only simple.When detecting NO₂^-,the linear relationship is obtained between the intensity of fluorescence and the concentration of[NO₂^-]in the range of 0.05-0.85?g/mL.The detection limit is as low as 4.25×10^-3?g/mL.Compared with the first method,the second method is has a smaller detection limit,and succeeds in the trace detection of NO₂^-in water.What'more,the color is changed from light purple to light blue and observed by naked eyes when[NO₂^-]was about 0.20?g/mL.It is expected to further development for sensitive visual inspection technolog.The fluorescent probes is not only equipped with high sensitivity,but also with anti-interference ability when testing NO₂^-in local waters,the recovery rate is above 99.0-102.0%.