Construction Of Phosphonates Fluorescent Probe And Its Response Mechanism

The detection methods of phosphonates established in the past mainly consists of high performance liquid chromatography,mass spectrometry and their combined technology,etc.Most of these methods have unavoidable disadvantages such as time-consuming,high cost,and complicated pre-treatment process.As a new chemical detection system,fluorescence sensing technology has attracted the attention of researchers due to its short response time,high sensitivity,and in-situ detection.At present,fluorescence sensing technology has been widely used in biological imaging,chemical sensing and other fields.In this paper,three fluorescent sensing platforms that can be used for single or multiple phosphonates were constructed with the help of fluorescent sensing technology.We systematically discussed the changes of fluorescence intensity and sensing mechanism,and studied the selectivity and anti-interference ability of the prepared fluorescent probes.The recovery rate and relative standard deviation of the fluorescent probe in the real samples were further calculated at the same time.The research content of this paper can be divided into the following three parts:（1）The hydrothermal synthesis method was adopted to prepare the carbon quantum dots（CQDs）with strong blue fluorescence.The complexes(Fe³⁺-CQDs)with weaker fluorescence was formed by fully complexing the ferric ion(Fe³⁺)with CQDs.The prepared fluorescent probe has a good linear relationship with HEDP in the concentration range of 0-70μM,and the limit of detection（LOD）is 1.60μM.The probe shows excellent anti-interference ability and high selectivity in the sensing,which has been used in the detection of real samples,and the results were satisfactory.（2）Quercetin-Zn²⁺complex（Zn QC）was prepared in absolute ethanol using natural extracts-quercetin as raw materials and zinc ion(Zn²⁺)as fluorescent modifier.Compared with free quercetin ethanol solution,the fluorescence intensity of Zn QC was significantly increased by Zn²⁺.And the addition of amino trimethylene phosphonic acid（ATMP）,1-hydroxyethylene-1,1-diphosphonic acid（HEDP）,diethylene triamine pentamethylene phosphonic acid（DTPMPA）can effectively quench the fluorescence of the system.Therefore,the fluorescent complex can be used as an effective fluorescent probe for the comparative detection of these three phosphonates.Within a certain linear range,the quenching efficiency（Q_e）of the fluorescence sensor for ATMP,HEDP and DTPMPA was 82.5%,75.4%and 85.2%,respectively,and the LODs were as low as 0.223,0.205 and 0.152μM.In the detection of real samples,the probe obtained a good sample recovery（97%-103%）（3）The light-emitting metal organic framework（Cu-MOF-74）was synthesized by hydrothermal synthesis using 2,5-dihydroxyterephthalic acid as raw material and copper nitrate trihydrate as metal source.The synthesized material can be used as an“turn-on”fluorescence sensor for the specific sensing of ATMP.Under the optimal conditions,the fluorescence intensity of Cu-MOF-74 can be enhanced by ATMP（10μΜ）to 3.43 times,and the LOD was 0.844μΜ.The fluorescent probe exhibited excellent anti-interference ability and high selectivity,which indicated that the Cu-MOF-74 solution can be used for the highly sensitive and quantitative detection of ATMP.