A doped porous carbon-silver nanoparticle for visual and rapid detection of mercury ions

Abstract

The invention relates to porous carbon doped silver nanoparticles DHPC@CS-AgNPs capable of visually and rapidly detecting mercury ions. The porous carbon doped silver nanoparticles DHPC@CS-AgNPs are prepared by taking organic glass latex as a template, sucrose and polypyrrole as carbon sources and sulfuric acid as a catalyst, carrying out in-situ self-assembling, drying and carbonization to obtain macroporous carbon; carrying out alkali liquid treatment to obtain the porous carbon, taking sodium borohydride as a reducing agent in a porous carbon-chitosan ultrasonic dispersion solution, and dropwise adding AgNO3. According to the particles provided by the invention, a preparation method of the particles is simple, reaction conditions are moderate and the dispersion stability is good; the particles coexist with Hg<2+> so as to have high mimetic oxidase activity, and can be used for rapidly, sensitively and highly selectively detecting trace Hg<2+> in foods and environment samples through a colorimetric manner. A detection method is visible, is simple in instruments and equipment, is rapid and sensitive and is high in selectivity, so that the detection method is suitable for being popularized and applied to primary laboratories can be widely applied to visible and rapid analysis of the trace Hg<2+> in the foods and the environment samples.

Description

technical field [0001] The invention belongs to the technical field of materials, and relates to a doped porous carbon-silver nanoparticle, in particular to a porous carbon-doped silver nanoparticle which coexists with mercury ions and has high oxidation-mimicking enzyme activity, and can be directly applied to food and environmental samples Visual rapid detection of trace mercury ions. Background technique [0002] Mercury is a heavy metal that is widely used. Common mercury vapor lamps, batteries, mercury thermometers, paints, pesticides, insecticides, dental amalgams, medicines for scabies, and raw materials for malignant sores contain mercury to varying degrees. Improper handling of these products during production and after use can easily cause mercury pollution. Mercury severely damages the central nervous system, manifesting the following symptoms: tremors, neuropsychiatric symptoms, toxic nephropathy, and stomatitis. In addition, it will also affect the human nervo...

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Problems solved by technology

At present, there are many mercury colorimetric sensors based on nanomaterials. For example, Liu et al. based on single-stranded DNA modified gold nanoparticles agglomerated in the presence of mercury ions, and the color of the solution changed from red to blue. A method for detecting trace mercury in water was established. The method of ions has a detection limit of 250nM (Liu C W, et al.Chem.Commun., 2008, 2242-2244), but the selectivity and sensitivity of the method are low, and the reagent chloroauric acid used is expensive

The complex formed by Li et al. based on T base-rich G-tetrad DNase and porphyrin iron (hemin) has horseradish peroxidase-like properties and can catalyze ABTS and H 2 o 2 The reaction produces a blue-green product. When mercury ions exist in the system, G-tetrad DNase specifically combines with mercury ions to form T-Hg 2+ -T stabilizes the structure so that porphyrin iron (hemin) cannot catalyze the oxidation of H by ABTS 2 o 2 Thereby realize the colorimetric detection to mercury (Li T, et al., Chem.Commun., 2009, 3551-3553), the selectivity of the method is high, the G-tetrad DNase that is rich in T base, the preparation is complicated ,high cost

Synthesis of a magnetic composite material Au@Fe by Zhang et al. 3 o 4 @GO, the material is in Hg 2+ Can catalyze TMB and H when present 2 o 2 The reaction produces a blue product, Hg 2+ Detection limit reaches 0.15nM (Zhang S, et al.Nanoscale, 2015,45 (7): 8495-8502), this method sensitivity and selectivity are high, but used material and reagent relate to chloroauric acid, graphene, cost High, which limits its popularization and application

For reducing cost, people such as Annadhasan M adopts tyrosine as stabilizer and reducing agent, the silver nanoparticle of synthesis, colorimetric detection mercury ion, detection limit 16nM (Annadhasan M, et al.ACS Sustainable Chemistry & Engineering, 2014,2 (4 ): 887-896.); Shen Z et al. used microwave radiation to synthesize silver nanoparticles in an alkaline solution of lignin, and colorimetrically detected mercury ions with a detection limit of 23nM (Shen Z, et al.ACS Applied Materials & Interfaces, 2014,6 (18):16147-16155.), but the selectivity of the above method is not high enough

Based on the fact that nano-manganese oxide has horseradish peroxidase-like properties, it can catalyze TMB and H 2 o 2 The reaction produces a blue product, and glutathione can prevent nano-manganese oxide from catalyzing TMB and H 2 o 2 The reaction makes the blue color disappear. When mercury ions exist, the catalytic activity of nano-manganese oxide can be restored due to the coordination of mercury ions and glutathione, so that the blue color of the solution can be restored, thereby constructing a mercury ion detection method with a detection limit of 80nM (Yang H, et al.Angew Chem Int Ed,2009,48(13):2308.), but this method is not simple enough, the sensitivity is not high enough, and the H used in the method 2 o 2 Unstable, affecting the reproducibility and accuracy of the results

Xu Xiufang used trisodium citrate as a stabilizer, NaBO 4 Silver nanoparticles were prepared as a reducing agent. The prepared silver nanoparticles can catalyze dissolved oxygen in the solution to oxidize TMB to produce blue products in the presence of mercury ions. A colorimetric detection method for trace mercury was established with a detection limit of 28nM (Xu Xiufang. Nanomaterials mimic enzymes and their analytical applications [D]. Jiangsu: Jiangnan University, 2014.), this method avoids the use of unstable and destructive hydrogen peroxide, but the sensitivity and selectivity need to be further improved

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