Method for visual detection of pesticide residues in quantum dot fluorescence turn-off/turn-on mode

A technology of pesticide residues and quantum dots, applied in the field of analysis of agricultural chemicals, can solve problems such as impact, achieve good selectivity, omit pretreatment process, and simple operation

Inactive Publication Date: 2010-09-22
HEFEI INSTITUTES OF PHYSICAL SCIENCE - CHINESE ACAD OF SCI
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  • Abstract
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  • Claims
  • Application Information

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Problems solved by technology

However, most fluorescence analysis detection is based on the turn-off fluorescence quenching process, which is easily aff...

Method used

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  • Method for visual detection of pesticide residues in quantum dot fluorescence turn-off/turn-on mode
  • Method for visual detection of pesticide residues in quantum dot fluorescence turn-off/turn-on mode
  • Method for visual detection of pesticide residues in quantum dot fluorescence turn-off/turn-on mode

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Embodiment 1

[0028] The detection of embodiment 1 chlorpyrifos

[0029] 1. Preparation of cadmium telluride quantum dots

[0030] 0.2284g cadmium chloride (CdCl 2 2.5H 2 O) Add to 250mL deoxygenated ultrapure water, then add 0.21mL mercaptopropionic acid, then adjust its pH value to 11.2 with 1M NaOH solution to form a solution containing mercapto compounds and cadmium ions. On the other hand, take 0.0319g of tellurium powder and 0.05g of sodium borohydride in 2mL of ultrapure water, and react in an ice bath for more than 8 hours under the protection of nitrogen. Inject 5mL of 0.5M dilute sulfuric acid solution into the resulting sodium hydride telluride solution. will generate H 2 Put all the Te into the cadmium ion solution, stir for 20 minutes, and then heat to reflux. By controlling the reflux time, an aqueous solution of cadmium telluride quantum dots with stable mercaptopropionic acid and a fluorescent emission peak at 490-680 nm can be obtained. The prepared original solution ...

Embodiment 2

[0035] The detection of embodiment 2 methyl parathion

[0036] 1. Preparation of cadmium selenide quantum dots

[0037] 0.2575g cadmium perchlorate (Cd(ClO 4 ) 2 ·6H 2 O) Add to 250mL deoxygenated ultrapure water, then add 0.175mL mercaptoacetic acid, then adjust its pH value to 9 with 1M NaOH solution to form a solution containing mercapto compounds and cadmium ions. On the other hand, take 0.0145g of selenium powder and 0.05g of sodium borohydride in 2mL of ultrapure water, under the protection of nitrogen, react in an ice bath for more than 8 hours. Inject 5mL of 0.5M dilute sulfuric acid solution into the resulting sodium selenide solution. will generate H 2Pass all of Se into the above-mentioned cadmium ion solution, stir for 20 minutes, and then heat to reflux. By controlling the reflux time, an aqueous solution of cadmium selenide quantum dots with stable thioglycolic acid and a fluorescence emission peak at 500 nm can be obtained. The prepared original solution ...

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Abstract

The invention discloses a method for the visual detection of pesticide residues in a quantum dot fluorescence turn-off/turn-on mode. The method comprises the steps of preparation of cadmium quantum dots and turn-off and turn-on of the fluorescence, wherein the step of the turn-off of the fluorescence comprises the specific steps of adding the solution of cadmium quantum dots into the alkali liquor at the concentration of 0.01 to 1M and then adding dithizone to turn off the bright green fluorescence; the step of turn-on of the fluorescence comprises the specific step of adding the solution of a sample to be detected into the solution of the quantum dots with turned-off fluorescence to turn on the bright green fluorescence; quantitative detection is realized according to the linear relationship between the sample concentration and the fluorescence turn-on intensity; and the cadmium quantum dots are the quantum dots emitting green fluorescence of any one of CdTe, CdTe/CdS, CdSe, CdSe/CdS or CdS. The method has the advantages of avoiding a large-scale instrument to a certain extent and effectively avoiding the interference from other impurities in the sample, along with simple operation, convenience and fastness.

Description

1. Technical field [0001] The invention relates to an analysis method of agricultural chemicals, in particular to an analysis and detection method of trace amount of agricultural chemicals, in particular to a method for visually detecting pesticide residues in quantum dot fluorescence off-on mode. 2. Background technology [0002] Quantum dots are mainly semiconductor nanoparticles composed of II-VI elements or III-V elements. As a fluorescent probe with potential application value, compared with traditional organic fluorescent dyes, the photoluminescence properties of quantum dots are very superior: wide excitation range, narrow and symmetrical emission peak, large Stokes shift, quantum production High efficiency, strong brightness, high light stability. In recent years, the fluorescent properties of quantum dots have been widely used to detect various ions, small organic molecules, and biological macromolecules. [0003] With the widespread use of pesticides in agricultu...

Claims

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Application Information

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IPC IPC(8): G01N21/64
Inventor 张忠平张奎王素华刘变化王振洋关贵俭
Owner HEFEI INSTITUTES OF PHYSICAL SCIENCE - CHINESE ACAD OF SCI
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