Method for detecting cadmium content in tea based on up-conversion and dithizone-specific system

A detection method and specific technology are applied in the field of detection of cadmium content in tea based on an up-conversion and dithizone specific system, and can solve the problems of inability to meet the real-time and rapid detection of cadmium content, expensive instruments and equipment, long detection time, and the like, Eliminate the interference of background fluorescence and other ions, wide linear detection range, high detection accuracy and high sensitivity

Inactive Publication Date: 2019-09-27
JIANGSU UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0003] The traditional detection method of cadmium content is atomic absorption spectrometry. Although the detection accuracy is high, the equipment is expensive, the

Method used

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  • Method for detecting cadmium content in tea based on up-conversion and dithizone-specific system
  • Method for detecting cadmium content in tea based on up-conversion and dithizone-specific system
  • Method for detecting cadmium content in tea based on up-conversion and dithizone-specific system

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Embodiment 1

[0028] The invention discloses a method for detecting cadmium content in tea based on an upconversion and dithizone specific system. The specific steps are:

[0029] Step 1, preparation of up-conversion nanomaterials: Weigh 0.087g of yttrium chloride hexahydrate, 0.047g of ytterbium chloride hexahydrate, 0.005g of holmium chloride hexahydrate and 0.066g of gadolinium chloride hexahydrate, and ultrasonically dissolve them in 3mL of methanol for 5min , transferred to a 250mL three-necked flask, and added 4.5mL oleic acid and 10.5mL 1-octadecene; under the protection of argon, heated to 160°C for the first time, magnetically stirred for 30min, and cooled to room temperature; Add 15mL of methanol solution containing 0.221g of ammonium fluoride and 0.45g of sodium hydroxide dropwise to the solution, react in a water bath at 50°C for 30min for the first time, and react in a water bath at 80°C for 40min in the second time to completely volatilize the methanol in the solution; Under t...

Embodiment 2

[0038] The invention discloses a method for detecting cadmium content in tea based on an upconversion and dithizone specific system. The specific steps are:

[0039] Step 1, preparation of up-conversion nanomaterials: Weigh 0.087g of yttrium chloride hexahydrate, 0.047g of ytterbium chloride hexahydrate, 0.005g of holmium chloride hexahydrate and 0.066g of gadolinium chloride hexahydrate, and ultrasonically dissolve them in 3mL of methanol for 10min , transferred to a 250mL three-necked flask, added 4.5mL oleic acid and 10.5mL 1-octadecene; under the protection of argon, heated to 150°C for the first time, magnetic stirring for 30min, cooled to room temperature; Add 15mL of methanol solution containing 0.221g of ammonium fluoride and 0.45g of sodium hydroxide dropwise to the solution, react in a water bath at 45°C for 30min for the first time, and react in a water bath at 85°C for 40min in the second time to completely volatilize the methanol in the solution; Under the protect...

Embodiment 3

[0045] The invention discloses a method for detecting cadmium content in tea based on an upconversion and dithizone specific system. The specific steps are:

[0046] Step 1, preparation of up-conversion nanomaterials: Weigh 0.087g of yttrium chloride hexahydrate, 0.047g of ytterbium chloride hexahydrate, 0.005g of holmium chloride hexahydrate and 0.066g of gadolinium chloride hexahydrate, and ultrasonically dissolve them in 3mL of methanol for 8min , transferred to a 250mL three-necked flask, added 4.5mL oleic acid and 10.5mL 1-octadecene; under argon protection, heated to 170°C for the first time, magnetically stirred for 30min, cooled to room temperature; Add 15 mL of methanol solution containing 0.221 g of ammonium fluoride and 0.45 g of sodium hydroxide dropwise to the solution, react in the first water bath at 55 ° C for 30 min, and in the second water bath at 75 ° C for 40 min, so that the methanol in the solution is completely volatilized; then, in Under the protection ...

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Abstract

The invention belongs to the technical field of food safety detection, and constructs a method for detecting cadmium content in tea based on up-conversion and a dithizone-specific system. The method comprises the following specific steps of taking yttrium chloride hexahydrate, ytterbium chloride hexahydrate, holmium chloride hexahydrate, gadolinium chloride hexahydrate, oleic acid, 1-octadecene, ammonium fluoride and methanol mixture of sodium hydroxide as raw materials to prepare up-conversion nanomaterials; adding ethanol, ammonium hydroxide, tetraethyl orthosilicate and 3-aminopropyltriethoxysilane to obtain amino functionalized up-conversion nanomaterials, mixing the amino functionalized up-conversion nanomaterials with a dithizone solution to obtain a specificity detection system, determining the characteristic value of a fluorescence intensity signal of the detection solution after adding the cadmium ion solution as the ordinate, and establishing a cadmium content detection standard curve by using the cadmium ion concentration as the abscissa to determine the cadmium content in the tea to be tested. The method provided by the invention realizes the high sensitivity and specificity detection of cadmium in the tea by constructing a steady-state specific cadmium ion fluorescence detection system, and has a wide linear detection range, low detection limit and good application prospect.

Description

technical field [0001] The invention belongs to the technical field of food safety detection, and in particular relates to a method for detecting cadmium content in tea based on an up-conversion and dithizone specific system. Background technique [0002] my country is a big tea-producing country, and tea is a traditional export agricultural product of our country. Strengthening the control of tea quality and safety is an important measure to ensure the safety of drinking tea, and it is also conducive to improving the competitiveness of tea products in the international market. With the rapid development of modern industry, water, air, and soil have been polluted by heavy metals to varying degrees. Tea trees can absorb heavy metals in the soil during their growth and development, resulting in excessive heavy metal content in tea leaves, such as cadmium, mercury, lead and other heavy metals. After cadmium is absorbed by the human body, it can form a cadmium-sulfur protein in...

Claims

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Application Information

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IPC IPC(8): G01N33/58G01N21/64
CPCG01N21/643G01N33/582G01N2021/6417G01N2021/6432
Inventor 欧阳琴陈全胜李欢欢陈敏郭志明
Owner JIANGSU UNIV
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