CN112461775A - Food nitrate and nitrite detection and analysis system and detection and analysis method - Google Patents
Food nitrate and nitrite detection and analysis system and detection and analysis method Download PDFInfo
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- CN112461775A CN112461775A CN202011366372.8A CN202011366372A CN112461775A CN 112461775 A CN112461775 A CN 112461775A CN 202011366372 A CN202011366372 A CN 202011366372A CN 112461775 A CN112461775 A CN 112461775A
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N21/00—Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light
- G01N21/17—Systems in which incident light is modified in accordance with the properties of the material investigated
- G01N21/25—Colour; Spectral properties, i.e. comparison of effect of material on the light at two or more different wavelengths or wavelength bands
- G01N21/31—Investigating relative effect of material at wavelengths characteristic of specific elements or molecules, e.g. atomic absorption spectrometry
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N1/00—Sampling; Preparing specimens for investigation
- G01N1/28—Preparing specimens for investigation including physical details of (bio-)chemical methods covered elsewhere, e.g. G01N33/50, C12Q
- G01N1/34—Purifying; Cleaning
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N21/00—Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light
- G01N21/75—Systems in which material is subjected to a chemical reaction, the progress or the result of the reaction being investigated
- G01N21/77—Systems in which material is subjected to a chemical reaction, the progress or the result of the reaction being investigated by observing the effect on a chemical indicator
- G01N21/78—Systems in which material is subjected to a chemical reaction, the progress or the result of the reaction being investigated by observing the effect on a chemical indicator producing a change of colour
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Abstract
A food nitrate and nitrite detection and analysis system and method comprises: placing the extracted food sample extracting solution in a sample pool; the cadmium column tube reduces nitrate in the sample extracting solution into nitrite; the measuring tank is used for detecting the content of nitrite in the food sample extracting solution introduced into the measuring tank; the data processing module determines the content of nitrate and nitrite in the food sample extracting solution according to the detection result of the measuring cell; the optimized arrangement of the cadmium column tube reduces the influence caused by accumulation of cadmium particles, and improves the detection efficiency and the detection quality.
Description
Technical Field
The invention relates to a food safety detection and analysis system, in particular to a food nitrate and nitrite detection and analysis system.
Background
Nitrate and nitrite are naturally existing ions, the use of a large amount of nitrogen fertilizer in agriculture and industrial wastewater, domestic sewage, garbage and the like are main causes of soil and water nitrate pollution in many areas, and further influence human life. In general, nitrate and nitrite are permitted in many countries as preservatives and color formers in food production processes, but the amounts are severely limited.
If the food is improperly preserved, the excessive nitrate added into the food can generate a certain chemical reaction with bacteria, so that nitrite is formed. In addition, the use of the nitrite can improve the color and luster degree of the food and make the mouthfeel better. After the nitrite enters the human body, the oxygen carrying capacity of hemoglobin in the human body is reduced, human tissues are anoxic, and peripheral blood vessels are expanded. In general, acute nitrite poisoning usually results in people who eat it as salt by mistake, causing mouth, tongue and finger tip cyanosis, dyspnea, nausea and vomiting.
Therefore, the research on the detection and monitoring analysis method of the residual nitrate/nitrite harmful substance in the food in the production, storage, processing and circulation processes provides scientific, accurate, rapid, timely and fair inspection data and means, controls the food with poor safety and quality to be sold on the market, and is vital to the protection of the benefits and health of consumers.
The cadmium column reduction method is a method for measuring nitrate and nitrite, the nitrate is reduced into nitrite, the nitrite reacts with a coupling reagent to form a colored compound, the content of the nitrite is determined by spectrophotometric colorimetry, and the content of the nitrite in a reduced sample is calculated, so that the content of the nitrate and the nitrite in food can be obtained. In the cadmium column reduction method, after a cadmium column is used for a period of time, cadmium particles are reduced due to oxidation, so that the cadmium particles are densely stacked, the flow rate of a water sample is reduced or the water sample is cut off, and the detection quality is influenced.
Disclosure of Invention
The invention provides a detection and analysis system and a detection and analysis method for food nitrate and nitrite, which can reduce the influence caused by cadmium particle accumulation.
As part of the present invention, there is provided a food nitrate and nitrite detection and analysis system comprising: a sample cell for placing the extracted food sample extract; the cadmium column tube is used for reducing nitrate in the sample extracting solution into nitrite; the measuring tank is used for detecting the content of nitrite in the food sample extracting solution introduced into the measuring tank; the data processing module is used for determining the content of nitrate and nitrite in the food sample extracting solution according to the detection result of the measuring pool; the cadmium column tube comprises a plurality of vertical tubes and horizontal tubes, one end of each horizontal tube is connected with the side surface of the lower end of the vertical tube above the horizontal tube, and the other end of each horizontal tube is connected with the side surface of the upper end of the vertical tube below the horizontal tube; a first separation net is arranged in the vertical pipe close to the bottom to form a first space on the separation net and a second space on the separation net, and cadmium particles are arranged in the first space; and a second separation net is arranged between the vertical pipe and the horizontal pipe.
Further, the mesh diameter of the first separation net is smaller than the diameter of the cadmium particles; the mesh diameter of the second separating net is smaller than that of the first separating net.
Further, the horizontal pipe is positioned higher than the second space.
Further, the sum of the effective lengths of the cadmium columns in the first space is more than 20 cm.
Further, the food includes vegetables, meat products, milks, and the like.
Further, the measuring cell measures the nitrite content by a naphthyl ethylenediamine hydrochloride spectrophotometry.
Furthermore, cadmium particles are not arranged in the horizontal tube.
Further, the device also comprises a regeneration reagent bottle which is used for inputting the cadmium column tube to recover the performance of cadmium particles in the cadmium column tube.
Furthermore, the particle size of the cadmium particles is 20-40 meshes.
Further, the particle size of the cadmium particles is larger than 25 meshes, the mesh diameter of the first separation net is 20 meshes, and the mesh diameter of the second separation net is 15 meshes.
Further, the device also comprises a reagent bottle which is used for inputting a reagent into the measuring cell to perform color reaction with the nitrite in the food sample extracting solution.
Further, the reagent comprises a naphthyl ethylenediamine hydrochloride solution, a sulfanilic acid solution and an ammonia chloride buffer solution.
Further, the device also comprises a waste liquid pool which receives waste liquid discharged by the measuring pool.
Furthermore, the sample cell is respectively connected with the cadmium column tube and the measuring cell through a three-way valve.
Further, the data processing module determines the nitrate content in the food sample extracting solution according to the nitrite content in the food sample extracting solution which does not pass through the cadmium column and the nitrite content in the food sample extracting solution which passes through the cadmium column.
As another part of the invention, the detection method of the food nitrate and nitrite detection and analysis system is provided, which comprises the following steps: (1) pretreating a sample to obtain a food sample extracting solution; (2) conveying the food sample extracting solution to a measuring pool through a first flow path, and detecting the nitrite content in the food sample extracting solution which does not pass through a cadmium column through the measuring pool; (3) conveying the sample extracting solution through a cadmium column tube by a second flow path, then feeding the sample extracting solution into a measuring pool, and detecting the nitrite content in the food sample extracting solution reduced by the cadmium column by the measuring pool; (4) the data processing module determines the nitrate content in the food sample extracting solution according to the nitrite content in the food sample extracting solution which does not pass through the cadmium column and the nitrite content in the food sample extracting solution which passes through the cadmium column.
Drawings
FIG. 1 is a schematic view of a food nitrate and nitrite detection and analysis system according to an embodiment of the present invention.
FIG. 2 is a schematic view of a cadmium column tube structure of a food nitrate and nitrite detection and analysis system according to an embodiment of the present invention.
Detailed Description
Reference will now be made in detail to embodiments of the present invention, examples of which are illustrated in the accompanying drawings, wherein like or similar reference numerals refer to the same or similar elements or elements having the same or similar function throughout. The embodiments described below with reference to the accompanying drawings are illustrative only for the purpose of explaining the present invention, and are not to be construed as limiting the present invention. Moreover, it is to be understood that the features of the various embodiments described herein are not mutually exclusive and can exist in a wide variety of combinations and permutations.
As shown in fig. 1, the food nitrate and nitrite detection and analysis system according to the embodiment of the present invention includes a sample cell 10, a three-way valve 20, an infusion pump (not shown), a cadmium column 30, a measurement cell 40, a plurality of reagent bottles 50, a waste liquid cell 60, and a data processing module (not shown).
The sample cell 10 is used for placing extracted food sample extracting solution, and the sample can be solid food or liquid food, such as vegetables, meat products, milk and the like. For liquid samples, they may be directly introduced into the sample cell 10, and for solid samples, after they have been pretreated, the extraction liquid is placed in the sample cell 10.
The sample cell 10 is connected to the cadmium column 30 and the measuring cell 40 through the three-way valve 20, the cadmium column 30 is connected to the measuring cell 40 through the on-off valve, and the infusion pump can be used to drive the flow of the sample extracting solution and the reagent in the measuring pipeline. The cadmium column tube 30 is used for reducing nitrate in the food sample extracting solution into nitrite; the measuring cell 40 is used for detecting the nitrite content in the food sample extract introduced into the measuring cell.
Referring to fig. 2, the cadmium column tube 30 includes a plurality of vertical tubes 31 and horizontal tubes 32, one end 321 of each horizontal tube 32 is connected to a lower end side surface of the vertical tube 31 above the horizontal tube, and the other end 322 is connected to an upper end side surface of the vertical tube 31 below the horizontal tube. The vertical pipe 31 is provided with a first separation net 311 near the bottom, so as to form a first space 312 on the separation net 311 and a second space 313 on the separation net, the first space 312 is used for accommodating cadmium particles, the second space 313 is used for receiving the cadmium particle lamination with the reduced particle size after oxidation, and the volume of the first space 312 can be set to be 4-6 times of the volume of the second space 313. A second separation net 33 is provided between the vertical pipe 31 and the horizontal pipe 32. The mesh diameter of the first separation net 311 is smaller than the diameter of cadmium particles; the mesh diameter of the second separating net 33 is smaller than that of the first separating net 311. Cadmium particles can be prepared by: putting enough zinc skin or zinc rod into the cadmium sulfate solution, when the cadmium in the cadmium is completely replaced by zinc, enabling the cadmium layer covering the surface of the zinc to fall off, transferring the cadmium layer into a mortar for grinding, and then washing the cadmium layer with water and sieving the washed cadmium layer with a 20-40-mesh sieve. Cadmium particles can be arranged to pass through a 25-mesh sieve, the mesh diameter of the first separation net 311 is 20 meshes, and the mesh diameter of the second separation net 33 is 15 meshes. The sum of the effective lengths of all the cadmium columns of the vertical tubes 31 can be set to be more than 20 cm.
The horizontal pipe 32 is not provided with cadmium particles, and the bottom of the horizontal pipe is higher than the second space 313 in the vertical pipe 31, so that the reduced cadmium particles are deposited in the second space 313 of the vertical pipe 31 through the first separation net 311 after the oxidized particle size of the cadmium particles in the first space 312 becomes smaller, and the food sample extracting solution flows into the horizontal pipe 32 through the side surface of the vertical pipe 31 without affecting the flow of the food sample extracting solution between the vertical pipe 31 and the horizontal pipe 32.
The measuring cell 40 can measure the nitrite content by naphthyl ethylenediamine hydrochloride spectrophotometry, and the various reagent bottles 50 are used for inputting reagents into the measuring cell to carry out color reaction with nitrite in the food sample extracting solution. The color reagent may include a solution of naphthyl ethylenediamine hydrochloride, a solution of sulfanilic acid, and a buffer solution of ammonium chloride. The absorbance can be detected at 538nm by using a spectrophotometer, and the content of nitrate and nitrite in the food sample extracting solution can be determined by the data processing module according to the detection result of the measuring cell. The data processing module determines the nitrite content according to the absorbance value in the food sample extracting solution which does not pass through the cadmium column tube 30, determines the total nitrite content according to the absorbance value in the food sample extracting solution which is reduced by the cadmium column tube 30, subtracts the nitrite content from the total nitrite content to obtain the nitrite content converted by the nitrate, and multiplies the nitrite content converted by the conversion coefficient 1.348 to obtain the nitrate content.
And a waste liquid tank 60 which is connected with the measuring tank through a switch valve and receives waste liquid discharged from the measuring tank 40. Preferably, a regeneration reagent bottle is also included for inputting the cadmium column tube 30 to restore the performance of the cadmium particles therein. The regeneration reagent may include hydrochloric acid.
The detection method of the food nitrate and nitrite detection and analysis system provided by the embodiment of the invention comprises the following steps: (1) pretreating a sample to obtain a food sample extracting solution; (2) conveying the food sample extracting solution to the measuring tank 40 through a first flow path of the sample tank 10 and the measuring tank 40, and detecting the nitrite content in the food sample extracting solution which does not pass through the cadmium column; (3) conveying the sample extracting solution through the cadmium column tube 30 and then into the measuring pool 40 through a second flow path among the sample pool 10, the cadmium column tube 30 and the measuring pool 40, and detecting the nitrite content in the food sample extracting solution reduced by the cadmium column; (4) the data processing module determines the nitrate content in the food sample extracting solution according to the nitrite content in the food sample extracting solution which does not pass through the cadmium column and the nitrite content in the food sample extracting solution which passes through the cadmium column.
The above description is only for the preferred embodiment of the present invention, and is not intended to limit the scope of the present invention. The particular features, structures, materials, or characteristics described in this disclosure may be combined in any suitable manner in any one or more embodiments or examples. Furthermore, various embodiments or examples and features of different embodiments or examples described in this specification can be combined and combined by one skilled in the art without contradiction. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention shall fall within the protection scope of the present invention.
Claims (10)
1. A food nitrate and nitrite detection and analysis system comprising: a sample cell for placing the extracted food sample extract; the cadmium column tube is used for reducing nitrate in the sample extracting solution into nitrite; the measuring tank is used for detecting the content of nitrite in the food sample extracting solution introduced into the measuring tank; the data processing module is used for determining the content of nitrate and nitrite in the food sample extracting solution according to the detection result of the measuring pool; the method is characterized in that: the cadmium column tube comprises a plurality of vertical tubes and horizontal tubes, one end of each horizontal tube is connected with the side surface of the lower end of the vertical tube above the horizontal tube, and the other end of each horizontal tube is connected with the side surface of the upper end of the vertical tube below the horizontal tube; a first separation net is arranged in the vertical pipe close to the bottom to form a first space on the separation net and a second space on the separation net, and cadmium particles are arranged in the first space; and a second separation net is arranged between the vertical pipe and the horizontal pipe.
2. The system for detecting and analyzing food nitrate and nitrite of claim 1, wherein: the sum of the effective lengths of the cadmium columns in the first space is more than 20 cm.
3. The food nitrate and nitrite detection and analysis system of claim 1, wherein; the food includes vegetables, meat products, milk, etc.
4. The system for detecting and analyzing food nitrate and nitrite of claim 1, wherein: the measuring cell measures the nitrite content by a naphthyl ethylenediamine hydrochloride spectrophotometry.
5. The system for detecting and analyzing food nitrate and nitrite of claim 1, wherein: the device also comprises a regeneration reagent bottle which is used for inputting the cadmium column tube to recover the performance of cadmium particles in the cadmium column tube.
6. The system for detecting and analyzing food nitrate and nitrite of claim 1, wherein: the food sample extracting solution color reaction device further comprises a reagent bottle which is used for inputting a reagent into the measuring pool and carrying out color reaction with the nitrite in the food sample extracting solution.
7. The system for detecting and analyzing food nitrate and nitrite of claim 1, wherein: the reagent comprises a naphthyl ethylenediamine hydrochloride solution, a sulfanilic acid solution and an ammonia chloride buffer solution.
8. The system for detecting and analyzing food nitrate and nitrite of claim 1, wherein: the device also comprises a waste liquid pool which receives the waste liquid discharged by the measuring pool.
9. The system for detecting and analyzing food nitrate and nitrite of claim 1, wherein: the data processing module determines the nitrate content in the food sample extracting solution according to the nitrite content in the food sample extracting solution which does not pass through the cadmium column and the nitrite content in the food sample extracting solution which passes through the cadmium column.
10. The detection method of the food nitrate and nitrite detection and analysis system according to claim 1, comprising the steps of: (1) pretreating a sample to obtain a food sample extracting solution; (2) conveying the food sample extracting solution to a measuring pool through a first flow path, and detecting the nitrite content in the food sample extracting solution which does not pass through a cadmium column through the measuring pool; (3) conveying the sample extracting solution through a cadmium column tube by a second flow path, then feeding the sample extracting solution into a measuring pool, and detecting the nitrite content in the food sample extracting solution reduced by the cadmium column by the measuring pool; (4) the data processing module determines the nitrate content in the food sample extracting solution according to the nitrite content in the food sample extracting solution which does not pass through the cadmium column and the nitrite content in the food sample extracting solution which passes through the cadmium column.
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202011366372.8A CN112461775A (en) | 2020-11-29 | 2020-11-29 | Food nitrate and nitrite detection and analysis system and detection and analysis method |
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| Application Number | Priority Date | Filing Date | Title |
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| CN202011366372.8A CN112461775A (en) | 2020-11-29 | 2020-11-29 | Food nitrate and nitrite detection and analysis system and detection and analysis method |
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| CN112461775A true CN112461775A (en) | 2021-03-09 |
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| CN202011366372.8A Withdrawn CN112461775A (en) | 2020-11-29 | 2020-11-29 | Food nitrate and nitrite detection and analysis system and detection and analysis method |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN114755388A (en) * | 2022-06-15 | 2022-07-15 | 自然资源部第二海洋研究所 | Spiral copper-cadmium reduction device and method for seawater nitrate online analysis |
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2020
- 2020-11-29 CN CN202011366372.8A patent/CN112461775A/en not_active Withdrawn
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN114755388A (en) * | 2022-06-15 | 2022-07-15 | 自然资源部第二海洋研究所 | Spiral copper-cadmium reduction device and method for seawater nitrate online analysis |
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Application publication date: 20210309 |