Nitrate and nitrite rapid testing paper and use thereof

A technology for rapid determination of nitrite, applied in the field of detection, can solve the problems that it is not suitable for the general public to use at any time, cannot judge the limit standard of nitrate and nitrite content in vegetables, and takes a long time.

Inactive Publication Date: 2005-07-27
ZHEJIANG UNIV
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  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0004] At present, there are many methods for the determination of nitrate and nitrite in vegetables, such as spectroscopy, chromatography, electrophoresis, polarography, etc., but most of them require special instruments, and the determination process is complicated and takes a long time
After retrieval, it can be seen that the "rapid detection test paper for nitrite and nitrate in vegetables and its detection method" invented by Xie Zenghong and others (application number: 0311666.6, publication number: CN 1445531A) is also a kind of nitrate and nitrite in vegetables. However, it only judges whether the nitrite content in vegetables exceeds 8mg / kg, and whether the nitrate content exceeds 10mg / kg, and it cannot judge whether the nitrate and nitrite contents in vegetables exceed the limit stipulated by the state. standard
In addition, when detecting nitrate, a reaction container and a reducing agent are required, which is cumbersome and not suitable for the general population to use at any time

Method used

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  • Nitrate and nitrite rapid testing paper and use thereof
  • Nitrate and nitrite rapid testing paper and use thereof
  • Nitrate and nitrite rapid testing paper and use thereof

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0019] Embodiment 1 The preparation method of test paper of the present invention

[0020] Preparation of reaction test paper: acidify the large filter paper first, divide the positive and negative sides, and then coat the reverse side of the filter paper with nitrate metal reducing agents such as zinc, copper, magnesium, cadmium, etc., the positive side of the prepared test paper is white, and store it away from light and low temperature , cut into small pieces of 1 × 0.8 cm (length × width) when used.

[0021] Preparation of chromogenic test paper: Immerse a large piece of filter paper in the mixture of diazotization reagent and coupling reagent of equal volume, soak it for 3-5 minutes, and immediately send it to an oven at 60°C-80°C to dry it . The prepared test paper is white, and should be kept away from light and low temperature, and cut into small pieces of 1×0.8 cm (length×width) when used.

[0022] Preparation of test paper for nitrate and nitrite determination: Use...

Embodiment 2

[0024] Embodiment 2 sample detection method

[0025] (1) Nitrite content: Take a few drops of vegetable juice (1-2 drops is appropriate) on the color test paper, observe the color change of the test paper after 1-2 minutes, compare with the standard color scale, and estimate the nitrite content , to judge whether it exceeds the standard, and the standard for exceeding the standard is issued on August 6, 2001 by the General Administration of Quality Supervision and Quarantine of the People's Republic of China and implemented on October 1, 2001. Safety requirements for agricultural products, quality and pollution-free vegetables (GB18406.1-2001) Vegetable Central Asia Nitrate limit (as NaNO 2 Count): ≤4

[0026] (2) Nitrate content: Take a few drops of the juice (1-2 drops are advisable) and drop it on the reaction test paper. After 1-3 minutes, the test paper is erected, and the reaction solution flows down to the lower end of the color test paper for color reaction. Observe ...

Embodiment 3

[0033] Embodiment 3 Application example

[0034] Compared with the routine analysis method (standard method) in the laboratory, the nitrate content of various vegetables (as NO 3 - In terms of) and nitrite content (in NaNO 2 Measured by the test paper method and the standard method, the results are shown in Table 2.

[0035] Table 2 Comparison between test paper method and standard method Unit (mg kg -1 )

[0036] Vegetable variety Measured value by standard method Measured value by test paper method Measured value by standard method Measured value by test paper method

[0037] (NO 3 - ) (NaNO 2 )

[0038] Cabbage 2597 2300 1.27 2

[0039] Chinese cabbage 4250 > 3000 (exceeding standard) 4.27 > 4 (exceeding standard)

[0040] Cabbage 2035 2000

[0041]Rapeseed 854 800

[0042] Spinach 2914 3000 3.35 3

[0043] Cucumber 645 500 (exceeding standard)

[0044] Lettuce 1769 1600 3.07 3

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Abstract

A test paper for fast measuring out nitrate and nitrite is composed of colour display test paper soaked with mixture in the same volume of diazotization reagent and coupling reagent, and reaction test paper coated with nitrate reducer, the test paper can provide quick detection of nitrate and nitrite contained in food or vegetables.

Description

technical field [0001] The invention belongs to detection technology, and relates to the technology for detecting the content of nitrate and nitrite, in particular to a rapid determination test paper for detecting the content of nitrate and nitrite in food (vegetables) and its application. Background technique [0002] With the improvement of living standards, people's demand for vegetables no longer only focuses on the quantity of consumption, but pays more attention to the quality. At present, a large amount of nitrogen fertilizer is applied in production, resulting in a generally high content of nitrate nitrogen in the soil, which is easily accumulated in the body after being absorbed by crops. Existing studies have shown that vegetables are a kind of crops that are easy to accumulate nitrate. Most of the nitrate ingested by the human body (accounting for 70%-80%) comes from vegetables, and nitrate can be reduced to nitrite under the action of bacteria in the human body. ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G01N21/78G01N31/00
Inventor 吴良欢伍少福许超
Owner ZHEJIANG UNIV
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