Sodium nitrite determination method

A sodium nitrite and determination method technology, applied in the direction of color/spectral characteristic measurement, etc., can solve the problems of harm, strong carcinogenicity of reagents, easy formation of secondary pollution, etc.

Inactive Publication Date: 2015-07-15
UNIV OF SHANGHAI FOR SCI & TECH
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  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0005] The purpose of the present invention is in order to solve the above-mentioned GB/T 5750.5-2006 drinking water standard inspection method - the mensuration of sodium nitrite - diazo coupling spectrophotometry and GB/T 5009.33 National Food Safety Standard-Determination of Sodium Nitrite-Naphthylethylenediamine Hydrochloride, a coupling reagent used in spectrophotometry, has strong carcinogenicity, will cause harm to the environment and operators, and is prone t...

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Effect test

Embodiment 1

[0029] A kind of assay method of sodium nitrite, specifically comprises the following steps:

[0030](1) Preparation of blank reagents

[0031] ①. Use a pipette to pipette 10.0mL of deionized water into a 25mL colorimetric tube, and add 1.0mL of potassium bromide aqueous solution with a mass percentage concentration of 1%, 1.0×10 -2 1.0mL of mol / L p-aminobenzenesulfonic acid aqueous solution, then add 1.0mL of 1.5 mol / L hydrochloric acid aqueous solution, shake well to obtain deionized water diazonium salt solution, let the deionized water diazonium salt solution stand for 1min;

[0032] ② Take another 25mL volumetric flask, add 3mL of 1.0mol / L sodium carbonate aqueous solution and 1.0×10 -2 mol / L 2-N-ethyl-5-naphthol-7-sulfonic acid aqueous solution 1.0mL, transfer the deionized water diazonium salt solution in the colorimetric tube of step ① to the above-mentioned sodium carbonate aqueous solution and 2-N-ethyl-5-naphthol-7-sulfonic acid aqueous solution in the volumetric ...

Embodiment 2

[0047] A kind of assay method of sodium nitrite, specifically comprises the following steps:

[0048] (1) Preparation of blank reagents

[0049] ①. Use a pipette to pipette 10.0mL of deionized water into a 25mL colorimetric tube, and add 1.0mL of potassium bromide aqueous solution with a mass percentage concentration of 1%, 1.0×10 -2 mol / L p-aminobenzenesulfonic acid aqueous solution 1.0mL, then add 1.5 mol / L hydrochloric acid aqueous solution 1.0mL, shake well to obtain deionized water diazonium salt solution, let the deionized water diazonium salt solution stand for 3min;

[0050] ② Take another 25mL volumetric flask, add 3mL of 1.0mol / L sodium carbonate aqueous solution and 1.0×10 -2 mol / L 2-N-ethyl-5-naphthol-7-sulfonic acid aqueous solution 1.0mL, transfer the deionized water diazonium salt solution in the colorimetric tube of step ① to the above-mentioned sodium carbonate aqueous solution and 2-N-ethyl-5-naphthol-7-sulfonic acid aqueous solution in the volumetric flask...

Embodiment 3

[0066] A kind of assay method of sodium nitrite, specifically comprises the following steps:

[0067] (1) Preparation of blank reagents

[0068] ①. Use a pipette to pipette 10.0mL of deionized water into a 25mL colorimetric tube, and add 1.0mL of potassium bromide aqueous solution with a mass percentage concentration of 1%, 1.0×10 -2 1.0mL of mol / L p-aminobenzenesulfonic acid aqueous solution, then add 1.0mL of 1.5 mol / L hydrochloric acid aqueous solution, shake well to obtain deionized water diazonium salt solution, let the deionized water diazonium salt solution stand for 5min;

[0069] ② Take another 25mL volumetric flask, add 3mL of 1.0mol / L sodium carbonate aqueous solution and 1.0×10 -2 mol / L 2-N-ethyl-5-naphthol-7-sulfonic acid aqueous solution 1.0mL, transfer the deionized water diazonium salt solution in the colorimetric tube of step ① to the above-mentioned sodium carbonate aqueous solution and 2-N-ethyl-5-naphthol-7-sulfonic acid aqueous solution in the volumetric...

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Abstract

The invention discloses a sodium nitrite determination method. The method comprises the following steps: taking a water sample to be determined, standing the water sample to be determined for 30min, transferring 10.0mL of the above obtained supernatant into a 25mL colorimetric pipe through a pipet, sequentially adding 1.0mL of an aqueous potassium bromide solution, 1.0mL of an aqueous sulfanilic acid solution and 1.0mL of an aqueous hydrochloric acid solution, shaking up, and standing to obtain a solution of diazo salt of the sample to be determined; taking a 25mL volumetric flask, and adding 3mL of an aqueous sodium carbonate solution and 1.0mL of an aqueous 2-N-ethyl-5-naphthol-7-sulfonic acid solution; transferring the solution of diazo salt of the sample to be determined into the volumetric flask, adding deionized water to a certain volume, and determining the absorbance of the above obtained orange diazo compound solution at a wavelength of 480nm by using 1cm cuvette with a blank reagent as a reference; and calculating according to the curve regression equation of standard sodium nitrite to obtain the content of sodium nitrite in the sample to be determined. The determination method has the advantages of convenient operation, high sensitivity, accurate result, and small toxicity of used reagents.

Description

technical field [0001] The invention relates to a method for determining sodium nitrite, belonging to the fields of food safety and environmental protection. Background technique [0002] Sodium nitrite entering the human body will generate high-priced hemoglobin in the blood, resulting in tissue hypoxia and acute poisoning. It will also be converted into carcinogen nitrosamines in the acidic environment of the gastrointestinal tract. The International Health Organization lists nitrous acid in food and environmental water as strict control objects. [0003] At present, the most commonly used method for determining sodium nitrite is spectrophotometry (National Standard of the People's Republic of China: GB / T 5750.5-2006 Standard Test Method for Drinking Water-Determination of Sodium Nitrite-Diazo Coupled Spectrophotometry; GB / T 5750.5-2006 T 5009.33 National Food Safety Standard-Determination of Sodium Nitrite-Spectrophotometric method) The coupling reagent used in these me...

Claims

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Application Information

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IPC IPC(8): G01N21/31
Inventor 尹晓航马骏涛沈昕黄颖莹张彩虹彭阳施文健闻海峰杨琴淋
Owner UNIV OF SHANGHAI FOR SCI & TECH
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