Method for determining nitrite in food by employing headspace-gas chromatography/mass spectrography

Abstract

The invention discloses a method for determining nitrite in food by employing a headspace-gas chromatography / mass spectrography. The method comprises the following steps: (1) carrying out ultrasonic extraction on to-be-tested food; (2) adding zinc acetate, a potassium ferrocyanide solution and purified water to a solution which is extracted from the step (1), precipitating protein and filtering; (3) enabling filtrate obtained from the step (2) to act on sodium cyclamate in an acidic condition, putting into a headspace bottle, determining and analyzing by adopting the gas chromatography and mass spectrography; and (4) drawing a calibration curve according to the content of the nitrite corresponding to response peak area of a derived product cyclohexene, and carrying out quantitative analysis. According to the method for detecting the nitrite in the food, the quantitative detection limit is 100miccrog / kg; the sodium nitrite standard is below 0.1mg / L to 5mg / L; the response value and the mass concentration are in a good linear relationship; the related coefficient is greater than 0.998; the recovery rate of the nitrite in a tested article is 85.3%-102%; and the relative standard deviation (RSD) is less than 5.0%.

Description

technical field

[0001] The invention relates to the field of food safety detection, in particular to a method for determining nitrite in food by applying headspace-gas chromatography / mass spectrometry. Background technique

[0002] Among the natural fresh foods, such as vegetables, contain a lot of nitrates. Over time, the food deteriorates, and nitrates will slowly generate raw nitrites; nitrites are also the most commonly used coloring agents in the production of meat products. The product exhibits a fresh color. It can also be found in frozen cans and sauces. Nitrite easily combines with amines to form nitrosamines. Nitrosamines have strong carcinogenic effects. Therefore, the detection of nitrite in food has become an important concern for quality and safety assurance.

[0003] At present, the determination method of nitrite in the national standard is naphthalene ethylenediamine hydrochloride spectrophotometry, and the three commonly used methods are chromatography, ...

Examples

Embodiment 1

[0060] Example 1: Establishment of a method for determining nitrite in food using headspace-gas chromatography / mass spectrometry of the present invention 1. Extraction step

[0061] Weigh 1g of food sample and put it into a centrifuge tube, add 2.5ml of zinc acetate solution (concentration of 219g / L), 2.5ml of potassium ferrocyanide solution (concentration of 109g / L), add 15ml of pure water, shake and mix thoroughly. After mixing, ultrasonic extraction was performed for 20 min, filtered with filter paper, and the filtrate was collected for use.

[0062] Take 5ml of the deproteinized filtrate, 5ml of 1% sulfuric acid solution and 0.1% sodium cyclamate solution in the headspace bottle, and quickly cover the bottle for headspace-gas chromatography / mass spectrometry (HS-GC / MS) analysis; The response peak area of ​​cyclohexene corresponds to the nitrite content as a calibration curve for quantitative analysis.

[0063] 2. Instrument parameters and measurement conditions

[0064] ...

Embodiment 2

[0115] Example 2: Determination experiment of detection limit, linear range and recovery range of the method of the present invention

[0116] According to the method in Example 1, the detection limit, precision and recovery rate of this method were determined. Table 2 is the regression equation and correlation coefficient of sodium nitrite standard.

[0117] Table 2

[0118] name

standard curve line

Correlation coefficient r

Sodium nitrite

Y=178314X-6528.8

0.9987

[0119] Image 6 is the correlation coefficient plot of nitrite concentration and response value. At the concentration of 0.1mg / L-5mg / L, the response value of sodium nitrite standard has a good linear relationship with the mass concentration. The correlation coefficient is greater than 0.998. The lower limit of detection (LOD) of the compounds was determined based on a 3-fold signal-to-noise ratio (S / N), and the limit of quantitative detection for nitrite in food was 100 ...

technical field

[0001] The invention relates to the field of food safety detection, in particular to a method for determining nitrite in food by applying headspace-gas chromatography / mass spectrometry. Background technique

[0002] Among the natural fresh foods, such as vegetables, contain a lot of nitrates. Over time, the food deteriorates, and nitrates will slowly generate raw nitrites; nitrites are also the most commonly used coloring agents in the production of meat products. The product exhibits a fresh color. It can also be found in frozen cans and sauces. Nitrite easily combines with amines to form nitrosamines. Nitrosamines have strong carcinogenic effects. Therefore, the detection of nitrite in food has become an important concern for quality and safety assurance.

[0003] At present, the determination method of nitrite in the national standard is naphthalene ethylenediamine hydrochloride spectrophotometry, and the three commonly used methods are chromatography, ...

Examples

Embodiment 1

[0060] Example 1: Establishment of a method for determining nitrite in food using headspace-gas chromatography / mass spectrometry of the present invention 1. Extraction step

[0061] Weigh 1g of food sample and put it into a centrifuge tube, add 2.5ml of zinc acetate solution (concentration of 219g / L), 2.5ml of potassium ferrocyanide solution (concentration of 109g / L), add 15ml of pure water, shake and mix thoroughly. After mixing, ultrasonic extraction was performed for 20 min, filtered with filter paper, and the filtrate was collected for use.

[0062] Take 5ml of the deproteinized filtrate, 5ml of 1% sulfuric acid solution and 0.1% sodium cyclamate solution in the headspace bottle, and quickly cover the bottle for headspace-gas chromatography / mass spectrometry (HS-GC / MS) analysis; The response peak area of ​​cyclohexene corresponds to the nitrite content as a calibration curve for quantitative analysis.

[0063] 2. Instrument parameters and measurement conditions

[0064] ...

Embodiment 2

[0115] Example 2: Determination experiment of detection limit, linear range and recovery range of the method of the present invention

[0116] According to the method in Example 1, the detection limit, precision and recovery rate of this method were determined. Table 2 is the regression equation and correlation coefficient of sodium nitrite standard.

[0117] Table 2

[0118] name

standard curve line

Correlation coefficient r

Sodium nitrite

Y=178314X-6528.8

0.9987

[0119] Image 6 is the correlation coefficient plot of nitrite concentration and response value. At the concentration of 0.1mg / L-5mg / L, the response value of sodium nitrite standard has a good linear relationship with the mass concentration. The correlation coefficient is greater than 0.998. The lower limit of detection (LOD) of the compounds was determined based on a 3-fold signal-to-noise ratio (S / N), and the limit of quantitative detection for nitrite in food was 100 ...

Images