Detection method for determining concentrations of phosphorus and bromine and application

Abstract

The invention relates to a detection method for determining the concentration of phosphorus and bromine and application. The detection method comprises the following steps: mixing a sample to be detected with an extracting solution, extracting to obtain the extracting solution, centrifuging the extracting solution, filtering to obtain a sample solution, adding an internal standard solution, mixing, and detecting by adopting inductively coupled plasma mass spectrometry, the extracting solution contains ammonia water and EDTA (ethylene diamine tetraacetic acid). According to the method, the ammonia water and the EDTA extracting solution are adopted, so that the sample treatment time is short, the interference in the measurement process is small, the measurement accuracy is high, and batch treatment is facilitated.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of food detection, and particularly relates to a detection method for measuring phosphorus and bromine concentration and application. BACKGROUND

[0002] Phosphorus is a trace element necessary for the human body, and participates in various physiological activities and metabolism in the form of phosphate in the human body. Meanwhile, phosphorus is an important component of bones, and food rich in phosphorus can supplement brain phospholipids, especially for children in the early years. Therefore, the content is an important indicator reflecting the nutritional level of food. However, phosphorus is also a common element in harmful substances such as pesticides, and the residual amount of phosphorus is very large, which is the focus of food quality monitoring. Therefore, the detection of phosphorus in water and food is related to the safety of food, and can also reflect the nutritional level of food, and thus has great significance.

[0003] Bromide ion is the main reason for the generation of brominated disinfection by-products in the disinfection process of drinking water. Studies have shown that when the content of organic matter in water is constant, the generation of disinfection by-products increases with the increase of the concentration of bromide ion, and the proportion of brominated disinfection by-products also increases significantly. Bromated disinfection by-products have extremely adverse effects on human health, among which bromate is not a strong carcinogen, but has a higher risk level. Many countries have begun to pay attention to bromate, a disinfection by-product, when formulating water quality standards. The United States Environmental Protection Agency drinking water standard stipulates that the maximum allowable concentration of bromate is 10 μg / L. In the mandatory standard for drinking natural mineral water, the maximum allowable concentration of bromate is 10 μg / L.

[0004] The World Health Organization has listed bromate as a 2B level potential carcinogen. Bromate is a "2B level" potential carcinogen, and China has listed it as a drinking water detection item as early as 2009, stipulating that the highest content shall not exceed 0.01 mg / L. The traditional method for analyzing non-metallic elements bromine and phosphorus is ion chromatography, colorimetry or volumetric method. The methods involved in the analysis of non-metallic elements bromine and phosphorus in water samples include ion chromatography, spectrophotometry and inductively coupled plasma mass spectrometry.

[0005] The methods involved in the analysis of non-metallic elements bromine and phosphorus in food samples include ion chromatography and spectrophotometry, such as ion chromatography (or liquid chromatography)-inductively coupled plasma mass spectrometry for determining bromate in wheat flour and its products and puffed food; post-column derivatization ion chromatography for determining bromate in bread, steamed buns, biscuits and fried dough sticks; ion chromatography for determining bromate in infant formula milk powder; and ion chromatography for testing phosphates in food.

[0006] The reagents involved in the above method are various, and the experimental steps are complex, which increases the operation requirement of the personnel. The ion chromatography can analyze a plurality of non-metal elements, but cannot simultaneously measure phosphorus and bromine, and the time for measuring the food solid sample is long and the efficiency is low.

[0007] Therefore, how to construct a simple and effective detection method to detect the phosphorus and bromine concentrations in food solid and semi-solid samples has become a problem to be solved. SUMMARY

[0008] To solve the above technical problems, the application provides a detection method for measuring the concentrations of phosphorus and bromine, and the use thereof. The extraction liquid of ammonia and EDTA can significantly improve the accuracy of detection.

[0009] To achieve this purpose, the application adopts the following technical solutions:

[0010] In a first aspect, the application provides a detection method for measuring the concentrations of phosphorus and bromine, which comprises mixing a sample to be measured with an extraction liquid to obtain an extraction liquid, centrifuging the extraction liquid to obtain a sample solution, adding an internal standard solution to mix, and detecting by an inductively coupled plasma mass spectrometer.

[0011] The extraction liquid contains ammonia and EDTA; and the sample to be measured includes solid food.

[0012] In the application, the ammonia and EDTA are used to extract phosphorus and bromine in the sample, which can significantly increase the accuracy of extraction. In addition, the background matrix of the sample is complex, and the addition of EDTA can significantly reduce the interference of impurities, thereby improving the detection accuracy.

[0013] Preferably, the extraction liquid contains 4%-6% ammonia and 1%-2% EDTA. The 4%-6% can be 4%, 4.5%, 5%, 5.5%, 6%, etc. The 1%-2% can be 1%, 1.2%, 1.4%, 1.6%, 1.8%, 2%, etc.

[0014] Preferably, the solid food includes any one or a combination of at least two of aquatic products, eggs, livestock and poultry meat, vegetables, fruits, seasonings, or cereals.

[0015] Preferably, the mass-to-volume ratio of the sample to be measured to the extraction liquid is 0.25g:(10-30)mL. The (20-40)mL can be 10mL, 12mL, 14mL, 16mL, 18mL, 20mL, 22mL, 24mL, 26mL, 28mL, or 30mL, etc.

[0016] Preferably, the temperature of the extraction is 85-92℃, and the time is 2.5-3h. The 85-92℃, for example, can be 85℃, 86℃, 87℃, 88℃, 89℃, 90℃, 91℃ or 92℃, etc. The 2.5-3h, for example, can be 2.5h, 2.6h, 2.7h, 2.8h, 2.9h or 3h, etc.

[0017] Preferably, after the extraction, water is added to make up to 25-100mL. For example, it can be 25mL, 30mL, 40mL, 50mL, 60mL, 70mL, 80mL, 90mL or 100mL, etc.

[0018] Preferably, the speed of the centrifugation is 4000-6000r / min, and the time is 2-8min. The 4000-6000r / min, for example, can be 4000r / min, 4500r / min, 5000r / min, 5500r / min or 6000r / min, etc. The 2-8min, for example, can be 2min, 3min, 4min, 5min, 6min, 7min or 8min, etc.

[0019] Preferably, the internal standard solution includes yttrium solution and / or scandium solution.

[0020] Preferably, after the mixing of the internal standard solution, the count per second (CPS) of the scandium solution ranges from (7-80)×10 4 , and the count per second (CPS) of the yttrium solution ranges from (3-30)×10 5 .

[0021] In the present application, by obtaining the CPS value of the internal standard solution in the mixed system, the concentration of the internal standard solution in the mixed solution is known

[0022] Preferably, the detection method further includes the preparation of a standard curve.

[0023] Preferably, the internal standard method standard curve includes a phosphorus standard curve and a bromine standard curve.

[0024] Preferably, the concentration range of the phosphorus standard curve is 0-1000μg / L. For example, it can be 0, 50μg / L, 100μg / L, 200μg / L, 400μg / L, 600μg / L, 800μg / L or 1000μg / L, etc.

[0025] Preferably, the concentration range of the bromine standard curve is 0-100μg / L. For example, it can be 0, 10μg / L, 20μg / L, 30μg / L, 40μg / L, 50μg / L, 60μg / L, 70μg / L, 80μg / L, 90μg / L or 100μg / L, etc.

[0026] Preferably, the plasma argon flow rate of the inductively coupled plasma emission mass spectrometer is 10-20 L / min. For example, it can be 10 L / min, 12 L / min, 14 L / min, 16 L / min, 18 L / min or 20 L / min, etc.

[0027] Preferably, the atomization chamber temperature of the inductively coupled plasma emission mass spectrometer is 2-5℃. For example, it can be 2℃, 3℃, 4℃ or 5℃, etc.

[0028] Preferably, the pump speed of the inductively coupled plasma emission mass spectrometer is 10-15 rpm. For example, it can be 10 rpm, 11 rpm, 12 rpm, 13 rpm, 14 rpm or 15 rpm, etc.

[0029] Preferably, the scanning mode of the inductively coupled plasma emission mass spectrometer is peak jumping.

[0030] Preferably, the calculation formula of the phosphorus and bromine content in the sample to be measured is:

[0031] X=(c1-c0)xfv / m;

[0032] Wherein, X is the content of phosphorus or bromine in the sample to be measured; c1 is the concentration of the phosphorus element or bromine element in the sample solution, c0 is the concentration of the phosphorus element or bromine element in the blank solution, f is the dilution multiple; v represents the constant volume of the sample solution; m is the mass of the sample to be measured.

[0033] In the second aspect, the application provides an application of the detection method for determining the concentration of phosphorus and bromine according to the first aspect in detecting the content of phosphorus and bromine in food.

[0034] Compared with the prior art, the application has at least the following beneficial effects:

[0035] 1. The application improves the method for determining the content of phosphorus and bromine in food, and simultaneously determines the content of phosphorus and bromine in food, with high accuracy, good precision, low detection cost, good stability and good safety. The main reagent used is an analytical pure ammonia and EDTA mixed solution, which is a common reagent in the laboratory, easy to obtain, and has low determination cost.

[0036] 2. In the application, ammonia and EDTA solution are used to treat food samples, and ICPMS is used to simultaneously determine phosphorus and bromine, with short sample treatment time, small determination process interference, high determination accuracy, and good batch processing.

[0037] 3. The sample detected in the present application is a solid food, and the method of the present application can accurately extract bromine and phosphorus from the complex components in the solid food and obtain high detection accuracy, realizing the conversion of bromine and phosphorus from liquid detection to solid sample detection, and improving the application scene and scope of the detection. BRIEF DESCRIPTION OF DRAWINGS

[0038] Figure 1 The standard curve for phosphorus.

[0039] Figure 2 The standard curve for bromine. DETAILED DESCRIPTION

[0040] The technical solutions of the present application will be further described below in combination with the drawings and through specific embodiments. However, the following examples are only simple examples of the present application and do not represent or limit the protection scope of the present application, and the protection scope of the present application is subject to the claims.

[0041] The sources of the instruments and reagents used in the following examples are as follows:

[0042] Inductively coupled plasma mass spectrometer: Agilent Company, USA;

[0043] Sartorius electronic balance: 1 / 1000, Beijing Sartorius Balance Co., Ltd.;

[0044] JW-3024HR high-speed refrigerated centrifuge: Anhui Jiwen Instrument and Equipment Co., Ltd.;

[0045] XW-80A vortex mixer: Shanghai Precision Industry Co., Ltd.;

[0046] Phosphorus standard: National Non-ferrous Metals and Electronic Materials Analysis and Testing Center, 24A014-1;

[0047] Bromine standard: China Institute of Metrology.

[0048] Example 1

[0049] In this embodiment, the concentrations and contents of phosphorus and bromine in the sample are detected

[0050] Preparation of shrimp sample: After washing the shrimp, remove the head, skin, and intestinal glands to obtain shrimp meat, crush and mix uniformly, freeze for preservation, and reserve for use.

[0051] Three centrifuge tubes were prepared and numbered as A1-1, A1-2 and A1-J1. 0.25 g of prawn sample was weighed into each centrifuge tube. Then 1.00 mL of 1000 mg / L phosphorus standard solution and 2.00 mL of 1 mg / L bromine standard solution were added into the centrifuge tube numbered as A1-J1, respectively. 3.00 mL of first grade water was added into the remaining samples, respectively. Then 10 mL of extraction solution, which was a 4% ammonia water and 2% EDTA aqueous solution, was added into each sample. The sample was extracted in a 90℃ constant temperature drying oven for 2.5 h. During the extraction process, the sample was taken out every half an hour and shaken for 1 min. After cooling, the sample was diluted with water to 25 mL. The sample was centrifuged at a speed of 5000 r / min for 5 min. The supernatant was filtered through a 0.45 μm filter membrane and used as the sample solution.

[0052] 10 mL of commercially available yttrium standard solution (1000 mg / L) and 1 mL of scandium standard solution (10000 mg / L) were accurately taken with a pipette, respectively. The solutions were diluted with deionized water to the mark in a 100 mL volumetric flask, and shaken to obtain 100 mg / L of yttrium and scandium standard stock solution. 1 mL of yttrium and scandium standard stock solution (100 mg / L) was accurately taken with a 1 mL pipette, diluted with deionized water to the mark in a 100 mL volumetric flask, and shaken to obtain 1 mg / L of yttrium and scandium internal standard solution, which was the internal standard solution.

[0053] The sample solutions A1-1 and A1-2 were diluted 100 times, and the sample solution A1-J1 was diluted 200 times, and then detected. The sample inlet device was a three-way valve connected with three pump tubes. One end of the three-way valve was connected with the atomization device of the Agilent inductively coupled plasma mass spectrometer. One of the three pump tubes was connected with the internal standard solution pump tube to continuously pump the internal standard solution. One of the three pump tubes was connected with the sample solution pump tube to pump the sample solution. The internal standard solution and the sample solution were mixed in the three-way valve, and then flowed into the atomization device of the inductively coupled plasma mass spectrometer from the other pump tube.

[0054] An Agilent inductively coupled plasma mass spectrometer (model 7700) was used. The instrument and related auxiliary equipment and computer were turned on, and the instrument was preheated for 20 min. The instrument test parameters were set as follows: RF power was 1.55 kW, plasma argon gas flow rate was 10.0 L / min, auxiliary gas flow rate was 1.00 L / min, atomization chamber temperature was 5℃, atomization gas flow rate was 0.70 L / min, pump speed was 10 rpm, stabilization time was 25 s, sample inlet diameter was 1.02 mm, internal standard tube diameter was 0.89 mm, scanning mode was peak jumping, integration time was 0.1 s / time, and repetition number was 3.

[0055] Example 2

[0056] In this example, the concentrations and contents of phosphorus and bromine in the sample were detected.

[0057] Shrimp sample preparation: After washing the shrimp, remove the head, skin, and intestinal gland to obtain shrimp meat, which is crushed and mixed uniformly, frozen and stored for use.

[0058] Prepare three centrifuge tubes, numbered A2-1, A2-2, and A2-J1, respectively. Weigh 0.25 g of shrimp sample into each centrifuge tube. Then, add 1.00 mL of 1000 mg / L phosphorus standard solution and 2.00 mL of 1 mg / L bromine standard solution to the centrifuge tube numbered A2-J1. Add 3.00 mL of primary water to the remaining samples. Then, add 20 mL of extraction solution, which is a 4% ammonia water and 2% EDTA aqueous solution, to each sample. Place the samples in a 85℃ constant temperature drying oven for extraction for 3 h. During the extraction process, remove the samples every half hour, shake for 1 min, cool, and dilute to 25 mL with water. Centrifuge at 5000 r / min for 5 min. Take the supernatant and filter it through a 0.45 μm filter membrane to obtain the sample solution.

[0059] Accurately pipette 10 mL of commercially available yttrium standard solution (1000 mg / L) and 1 mL of scandium standard solution (10000 mg / L) into a 100 mL volumetric flask. Dilute to the mark with deionized water and shake to obtain 100 mg / L of yttrium and scandium standard stock solution. Accurately pipette 1 mL of yttrium and scandium standard stock solution (100 mg / L) into a 100 mL volumetric flask. Dilute to the mark with deionized water and shake to obtain 1 mg / L of yttrium and scandium internal standard solution, which is the internal standard solution.

[0060] After diluting the sample solutions A2-1 and A2-2 by 100 times and the sample solution A2-J1 by 200 times, detect the phosphorus item. After diluting the sample solution A2-J1 by 2 times, detect the bromine item. The sample introduction device is a three-way valve connected to three pump tubes. One end of the three-way valve is connected to the atomization device of the Agilent inductively coupled plasma mass spectrometer. One of the three pump tubes is connected to the internal standard solution pump tube to continuously pump the internal standard solution. One of the three pump tubes is connected to the sample solution pump tube to pump the sample solution. The internal standard solution and the sample solution are mixed in the three-way valve and then flow into the atomization device of the inductively coupled plasma mass spectrometer through the other pump tube.

[0061] Use the Agilent inductively coupled plasma mass spectrometer (model 7700). Turn on the instrument and related auxiliary equipment and computer. Preheat the instrument for 20 min. Set the instrument test parameters as follows: RF power is 1.55 kW, plasma argon gas flow rate is 15.0 L / min, auxiliary gas flow rate is 1.00 L / min, atomization chamber temperature is 2℃, atomization gas flow rate is 0.70 L / min. Pump speed is 12 rpm, stabilization time is 25 s, sample tube inner diameter is 1.02 mm, internal standard tube inner diameter is 0.89 mm, scanning mode is peak jumping, integration time is 0.1 s / time, and repetition number is 3.

[0062] Example 3

[0063] The embodiment detects the concentration and content of phosphorus and bromine in the sample

[0064] Preparation of shrimp samples: after washing the shrimp, remove the head, skin, and intestinal glands to obtain shrimp meat, crush and mix evenly, freeze for preservation, and reserve for use.

[0065] Prepare three centrifuge tubes numbered A3-1, A3-2, and A3-J1 in sequence, and weigh 0.25 g of shrimp sample into each centrifuge tube. Then add 1.00 mL of 1000 mg / L phosphorus standard solution and 2.00 mL of 1 mg / L bromine standard solution to the centrifuge tube numbered A3-J1, respectively. Add 3.00 mL of first-grade water to the remaining samples, respectively. Then add 10 mL of extraction solution, which is a 6% ammonia water and 1% EDTA aqueous solution, to each sample. Place the samples in a 92°C constant temperature drying oven for extraction for 2.5 h. During the extraction process, take out each sample every half hour, shake for 1 min, cool, and dilute to 25 mL with water. Centrifuge at a speed of 5000 r / min for 5 min. Take the supernatant, filter it through a 0.45 μm filter membrane, and use it as the sample solution.

[0066] Accurately pipette 10 mL of commercially available yttrium standard solution (1000 mg / L) and 1 mL of scandium standard solution (10000 mg / L) into a 100 mL volumetric flask, and dilute to the mark with deionized water to obtain 100 mg / L of yttrium and scandium standard stock solution. Accurately pipette 1 mL of yttrium and scandium standard stock solution (100 mg / L) into a 100 mL volumetric flask, and dilute to the mark with deionized water to obtain 1 mg / L of yttrium and scandium internal standard solution, which is the internal standard solution.

[0067] The sample inlet device is a three-way valve connected to three pump tubes, one end of which is connected to the atomization device of the Agilent inductively coupled plasma mass spectrometer. One of the three pump tubes is connected to the internal standard solution pump tube to continuously pump the internal standard solution, and one is connected to the sample solution pump tube to pump the sample solution. After the internal standard solution and the sample solution are mixed in the three-way valve, they flow into the atomization device of the inductively coupled plasma mass spectrometer from the other pump tube.

[0068] An Agilent inductively coupled plasma mass spectrometer (model 7700) is used. The instrument and related auxiliary equipment and computer are turned on, and the instrument is preheated for 20 min. The instrument test parameters are set as follows: RF power is 1.55 kW, plasma argon gas flow rate is 20.0 L / min, auxiliary gas flow rate is 1.00 L / min, atomization chamber temperature is 2°C, atomization gas flow rate is 0.70 L / min. Pump speed is 15 rpm, stabilization time is 25 s, sample inlet diameter is 1.02 mm, internal standard tube diameter is 0.89 mm, scanning mode is peak jumping, integration time is 0.1 s / time, and repetition number is 3.

[0069] Example 4

[0070] This example detects the concentration and content of phosphorus and bromine in the sample, which is only different from example 1 in that the concentration of ammonia in the extraction solution is 2%, and the rest is consistent with example 1.

[0071] Example 5

[0072] This example detects the concentration and content of phosphorus and bromine in the sample, which is only different from example 1 in that the concentration of EDTA in the extraction solution is 0.1%, and the rest is consistent with example 1.

[0073] Example 6

[0074] This example detects the concentration and content of phosphorus and bromine in the sample, which is only different from example 1 in that the extraction temperature is 60°C, and the rest is consistent with example 1.

[0075] Example 7

[0076] This example detects the concentration and content of phosphorus and bromine in the sample, which is only different from example 1 in that the extraction solution is 1h, and the rest is consistent with example 1.

[0077] Example 8

[0078] This example detects the concentration and content of phosphorus and bromine in the sample, which is only different from example 1 in that the amount of extraction solution added is 3mL, and the rest is consistent with example 1.

[0079] Example 9

[0080] This example detects the concentration and content of phosphorus and bromine in the sample, which is only different from example 1 in that the sample to be tested is a green onion sample, and the edible part of the green onion is washed, dried, cut, mixed, and made into a homogenate with a blender, and the rest is consistent with example 1.

[0081] Comparative Example 1

[0082] This comparative example detects the concentration and content of phosphorus and bromine in the sample, which is only different from example 1 in that no ammonia is added to the extraction solution, and the rest is consistent with example 1.

[0083] Comparative Example 2

[0084] This comparative example detects the concentration and content of phosphorus and bromine in the sample, which is only different from example 1 in that no EDTA is added to the extraction solution, and the rest is consistent with example 1.

[0085] Comparative Example 3

[0086] The concentration and content of phosphorus and bromine in the sample are detected in this comparative example, which is different from Example 1 only in that acetonitrile is replaced by EDTA in the extraction solution, and the rest is consistent with Example 1.

[0087] Comparative Example 4

[0088] The concentration and content of phosphorus and bromine in the sample are detected in this example

[0089] Shrimp sample preparation: After washing the shrimp, remove the head, skin, and intestinal glands to obtain shrimp meat, crush and mix evenly, freeze for preservation, and reserve for use.

[0090] Prepare 3 microwave tubes numbered DA4-1, DA4-2, and DA4-J1, respectively. Weigh 0.25 g of crushed shrimp sample into each microwave tube. Then add 1.00 mL of 1000 mg / L phosphorus standard solution and 2.00 mL of 1 mg / L bromine standard solution to the numbered DA1-J1 and centrifuge tube, respectively. Add 3.00 mL of first-grade water to the remaining samples, respectively. Then add 5 mL of concentrated nitric acid to each sample, pre-digest at 50°C, remove the cooling, add 0.5 mL of H2O2, cover the plug, tighten the seal cover, and place it in the microwave digestion instrument for digestion. The temperature is raised to 150°C for 8 min, maintained for 10 min, raised to 190°C for 5 min, and maintained for 10 min. After digestion, remove and cool. After cooling to room temperature, remove the microwave tube and chase the acid in the digested sample solution to 3 mL. Add sodium hydroxide solution and dilute to 25 mL with water to make the sodium hydroxide concentration 0.1%. At the same time, perform double blank tests.

[0091] Accurately pipette 10 mL of commercially available yttrium standard solution (1000 mg / L) and 1 mL of scandium standard solution (10000 mg / L) into a 100 mL volumetric flask, and dilute to the mark with deionized water to obtain 100 mg / L of yttrium and scandium standard stock solution. Accurately pipette 1 mL of yttrium and scandium standard stock solution (100 mg / L) into a 100 mL volumetric flask, and dilute to the mark with deionized water to obtain 1 mg / L of yttrium and scandium internal standard solution, which is the internal standard solution.

[0092] After diluting the sample solutions DA4-1, DA4-2, and DA4-J1 by 100 times for the phosphorus test and by 200 times for the bromine test, directly test the sample solutions DA4-1, DA4-2, and DA4-J1 for the bromine test. The sample inlet device is a three-way valve connected to three pump tubes, one end of which is connected to the atomization device of the Agilent inductively coupled plasma mass spectrometer. One of the three pump tubes is connected to the internal standard solution pump tube to continuously pump the internal standard solution, and the other is connected to the sample solution pump tube to pump in the sample solution. The internal standard solution and the sample solution are mixed in the three-way valve and then flow into the atomization device of the inductively coupled plasma mass spectrometer from the other pump tube.

[0093] Using Agilent inductively coupled plasma mass spectrometer (model 7700), open the instrument and related auxiliary equipment and computer, and preheat the instrument for 20 min. Set the instrument test parameters as follows: RF power is 1.55 kW, argon plasma gas flow rate is 10.0 L / min, auxiliary gas flow rate is 1.00 L / min, atomization chamber temperature is 5℃, atomization gas flow is 0.70 L / min. Pump speed is 10 rpm, stabilization time is 25 s, sample tube inner diameter is 1.02 mm, internal standard tube inner diameter is 0.89 mm, scanning mode is peak jumping, integration time is 0.1 s / time, and repetition number is 3 times.

[0094] Test Example 1

[0095] The present test example is for preparation of a standard curve

[0096] (1) Preparation of a standard curve

[0097] Accurately pipette 10 mL of a commercially available phosphorus standard solution (1000 mg / L) into a 100 mL volumetric flask, and dilute to the mark with deionized water, and shake to obtain a 100 mg / L phosphorus standard stock solution; accurately pipette 10 mL of the phosphorus standard stock solution (100 mg / L) into a 100 mL volumetric flask, and dilute to the mark with deionized water, and shake to obtain a 10 mg / L phosphorus standard intermediate solution; pipette 0.0 mL, 1.0 mL, 2.0 mL, 4.0 mL, 8.0 mL and 10.0 mL of the 10 mg / L phosphorus standard intermediate solution into six 100 mL volumetric flasks, respectively, and dilute to the mark with 4% (V / V) ammonia solution, and shake to obtain 0.0 μg / L, 100 μg / L, 200 μg / L, 400 μg / L, 800 μg / L and 1000 μg / L standard working curve solutions, and shake to obtain the phosphorus standard working curve solution to be tested.

[0098] Accurately pipette a 10 mL pipette onto a 100 mL volumetric flask containing commercially available bromine standard solution (1000 mg / L), dilute to the mark with deionized water, and mix well to obtain a 100 mg / L bromine standard stock solution; accurately pipette a 10 mL pipette onto a 100 mL volumetric flask containing bromine standard stock solution (100 mg / L), dilute to the mark with deionized water, and mix well to obtain a 10 mg / L bromine standard intermediate solution; accurately pipette a 10 mL pipette onto a 100 mL volumetric flask containing bromine standard stock solution (1 .... Dilute to the mark and shake well to obtain a 1 mg / L bromine standard intermediate solution; transfer 0.0 mL, 2.0 mL, 4.0 mL, 6.0 mL, 8.0 mL, and 10.0 mL of the 1 mg / L bromine standard intermediate solution into six 100 mL volumetric flasks, respectively, dilute to the mark with 4% (V / V) ammonia solution, and shake well to obtain standard working curve solutions of 0.0 μg / L, 20 μg / L, 40 μg / L, 60 μg / L, 80 μg / L, and 100 μg / L, and shake well to obtain the bromine standard working curve solution for testing.

[0099] The above solutions were tested separately using the detection method of Example 1, and the test results were as follows. Figure 1 and Figure 2 As shown, Figure 1 For the standard curve of phosphorus, Y = 1.460 × 10⁻⁶ -5 X + 5.479 × 10 -4 R = 0.9997, detection limit is 14.44 μg / L; Figure 2 The standard curve for bromine is given by Y = 1.098 × 10⁻⁶. -5 X + 5.179 × 10 -5 The R-squared value was 0.9996, and the detection limit was 3.586 μg / L. The detection limit was calculated by performing 20 tests on a blank solution and calculating the relative standard deviation; three times the standard deviation was taken as the detection limit.

[0100] (2) Preparation of blank samples

[0101] Prepare 20 centrifuge tubes numbered KB-A-1, KB-A-2, KB-A-3, KB-A-4, KB-A-5, KB-A-6, KB-A-7, KB-A-8, KB-A-9, KB-A-10, KB-A-11, KB-A-12, KB-A-13, KB-A-14, KB-A-15, KB-A-16, KB-A-17, KB-A-18, KB-A-19 and KB-A-20 in turn, and add 10 mL of an extraction solution, which is a 4% ammonia water and 2% EDTA aqueous solution, into each centrifuge tube. The centrifuge tubes are placed in a 90℃ constant temperature drying box for extraction for 3 h. During the extraction process, the centrifuge tubes are taken out every half an hour, shaken for 1 min, cooled, and diluted with water to 25 mL. The solution is centrifuged at a speed of 5000 r / min for 5 min, and the supernatant is filtered through a 0.45 μm filter membrane to obtain a blank solution.

[0102] The detection is performed by the method of Example 1, and the detection results are shown in Table 1.

[0103] Table 1

[0104]

[0105]

[0106] Test Example 2

[0107] The test example is performed to analyze the contents of phosphorus and bromine in the sample to be tested

[0108] The detection results are analyzed in this example. The concentrations of phosphorus and bromine in the sample solution are obtained by detection, and the contents of phosphorus and bromine in the sample are obtained by using a content calculation formula. The calculation formula is: X=(c1-c0)xfxv / m.

[0109] Wherein, X is the content of phosphorus or bromine in the sample to be tested; c1 is the concentration of the phosphorus element or the bromine element in the sample solution, c0 is the concentration of the phosphorus element or the bromine element in the blank solution, f is the dilution multiple; v represents the constant volume of the sample solution; and m is the mass of the sample to be tested.

[0110] The specific detection results are shown in Table 2.

[0111] Table 2

[0112]

[0113]

[0114] It can be known from the results that:

[0115] (1) It can be seen from the comparison of Examples 1-3 that the detection method of the present application can effectively detect the phosphorus and bromine in the sample, and has high detection accuracy.

[0116] (2) By comparing Example 1 with Examples 4-5, it can be seen that the concentration of ammonia and EDTA is too low and has a great impact on the detection results. By comparing with 6-7, it can be seen that the extraction conditions have a great impact on the detection results. Under certain extraction time and temperature, it is ensured that the tested items in the sample can be completely freed in the extract.

[0117] (4) By comparing Example 1 and Example 8, it can be seen that the amount of extract added has a significant impact on the test results. A certain amount of extract is needed to completely soak the sample, and the test item can be released into the extract during the extraction process, and the sample is also in a state of complete soaking during the extraction process.

[0118] (5) By comparing Example 1 and Example 9, it can be seen that the method of the present invention has high detection accuracy for other foods.

[0119] (6) As can be seen from the comparison between Example 1 and Comparative Examples 1-3, the absence of any one of the extracts will reduce the accuracy of the detection. Replacing EDTA with other reagents such as acetonitrile will also have a significant impact on the detection results. Acetonitrile cannot reduce the interference of many impurities in food, thus failing to achieve the technical effect of the present invention.

[0120] (7) By comparing Example 1 and Comparative Example 4, it can be seen that the sample treated with concentrated nitric acid has a greater impact on the detection results of bromine and has a higher detection accuracy for phosphorus, but it cannot have a higher detection accuracy for both bromine and phosphorus at the same time.

[0121] Test Example 3

[0122] This test case explores the accuracy of the detection.

[0123] Prepare 6 centrifuge tubes, numbered A0-1, A0-2, A0-3, A0-4, A0-5, and A0-6. Weigh 0.23g (accurate to 0.1mg) of shrimp sample into each of the 6 A0 tubes. Add 10mL of 4% ammonia + 2% EDTA extraction solution to each centrifuge tube. Place the tubes in a 90℃ constant temperature drying oven (shake for 1min every half hour) for 2.5h. After cooling, dilute to 25mL with water and centrifuge at 5000r / min for 5min. Filter the supernatant through a 0.45μm filter membrane and set aside. Meanwhile, prepare a reagent blank and shake well before testing.

[0124] The detection was performed using the method described in Example 1, and the results are shown in Table 3.

[0125] Table 3

[0126] Serial number Content of phosphorus Content of bromine A0-1 7327.9 mg / kg 7.343 mg / kg A0-2 7508.1 mg / kg 7.591 mg / kg A0-3 7151.9 mg / kg 7.788 mg / kg A0-4 7662.7 mg / kg 7.378 mg / kg A0-5 7240.6 mg / kg 8.072 mg / kg A0-6 7269.8 mg / kg 7.337 mg / kg

[0127] The relative standard deviation of phosphorus is 2.6%, and the relative standard deviation of bromine is 3.9%, which proves that the method has high detection accuracy.

[0128] Test Example 4

[0129] The test example explores the detection accuracy of phosphorus and bromine in egg, chicken, banana, monosodium glutamate and rice products

[0130] Prepare 15 centrifuge tubes, and respectively take 0.25 g (accurate to 0.1 mg) of egg samples for A4-1a, A4-1b and A4-J1, respectively, 0.25 g (accurate to 0.1 mg) of chicken samples for A4-2a, A4-2b and A4-J2, respectively, 0.25 g (accurate to 0.1 mg) of banana samples for A4-3a, A4-3b and A4-J3, respectively, 0.25 g (accurate to 0.1 mg) of monosodium glutamate samples for A4-4a, A4-4b and A4-J4, respectively, and 0.25 g (accurate to 0.1 mg) of rice samples for A4-5a, A4-5b and A4-J5, respectively. After the samples are weighed, 10 mL of 4% ammonia water + 2% EDTA extraction solution is added to each centrifuge tube, and the extraction is carried out in a 90℃ constant temperature drying box (removed every half hour and shaken for 1 min) for 2.5 h. After cooling, the volume is adjusted to 25 mL with water, centrifuged at a speed of 5000 r / min for 5 min, and the upper clear liquid is filtered with a 0.45 μm filter membrane for standby, and a reagent blank is prepared and shaken for measurement. L 4% ammonia water + 2% EDTA extraction solution, placed in a 90℃ constant temperature drying box (removed every half hour and shaken for 1 min) for extraction for 2.5 h, cooled, and the volume was adjusted to 25 mL with water. Centrifuged at a speed of 5000 r / min for 5 min, and the upper clear liquid was filtered with a 0.45 μm filter membrane for standby, and a reagent blank was prepared and shaken for measurement.

[0131] The detection is carried out by the method of Example 1, and the detection results are shown in Table 4

[0132] Table 4

[0133]

[0134]

[0135] The recovery rate of phosphorus is in the range of 95.0%-105%, and the recovery rate of bromine is in the range of 95.0%-105%, which proves that the method has high detection accuracy.

[0136] In summary, in the present application, the extraction solution of ammonia water and EDTA has short sample processing time, small measurement interference, high measurement accuracy, and is beneficial to batch processing.

[0137] The applicant states that the above description is only a specific embodiment of the present application, but the protection scope of the present application is not limited thereto, and it should be understood by those skilled in the art that any changes or replacements within the technical scope disclosed by the present application can be easily thought out by those skilled in the art, and all of them fall within the protection scope and disclosure scope of the present application.

Claims

1. A method for determining the concentrations of phosphorus and bromine, characterized in that, The detection method includes mixing the sample to be tested with an extractant to extract the sample, centrifuging the extractant and filtering it to obtain a sample solution, adding an internal standard solution and mixing, and then using an inductively coupled plasma mass spectrometer for detection. The extract contains ammonia and EDTA; the sample to be tested includes solid food products.

2. The detection method for determining phosphorus and bromine concentrations according to claim 1, characterized in that, The extract contains 4%-6% ammonia and 1%-2% EDTA.

3. The detection method for determining phosphorus and bromine concentrations according to claim 1 or 2, characterized in that, The mass-to-volume ratio of the sample to the extract is 0.25 g:(10-30) mL; Preferably, the solid food includes any one or a combination of at least two of the following: aquatic products, eggs, livestock and poultry meat, vegetables, fruits, seasonings, or grains.

4. The detection method for determining phosphorus and bromine concentrations according to any one of claims 1-3, characterized in that, The extraction temperature is 85℃-92℃, and the time is 2.5-3h.

5. The method for determining phosphorus and bromine content according to any one of claims 1-4, characterized in that, After extraction, water is added to bring the volume to 25-100 mL. Preferably, the centrifugation speed is 4000-6000 r / min and the time is 2-8 min.

6. The detection method for determining phosphorus and bromine concentrations according to any one of claims 1-5, characterized in that, The internal standard solution includes yttrium solution and / or scandium solution; Preferably, the scandium solution after mixing with the internal standard solution has a count value per second ranging from (7-80) × 10⁻⁶. 4 The count value per second for yttrium solution ranges from (3-30)×10⁻⁶. 5 .

7. The detection method for determining phosphorus and bromine concentrations according to any one of claims 1-6, characterized in that, The detection method also includes the preparation of a standard curve; Preferably, the standard curve includes a phosphorus standard curve and a bromine standard curve; Preferably, the concentration range of the phosphorus standard curve is 0-1000 μg / L; Preferably, the concentration range of the bromine standard curve is 0-100 μg / L.

8. The method for determining phosphorus and bromine concentrations according to any one of claims 1-7, characterized in that, The plasma argon flow rate of the inductively coupled plasma mass spectrometer is 10-20 L / min; Preferably, the temperature of the atomization chamber of the inductively coupled plasma mass spectrometer is 2-5°C.

9. The method for determining phosphorus and bromine concentrations according to any one of claims 1-8, characterized in that, The pumping speed of the inductively coupled plasma mass spectrometer is 10-15 rpm; Preferably, the scanning mode of the inductively coupled plasma mass spectrometry is peak skipping.

10. The application of the detection method for determining phosphorus and bromine concentration according to any one of claims 1-9 in the detection of phosphorus and bromine content in food.

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