[0041] The present invention will be described in further detail below through specific examples. The following examples are only descriptive and not restrictive, and the protection scope of the present invention cannot be limited by this.
[0042] A pretreatment and rapid detection method for solid food acesulfame potassium, which is characterized in that the method includes the following steps:
[0043] 1) Standard solution preparation:
[0044] Accurately weigh the standard substance of acesulfame potassium, dissolve and dilute it with ultrapure water, dilute it to 1L with a 2:98 methanolic ammonium acetate mixed solution, and configure it into a standard mother liquor of acesulfame potassium with a concentration of 0.8g/L. Measure 0.05mL, 0.5mL, 2mL, 5mL, 8mL, 10mL of acesulfame potassium standard mother solution to 100mL, configure to 0.5mL/L, 5mL/L, 20mL/L, 50mL/L, 80mL/L, 100mL /L acesulfame potassium standard solution, spare;
[0045] 2) Pretreatment and preparation of sample solution:
[0046] a. Noodle food samples:
[0047] Crush and mix the sample and accurately weigh 2~3g in a 25ml beaker, add 20ml of ultrapure water to dissolve, transfer the sample diluent to a 25mL volumetric flask in 3-5 times, extract with ultrasonic vibration for 5min, take it out, and transfer it to the volumetric flask. Add 1mL of potassium ferrocyanide, 1mL of zinc acetate and 1mL of ammonium sulfate solution respectively, vortex precipitation for 1min, dilute to volume with ultrapure water and mix well, take an appropriate amount in a centrifuge tube and centrifuge at 4000r/min for 5min, draw Filter the supernatant with a microporous membrane for use;
[0048] b. Oil and fat food samples:
[0049] Crush and mix the sample and accurately weigh 2~3g into a 50ml centrifuge tube with stopper, add 10ml phosphate buffer and 0.1g activated carbon, mix evenly with a vortex mixer, centrifuge at 4000r/min for 5min, and suck up After the clear solution is transferred to a 25ml volumetric flask and repeat the above steps, the two supernatants are combined for use; the phosphate buffer is made up to the mark and filtered with a microporous membrane for use;
[0050] c. Confectionery food samples:
[0051] Crush the sample and accurately weigh 0.5~1g, add ultrapure water to dissolve and transfer to a 25ml volumetric flask, add ultrapure water to make the volume and heat in a water bath at 60℃-70℃ for 30min, add ammonia water to adjust the pH of the solution to Neutral, stoppered, shake well and ultrasonically shake for 5 minutes, filter with a microporous membrane after cooling, and set aside.
[0052] 3) Detection and analysis by high performance liquid chromatography:
[0053] The standard solution and the sample solution are injected into the liquid chromatograph for liquid chromatographic analysis. The peak area of the standard solution and the peak area of Yangpin solution are quantitatively compared, the retention time is qualitative, and the external standard method is used for calculation.
[0054] The liquid chromatograph adopts Waters H-class high performance liquid chromatograph.
[0055] The liquid chromatography conditions are:
[0056] Column: C 18 1.7μm 50×2.1mm;
[0057] Mobile phase: the organic phase is methanol, the water phase is 0.02mol/L ammonium acetate solution, and the volume ratio of methanol to ammonium acetate solution is 2:98;
[0058] Flow rate: 1mL/min;
[0059] Column temperature: 40℃;
[0060] Injection volume: 10μL;
[0061] The detector adopts a UV ultraviolet detector, and the detection wavelength of the UV ultraviolet detector is 220 nm.
[0062] The method for preparing potassium ferrocyanide solution is to weigh 220 g of potassium ferrocyanide and dissolve it with ultrapure water to make the volume 1000 mL.
[0063] The preparation method of zinc acetate solution is to weigh 300g of zinc acetate and dissolve it in a small amount of water, add 30mL of glacial acetic acid and dilute to 1000mL with ultrapure water.
[0064] The preparation method of ammonium sulfate solution is to weigh 200g of ammonium sulfate and dissolve it with ultrapure water to make the volume 1000mL.
[0065] The phosphate buffer is a phosphate buffer with a pH of 7.2. The preparation method of the phosphate buffer is to weigh 23.88g of disodium hydrogen phosphate, dissolve it with water and dilute to 1000 mL to obtain a disodium hydrogen phosphate solution; weigh 9.07g of phosphoric acid Dissolve the potassium dihydrogen solution to 1000 mL with water to obtain a potassium dihydrogen phosphate solution. Mix the disodium hydrogen phosphate solution with B in a volume ratio of 7:3 to obtain a phosphate buffer with a pH of 7.2.
[0066] Activated carbon undergoes a high temperature treatment of 400℃ under the protection of nitrogen.
[0067] Ammonia is prepared by mixing liquid ammonia and water in a volume ratio of 1:1.
[0068] Ultrapure water meets the requirements of first-class water in "GB/T 6682-2008 Water Specifications and Test Methods for Analytical Laboratory".
[0069] In this example, biscuits were used as samples to perform acesulfame potassium liquid chromatography analysis. The specific processing methods are as follows:
[0070] After crushing and mixing the biscuit sample, accurately weigh 2g in a beaker, add 20mL ultrapure water to dissolve, transfer the sample diluent to a 25mL volumetric flask for 3 to 5 times, extract with ultrasonic vibration for 5 minutes, take it out, and transfer it to the volumetric flask. After adding 1mL potassium ferrocyanide, 1mL zinc acetate and 1mL ammonium sulfate solution respectively, vortex precipitation for 1min, dilute to volume with ultrapure water and mix evenly, take an appropriate amount in a centrifuge tube and centrifuge at 4000r/min for 5min, draw The supernatant is filtered with a microporous membrane to prepare a sample solution, and the sample solution is injected into the liquid chromatograph. The chromatogram of the sample is as follows figure 1 Shown. by figure 1 It can be seen that the peak time of acesulfame potassium is 3.5 min, and the peak area is 170 mAU at this time; figure 2 It is a liquid chromatogram obtained in the prior art without material pretreatment. It can be seen from the figure that the peak time of acesulfame potassium is 5.7 min and the peak area is -20 mAU. Compared figure 1 with figure 2 It can be seen that after the targeted pretreatment of the sample, the peak time of the liquid chromatography detection is shortened, the detection is faster and more convenient, and the detection content is higher and more accurate, which can fully extract the acesulfame potassium in the sample and improve the detection efficiency.
[0071] Analysis of results:
[0072] 1. Recovery rate
[0073] In this experiment, the external standard method was used for quantification, and the sample was subjected to a three-level spike recovery test. The experimental data results are shown in Table 1.
[0074] Table 1 Recovery rate
[0075]
[0076] It can be seen from the above experimental data that this method has a high recovery rate, a wide linear range, and good linearity. The standard addition recovery rate can reach more than 98%, the detection and extraction time of acesulfame potassium is shortened, and the efficiency is improved.
[0077] 2. Detection limit
[0078] The parallel determination was performed 20 times, and the detection limit of acesulfame potassium was tested. The experimental data results are shown in Table 2.
[0079] Table 2 Detection limit of acesulfame potassium
[0080]
[0081] It can be seen from the above experimental data that the detection limit of acesulfame potassium is 0.5743 mg/L, which meets the requirements of the national standard.
[0082] 3. Precision
[0083] The three-level spiked sample group was used to repeat the test 6 times to investigate the coefficient of variation. The experimental data results are shown in Table 3.
[0084] Table 3 Experimental accuracy
[0085]
[0086]
[0087] It can be seen from the above experimental data that the small coefficient of variation indicates that the experiment has good repeatability, the experimental results are accurate and reliable, and the experimental precision is high.
[0088] Although the embodiments and drawings of the present invention are disclosed for illustrative purposes, those skilled in the art can understand that various substitutions, changes and modifications are possible without departing from the spirit and scope of the present invention and the appended claims Therefore, the scope of the present invention is not limited to the content disclosed in the embodiments and drawings.
