Lily matrix standard substance containing multiple elements and preparation method thereof

Abstract

The invention discloses a lily matrix standard substance containing multiple elements and a preparation method thereof, and belongs to the technical field of development of standard substances, fresh lily bulbs are used as raw materials, and are cleaned, dried and peeled to obtain lily bulb slices; the method comprises the following steps: drying, crushing, grinding, sieving and uniformly shaking lily bulb slices, performing particle size analysis on lily powder, performing primary homogeneity detection on the lily powder passing through the particle size analysis, performing irradiation on the lily powder passing through the primary homogeneity detection, and performing split charging and numbering after irradiation to obtain the lily powder. Performing uniformity test, stability test, constant value analysis and standard value determination to obtain the lily matrix standard substance containing multiple elements; and drying the lily powder for 5 hours at the temperature of 80 DEG C. The lily matrix standard substance containing the multiple elements has good uniformity and stability, and can be used for measurement method verification, quality control, analysis method confirmation, evaluation and the like in detection laboratories in the industries of agriculture and animal husbandry, food, environment and the like.

Description

Technical Field

[0001] The invention belongs to the technical field of preparation of standard substances, and in particular relates to a lily matrix standard substance containing multiple elements and a preparation method thereof. Background Art

[0002] Lily (Lilium spp.) is a perennial herbaceous plant in the genus Liliaceae, a traditional medicinal and edible treasure, listed in the Chinese Pharmacopoeia as a legally recognized medicinal material. Its bulbs are white as jade, its flesh is delicate, and its flavor is sweet and refreshing. They are rich in protein, reducing sugars, vitamins B and C, and various trace elements. They also contain bioactive ingredients such as phenols, steroidal saponins, and polysaccharides. Traditional medicine believes that lilies have the effects of moistening the lungs and relieving coughs, calming the mind, and clearing heat and promoting urination. Modern research indicates that their extracts possess significant antioxidant, anti-inflammatory, hypoglycemic, and anti-tumor properties.

[0003] As a high-quality cultivar of the lily family, the Lanzhou lily (Lilium davidii var. unicolor) is renowned for its "extremely sweet flavor, low fiber content, and absence of bitterness." Not only is it large in size, but it also boasts a high soluble sugar content of 13%. To ensure food safety for consumers, my country has established comprehensive standards for the maximum limits of contaminants in food. The "National Food Safety Standard - Limits of Contaminants in Food" (GB 2762-2022) specifies limits for Cd, Cr, and As. Furthermore, Cu, Fe, Zn, Mn, and Sr are essential trace elements crucial to human health and life. Accurately determining the limited and trace elements in lilies is crucial for further enhancing their edible and medicinal value, ensuring the quality of traditional Chinese medicine, and ensuring food safety.

[0004] At present, when testing limited elements and trace elements in lily, various testing laboratories lack lily matrix standard substances. Laboratories generally use single-element solution standard substances for instrument calibration and quality control. Since the matrix of the single-element solution is inconsistent with that of the sample to be tested, there is a matrix effect. The above-mentioned detection method cannot control the interference caused by the matrix effect, and the accuracy and reliability of the test results are difficult to guarantee.

[0005] Therefore, how to prepare a lily matrix standard material containing multiple elements and eliminate the error caused by the matrix effect is a problem that needs to be solved urgently by those skilled in the art. Summary of the Invention

[0006] In order to solve the above technical problems, the present invention proposes a multi-element lily matrix standard substance and a preparation method thereof.

[0007] To achieve the above object, the present invention provides a method for preparing a multi-element lily matrix standard substance, comprising: using fresh lily bulbs as raw materials to prepare clean, dry lily bulb slices; crushing, grinding, sieving, and shaking to prepare lily powder; subjecting the lily powder to a particle size analysis and a preliminary uniformity inspection; irradiating the lily powder that passes the preliminary inspection; and packaging and numbering the powder after irradiation. The powder is then subjected to a uniformity inspection, a stability inspection, a fixed value analysis, and a standard value determination to obtain the multi-element lily matrix standard substance.

[0008] Before the determination analysis, the lily powder was dried at 80°C for 5 hours. The lily matrix standard material will introduce some moisture during the preparation process, so moisture correction was performed by drying in the determination step.

[0009] The multiple elements are Cd, Cr, As, Cu, Fe, Zn, Mn and Sr.

[0010] In national and international standards for limiting harmful elements, such as the National Food Safety Standard Limits of Contaminants in Food (GB2762-2022) and European Commission Regulation (EU) 2023 / 915, GB2762-2022 sets limits for Pb, Cd, Hg, As, and Cr in tuber and fresh vegetables. The limits for Pb and Cd in tuber vegetables are 0.2 mg / kg and 0.1 mg / kg, respectively, while the limits for total Hg, total As, and Cr in fresh vegetables are 0.01 mg / kg, 0.5 mg / kg, and 0.5 mg / kg, respectively. (EU) 2023 / 915 sets limits for Pb and Cd in vegetables, with limits of 0.1 mg / kg and 0.3 mg / kg, respectively. According to these standards, the present invention uses ICP-MS to perform a full-element semi-quantitative method on lily powder, estimates the content of all elements, and then uses the ICP-MS quantitative method to confirm the element values. Through measurement, the limited elements Pb and Hg were not detected. Finally, three limited elements Cd, Cr, and As and five essential trace elements for the human body, Cu, Fe, Zn, Mn, and Sr, were selected as target elements. The method also complies with the components and measurement methods in national standards such as the "National Food Safety Standard - Determination of Multiple Elements in Food" (GB5009.268-2016).

[0011] Furthermore, the method for preparing the multi-element lily matrix standard substance comprises the following steps:

[0012] (1) Collecting a number of fresh lilies, and selecting lily bulbs that are well grown, free of pests and diseases, and of suitable maturity as raw materials;

[0013] (2) Clean the selected fresh lily bulbs, remove the dirt, impurities and fibrous roots on the surface, and spread them out in the sun to dry the surface moisture;

[0014] (3) peeling the cleaned lily bulbs to obtain lily bulb slices;

[0015] (4) drying the lily bulb slices;

[0016] (5) crushing the dried lily bulb slices;

[0017] (6) Grinding the crushed material to obtain lily powder;

[0018] (7) Sieve the ground lily powder through a 100-mesh sieve;

[0019] (8) Place all the sieved lily powder in a drum shaker and shake 360 ​​degrees for 48 hours to achieve the greatest possible homogenization effect;

[0020] (9) Perform particle size analysis on the shaken lily powder;

[0021] (10) Conducting a preliminary homogeneity test on the lily powder that has passed the particle size analysis;

[0022] (11) Sterilize the lily powder that has passed the initial homogeneity test by irradiation with γ-rays;

[0023] (12) The irradiated lily powder was vacuum sealed in PA-PE composite bags, with 10 g per bag, and divided into 960 bags;

[0024] (13) Sequentially number the packaged lily powder;

[0025] (14) Store the numbered lily powder in a cool and dry place;

[0026] (15) Uniformity test;

[0027] (16) Stability test;

[0028] (17) Fixed value analysis: before performing the fixed value analysis, the lily powder was dried at 80° C. for 5 hours;

[0029] (18) Determine the standard value and obtain the multi-element lily matrix standard substance.

[0030] Furthermore, in step (3), the method of flaking is not limited. For example, the flaking can be done by hand, or by making a horizontal cut at the base of the bulb, as long as the scales are successfully separated.

[0031] Furthermore, in step (4), the drying temperature is 60° C. and the drying time is 48 hours. Exemplarily, the drying is to place the lily bulb slices in a forced air drying oven and bake them at 60° C. for 48 hours.

[0032] Furthermore, in step (5), the lily bulb powder is crushed to a particle size of ≤0.5 mm. Exemplarily, the pulverization is performed in a pulverizer equipped with titanium alloy blades at a pulverizer speed of 1690 rpm, a rotor circumferential speed of 12.4 m / s, and a power of 1.5 kW. When the particle size is smaller than the aperture of the bottom sieve (0.5 mm), it is discharged from the pulverization chamber and collected in a receiving container until all the lily bulb pieces are discharged from the pulverization chamber and the pulverization is completed.

[0033] Furthermore, in step (6), the lily bulb pieces are ground until the particle size of the lily powder is ≤0.12 mm. For example, the crushed lily bulb pieces are placed in a grinder and ground at a speed of 18,000 rpm, a rotor circumferential speed of 93 m / s, and a power of 1.3 kW. When the particle size is smaller than the aperture of the bottom sieve (0.12 mm), it is discharged from the grinding chamber and collected in a receiving container until all the lily bulb pieces are discharged from the grinding chamber and the grinding is completed to obtain lily powder.

[0034] For example, in step (9), 0.2 g of the shaken lily powder sample is placed in a clean 150 mL beaker, 100 mL of distilled water is added as a dispersant, and the particle size distribution is measured.

[0035] Exemplarily, in step (11), the γ-ray is 60 The γ-rays produced by Co have an irradiation intensity of 25 kGy.

[0036] Furthermore, in step (15), microwave digestion-inductively coupled plasma mass spectrometry (ICP-MS) combined with variance analysis is used to perform a uniformity test.

[0037] Furthermore, in step (16), the stability is tested using the ICP-MS method combined with a linear regression model.

[0038] Furthermore, the stability test includes a long-term stability test, a stability test under extreme transportation conditions, and a stability test after opening. The test results show that the multi-element lily matrix standard material of the present invention has good uniformity and stability.

[0039] Furthermore, in step (17), microwave digestion-inductively coupled plasma mass spectrometry (ICP-MS), inductively coupled plasma optical emission spectrometry (ICP-OES), graphite furnace atomic absorption spectrometry (GF-AAS) and atomic fluorescence spectrometry (AFS) were used in conjunction with 8 laboratories to determine the values ​​of 8 elements in lily powder.

[0040] The present invention also provides a multi-element lily matrix standard substance prepared according to the above preparation method.

[0041] The present invention also provides an application of the multi-element lily matrix standard substance in measurement method verification, quality control, confirmation and evaluation of analytical methods.

[0042] Compared with the prior art, the present invention has the following advantages and technical effects:

[0043] The multi-element lily matrix standard material of the present invention is prepared using fresh lily bulbs as raw material. The elements Cd, Cr, As, Cu, Fe, Zn, Mn, and Sr are analyzed and quantified. The values ​​used to test the uniformity and stability of the components of the standard material are measured using microwave digestion-inductively coupled plasma mass spectrometry (ICP-MS), the same method used for determining the values. The measurement results are then tested for uniformity and stability using analysis of variance and a linear regression model, respectively. The test results demonstrate that the multi-element lily matrix standard material of the present invention exhibits good uniformity and stability. Eight elements, including Cd, Cr, and As, were determined in lily powder using microwave digestion-inductively coupled plasma mass spectrometry (ICP-MS), inductively coupled plasma optical emission spectrometry (ICP-OES), graphite furnace atomic absorption spectrometry (GF-AAS), and atomic fluorescence spectrometry (AFS) in a collaborative study of eight laboratories. The results were found to be normally distributed using the D'Agostino and Shapiro-Wilk methods. Outliers were removed using both the Grubbs and Dixon methods, and the Cochran method was used to verify the data were equally accurate. After eliminating outliers and ensuring that all data groups were consistent, equally accurate, and normally distributed, the mean values ​​of the data groups were averaged to establish the standard values ​​for each elemental component in lily powder. The standard values ​​and uncertainties for each element constitute the quantitative standard material for elemental analysis of lily powder. After stability testing and verification, the validity period of this standard substance is 12 months and it can be used for measurement method verification, quality control, analytical method confirmation and evaluation in testing laboratories in industries such as agriculture, animal husbandry, food and environment.

[0044] Water loss from standard substances can affect the accuracy of their concentration and composition, thereby affecting the reliability of test results. Water loss correction ensures the accuracy and reliability of measurement results, meeting metrological requirements. This paper uses two technical solutions to determine the water loss rate of lily powder: the first solution calculates the water loss rate by drying at different temperatures, while the second solution calculates the water loss rate by drying with different desiccants. Through comparative analysis, we find water loss values ​​that agree between the two solutions. Based on this, we determine the water loss control conditions for conventional experiments: drying the lily powder at 80°C for 5 hours before performing water loss correction before measurement.

[0045] The multi-element lily matrix standard substance prepared by the present invention retains the background characteristics of the matrix sample to the greatest extent, ensuring consistency between the matrix of the standard substance and the matrix of the sample being tested, reducing errors caused by matrix effects, and is of great significance for the quality testing of lily products. The multi-element lily matrix standard substance prepared by the present invention has excellent uniformity and stability, and can be used as a national first-level standard substance, with strong economic and social benefits. BRIEF DESCRIPTION OF THE DRAWINGS

[0046] The accompanying drawings, which constitute part of the present invention, are provided to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are provided to explain the present invention and do not constitute an undue limitation of the present invention. In the accompanying drawings:

[0047] Figure 1 This is the frequency curve of lily powder particle size distribution. DETAILED DESCRIPTION

[0048] Various exemplary embodiments of the present invention will now be described in detail. This detailed description should not be considered as limiting the present invention, but rather as a more detailed description of certain aspects, features, and embodiments of the present invention.

[0049] It should be understood that the terms described herein are intended only to describe particular embodiments and are not intended to limit the present invention. In addition, for numerical ranges herein, it should be understood that each intermediate value between the upper and lower limits of the range is also specifically disclosed. Each smaller range between any intermediate value within a stated value or stated range and any other stated value or intermediate value within the stated range is also encompassed by the present invention. The upper and lower limits of these smaller ranges may be independently included or excluded within the scope.

[0050] Unless otherwise indicated, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art. Although only preferred methods and materials are described herein, any methods and materials similar or equivalent to those described herein may also be used in the practice or testing of the present invention. All documents mentioned in this specification are incorporated by reference to disclose and describe the methods and / or materials associated with the documents. In the event of any conflict with any incorporated document, the contents of this specification shall prevail.

[0051] It will be apparent to those skilled in the art that various modifications and variations may be made to the specific embodiments described herein without departing from the scope or spirit of the invention. Other embodiments will be apparent to those skilled in the art from the description of the invention. The description and examples are intended to be exemplary only.

[0052] The words “include,” “including,” “have,” “contain,” etc. used in this document are open-ended terms, meaning including but not limited to.

[0053] The multi-element lily matrix standard substance prepared by the present invention has good uniformity and stability, retains the background characteristics of the matrix sample to a great extent, and reduces the error caused by matrix effect interference. It can be used for measurement method verification, quality control, analysis method confirmation and evaluation in testing laboratories in industries such as agriculture, animal husbandry, food and environment. It can also be used for calibrating measuring instruments and evaluating measurement methods. It is simple to operate and easy to promote.

[0054] The matrix standard substance of the present invention is a standard substance with actual sample characteristics, which can effectively avoid the influence of matrix (quality) effect on material composition analysis during the detection process. At present, similar lily matrix standard substances are still in a blank at home and abroad. Therefore, the development of this lily matrix standard substance can facilitate the measurement method verification, quality control, analytical method confirmation and evaluation of similar matrix samples in laboratories and testing institutions, etc., not only ensuring the reliability and traceability of measurement results, but also having important significance for protecting people's health. For example, the multi-element lily matrix standard substance of the present invention can be used as a standard substance to detect the element contents of Cd, Cr, As, Cu, Fe, Zn, Mn and Sr in lilies.

[0055] "Lily bulb" refers to the modified stem of the underground part of lily. Lily bulbs are usually oblate or nearly spherical, and the size varies depending on the variety and the number of years of growth. The diameter is generally about 3-10 cm, and the surface is covered with multiple layers of dry membranous scales. These scales are wrapped layer by layer to form an onion-like structure. After peeling off the outer layer of dry scales, the inside is a thick and juicy bulb disk, on which many fleshy scales grow. These scales are the main part of the lily bulb and are rich in water and nutrients. The present invention selects lily bulb as the raw material to prepare lily powder, mainly based on its biological characteristics, nutritional components, processing applicability and traditional application value and other scientific principles. Lily is a perennial herb, and its bulb undertakes the core function of nutrient storage during the growth cycle. The scales are thick and fleshy: easy to crush and grind. The bulb grows underground, is less affected by environmental fluctuations, and has a stable composition.

[0056] In the present invention, the characteristic values ​​of the lily matrix standard substance can be traced back to appropriate units or reference standards.

[0057] Unless otherwise specified, the room temperature in the present invention is 25±2°C.

[0058] All raw materials used in the examples of the present invention were purchased from commercial sources. Thickened PA-PE composite material was purchased from Jiangyin Yongda Composite Packaging Co., Ltd., with a thickness of 19 threads and a specification of 9.5 cm×14 cm.

[0059] It should be pointed out that the matters not described in detail in the present invention are conventional operating means in this field and are not the focus of the present invention.

[0060] The technical solution of the present invention is further illustrated by the following examples.

[0061] Example 1

[0062] This embodiment provides a method for preparing a multi-element lily matrix standard substance, the steps of which are as follows:

[0063] (1) Collection: Collect a number of fresh lilies from the lily planting base in Qilihe District, Lanzhou City, and select lily bulbs with good growth, no pests and diseases, and appropriate maturity as raw materials;

[0064] (2) Cleaning: Clean the selected fresh lily bulbs to remove dirt, impurities and fibrous roots on the surface, and spread them out in the sun to dry the surface moisture;

[0065] (3) Slicing: Manually slice the cleaned lily bulbs (cut a horizontal cut at the base of the bulb to separate the scales) to obtain lily bulb slices;

[0066] (4) Drying: Place the lily bulb pieces in a forced air drying oven and bake at 60°C for 48 hours;

[0067] (5) Crushing: The dried lily bulb slices are placed in a grinder equipped with titanium alloy blades and crushed at a speed of 1690 rpm, a rotor circumferential speed of 12.4 m / s, and a power of 1.5 kW. When the particle size is smaller than the aperture of the bottom sieve (0.5 mm), it will be discharged from the crushing chamber and collected in a receiving container until all the lily bulb slices are discharged from the crushing chamber and the crushing is completed;

[0068] (6) Grinding: The crushed lily bulb pieces are placed in a grinder and ground at a speed of 18,000 rpm, a rotor circumferential speed of 93 m / s, and a power of 1.3 kW. When the particle size is smaller than the aperture of the bottom sieve (0.12 mm), it will be discharged from the grinding chamber and collected in a receiving container until all the lily bulb pieces are discharged from the grinding chamber. Grinding is completed to obtain lily powder.

[0069] (7) Sieving: Sieve the ground lily powder through a 100-mesh sieve;

[0070] (8) Shake well: Place all the sifted lily powder in a drum shaker and shake 360 ​​degrees for 48 hours to achieve the best possible homogenization effect;

[0071] (9) Particle size analysis: 0.2 g of the shaken lily powder sample was placed in a clean 150 mL beaker, 100 mL of distilled water was added as a dispersant, and the particle size distribution was measured. The specific steps are as follows: The particle size distribution of the lily powder was analyzed using a Mastersizer 3000 laser particle size analyzer. During the measurement, 0.2 g of the lily powder sample was placed in a clean 150 mL beaker, 100 mL of distilled water was added as a dispersant, and the SOP standardized measurement operation procedure was used. Under the conditions that the refractive index and absorbance of the lily powder were 1.520 and 0.100, the refractive index of the dispersant (water) was 1.330, and the laser shading degree was 11.05%, the sample was injected through a HydroLV wet method large-capacity sampler, and the laser particle size analyzer was used for measurement. Each sample was repeated 3 times, and the average value was automatically calculated. The weighted residual was 0.94%. The analysis results and the frequency curve of the particle size distribution of the sample are shown in Tables 1 and Figure 1 .

[0072] Table 1 Lily powder particle size analysis results

[0073] Sample measurement Sample number Dx(10)(μm) Dx(50)(μm) Dx(90)(μm) 1 350 10.4 63.6 139 2 350 10.4 63.5 138 3 350 10.4 63.5 139 average value / 10.4 63.5 139 Standard Deviation / 0.0227 0.0368 0.245 RSD (%) / 0.218 0.058 0.177

[0074] The above measurement results show that more than 90% of the particles in the lily powder samples have a particle size of less than 150 μm, and the overall particle size range is 0-210 μm, which is consistent with the sieve aperture value (150 μm) used during screening. In addition, each sample was measured three times, and the standard deviation of the measurement results was less than 0.5%, indicating that the particle size distribution of the lily powder samples is relatively uniform and meets the preparation requirements.

[0075] (10) Initial homogeneity test: The lily powder that passed the particle size analysis was subjected to an initial homogeneity test. Six samples of approximately 0.5 g were taken from different parts of the shaken lily powder sample and dried at 80°C for 5 hours. Microwave digestion-inductively coupled plasma mass spectrometry (ICP-MS) was used for measurement, and the uncertainty of the measurement results was evaluated. The standard deviation of the mean value of each component was taken as the Class A uncertainty. The Class B uncertainty was determined by multiple factors. Here, only the uncertainty of the standard solution used to draw the standard curve was considered. Class A and Class B were combined to obtain the relative uncertainty U introduced by the initial homogeneity test. rel , (k = 2), (results are shown in Table 2). Comparison of the uncertainty of the initial uniformity test results with the uncertainty level of the national primary standard material shows that the uncertainty of the initial uniformity test results is within the expected uncertainty level, and sample packaging can be carried out.

[0076] Table 2 Preliminary inspection results of the uniformity of each element in lily powder (unit: mg / kg)

[0077] Serial number Cd Cr As Cu Fe Zn Mn Sr 1 0.0784 0.191 0.0282 3.69 21.3 12.1 6.71 6.06 2 0.0803 0.188 0.0274 3.66 22.1 12.5 6.94 6.14 3 0.0785 0.178 0.0272 3.75 22.7 12.4 6.73 5.86 4 0.0761 0.189 0.0267 3.51 21.9 12.9 6.84 5.93 5 0.0772 0.193 0.0281 3.59 22.5 12.7 6.98 6.11 6 0.0815 0.176 0.0265 3.65 21.3 12.2 6.92 5.96 average value 0.0787 0.186 0.0274 3.64 22.0 12.5 6.86 6.01 SD 0.0020 0.0071 0.0007 0.0830 0.5888 0.3011 0.1154 0.1103 RSD (%) 2.51 3.81 2.56 2.28 2.68 2.42 1.68 1.83 <![CDATA[u A,rel (%)]]> 1.03 1.56 1.05 0.93 1.09 0.99 0.69 0.75 <![CDATA[u B,rel (%)]]> 0.1 0.05 0.05 0.05 0.1 0.05 0.5 0.5 <![CDATA[u c,rel (%)]]> 1.03 1.56 1.05 0.93 1.10 0.99 0.85 0.90 <![CDATA[U rel (%),k=2]]> 2.1 3.1 2.1 1.9 2.2 2.0 1.7 1.8

[0078] (11) Irradiation: The lily powder that passed the initial uniformity inspection was irradiated with an intensity of 25 kGy. 60 Sterilization by γ-ray irradiation produced by Co;

[0079] (12) Packaging: The irradiated lily powder was vacuum sealed with thickened PA-PE composite bags, each bag was 10 grams, and the bags were divided into 960 bags. To prevent the samples from being contaminated and deteriorating, all tools and instruments used for mixing and packaging were rinsed with tap water and deionized water in advance, and then disinfected with anhydrous ethanol. After the mixed samples met the requirements of the initial uniformity inspection, they were vacuum sealed with thickened PA-PE composite bags. No sample backflow was found during vacuuming. The PA-PE composite bags were not damaged or leaked within two years of packaging. The packaging unit specification was 10 grams / bag. The bags were then vacuum packed again with composite film aluminum foil bags.

[0080] (13) Numbering: Sequentially number the packaged lily powder;

[0081] (14) Storage: Store the numbered lily powder in a cool, dry place;

[0082] (15) Uniformity test

[0083] S1. Detection Method

[0084] a. Sample digestion

[0085] To prevent sample contamination during the digestion process, 65% (mass fraction, the same below) concentrated nitric acid (6 mL) was first added to the digestion tank. The digestion tank was then heated and cleaned using a microwave digestion instrument program. The digestion tank was then rinsed three times with tap water and then ultrapure water, followed by drying. During sample digestion, lily powder samples were randomly selected, dried at 80°C for 5 hours, and then cooled to room temperature in a desiccator. Two replicates of 0.5 g (accurate to 0.0001 g) were weighed from each bag. 65% concentrated nitric acid (6 mL) was then added to the sample, and the sample was heated and digested in a microwave digestion instrument (conditions and parameters are shown in Table 3). After digestion, the digestion tank was placed in an acid removal rotor (conditions and parameters are shown in Table 4) and heated to remove the acid until 0.5 mL of the digestate remained. The digestate was then transferred to a 50 mL polyethylene tube, made up to 50 mL with ultrapure water, and accurately weighed on an electronic balance. The sample dilution factor was calculated.

[0086] Table 3 Microwave digestion parameters

[0087]

[0088] Table 4 Microwave acid removal parameters

[0089]

[0090] b. On-machine testing

[0091] The digestion solution (sample solution) was measured using an inductively coupled plasma mass spectrometer (ICP-MS) using an internal standard method with In as the internal standard element at a concentration of 1 mg / L.

[0092] ICP-MS standard curve: 1000 μg / mL cadmium single element solution standard substance was diluted stepwise with 2 wt% HNO3 to prepare a series of cadmium element standard working solutions with mass concentrations of 0.00, 0.25, 0.5, 1.0, 2.0, and 4.0 μg / kg, respectively. The ICP-MS was adjusted to the optimal working conditions (RF power of 1500 W, carrier gas of 0.90 L / min, He flow rate of 4.3 mL / min, Omega lens voltage of 10.8 V, Omega deflection voltage of -80 V, extraction lens of -160 V, Deflect of 1.4 V, skimmer and sampling cones of platinum; PFA concentric nebulizer, integration time of 0.5 s, sampling depth of 8 mm) using a tuning solution (Ce, Co, Li, Tl, Y concentrations of 10 μg / L). The cadmium standard working solutions, blank samples, and sample solutions were measured. The signal values ​​of the cadmium standard working solutions showed a good linear relationship with the mass concentration, and the linear equation was y = 0.0010x + 5.5029 × 10 -6 , the correlation coefficient is 0.9998, and the mass fraction of cadmium in the sample is calculated according to formula (1):

[0093]

[0094] In formula (1): x is the mass concentration of cadmium in the sample, mg / kg;

[0095] c—mass concentration of cadmium in the sample solution, μg / kg;

[0096] m1—the weight of the sample when it is digested, g;

[0097] m2—total mass of sample digestion solution after dilution, g.

[0098] c. Method Validation

[0099] In order to verify the accuracy and reliability of the measurement method and the measurement results, the national first-level standard material garlic powder component analysis standard material GBW10022 was selected to verify the determination method. The same digestion method and measurement method were used for determination. The results of the determination fell within the uncertainty range of the nominal value of the standard material, as shown in Table 5. At the same time, the normalized deviation (E n ) Evaluate the verification results, E n The value is less than 1, indicating that this method is accurate and reliable for the determination of cadmium in lily powder.

[0100] Table 5 Method Validation Results

[0101] Standard substance name Garlic powder component analysis standard material GBW10022 element Cd Certified value and uncertainty (mg / kg) 0.062±0.003 Measured value and standard deviation (mg / kg) 0.0648±0.002 <![CDATA[E n ]]> 0.78

[0102] S2. Statistical Results of Homogeneity Test

[0103] After sub-packaging the lily powder reference material, 960 units (bags) of samples were obtained. According to the sampling principle of JJF1343-2022 "Certification and Evaluation of the Homogeneity and Stability of Reference Materials", if the total number of units is N, when 500 < N ≤ 1000, the number of sampled units is not less than 25. 26 bags were randomly selected in the order before and after sample packaging and measured in a single sequence random order. The random order 1 is: 102-258-204-761-39-347-502-223-907-315-798-93-9; The random order 2 is: 568-922-212-204-487-258-93-820-682-661-182-502-352-39-673-267-487-352-113-212-69-223-182-315-69-820. Then, the measured data were respectively evaluated for homogeneity using the analysis of variance method. The statistical results of the variance test are listed in Tables 6-1 to 6-4. Taking the significance level α = 0.05, the statistic F of 8 elements 计算值 less than F α = 0.05, it can be considered that there is no significant difference between groups and the homogeneity is good.

[0104] Table 6-1 Homogeneity Test Results of Cd and Cr Elements in Lily Powder (Unit: mg / kg)

[0105]

[0106]

[0107] Table 6-2 Homogeneity Test Results of As and Cu Elements in Lily Powder (Unit: mg / kg)

[0108]

[0109]

[0110] Table 6-3 Homogeneity Test Results of Fe and Zn Elements in Lily Powder (Unit: mg / kg)

[0111]

[0112]

[0113] Table 6-4 Test results of uniformity of Mn and Sr elements in lily powder (unit: mg / kg)

[0114]

[0115]

[0116] Note: v1 is the numerator degree of freedom, v2 is the denominator degree of freedom; Q1 is the sum of variance between groups; Q2 is the sum of variance within groups; M betwen is the between-group variance; M within is the within-group variance; S bb is the standard deviation between bottles; u bb is the uncertainty component caused by the inhomogeneity between bottles; S r is the standard deviation within the group; F 计算值 Calculate the value for the F test; F α-0.05 is the F critical value.

[0117] (16) Stability test

[0118] According to JJF1343-2022 "Value determination, uniformity and stability evaluation of reference materials", the measurement results are fitted with a linear regression model, and the time intervals of the stability test are carried out according to the principle of first dense and then sparse. In order to ensure the reliability of the mass value of the reference material, the stability should be evaluated at multiple time intervals within the expected validity period. At the same time, the environmental conditions during the stability evaluation period should be recorded, and the measurement results of multiple time intervals should be subjected to t distribution test. Under the confidence probability of 95%, when the t of n tests is β1 <t (0.95,n-2) , it indicates that the characteristic quantity value of the standard substance has no significant change.

[0119] S1. Long-term stability test

[0120] The lily matrix standard material stored in a dry and cool place indoors (temperature is (22±2)℃) was dried at 80℃ for 5h, and then the stability was investigated by microwave digestion pretreatment method and inductively coupled plasma mass spectrometry. Three bags of samples were randomly selected each time, and each bag of samples was sampled twice independently from different parts. From February 2023 to March 2024, five stability tests were conducted, with intervals of 1 month, 5 months, 9 months and 13 months. The test results were subjected to t-distribution test. The test results are shown in Tables 7-1 to 7-8. After stability test t β1 <t (0.95,3) , indicating that all eight elements have good stability.

[0121] Table 7-1 Cd stability test results in lily powder (unit: mg / kg)

[0122]

[0123] Table 7-2 Cr stability test results in lily powder (unit: mg / kg)

[0124]

[0125] Table 7-3 As stability test results in lily powder (unit: mg / kg)

[0126]

[0127]

[0128] Table 7-4 Cu stability test results in lily powder (unit: mg / kg)

[0129]

[0130] Table 7-5 Test results of Fe stability in lily powder (unit: mg / kg)

[0131]

[0132] Table 7-6 Test results of Zn stability in lily powder (unit: mg / kg)

[0133]

[0134] Table 7-7 Test results of Mn stability in lily powder (unit: mg / kg)

[0135]

[0136] Table 7-8 Test results of Sr stability in lily powder (unit: mg / kg)

[0137]

[0138]

[0139] Note: β1 is the slope; β0 is the intercept; s( β1 ) is the standard deviation of the slope; t (0.95,3) is the critical value of the t test; t β1 Calculated value for t test; u s Standard uncertainty introduced for long-term stability; u s,rel Introducing relative uncertainty for long-term stability.

[0140] S2. Stability test under extreme transportation conditions

[0141] In order to investigate the effect of temperature conditions on the characteristic values ​​of cadmium in lily matrix reference materials, two bags were randomly sampled each time according to the synchronous stability evaluation plan. They were stored at 60℃ and -20℃ for 0, 1, 3, 6 and 10 days respectively. After drying at 80℃ (5h), the stability was investigated by microwave digestion pretreatment method and inductively coupled plasma mass spectrometry. Three bags of samples were randomly selected each time. Each bag of samples was sampled twice independently from different parts. The test results were subjected to t-distribution test. The test results are shown in Tables 8-1 to 8-8. After stability test t β1 <t (0.95,3) , indicating that the eight elements in the sample have good stability at 60℃ and -20℃.

[0142] Table 8-1 Stability test results of Cd in lily powder under extreme transportation conditions (unit: mg / kg)

[0143]

[0144] Table 8-2 Stability test results of Cr in lily powder under extreme transportation conditions (unit: mg / kg)

[0145]

[0146]

[0147] Table 8-3 Stability test results of As in lily powder under extreme transportation conditions (unit: mg / kg)

[0148]

[0149] Table 8-4 Stability test results of Cu in lily powder under extreme transportation conditions (unit: mg / kg)

[0150]

[0151]

[0152] Table 8-5 Stability test results of lily powder Fe under extreme transportation conditions (unit: mg / kg)

[0153]

[0154] Table 8-6 Lily powder Zn stability test results under extreme transportation conditions (unit: mg / kg)

[0155]

[0156]

[0157] Table 8-7 Stability test results of Mn in lily powder under extreme transportation conditions (unit: mg / kg)

[0158]

[0159] Table 8-8 Stability test results of Sr in lily powder under extreme transportation conditions (unit: mg / kg)

[0160]

[0161]

[0162] S3. Stability monitoring after opening: According to the stability monitoring method in JJF1343 "Determination of value, uniformity and stability evaluation of reference materials", any lily powder sample was opened and placed in a thickened PA-PE composite self-sealing bag, and then placed in a refrigerator at a temperature of 4°C for 130 days. Each unit was sampled twice and dried at 80°C for 5 hours. The same method as the determination method was used for measurement by microwave digestion-inductively coupled plasma mass spectrometry (ICP-MS). The monitoring results are shown in Table 9.

[0163] The monitoring result x mon and the identified value x CRM By comparison, when the following conditions are not met, it can be inferred that there is evidence that the standard substance is unstable:

[0164] Wherein, k is the coverage factor at the 95% confidence level, k=2.

[0165] According to the monitoring results x in Table 9 mon and the identified value x CRM By comparison, the above conditions are met, so within the monitoring conditions and period, the changes in the values ​​of the various elements in lily powder are not significant.

[0166] Table 9 Stability monitoring results of 8 elements in lily powder after opening (unit: mg / kg)

[0167]

[0168] (17) Fixed value

[0169] The lily matrix reference material introduces some moisture during preparation, so moisture correction is performed during the calibration phase through drying and moisture content testing. The moisture content testing process is as follows: Randomly select samples for testing. First, accurately weigh 0.5g (accurate to 0.0001g) of sample using a balance into a weighing bottle at three temperatures: 60°C, 80°C, and 100°C. The sample is then placed in an oven. Every hour, the sample is removed from the oven and immediately placed in a desiccator to be brought to room temperature and weighed. The sample is then placed in the oven again and weighed eight times. The measurement results are shown in Tables 10-1 to 10-3. Next, 0.5g (accurate to 0.0001g) of randomly selected sample is weighed and placed in a desiccator containing anhydrous magnesium chloride and anhydrous magnesium perchlorate, respectively. The sample is weighed every other day for the first four days, and then every three to four days thereafter. The moisture content results are shown in Table 10-4. Under 80°C drying conditions, the sample's moisture content stabilized after 5 hours, while the moisture content in the desiccator stabilized after 20 days. At this point, the moisture content under the two conditions was comparable. Calculating the average value of multiple measurements revealed a moisture content within the range of (5.5-5.7)%. Reference to NIST standard material certificates such as SRM1547 (pear leaves), SRM1515 (apple leaves), and SRM1570a (spinach leaves) shows that oven drying at high temperatures can lead to excessive mass loss. Based on the analysis of these measurement results, and to facilitate the control of moisture content experiment conditions and mass loss between different laboratories, moisture content correction was performed before sample measurement using a drying oven at 80°C for 5 hours.

[0170] Table 10-1 Test data of water content of lily matrix standard material at 60℃

[0171]

[0172] Note: “774-1” indicates the first measurement result of sample No. 774; “774-2” indicates the second measurement result of sample No. 774;

[0173] "774-3" indicates the third measurement result of sample numbered 774, and so on.

[0174] Table 10-2 Test data of water content of lily matrix standard material at 80℃

[0175]

[0176] Table 10-3 Test data of water content of lily matrix standard material at 100℃

[0177]

[0178]

[0179] Table 10-4 Water content test data of lily matrix standard material under MgCl2 and Mg(ClO4)2 drying conditions

[0180]

[0181] Eight units with experience and capabilities in determining the values ​​of reference materials were selected to participate in the determination of values ​​(before the determination, the samples were dried in a drying oven at 80°C for 5 hours and the moisture content was corrected before measurement). The measurement results of the eight laboratories were tested for outliers. The Grubbs and Dixon methods were used to determine whether there were outliers. If a data was determined to be an outlier by both methods, it was eliminated. The Cochran method was used to test the 9 sets of data from the eight laboratories for equal precision. If C 计算 <C (0.05,9,6) When , it can be determined to be equal precision; and the mean consistency test of each group of data is performed through the t-test method to determine whether the statistic satisfies |t|<t (0.05,10) The 54 measurement data were statistically analyzed by the D'Agostino method to test the normal distribution, and the statistic Y value was calculated. The normality of the data was judged based on Y. The above statistical results are shown in Tables 11-1 to 11-9.

[0182] The Grubbs and Dixon methods showed that there were no outliers in the 9 data sets, and the Cochran method showed that the C 计算 <C (0.05,9,6) , indicating that the nine groups of data have equal accuracy among their average values, and the t-test method determines that |t|<t (0.05,10) , indicating that the means were consistent, and the D'Agostino test Y was in the range of -2.68 to 1.13, indicating that the data were normally distributed.

[0183] Table 11-1 Statistical results of Cd values ​​in lily powder from various companies (unit: mg / kg)

[0184]

[0185]

[0186] Table 11-2 Statistical results of Cr element values ​​in lily powder from various companies (unit: mg / kg)

[0187]

[0188]

[0189] Table 11-3 Statistical results of various fixed values ​​of As in lily powder (unit: mg / kg)

[0190]

[0191] Table 11-4 Statistical results of Cu element values ​​in lily powder from various companies (unit: mg / kg)

[0192]

[0193]

[0194] Table 11-5 Statistical results of various fixed values ​​of Fe in lily powder (unit: mg / kg)

[0195]

[0196]

[0197] Table 11-6 Statistical results of Zn values ​​in lily powder from various companies (unit: mg / kg)

[0198]

[0199] Table 11-7 Statistical results of various fixed values ​​of Mn element in lily powder (unit: mg / kg)

[0200]

[0201]

[0202] Table 11-8 Statistical results of the Sr element in lily powder from various sources (unit: mg / kg)

[0203]

[0204]

[0205] Table 11-9 Statistical results of fixed values ​​of various elements in lily powder (unit: mg / kg)

[0206]

[0207] Note: D1-D82 represent fixed value units respectively: D1-China National Institute of Metrology, D2-Gansu Provincial Food Inspection Institute, D3-Hunan Academy of Agricultural Sciences, D4-Ordnance Industry Non-metallic Materials Physical and Chemical Inspection, D5-Gansu Academy of Agricultural Sciences, D6-Shanghai Institute of Metrology and Testing Technology, D7-Gansu Provincial Product Quality Supervision and Inspection Institute, D81-Gansu Provincial Institute of Metrology, D82-Gansu Provincial Institute of Metrology; AVG is the average value; SD is the standard deviation; RSD is the relative standard deviation; |v max | is the maximum residual; λ (0.05,6).S is the product of the value related to the number of measurements and the given significance level α and the standard deviation; r1 is the calculated value of the Dixon test statistic; r6 is the calculated value of the Dixon test statistic; f (0.05,6) is the critical value of the Dixon test; C 计算 is the calculated value of Cochran test; C (0.05,9,6) is the critical value of the Cochran test; |t| is the value calculated by the t-test; t(0.05,10) is the value calculated by the t-test; Y is the value calculated by the D'Agostino method; a-a(0.95,60) is the critical interval of the D'Agostino method; W 计算 is the value calculated by Shapiro-Wilk method; W (10,0.95) is the Shapiro-Wilk critical value.

[0208] (18) Determine the standard value

[0209] The standard value can be determined by the statistical results of each data set. When the measurement data of multiple sources conform to the normal distribution, the fixed value data are tested for accuracy by the Cochran method and tested for outliers by the Grubbs and Dixon methods. The average of the fixed value results is the standard value. The results are shown in Table 12. It should be noted that each result obtained in the collaborative fixed value determination of the present invention meets the traceability requirements specified in Section 6.1.1 of JJF1343-2022 "Reference Material Determination and Uniformity and Stability Evaluation".

[0210] Table 12 Calculation results of standard values ​​of various elements in lily powder

[0211]

[0212] (19) Uncertainty assessment

[0213] The uncertainty of the standard value of lily reference material is mainly composed of the uncertainty introduced by uniformity, stability and the determination process.

[0214] S1. Uncertainty introduced by uniformity

[0215] The mean square between groups M betwen , within-group mean square M within And n0 calculates the standard deviation between units as the uncertainty introduced by uniformity (u bb,rel ), see Table 13-1.

[0216] Table 13-1 Uncertainty introduced by the uniformity of each element in lily powder

[0217] element Cd Cr As Cu Fe Zn Mn Sr Standard value (mg / kg) 0.0761 0.201 0.0275 3.71 21.9 13.1 7.04 5.76 <![CDATA[u bb (mg / kg)]]> <![CDATA[1.05×10 -3 ]]> <![CDATA[6.30×10 -3 ]]> <![CDATA[7.11×10 -4 ]]> <![CDATA[6.06×10 -2 ]]> <![CDATA[3.73×10 -1 ]]> <![CDATA[2.04×10 -1 ]]> <![CDATA[7.81×10 -2 ]]> <![CDATA[5.76×10 -2 ]]> <![CDATA[u bb,rel (%)]]> 1.35 3.20 2.57 1.66 1.68 1.60 1.10 0.96

[0218] S2. Uncertainty introduced by stability

[0219] The uncertainty introduced by stability includes the uncertainty introduced by long-term stability u s1,rel and the uncertainty u introduced by stability under extreme transportation conditions s2,rel . will u s1,rel and u s2,rel The uncertainty u introduced by determinism is synthesized s,rel , see Table 13-2.

[0220]

[0221] Table 13-2 Uncertainty introduced by the stability of each element in lily powder

[0222] element Cd Cr As Cu Fe Zn Mn Sr Standard value 0.0761 0.201 0.0275 3.71 21.9 13.1 7.04 5.76 <![CDATA[u s1 (mg / kg)]]> <![CDATA[2.14×10 -3 ]]> <![CDATA[5.06×10 -3 ]]> <![CDATA[4.77×10 -4 ]]> <![CDATA[7.93×10 -2 ]]> <![CDATA[5.06×10 -1 ]]> <![CDATA[2.60×10 -1 ]]> <![CDATA[8.38×10 -2 ]]> <![CDATA[1.40×10 -1 ]]> <![CDATA[u s2 (mg / kg)]]> <![CDATA[2.03×10 -3 ]]> <![CDATA[7.16×10 -3 ]]> <![CDATA[5.37×10 -3 ]]> <![CDATA[7.54×10 -2 ]]> <![CDATA[4.28×10 -1 ]]> <![CDATA[2.59×10 -1 ]]> <![CDATA[9.50×10 -2 ]]> <![CDATA[1.10×10 -1 ]]> <![CDATA[u s1 ,rel(%)]]> 2.38 3.66 1.72 2.15 2.26 2.08 1.20 2.35 <![CDATA[u s2 ,rel(%)]]> 2.25 2.58 1.95 2.00 1.95 2.02 1.36 1.84 <![CDATA[u s,rel (%)]]> 3.28 4.48 2.61 2.94 2.99 2.90 1.82 2.99

[0223] S3. Uncertainty introduced by fixed values

[0224] The uncertainty introduced in the determination process is divided into two parts. One is the type A uncertainty u calculated by statistical methods. A,rel ; The second is the Class B uncertainty u evaluated by non-statistical analysis of the factors affecting the measurement B,rel .

[0225] will u A,rel and u B,rel The uncertainty u introduced by the fixed value is obtained by synthesis C,rel , see Table 13-3.

[0226]

[0227] Table 13-3 Uncertainty introduced by the fixed values ​​of each element in lily powder

[0228]

[0229] S4.Combined total uncertainty (u rel )

[0230]

[0231] Take coverage factor k = 2, expanded uncertainty U rel =k×u rel , see Table 13-4.

[0232] Table 13-4 Uncertainty of the standard values ​​of each element in the elemental analysis standard substance of lily powder

[0233] element Cd Cr As Cu Fe Zn Mn Sr Standard value (mg / kg) 0.0761 0.201 0.0275 3.71 21.9 13.1 7.04 5.76 <![CDATA[u bb,rel (%)]]> 1.35 3.20 2.57 1.66 1.68 1.60 1.10 0.96 <![CDATA[u s,rel (%)]]> 3.28 4.48 2.61 2.94 2.99 2.90 1.82 2.99 <![CDATA[u c,rel (%)]]> 1.35 2.06 2.16 0.84 1.44 1.59 0.63 0.94 <![CDATA[u rel (%)]]> 3.80 5.88 4.26 3.48 3.72 3.68 2.22 3.28 <![CDATA[U rel (%)k=2]]> 7.6 11.8 8.6 7.0 7.5 7.4 4.5 6.6 U(mg / kg),k=2 0.0058 0.024 0.0024 0.26 1.7 1.0 0.32 0.39

[0234] S5. Results

[0235] The eight elements in the lily powder matrix standard material were tested by microwave digestion-inductively coupled plasma mass spectrometry, and the results showed good uniformity, stability of more than 12 months, and met the requirements of extreme transportation conditions; the standard values ​​and synthetic expanded uncertainties are shown in Table 13-5, and the uncertainty level is comparable to that of existing similar national first-level standard materials.

[0236] Table 13-5 Certified values ​​and expanded uncertainties of elemental analysis of lily powder (unit: mg / kg)

[0237] element Cd Cr As Cu Fe Zn Mn Sr Standard value 0.0761 0.201 0.0275 3.71 21.9 13.1 7.04 5.76 U,k=2 0.0058 0.024 0.0024 0.26 1.7 1.0 0.32 0.39

[0238] The above are merely preferred embodiments of the present invention, but the scope of protection of the present invention is not limited thereto. Any changes or substitutions that can be easily conceived by a person skilled in the art within the technical scope disclosed in the present invention should be included in the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be based on the scope of protection of the claims.

Claims

1. A method for preparing a multi-element lily matrix standard substance, characterized in that: Fresh lily bulbs are used as raw materials to prepare clean and dry lily bulb slices, which are then crushed, ground, sieved, and shaken to prepare lily powder. The lily powder is subjected to a particle size analysis and a preliminary uniformity inspection. The lily powder that passes the preliminary inspection is irradiated. After irradiation, the powder is packaged and numbered, and a uniformity test, a stability test, a fixed value analysis, and a standard value determination are performed to obtain the multi-element lily matrix standard material. Before the determination analysis, the lily powder was dried at 80°C for 5 hours; The multiple elements are Cd, Cr, As, Cu, Fe, Zn, Mn and Sr.

2. The method for preparing a multi-element lily matrix standard substance according to claim 1, characterized in that: The following steps are involved: (1) Collecting a number of fresh lilies, and selecting lily bulbs that are well grown, free of pests and diseases, and of suitable maturity as raw materials; (2) Clean the selected fresh lily bulbs, remove the dirt, impurities and fibrous roots on the surface, and spread them out in the sun to dry the surface moisture; (3) peeling the cleaned lily bulbs to obtain lily bulb slices; (4) drying the lily bulb slices; (5) crushing the dried lily bulb slices; (6) Grinding the crushed material to obtain lily powder; (7) Sieve the ground lily powder through a 100-mesh sieve; (8) Place all the sieved lily powder in a drum shaker and shake 360 ​​degrees for 48 hours; (9) Perform particle size analysis on the shaken lily powder; (10) Conducting a preliminary homogeneity test on the lily powder that has passed the particle size analysis; (11) irradiating lily powder that has passed the initial homogeneity test with gamma rays; (12) The irradiated lily powder was vacuum sealed in PA-PE composite bags, with 10 g per bag, and divided into 960 bags; (13) Sequentially number the packaged lily powder; (14) Store the numbered lily powder in a cool and dry place; (15) Uniformity test; (16) Stability test; (17) Fixed value analysis: before performing the fixed value analysis, the lily powder was dried at 80° C. for 5 hours; (18) Determine the standard value and obtain the multi-element lily matrix standard substance.

3. The method for preparing a multi-element lily matrix standard substance according to claim 2, wherein: In step (4), the drying temperature is 60° C. and the drying time is 48 hours.

4. The method for preparing a multi-element lily matrix standard substance according to claim 2, wherein: In step (5), the lily powder is crushed to a particle size of ≤0.5 mm.

5. The method for preparing a multi-element lily matrix standard substance according to claim 2, wherein: In step (6), the lily powder is ground to a particle size of ≤0.12 mm.

6. The method for preparing a multi-element lily matrix standard substance according to claim 2, wherein: In step (15), microwave digestion-inductively coupled plasma mass spectrometry combined with variance analysis is used to perform a uniformity test.

7. The method for preparing a multi-element lily matrix standard substance according to claim 2, characterized in that: In step (16), the stability is tested using microwave digestion-inductively coupled plasma mass spectrometry combined with a linear regression model.

8. The method for preparing a multi-element lily matrix standard substance according to claim 7, characterized in that: Stability testing includes long-term stability testing, stability testing under extreme transportation conditions, and stability testing after opening.

9. A multi-element lily matrix standard substance, characterized in that: Prepared according to the preparation method according to any one of claims 1 to 8.

10. Use of the multi-element lily matrix standard material according to claim 9 in measurement method verification, quality control, confirmation and evaluation of analytical methods.

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