Method for detecting the residual amount and migration amount of 20 kinds of chemicals in baby dental adhesive

Abstract

This invention discloses a method for detecting the residue and migration of 20 chemical substances in baby teething toys, comprising the following steps: (1) sample pretreatment; (2) detection: gas chromatography-triple quadrupole tandem mass spectrometry is used to detect the 20 chemical substances; (3) the migration rate of the chemical substances is calculated. This invention fills the gap in the quantitative detection technology of chemical hazardous substances in teething toys, and can achieve highly sensitive and accurate quantitative detection of 20 chemical substances in baby teething toys. The limit of quantitation for the residue determination method is 0.01 mg / kg to 2 mg / kg, and the limit of quantitation for the migration determination method is 0.5 μg / L to 100 μg / L. It also obtains migration rate data of chemical hazardous substances in teething toys for the first time, providing a scientific basis and technical support for the quality and safety supervision of teething toys and the formulation of relevant limit standards.

Description

Technical Field

[0001] This invention relates to a method for detecting chemical substances, and in particular to a method for detecting the residual and migration amounts of 20 chemical substances in baby teething gel. Background Technology

[0002] Infants under one year old develop hand-eye coordination and explore the world by grasping and biting objects. Teething toys, typically made of silicone or thermoplastic polyurethane elastomer (TPU), are common baby products that effectively relieve teething discomfort, stimulate the growth of primary teeth, and help children practice chewing and biting. Given that teething toys come into close contact with an infant's mouth, their chemical safety requires serious attention. During production, packaging, and storage, additives such as plasticizers, bisphenol A (BPA), and nitrosamines, as well as some unintentionally added substances, may be introduced. These chemicals may migrate into the infant's body through saliva during use, causing cumulative chemical hazards. Currently, regulations for teething toys worldwide follow those for toys and children's products. Key regulations include the EU Toy Safety Directive 2009 / 48 / EC and its corresponding harmonized standard EN71, the US Consumer Product Safety Improvement Act, the CHCC list of Substances of Very High Concern (CHCs) in children's products under the Washington Child Safety Products Act, and the Chinese National Toy Safety Standard GB6675-2014.

[0003] In recent years, the testing of chemicals in children's products, such as toys that can be put in the mouth, has mainly focused on substances regulated by the aforementioned regulations. Researchers have successively tested for heavy metals, phthalate plasticizers, nitrosamines, preservatives, bisphenol A (BPA), and sensitizing fragrances to determine whether products comply with regulatory requirements. Some institutions have also conducted risk assessments to explore the chemical risks faced by infants and young children. Infants' immune systems and liver metabolism are not yet fully developed; compared to adults, they are exposed to more chemicals per kilogram of body weight, and the risks of long-term exposure to unsafe products are incalculable. Compared to toys, teething toys have not received widespread public attention. Although some known indicators in teething toys meet regulatory limits, unknown chemical hazards in these products still threaten the health of infants and young children. In addition to targeted analysis of specific substances, some researchers have begun to focus on other unknown contaminants when conducting product safety research and are attempting to use non-targeted screening methods to discover potential unknown harmful substances in products. In previous work, by using gas chromatography-orbit trap high-resolution mass spectrometry non-targeted screening, 28 potential chemical risk substances in teething products were accurately identified (20 of which are currently available as standard samples). These substances were discovered in teething products for the first time, and there is currently no quantitative detection method. No related research reports have been found at home and abroad.

[0004] Because teething toys come into close contact with infants' and young children's mouths, their quantitative testing methods must include two aspects: first, residue level, which is the total content of chemical substances in the product, used to evaluate the product's quality and safety; and second, migration level, which is the amount of chemical substances in the product that can migrate into the human body via saliva, used to assess the risk level for infants and young children when actually using the product. Therefore, establishing methods for determining the residue level and migration level of hazardous substances in teething toys, and obtaining migration rate data for chemical substances, is essential. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to provide a method for detecting the residual and migration amounts of 20 chemical substances in baby teething gel.

[0006] The present invention discloses a method for detecting the residual and migration amounts of 20 chemical substances in baby teething gel, comprising the following steps:

[0007] (1) Sample pretreatment;

[0008] (2) Detection: Gas chromatography-triple quadrupole tandem mass spectrometry was used to detect 20 chemical substances;

[0009] (3) The migration rate of chemical substances was calculated;

[0010] The 20 chemical substances are cyclohexanone, benzaldehyde, phenol, benzyl alcohol, N-methylaniline, dimethyl glutarate, diethylene glycol butyl ether, 3,4-dimethylbenzaldehyde, benzothiazole, 3,4-dimethylbenzyl alcohol, 2,4,6-trimethylaniline, N-methylformaniline, 2-hydroxy-2-methylphenylacetone, isobutyl benzoate, 4-(methylthio)benzaldehyde, dimethyl phthalate, ethyl 4-aminobenzoate, dimethyl sebacate, 4-methylbenzophenone, and triphenylphosphine oxide.

[0011] The present invention discloses a method for detecting the residue and migration of 20 chemical substances in baby teething gel, wherein the chromatographic conditions are as follows: Agilent HP-5MS column, 30m×0.25mm×0.25μm; injection port temperature of 280℃; carrier gas is high-purity helium, flow rate of 1mL / min; split injection, split ratio of 10:1, injection volume of 1μL; temperature program: initial temperature 60℃, increased to 150℃ at 10℃ / min, then increased to 310℃ at 20℃ / min, and held for 1min.

[0012] The present invention discloses a method for detecting the residual and migration amounts of 20 chemical substances in baby teething gel, wherein the mass spectrometry conditions are as follows: EI source; ionization energy 70 eV; transfer line temperature 250℃; ion source temperature 280℃; solvent delay 3.5 min; SRM scan, mass range 50-500 m / z.

[0013] The method for detecting the residual and migration amounts of 20 chemical substances in baby teething gel as described in this invention, wherein:

[0014]

[0015] The chromatographic and mass spectrometric analysis parameters for the 20 chemical substances are shown in the table above.

[0016] The present invention discloses a method for detecting the residue and migration of 20 chemical substances in baby teething gel. The sample pretreatment for determining the residue of the 20 chemical substances includes the following steps: Weigh 0.5g of shredded teething gel sample into a 40mL colorimetric tube, add 10mL of methanol, seal with sealing film, and then extract twice by ultrasonication at room temperature, each time using 10mL of methanol for 30min. Mix the two extraction solutions, filter through a 0.22μm filter membrane, and take 1mL for instrumental analysis.

[0017] The method for detecting the residual and migration amounts of 20 chemical substances in baby teething gel according to the present invention includes the following steps in the sample pretreatment when determining the migration amount of the 20 chemical substances: taking a smooth and flat surface area of ​​approximately 10 ± 1 cm² of the sample. 2 The sample was weighed and recorded, placed in a dry 40 mL colorimetric tube, and 20 mL of simulated saliva was added. The tube was then placed in a constant temperature shaker and shaken at 37 °C for 240 min to obtain a migration solution. The migration solution was purified by solid-phase extraction and then measured.

[0018] The present invention discloses a method for detecting the residue and migration of 20 chemical substances in baby teething gel, wherein the solid-phase extraction includes the following steps: rinsing the Chromabond Easy solid-phase extraction column with 5 mL of methanol, equilibrating it with 5 mL of ultrapure water, and when the aqueous solution drops close to the sieve plate, slowly adding the migration solution to the solid-phase extraction column at a flow rate of 6-8 mL / min. After sample loading, the residual solution in the column is dried, and finally the target analytes are eluted with 10 mL of methanol at a rate of 3 mL / min. The eluent is collected, dried with an appropriate amount of anhydrous Na2SO4, and then analyzed by instrument.

[0019] The method for detecting the residual and migration amounts of 20 chemical substances in baby teething gel according to the present invention, wherein the migration rate is calculated using the following formula: Migration rate = C 迁移 / C 残留 ×100%.

[0020] The method for detecting the residual and migration amounts of 20 chemical substances in baby teething gel in this invention differs from existing technologies in that:

[0021] This invention presents a method for detecting the residues and migration of 20 chemical substances in baby teething toys. The method is based on gas chromatography-triple quadrupole tandem mass spectrometry (GC-MS). The instrument detection conditions for these 20 substances were investigated and optimized, yielding qualitative and quantitative ion pairs and optimal collision energies. The extraction conditions for residue and migration detection were also investigated and optimized, resulting in the optimal extraction conditions. The residue and migration levels of these 20 hazardous substances were screened in 59 commercially available teething toy products. This invention fills the gap in quantitative detection technology for hazardous chemical substances in teething toys, enabling highly sensitive and accurate quantitative detection of 20 chemical substances in baby teething toys. The limit of quantitation (LOQ) for residue determination is 0.01 mg / kg-2 mg / kg, and for migration determination, it is 0.5 μg / L-100 μg / L. Furthermore, it provides the first data on the migration rates of hazardous chemical substances in teething toys, offering a scientific basis and technical support for the quality and safety supervision of teething toy products and the formulation of relevant limit standards.

[0022] The following description, in conjunction with the accompanying drawings, further illustrates the method for detecting the residual and migration amounts of 20 chemical substances in baby teething gel of the present invention. Attached Figure Description

[0023] Figure 1 The SRM chromatograms of 20 hazardous substances in the gutta-percha of this invention are shown (the peak numbers of each substance are the same as those in Table 1).

[0024] Figure 2 To optimize the ultrasonic extraction conditions in this invention (a. selection of extraction solvent; b. selection of solvent volume; c. selection of extraction times);

[0025] Figure 3 To optimize the solid-phase extraction conditions in this invention: (a. selection of solid-phase extraction column; b. selection of elution solvent; c. selection of elution volume);

[0026] Figure 4 To improve the recovery rate and precision of the residue determination method in this invention;

[0027] Figure 5 To assess the recovery rate and precision of the migration measurement method in this invention;

[0028] Figure 6 This is a heatmap showing the determination of residual amounts of 20 hazardous substances in gutta-percha samples in this invention.

[0029] Figure 7 This is a heatmap showing the migration levels of 20 hazardous substances in gutta-percha samples used in this invention.

[0030] Figure 8 The migration rate of hazardous substances in gutta-percha in this invention. Detailed Implementation

[0031] I. Materials and Methods

[0032] 1. Instruments and reagents

[0033] Gas chromatography-triple quadrupole tandem mass spectrometry: TRACE 1310 / TSQ8000 Evo (Thermo Fisher Scientific, USA); solid phase extraction apparatus (Supelco, USA); Chromabond Easy solid phase extraction column (6 mL, 0.2 g, MN, Germany); Milli-Q ultrapure water system (Millipore, USA); P300H ultrasonic cleaner (Elma, Germany); NTS-4000 constant temperature water bath shaker (Eyela, Japan).

[0034] The 20 standards used in the experiment were purchased from suppliers such as J&K, CNW, Alfa Aesar, TCI, Aladdin, and LGC, with a purity greater than 94%. Methanol (chromatographic grade, Fisher Scientific, USA); anhydrous Na2SO4 (analytical grade); PTFE filter membrane (0.22 μm, CNW).

[0035] Fifty-nine teething toy samples of different brands and materials (silicone and TPU) were randomly purchased from online shopping platforms and offline physical stores (supermarkets and shopping malls). Before the experiment, they were placed in PE sealed bags separately to avoid cross-contamination.

[0036] 2. Solution preparation

[0037] Preparation of standard solutions: Weigh 50 mg of each of the 20 standard substances into 50 mL brown volumetric flasks, dilute to volume with methanol to obtain 1000 mg / L standard stock solutions, and store at 4°C. When using, dilute with methanol to the corresponding concentration of standard working solution as needed.

[0038] Simulated saliva: Following the DIN 53160 standard method, weigh out 0.17g MgCl2·6H2O, 0.15g CaCl2·2H2O, 0.76g K2HPO4·3H2O, 0.53g K2CO3, 0.33g NaCl, and 0.75g KCl, respectively. First, dissolve the potassium and sodium salts in 900mL of deionized water. Then add MgCl2·6H2O and CaCl2·2H2O. After complete dissolution, adjust the pH to (6.8±0.1) with 1% hydrochloric acid aqueous solution, and then bring the volume to 1L with deionized water. Store protected from light, ensuring the pH is approximately 6.8±0.1 before use.

[0039] 3. Sample pretreatment

[0040] Residual content determination: Weigh 0.5g of shredded gutta-percha sample into a 40mL colorimetric tube, add 10mL of methanol, seal with sealing film, and extract twice by sonication at room temperature, each time using 10mL of methanol for 30min. Mix the two extraction solutions, filter through a 0.22μm filter membrane, and take 1mL for instrumental analysis.

[0041] Migration measurement: Take a sample with a smooth and flat surface area of ​​approximately 10 ± 1 cm². 2 Weigh and record the sample, place it in a dry 40mL colorimetric tube, add 20mL of simulated saliva, and place it in a constant temperature shaker at 37℃ for 240min to obtain the migration solution. The migration solution is then purified by solid-phase extraction (SPE) before analysis. Solid-phase extraction: The Chromabond Easy SPE column is rinsed with 5mL of methanol and equilibrated with 5mL of ultrapure water. When the aqueous solution level approaches the sieve plate, the migration solution is slowly added to the SPE column at a flow rate of 6-8mL / min. After loading, the residual solution in the column is dried, and finally, the target analyte is eluted with 10mL of methanol at a rate of 3mL / min. The eluent is collected, dried with an appropriate amount of anhydrous Na2SO4, and then analyzed.

[0042] 4. Instrument conditions

[0043] Chromatographic conditions: Agilent HP-5MS column (30m×0.25mm×0.25μm); injection port temperature 280℃; carrier gas high-purity helium, flow rate 1mL / min; split injection, split ratio 10:1, injection volume 1μL; temperature program: initial temperature 60℃, increased to 150℃ at 10℃ / min, then increased to 310℃ at 20℃ / min (hold for 1min).

[0044] Mass spectrometry conditions: EI source; ionization energy 70 eV; transfer line temperature 250 °C; ion source temperature 280 °C; solvent delay 3.5 min; SRM scan, mass range 50-500 m / z. Optimized chromatographic and mass spectrometry parameters are shown in Table 1.

[0045] Table 1. Chromatographic and mass spectrometric analysis parameters of 20 substances

[0046]

[0047]

[0048] II. Results and Discussion

[0049] 1. Optimization of residual determination conditions

[0050] 1.1 Optimization of chromatographic and mass spectrometric conditions

[0051] This invention selected 20 hazardous substances as research objects. Based on the structure, polarity, and boiling point of each substance, a weakly polar HP-5MS column was used for separation. Chromatograms of the 20 substances were obtained by optimizing chromatographic conditions, as shown in the figure. Figure 1 As shown, 20 substances can be well separated under optimized chromatographic conditions. The qualitative and quantitative ion pairs of each substance were then optimized, and the optimized chromatographic and mass spectrometric parameters are shown in Table 1. Tandem mass spectrometry (SRM) scanning effectively eliminates matrix interference, enabling accurate qualitative and quantitative analysis of the target substances.

[0052] 1.2 Optimization of ultrasonic extraction conditions

[0053] After initial screening of 59 gutta-percha samples, no single sample contained all 20 target analytes. To optimize extraction conditions, the sample containing the most target analytes was selected as a positive sample for further optimization. Sample No. 38 showed the highest detection rate of target analytes, with a total of 19 analytes detected. Therefore, this sample was selected as a positive sample for further optimization.

[0054] The experiment optimized the type of solvent, extraction time, and number of extractions used in ultrasonic extraction. First, the extraction solvents (10 mL of n-hexane, ethyl acetate, acetone, and methanol) were investigated for their effectiveness in extracting hazardous substances from gutta-percha samples. Figure 2 As can be seen, methanol has a superior extraction effect on the vast majority of substances among the four solvents, therefore methanol was selected as the extraction solvent. Then, the extraction effects of different extraction times of 10, 20, 30, 40, and 50 min on hazardous substances in gutta-percha samples were investigated. Figure 2 As can be seen from b, the extraction effect increases with time. After 30 minutes, the extraction effect no longer shows a significant increasing trend with time; therefore, the extraction time was set at 30 minutes. Finally, to fully extract potential risk substances from the gutta-percha, the same gutta-percha sample was repeatedly subjected to ultrasonic extraction multiple times. Figure 2 As can be seen from c, after two extractions, the vast majority of substances have been completely extracted, so the number of extractions is set to 2.

[0055] 2. Optimization of migration measurement conditions

[0056] A mixed standard solution of 200 μg / L was added to 20 mL of simulated saliva, and the mixture was shaken and migrated at 37 °C for 240 min to obtain the migration solution. The extraction conditions, including the solid-phase extraction column, elution solvent, and elution solvent volume, were then optimized based on the recovery rate of the target analyte.

[0057] First, five solid-phase extraction (SPE) columns—Chromabond Easy, ENVI-Chrom P, Oasis HLB, Chhromabond HR-P, and Sep-Pak Vac C18—were selected for SPE column selection. Figure 3 As can be seen, the Chromabond Easy extraction column exhibits superior extraction performance compared to other extraction columns, with recoveries exceeding 80% for all 20 substances. Therefore, the Chromabond Easy extraction column was selected as the solid-phase extraction column for this study. Then, the elution effects of methanol, acetone, ethyl acetate, and n-hexane on the target analytes were optimized. Figure 3 As shown in b, methanol exhibits the best elution effect, with recoveries of all substances exceeding 80%. Therefore, methanol was chosen as the elution solvent. Finally, the elution volumes of 3, 5, 7, and 10 mL of methanol were optimized. The results are as follows... Figure 3 As shown in c, when the methanol volume reaches 10 mL, the recovery rate of most substances can reach over 85.4%. Therefore, 10 mL of methanol was chosen for elution of the target analytes.

[0058] 3. Methodological Validation

[0059] 3.1 Validation of the method for determining residual content

[0060] Standard solutions of 20 hazardous substances were diluted to prepare working standard solutions ranging from 0.2 μg / L to 2000 μg / L, and standard working curves were plotted. The linearity was good within the range of 0.01 mg / kg to 100 mg / kg, with R... 2 ≥0.9981. The limit of detection (LOD) was determined to be 0.004 mg / kg-1 mg / kg using a signal-to-noise ratio of 3, and the limit of quantitation (LOQ) was determined to be 0.01 mg / kg-2 mg / kg using a signal-to-noise ratio of 10. The results are shown in Table 1.

[0061] Recovery and precision tests were conducted using blank samples. Three spiking concentrations (low, medium, and high) were set for each substance, with each concentration tested in triplicate. The low-level spiking concentration represented the limit of quantitation (LOQ) of the substance, ranging from 0.01 mg / kg to 2 mg / kg. Since the LQ of diethylene glycol butyl ether is 2 mg / kg, the medium-level spiking concentration for this substance was set at 4 mg / kg. The medium-level spiking concentration for the remaining 19 substances was 2 mg / kg. The high-level spiking concentration for all substances was 10 mg / kg. Figure 4 It can be seen that the recoveries of the 20 hazardous substances ranged from 80.5% to 104.1%, and the relative standard deviations (RSDs) were 1.4% to 9.9%, which met the requirements for quantitative analysis.

[0062] 3.2 Methodological Validation for Migration Measurement

[0063] A mixed standard solution of 20 hazardous substances was measured sequentially from low to high concentration, and a standard curve was plotted. The linearity was good within the range of 0.5 μg / L–5000 μg / L, with R0 being [missing value]. 2 ≥0.9988. The limit of detection (LOD) was determined to be 0.2 μg / L-50 μg / L using a signal-to-noise ratio of 3, and the limit of quantitation (LOQ) was determined to be 0.5 μg / L-100 μg / L using a signal-to-noise ratio of 10. The results are shown in Table 1.

[0064] Under the experimental conditions determined by this method, three different concentration levels of mixed standard solutions were added to blank simulated saliva. Each added concentration was tested in parallel six times, and the recovery rate and precision of the method were calculated. Figure 5 As can be seen, the recoveries of the 20 substances in the gutta-percha samples ranged from 86.9% to 100.5%, with relative standard deviations (RSD) ranging from 0.2% to 8.6%. The results indicate that this method has high accuracy and reproducibility.

[0065] 4. Actual sample measurement

[0066] 4.1 Results of Residual Content Determination

[0067] The established method was used to analyze 59 samples, and 15 substances were detected. The detection results are as follows: Figure 6 As shown in the figure, the color scale on the right represents the concentration of substances. It can be seen from the graph that phenol's detection content is significantly higher than other substances, ranging from 1.65 mg / kg to 55.55 mg / kg, with a detection rate of 30.5%. N-methylaniline's detection content ranges from 0.12 mg / kg to 4.40 mg / kg, but its detection rate is the highest at 84.7%. Isobutyl benzoate's detection content ranges from 0.01 mg / kg to 0.17 mg / kg, with a detection rate of approximately 50%. Although the highest detection limit for triphenylphosphine oxide is 106.15 mg / kg, its detection rate is relatively low compared to other substances.

[0068] 4.2 Migration Measurement Results

[0069] The migration amount of 59 gutta-percha samples was measured using this method, and the results are as follows: Figure 7As shown, 12 substances migrated through simulated saliva. 3,4-Dimethylbenzaldehyde, isobutyl benzoate, and 4-methylbenzophenone, which had residual levels, did not show any migration, indicating that these three substances are not easily migrated through simulated saliva. Phenol remained highly detected at 27.1%, with concentrations ranging from 0.31 mg / kg to 20.03 mg / kg. The EU Toy Directive limits phenol to 5 mg / L (migration limit) and 10 mg / kg (content limit), indicating that the migration of phenol in some samples exceeded the standard limits. N-Methylaniline had a detection rate of 28.8%, with concentrations ranging from 0.04 mg / kg to 1.13 mg / kg. Furthermore, triphenylphosphine oxide (8.69 mg / kg) was detected in only one sample; the residual amount of this substance in the sample was 13 times the migration amount, indicating that this substance has weak migration ability.

[0070] 5. Migration rate

[0071] Migration rate was used to observe the ease with which hazardous substances in gutta-percha migrate from the product to simulated saliva. The migration rate of hazardous substances in gutta-percha can be determined by the concentration of residual substances (C). 残留 (mg·kg -1 ) and migration concentration C in simulated saliva 迁移 (mg·kg -1 The ratio of ) is calculated to obtain:

[0072] Mobility = C 迁移 / C 残留 ×100%

[0073] Calculated according to the above formula, by Figure 8 As can be seen, the migration rates of the various risk substances that migrated from the gutta-percha were not high. The substance with the highest migration rate was cyclohexanone, with an average migration rate of 55.57%. The average migration rates of benzaldehyde, phenol, benzyl alcohol, N-methylaniline, benzothiazole, N-methylformamide, dimethyl phthalate, ethyl 4-aminobenzoate, and dimethyl sebacate were all between 38.05% and 12.64%. Triphenylphosphine oxide, which was the substance with the highest detected content in the sample, had the lowest average migration rate, at only 4.09%. The remaining substances had low detected levels in the sample and were not migrated from the simulated saliva, with a migration rate of 0%.

[0074] 6. Conclusion

[0075] This paper establishes for the first time a method for determining the residue and migration of 20 hazardous substances in teething toys using ultrasonic extraction / solid-phase extraction-gas chromatography-triple quadrupole tandem mass spectrometry. The method is simple, accurate, stable, and highly sensitive, suitable for the analysis and determination of the residue and migration of hazardous substances in infant teething toys, and has significant practical implications for improving the quality and safety of teething toys and protecting the health of infants and young children. Furthermore, the detection of varying degrees of residue and migration of all 20 substances in the samples warrants attention, and further health risk assessment for infants and young children is urgently needed.

[0076] The embodiments described above are merely preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Various modifications and improvements made by those skilled in the art to the technical solutions of the present invention without departing from the spirit of the present invention should fall within the protection scope defined by the claims of the present invention.

Claims

1. A method for detecting the residual and migration amounts of 20 chemical substances in baby teething gel, characterized in that: Includes the following steps: (1) Sample pretreatment; (2) Detection: Gas chromatography-triple quadrupole tandem mass spectrometry was used to detect 20 chemical substances; (3) The migration rate of the chemical substances was calculated; The 20 chemical substances are cyclohexanone, benzaldehyde, phenol, benzyl alcohol, N-methylaniline, dimethyl glutarate, diethylene glycol butyl ether, 3,4-dimethylbenzaldehyde, benzothiazole, 3,4-dimethylbenzyl alcohol, 2,4,6-trimethylaniline, N-methylformamide, 2-hydroxy-2-methylphenylacetone, isobutyl benzoate, 4-(methylthio)benzaldehyde, dimethyl phthalate, ethyl 4-aminobenzoate, dimethyl sebacate, 4-methylbenzophenone, and triphenylphosphine oxide; The chromatographic conditions were as follows: Agilent HP-5 MS column, 30 m × 0.25 mm × 0.25 μm; injection port temperature: 280℃; carrier gas: high-purity helium, flow rate: 1 mL / min; split injection, split ratio: 10:1, injection volume: 1 μL; temperature program: initial temperature 60℃, increased to 150℃ at 10℃ / min, then increased to 310℃ at 20℃ / min, held for 1 min. The mass spectrometry conditions were as follows: EI source; ionization energy 70 eV; transfer line temperature 250℃; ion source temperature 280℃; solvent delay 3.5 min; SRM scan, mass range 50-500 m / z; the chromatographic and mass spectrometric analysis parameters for 20 chemical substances are as follows: ， When determining the residue of 20 chemical substances, the sample pretreatment includes the following steps: Weigh 0.5 g of shredded gutta-percha sample into a 40 mL colorimetric tube, add 10 mL of methanol, seal with sealing film, and extract twice with ultrasonication at room temperature, each time using 10 mL of methanol for 30 min. Mix the two extraction solutions, filter through a 0.22 μm filter membrane, and take 1 mL for instrumental analysis. When determining the migration of 20 chemical substances, the sample pretreatment includes the following steps: taking a smooth and flat surface area of ​​10 ± 1 cm² of the sample. 2 The sample was weighed and recorded, placed in a dry 40 mL colorimetric tube, and 20 mL of simulated saliva was added. The tube was then placed in a constant temperature shaker and shaken at 37 °C for 240 min to obtain the migration solution. The migration solution was purified by solid-phase extraction and then analyzed. The solid-phase extraction included the following steps: the Chromabond Easy solid-phase extraction column was rinsed with 5 mL of methanol and equilibrated with 5 mL of ultrapure water. When the aqueous solution level was close to the sieve plate, the migration solution was slowly added to the solid-phase extraction column at a flow rate of 6-8 mL / min. After the sample was loaded, the residual solution in the column was dried. Finally, the target analyte was eluted with 10 mL of methanol at a rate of 3 mL / min. The eluent was collected, dried with an appropriate amount of anhydrous Na2SO4, and then analyzed.

2. The method for detecting the residual and migration amounts of 20 chemical substances in baby teething gel according to claim 1, characterized in that: Mobility is calculated using the following formula: Mobility = C 迁移 / C 残留 ×100%.

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