On-site rapid screening device and method for polycyclic aromatic hydrocarbon in toys

Abstract

The invention discloses an on-site rapid screening device and method for polycyclic aromatic hydrocarbon in toys, the device comprises a carbon nano tube fiber ion source and a mass spectrometer (1), the carbon nano tube fiber ion source comprises a plastic tube (2) and a carbon nano tube fiber bundle (3) embedded in one end of the plastic tube (2), and a peek head (4) is sleeved at the joint of the plastic tube (2) and the carbon nano tube fiber bundle (3). The method comprises the following steps: immersing a carbon nanotube fiber bundle into a liquid toy sample for direct adsorption and extraction, placing the liquid toy sample at the front end of a sample inlet of a small portable mass spectrometer, then dropwise adding an elution / ionization solvent, and applying ionization voltage to complete detection. According to the method, the carbon nanotube fiber ion source is combined with the small portable mass spectrometer, the on-site rapid screening method for polycyclic aromatic hydrocarbon in toys is established, and technical support can be provided for on-site screening detection, supervision and law enforcement of quality safety of toys.

Description

Technical Field

[0001] The present invention relates to the fields of toys and analytical chemistry, and particularly relates to a device and method for rapid on-site screening of polycyclic aromatic hydrocarbons in toys. Background Art

[0002] China is the world's largest toy manufacturer and exporter, with a huge consumer group and growing market demand. The quality and safety of toys not only have an important impact on the physical and mental health of children, but also play an important role in China's economic development. Data from the General Administration of Customs shows that China's toy export value reached 40.57 billion US dollars in 2023. Facing the high-throughput detection requirements, traditional detection methods are slow in detection speed and long in cycle, and can no longer meet the needs. Therefore, it is particularly important to develop rapid on-site screening methods.

[0003] Polycyclic aromatic hydrocarbons are a class of organic compounds bonded by multiple benzene rings. So far, more than 200 kinds have been discovered. Polycyclic aromatic hydrocarbons are important basic raw materials for organic chemical industry, mostly from petroleum and coal tar, and are raw materials for dyes and plasticizers used in textile and leather products. Polycyclic aromatic hydrocarbons are a class of persistent organic pollutants, which are prone to induce various diseases, and their control in the toy field is becoming increasingly strict. The most common detection method is gas chromatography-tandem mass spectrometry. This method has the advantages of accuracy, stability, sensitivity, etc., but usually requires a complex and cumbersome sample pretreatment process, with problems such as long detection cycle, high time cost, and large consumption of organic reagents; at the same time, it relies on large-scale instrument equipment, has poor mobility, and cannot meet the urgent need for on-site rapid detection. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to provide a device and method for rapid on-site screening of polycyclic aromatic hydrocarbons in toys, which are simple, fast, real-time and efficient.

[0005] The on-site rapid screening device for polycyclic aromatic hydrocarbons in toys of the present invention includes a carbon nanotube fiber ion source and a mass spectrometer. The carbon nanotube fiber ion source includes a plastic tube and a carbon nanotube fiber bundle embedded at one end thereof, and a peek head is sleeved at the connection between the two.

[0006] In the on-site rapid screening device for polycyclic aromatic hydrocarbons in toys of the present invention, the carbon nanotube fiber bundle is composed of 50 multi-walled carbon nanotube fibers, and the diameter of each multi-walled carbon nanotube fiber is 60-80 μm and the length is 1 cm.

[0007] In the on-site rapid screening device for polycyclic aromatic hydrocarbons in toys of the present invention, the front end of the plastic tube is inserted into the peek head and is flush with its tip. The latter half of the carbon nanotube fiber bundle is embedded inside the front end of the plastic tube, and the front end of the carbon nanotube fiber bundle is arranged 1 mm in front of the inlet of the mass spectrometer.

[0008] For the on-site rapid screening device for polycyclic aromatic hydrocarbons in the toys described in the present invention, the mass spectrometer is a Miniβ small portable mass spectrometer, and the carbon nanotube fiber bundle is connected to the high-voltage source of the Miniβ small portable mass spectrometer through a metal wire.

[0009] The on-site rapid screening method for polycyclic aromatic hydrocarbons in toys using the on-site rapid screening device for polycyclic aromatic hydrocarbons in toys described in the present invention includes the following steps:

[0010] Immerse the carbon nanotube fiber bundle into the liquid toy sample for direct adsorption extraction, place it at the front end of the injection port of the Miniβ small portable mass spectrometer, then drop the elution / ionization solvent, apply the ionization voltage, and immediately be detected by the Miniβ small portable mass spectrometer.

[0011] For the on-site rapid screening method for polycyclic aromatic hydrocarbons in toys described in the present invention, the polycyclic aromatic hydrocarbons are naphthalene, acenaphthylene, acenaphthene, and fluoranthene.

[0012] For the on-site rapid screening method for polycyclic aromatic hydrocarbons in toys described in the present invention, the analysis conditions of the Miniβ small portable mass spectrometer are as follows: ionization mode: positive ion mode; injection time: 40 ms;

[0013] Table 1 Miniature portable mass spectrometry analysis parameters for 4 polycyclic aromatic hydrocarbons

[0014]

[0015] The ionization voltages, parent ions, and detection limits of the 4 polycyclic aromatic hydrocarbons are shown in Table 1.

[0016] For the on-site rapid screening method for polycyclic aromatic hydrocarbons in toys described in the present invention, the elution / ionization solvent is n-hexane with a volume of 4 μL.

[0017] The difference between the on-site rapid screening method for polycyclic aromatic hydrocarbons in toys of the present invention and the prior art lies in:

[0018] For the on-site rapid screening device and method for polycyclic aromatic hydrocarbons in toys of the present invention, a carbon nanotube fiber ion source is combined with a small portable mass spectrometer to establish an on-site rapid screening method for polycyclic aromatic hydrocarbons in toys, which can provide technical support for on-site screening detection, supervision, and law enforcement of toy quality and safety.

[0019] The method of the present invention does not require any sample pretreatment process. The carbon nanotube fiber bundle is immersed in the liquid sample for direct adsorption extraction, placed at the front end of the inlet of the small portable mass spectrometer, then the elution / ionization solvent is dropped, the ionization voltage is applied, and then it is detected by the small portable mass spectrometer. The detection limit is between 100 and 200 μg / kg, and the screening period is less than 1 min. This method is simple, rapid, real-time and efficient, and is suitable for the on-site rapid screening of polycyclic aromatic hydrocarbons in toys.

[0020] The on-site rapid screening device and method for polycyclic aromatic hydrocarbons in toys of the present invention will be further described below with reference to the accompanying drawings. Description of the Drawings

[0021] Figure 1 It is a schematic structural diagram of the on-site rapid screening device for polycyclic aromatic hydrocarbons in toys of the present invention;

[0022] Figure 2 It is an experimental flow chart of the on-site rapid screening method for polycyclic aromatic hydrocarbons in toys of the present invention;

[0023] Figure 3 It is a scanning electron microscope image of the microstructure of multi-walled carbon nanotube fibers in the present invention;

[0024] Figure 4 It is the first-level mass spectrum of the toy positive sample in the present invention, where: a - naphthalene, b - acenaphthylene, c - acenaphthene, d - fluoranthene;

[0025] The translations of all the English words that appear in the accompanying drawings of the present invention are as follows:

[0026] Relative abundance: relative abundance; Naphthalene: naphthalene; Acenaphthylene: acenaphthylene; Acenaphthene: acenaphthene; Fluoranthene: fluoranthene; m / z: mass-to-charge ratio. Detailed Embodiments

[0027] 1. Experimental Part

[0028] 1.1 Main Instruments and Devices

[0029] Miniβ small portable mass spectrometry analysis system (length 55 cm, width 24 cm, height 31 cm, weight 20 kg, power ≤ 100 W): Beijing Qingpu Technology Co., Ltd.; S-4800 type scanning electron microscope: Hitachi, Ltd., Japan; Multi-walled carbon nanotube fibers: Jiangsu Xianfeng Nano Materials Technology Co., Ltd.

[0030] peek head (inner diameter 1.6 mm) and plastic tube (material is ethylene-propylene fluoride copolymer, outer diameter 1.6 mm, inner diameter 0.8 mm): Agilent Technologies (China) Co., Ltd.

[0031] As Figure 1 shown, the on-site rapid screening device for polycyclic aromatic hydrocarbons in the toy of the present invention includes a carbon nanotube fiber ion source and a mass spectrometer 1. The carbon nanotube fiber ion source includes a plastic tube 2 and a carbon nanotube fiber bundle 3 embedded at one end thereof, and a peek head 4 is sleeved at the connection of the two. The peek head 4 is used to firmly hold the plastic tube 2, so that the plastic tube 2 can tightly hold the carbon nanotube fiber bundle 3 inside it, making the entire carbon nanotube fiber ion source device more stable and firm. The carbon nanotube fiber bundle 3 is composed of 50 multi-walled carbon nanotube fibers, and each multi-walled carbon nanotube fiber has a diameter of 60-80 μm and a length of 1 cm. The front end of the plastic tube 2 is inserted into the peek head 4 and is flush with its tip. The latter half of the carbon nanotube fiber bundle 3 is embedded inside the front end of the plastic tube 2, and the front end of the carbon nanotube fiber bundle 3 is arranged 1 mm in front of the inlet of the mass spectrometer 1. The mass spectrometer 1 is a Miniβ small portable mass spectrometer, and the carbon nanotube fiber bundle 3 is connected to the high-voltage source of the Miniβ small portable mass spectrometer through a metal wire.

[0032] 1.2 Main materials and reagents

[0033] Standard products: naphthalene, acenaphthylene, acenaphthene, fluoranthene, with a purity of more than 98%, purchased from Sigma-Aldrich Company, USA. Other reagents are of analytical grade. The actual toy samples are purchased from local markets and e-commerce platforms.

[0034] 1.3 Experimental procedures

[0035] The carbon nanotube fiber bundle is directly immersed in the liquid sample. Since polycyclic aromatic hydrocarbons have a benzene ring structure, they will form π-π bonds with the benzene ring structure of the multi-walled carbon nanotube fiber to achieve adsorption and extraction of the sample. Then it is placed 1 mm in front of the inlet of the small portable mass spectrometer, and then 4 μL of elution / ionization solvent n-hexane is added dropwise, and the ionization voltage is applied. Due to the potential difference between the carbon nanotube fiber bundle (high-voltage end) and the instrument inlet (low-voltage end), polycyclic aromatic hydrocarbons will be eluted from the carbon nanotube fiber bundle under the action of n-hexane, and along with the volatilization of n-hexane and the ionization high voltage, the polycyclic aromatic hydrocarbons will be atomized and form gas-phase charged ions, which will then be detected by the small portable mass spectrometer.

[0036] The flow chart of the on-site rapid screening experiment for polycyclic aromatic hydrocarbons in toys is as Figure 2 shown.

[0037] 1.4 Small portable mass spectrometry analysis conditions

[0038] Ionization mode: positive ion mode; injection time: 40 ms; The ionization voltage, parent ion and detection limit of 4 polycyclic aromatic hydrocarbons are shown in Table 1.

[0039] Table 1 Small portable mass spectrometry analysis parameters of 4 polycyclic aromatic hydrocarbons

[0040]

[0041] 2. Results and Discussion

[0042] 2.1 Characterization of Multi-Walled Carbon Nanotube Fibers

[0043] Multi-walled carbon nanotube fibers have strong hardness, good electrical conductivity, and a large specific surface area. The benzene rings contained therein achieve efficient adsorption and extraction of polycyclic aromatic hydrocarbons through π-π bonds. Observing the microstructure of the multi-walled carbon nanotube fibers, its scanning electron microscope image is as shown Figure 3 in the figure. After magnifying the end of the multi-walled carbon nanotube fiber by 600 times, it consists of many loose multi-walled carbon nanotubes ( Figure 3 a). Continuing to magnify to 15,000 times, each loose multi-walled carbon nanotube can be clearly observed ( Figure 3 b). This structure helps the multi-walled carbon nanotube fibers to come into full contact with the sample, which is beneficial to the adsorption and extraction of polycyclic aromatic hydrocarbons in the sample.

[0044] 2.2 Optimization of the Distance from the Ion Source to the Injection Port

[0045] The distance between the ion source and the mass spectrometry injection port is also an important factor affecting the response of the target substance. If the distance is too close, due to the high electrical conductivity of the multi-walled carbon nanotube fibers, there may be a discharge phenomenon; conversely, the number of charged ions entering the mass spectrometry decreases, and the response value decreases. The experimental results show that when the distance between the carbon nanotube fiber ion source is greater than 1 mm, the detection signal is unstable and even has no response. Therefore, in the present invention, the distance from the carbon nanotube fiber ion source to the injection port of the small portable mass spectrometry is set to 1 mm.

[0046] 2.3 Optimization of the Elution / Ionization Solvent

[0047] The polarity of the elution / ionization solvent has an important influence on the elution and ionization processes of polycyclic aromatic hydrocarbons. In the present invention, five solvents with different polarities, namely methanol, acetonitrile, ethyl acetate, n-hexane, and dichloromethane, are selected as the elution / spray solvents. The results show that when n-hexane is used as the elution / ionization solvent, the response values of the four polycyclic aromatic hydrocarbons are the strongest. This may be because n-hexane is a non-polar solvent, and according to the principle of similar solubility, it is easier to elute the adsorbed polycyclic aromatic hydrocarbons from the surface of the multi-walled carbon nanotube fibers.

[0048] 2.4 Optimization of the Volume of the Elution / Ionization Solvent

[0049] The volume of the elution / ionization solvent is also equally important for the ionization process. In the present invention, the volumes of n-hexane are selected as 2, 4, 6, and 8 μL for optimization. The results show that when the volume of n-hexane is 4 μL, the response of the four polycyclic aromatic hydrocarbons is the strongest.

[0050] 2.5 On-site Rapid Screening Method for Small Portable Mass Spectrometry Based on Carbon Nanotube Fiber Ion Source

[0051] A bubble water sample determined to contain no naphthalene, acenaphthylene, acenaphthene, and fluoranthene was selected as a blank sample, and a positive sample was prepared. Analysis was carried out according to the experimental steps, and the parent ions of four polycyclic aromatic hydrocarbons were screened out, namely naphthalene (m / z 128.4), acenaphthylene (m / z 152.3), acenaphthene (m / z 154.3), and fluoranthene (m / z 202.3). Their primary scan mass spectra are as Figure 4 shown.

[0052] 2.6 Detection of Actual Samples

[0053] The screening method established by this invention was applied to screen and analyze 6 bubble water toys purchased from the local market and e-commerce platforms. After screening, none of the above polycyclic aromatic hydrocarbons were detected in the samples tested.

[0054] 3. Conclusion

[0055] This invention uses a carbon nanotube fiber ion source combined with small portable mass spectrometry technology to establish an on-site rapid screening method for polycyclic aromatic hydrocarbons, non-polar substances in toys. The method is simple and efficient, and can complete the rapid screening of samples within 1 minute, effectively solving the drawbacks of traditional detection methods such as cumbersome operation and long time consumption, and has good application prospects and practical value.

[0056] The embodiments described above are only descriptions of the preferred embodiments of the present invention, and do not limit the scope of the present invention. Without departing from the design spirit of the present invention, various deformations and improvements made by those of ordinary skill in the art to the technical solutions of the present invention shall fall within the protection scope determined by the claims of the present invention.

Claims

1. A field rapid screening device for polycyclic aromatic hydrocarbons in toys, characterized in that: It includes a carbon nanotube fiber ion source and a mass spectrometer (1). The carbon nanotube fiber ion source includes a plastic tube (2) and a carbon nanotube fiber bundle (3) embedded at one end thereof. A peek head (4) is sleeved at the connection of the two.

2. The on-site rapid screening device for polycyclic aromatic hydrocarbons in the toy according to claim 1, wherein: The carbon nanotube fiber bundle (3) is composed of 50 multi-walled carbon nanotube fibers. Each multi-walled carbon nanotube fiber has a diameter of 60 - 80 μm and a length of 1 cm.

3. The on-site rapid screening device for polycyclic aromatic hydrocarbons in the toy according to claim 2, wherein: The front end of the plastic tube (2) is inserted into the peek head (4) and is flush with its tip. The latter half of the carbon nanotube fiber bundle (3) is embedded inside the front end of the plastic tube (2). The front end of the carbon nanotube fiber bundle (3) is arranged 1 mm in front of the inlet of the mass spectrometer (1).

4. The on-site rapid screening device for polycyclic aromatic hydrocarbons in the toy according to claim 3, characterized in that: The mass spectrometer (1) is a Miniβ small portable mass spectrometer. The carbon nanotube fiber bundle (3) is connected to the high-voltage source of the Miniβ small portable mass spectrometer through a metal wire.

5. A method for on-site rapid screening of polycyclic aromatic hydrocarbons in toys using the on-site rapid screening device for polycyclic aromatic hydrocarbons in toys according to claim 4, characterized in that: It includes the following steps: The carbon nanotube fiber bundle is immersed in the liquid toy sample for direct adsorption extraction, placed in front of the inlet of the Miniβ small portable mass spectrometer, then the elution / ionization solvent is added dropwise, the ionization voltage is applied, and then it is detected by the Miniβ small portable mass spectrometer immediately.

6. The on-site rapid screening method for polycyclic aromatic hydrocarbons in the toy according to claim 5, characterized in that: The polycyclic aromatic hydrocarbons are naphthalene, acenaphthylene, acenaphthene and fluoranthene.

7. The on-site rapid screening method for polycyclic aromatic hydrocarbons in the toy according to claim 6, characterized in that: The analysis conditions of the Miniβ small portable mass spectrometer are as follows: Ionization mode: positive ion mode; Sampling time: 40 ms; Table 1 Small portable mass spectrometry analysis parameters of 4 polycyclic aromatic hydrocarbons The ionization voltages, parent ions and detection limits of the 4 polycyclic aromatic hydrocarbons are shown in Table 1.

8. The on-site rapid screening method for polycyclic aromatic hydrocarbons in the toy according to claim 7, characterized in that: The elution / ionization solvent is n-hexane with a volume of 4 μL.

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