Method for determining titanium dioxide nanoparticles in biological sample

Abstract

The invention provides a method for determining titanium dioxide nanoparticles in a biological sample, and belongs to the technical field of biological material detection. The method for determining the titanium dioxide nanoparticles in the biological sample comprises the following steps: mixing the biological sample with a diluent to obtain a treated sample; and determining the treated sample by adopting a single-particle inductively coupled plasma mass spectrometry method, wherein the reaction gas of the single-particle inductively coupled plasma mass spectrometry method is ammonia gas. According to the method, a direct dilution pretreatment method is adopted, so that the sample loss and the operation complexity are reduced, and the detection efficiency is improved; on the basis of a single-particle inductively coupled plasma mass spectrometry technology, ammonia gas is adopted as a reaction gas in a collision reaction tank, titanium ions passing through a quadrupole and the ammonia gas generate an adduct, and then the adduct is tested, so that interference brought by composite polyatoms in a biological sample is avoided, the titanium dioxide nanoparticles can be accurately determined, and the detection accuracy of the titanium dioxide nanoparticles is improved. And the detection sensitivity and accuracy are improved.

Description

Technical Field

[0001] The invention belongs to the technical field of biological material detection, and in particular relates to a method for determining titanium dioxide nanoparticles in a biological sample. Background Art

[0002] With the rapid development of nanotechnology, titanium dioxide nanoparticles are widely used in various products, including food additives, personal care products, medicines and industrial materials. However, the widespread use of titanium dioxide nanoparticles also brings potential health risks, especially nanoparticles that enter the human body through ingestion, inhalation or skin exposure. The exposure level, distribution, morphology and potential toxicity of nanoparticles in the human body have attracted widespread attention. Therefore, it is of great scientific and public health significance to accurately and reliably determine the content and morphology of titanium dioxide nanoparticles in human biological samples.

[0003] Currently, the methods for measuring titanium dioxide nanoparticles include transmission electron microscopy (TEM), dynamic light scattering (DLS) and Raman spectroscopy.

[0004] Limited detection sensitivity and resolution: Although TEM can observe the morphology of nanoparticles, it is difficult to quantify the concentration of nanoparticles in biological samples; DLS is greatly affected by factors such as particle aggregation and sample matrix interference when detecting the particle size distribution in the sample, resulting in unstable results; although Raman spectroscopy can provide chemical composition information, it is not sensitive enough in complex matrices and it is difficult to accurately quantify the concentration of nano-level particles. At the same time, these methods require complex sample pre-treatment steps, such as filtration, concentration or chemical treatment, low detection efficiency, and cumbersome pre-treatment. Therefore, how to improve the sensitivity, accuracy and efficiency of the determination method has become a technical problem that needs to be solved in this field. Summary of the invention

[0005] The purpose of the present invention is to provide a method for determining titanium dioxide nanoparticles in biological samples. The method provided by the present invention has high sensitivity, high accuracy and high efficiency.

[0006] In order to achieve the above-mentioned object of the invention, the present invention provides the following technical solutions: The present invention provides a method for determining titanium dioxide nanoparticles in a biological sample, comprising the following steps: (1) Mixing the biological sample with a diluent to obtain a processed sample; (2) Using single particle inductively coupled plasma mass spectrometry (sp-ICP-MS) to measure the treated sample obtained in step (1), wherein the reaction gas of the sp-ICP-MS is ammonia.

[0007] Preferably, the diluent in step (1) is an aqueous solution of polyvinyl pyrrolidone.

[0008] Preferably, the mass concentration of the diluent is 1.0-1.5%.

[0009] Preferably, the mixing in step (1) is performed under ultrasonic conditions.

[0010] Preferably, the frequency of the ultrasound is 90-110 Hz, the time of the ultrasound is 12-25 min, and the temperature of the ultrasound is 23-28° C.

[0011] Preferably, the flow rate of ammonia in step (2) is 0.55-0.65 mL / min.

[0012] Preferably, the flow rate of ammonia in step (2) is 0.60 mL / min.

[0013] Preferably, the flow rate of the sample processed in step (2) is 0.14-0.30 mL / min.

[0014] Preferably, the process parameters of the single particle inductively coupled plasma mass spectrometry in step (2) include: RF power 1500~1700W, plasma gas flow rate 15.5~16.5L / min, nebulizer gas flow rate 0.98~1.02mL / min, transmission efficiency 5~20%, residence time 90~110μs, AFT voltage 90~110V, and RPq parameter 0.45.

[0015] Preferably, the process parameters of the single particle inductively coupled plasma mass spectrometry in step (2) include: RF power 1600 W, plasma gas flow rate 16 L / min, nebulizer gas flow rate 1.0 mL / min, transmission efficiency 8-15%, residence time 100 μs, AFT voltage 100 V, and RPq parameter 0.45.

[0016] The present invention provides a method for determining titanium dioxide nanoparticles in biological samples, comprising the following steps: mixing the biological sample with a diluent to obtain a processed sample; and using single-particle inductively coupled plasma mass spectrometry to determine the processed sample, wherein the reaction gas of the single-particle inductively coupled plasma mass spectrometry is ammonia. The present invention adopts a direct dilution pretreatment method, which reduces sample loss and operation complexity, and significantly improves detection efficiency; based on single-particle inductively coupled plasma mass spectrometry technology, ammonia is used as a reaction gas in a collision reaction cell, so that titanium ions passing through the quadrupole are combined with ammonia to generate adducts. 48 Ti(NH)(NH3)4 was then tested for the adduct, thus circumventing the 31 P 16 O + , 32 S15 N + , 48 Ca + , 34 S 15 N + and 31 P 18 O + Isocomplex polyatomic pairs of total Ti + The interference caused by the method can accurately determine the titanium dioxide nanoparticles in biological samples, thereby significantly improving the detection sensitivity and accuracy. The experimental results show that the method provided by the present invention can detect the exposure concentration, the highest frequency exposure size and the average exposure size of nano-titanium dioxide in blood and urine with high accuracy. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 is the titanium dioxide nanoparticle exposure level in Example 3; Figure 2 is the titanium dioxide nanoparticle exposure level in Example 3; Figure 3 is the titanium dioxide nanoparticle exposure level in Example 3; Figure 4 is the titanium dioxide nanoparticle exposure level in Example 3; Figure 5 is the titanium dioxide nanoparticle exposure level in Example 3; Figure 6 is the titanium dioxide nanoparticle exposure level in Example 3; Figure 7 is the curve of background equivalent concentration and pulse peak signal intensity changing with AFT voltage; Figure 8 is the curve of background equivalent concentration and pulse peak signal intensity changing with RPq parameter; Fig. 9 is the curve of background equivalent concentration and pulse peak signal intensity changing with ammonia flow rate; Fig.10 is the titanium-ammonia adduct in Example 4 48 The signal of Ti(NH)(NH3)4; Fig.11 is the pulse peak signal intensity of titanium in Example 5; Fig.12 is the pulse peak signal intensity of titanium in Comparative Example 9; Fig.13 is the pulse peak signal intensity of titanium in Comparative Example 10; Fig.14 is the pulse peak signal intensity of titanium in Comparative Example 11; Fig.15The size of the titanium dioxide nanoparticles measured in Examples 6 to 7 and Comparative Examples 9 to 14; Fig.16 Zeta potential of Examples 6 to 7 and Comparative Examples 9 to 14 at 0 to 120 min; Fig.17 The spiked recoveries of the highest frequency exposed size and particle number of titanium dioxide nanoparticles were determined for Examples 8-9 and Comparative Examples 15-16. DETAILED DESCRIPTION

[0018] The present invention provides a method for determining titanium dioxide nanoparticles in a biological sample, comprising the following steps: (1) Mixing the biological sample with a diluent to obtain a processed sample; (2) Using single particle inductively coupled plasma mass spectrometry to measure the treated sample obtained in step (1), wherein the reaction gas of the single particle inductively coupled plasma mass spectrometry is ammonia.

[0019] The method provided by the present invention is applicable to any biological sample.

[0020] The present invention has no particular limitation on the sources of the raw materials, and commercially available products known to those skilled in the art may be used.

[0021] The present invention mixes the biological sample with a diluent to obtain a processed sample.

[0022] In the present invention, the biological sample preferably includes one of serum, whole blood and urine. The present invention has no particular limitation on the source of the biological sample, and any biological sample well known to those skilled in the art can be used.

[0023] In the present invention, the diluent is preferably an aqueous solution of polyvinyl pyrrolidone; the polyvinyl pyrrolidone is preferably PVP-10; the mass concentration of the diluent is preferably 1.0-1.5%, more preferably 1.0%. The present invention uses an aqueous solution of polyvinyl pyrrolidone as a diluent, which has excellent dispersion effect and high long-term dispersion stability compared to other diluents, thereby improving the sensitivity and accuracy of detection.

[0024] In the present invention, the biological sample is preferably subjected to ultrasound before use; the frequency of the ultrasound is preferably 90-110 Hz; the time of the ultrasound is preferably 12-20 min; and the temperature of the ultrasound is preferably 23-28° C. As an embodiment, the frequency of the ultrasound can be 100-108 Hz, or 102-105 Hz; the time of the ultrasound can be 15-18 min, or 16-17 min; and the temperature of the ultrasound can be 24° C., 25° C., 26° C., or 27° C.

[0025] In the present invention, the biological sample is preferably diluted 15 to 20 times using a diluent.

[0026] In the present invention, the biological sample and the diluent are preferably mixed under ultrasound conditions; the ultrasound frequency is preferably 90-110 Hz; the ultrasound time is preferably 12-25 min; and the ultrasound temperature is preferably 23-28° C. As an embodiment, the ultrasound frequency can be 100-108 Hz, or 104-106 Hz; the ultrasound time can be 15-18 min, or 16-17 min; and the ultrasound temperature can be 24° C., 25° C., 26° C., or 27° C.

[0027] Compared with the cumbersome pre-treatment in the prior art, the present invention adopts direct dilution and ultrasonic treatment, which reduces sample loss and operation complexity, simplifies sample pre-treatment, and significantly improves detection efficiency; at the same time, it does not require complicated sample preparation steps, reduces costs and makes the method suitable for rapid analysis of large-scale samples.

[0028] After obtaining the processed sample, the present invention uses single particle inductively coupled plasma mass spectrometry to measure the processed sample. In the present invention, when using single particle inductively coupled plasma mass spectrometry for measurement, the processed sample is fully atomized in the atomization device, and the atomized sample enters the quadrupole to remove interfering atoms to form an ion cloud. The quadrupole mass analyzer uses the mass-to-charge ratio of the ions to sort the ion cloud and generates a very strong pulse signal during the residence time; wherein the ion cloud combines with the ammonia in the reaction cell to generate 48 Ti(NH)(NH3)4, to achieve 48 Ti + Transfer to avoid biological samples 31 P 16 O + , 2 S 15 N + , 48 Ca + , 34 S 15 N + and 31 P 18 O + Isocomplex polyatomic pairs of total Ti + The interference caused by this was eliminated and the sample analysis was finally completed.

[0029] As an embodiment, the determination is preferably performed in PerkinElmer NexION 5000. The present invention has no particular limitation on the PerkinElmer NexION 5000, and any instrument or device known to those skilled in the art can be used. The PerkinElmer NexION 5000 of the present invention is a multi-quadrupole inductively coupled plasma mass spectrometer.

[0030] As an implementation manner, during the measurement, the material of the spray chamber may be quartz, and the type of the atomizer may be a concentric circle atomizer.

[0031] In the present invention, the reaction gas of the single particle inductively coupled plasma mass spectrometry is ammonia. In the present invention, ammonia is used as a reaction gas, and combines with titanium ions passing through the quadrupole in the collision reaction cell to form adducts. 48 Ti(NH)(NH3)4 was then tested for the adduct, thus circumventing the 31 P 16 O + , 32 S 15 N + , 48 Ca + , 34 S 15 N + and 31 P 18 O + Isocomplex polyatomic pairs of total Ti + The interference caused by it can accurately determine the titanium dioxide nanoparticles in biological samples, thereby significantly improving the detection sensitivity and accuracy.

[0032] In the present invention, the flow rate of ammonia is preferably 0.55-0.65 mL / min, more preferably 0.58-0.62 mL / min, and more preferably 0.60 mL / min. The present invention limits the flow rate of ammonia to the above range to obtain a higher intensity and a more ideal background equivalent concentration (BEC) with less interference. 48 The signal of Ti(NH)(NH3)4 can be further enhanced, thereby further improving the detection sensitivity and accuracy.

[0033] In the present invention, the flow rate of the sample is preferably 0.14-0.30 mL / min. As an embodiment, the flow rate of the sample can be 0.15-0.28 mL / min, or 0.18-0.22 mL / min.

[0034] In the present invention, the process parameters of the single particle inductively coupled plasma mass spectrometry preferably include: RF power 1500~1700W, plasma gas flow rate 15.5~16.5L / min, nebulizer gas flow rate 0.98~1.02mL / min, transmission efficiency 5~20%, residence time 90~110μs, AFT voltage 90~110V, RPq parameter 0.45. As an embodiment, the process parameters of the single particle inductively coupled plasma mass spectrometry can be: RF power 1600~1650W, plasma gas flow rate 16L / min, nebulizer gas flow rate 1.0~1.01mL / min, transmission efficiency 8~15%, residence time 100μs, AFT voltage 100V, RPq parameter 0.45. The present invention can obtain higher signal intensity and signal-to-noise ratio by limiting the above process parameters, while maintaining good time resolution, ensuring accurate characterization and quantitative analysis of titanium dioxide nanoparticles, and further improving detection sensitivity and accuracy.

[0035] In the present invention, the AFT voltage refers to the advanced frequency technology voltage applied to inductively coupled plasma (ICP), which is used to optimize the stability of plasma and improve the analytical sensitivity; the present invention can further improve the sensitivity by limiting the AFT voltage to 100V.

[0036] In the present invention, the RPq parameter is the Rejection Parameter "q". By limiting the RPq parameter within the above range, the background noise can be effectively suppressed, the signal-to-noise ratio (S / N) can be improved, and the detection accuracy can be improved.

[0037] The present invention is based on single-particle inductively coupled plasma mass spectrometry and uses mass shift technology to accurately characterize and measure the size and concentration of titanium dioxide nanoparticles exposed in biological samples. Compared with traditional nanoparticle characterization techniques, such as electron microscopy (TEM), dynamic light scattering (DLS) or Raman spectroscopy, sp-ICP-MS has a residence time of μS level, which can convert the signal of a single particle in a biological sample into a pulse peak, and analyze the signal intensity of the pulse peak through a computing platform, thereby realizing multi-dimensional determination of size and concentration at the same time; the present invention is not only simple to operate, has few pre-treatment steps, but also has the characteristics of low economic cost. In addition, the mass shift technology can effectively avoid multiple atomic interferences in ICP-MS by introducing reaction gas into the collision reaction cell, so that the target atoms interfered by multiple atoms combine with the reaction gas to form adducts, and then measure the transferred adducts, which significantly improves the detection sensitivity and reduces the detection limit of size and concentration, and is particularly suitable for the detection of trace nanoparticles in biological samples. This enables higher accuracy and reliability in monitoring nanoscale titanium dioxide particles in biological samples.

[0038] By improving the existing technology, the present invention not only solves the shortcomings of traditional methods in terms of sensitivity, accuracy and efficiency, but also provides a simpler and more economical operation process, which is particularly suitable for the accurate characterization and quantitative detection of titanium dioxide nanoparticles in human biological samples.

[0039] The present invention not only solves the technical bottleneck of insufficient sensitivity of traditional detection technology in complex samples, but also can provide more comprehensive nanoparticle exposure information, providing strong support for toxicological research and risk assessment of nanoparticles.

[0040] The technical solutions in the present invention will be described clearly and completely below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0041] Example 1 The method for determining titanium dioxide nanoparticles in biological samples is as follows: (1) Blood samples from 30 volunteers were ultrasonicated in a water bath at 100 Hz and 25°C for 15 min, and then 15 mL was taken into a conical centrifuge tube, diluted 20 times with a 1.0 wt% PVP-10 aqueous solution as a diluent, and then ultrasonicated in a water bath at 25°C at 100 Hz for 15 min to obtain the processed samples; (2) The treated sample obtained in step (1) was measured in a PerkinElmer NexION 5000 using single particle inductively coupled plasma mass spectrometry; wherein the reaction gas of the single particle inductively coupled plasma mass spectrometry was ammonia with a flow rate of 0.60 mL / min; the flow rate of the treated sample was 0.22 mL / min; the RF power was 1600 W, the plasma gas flow rate was 16 L / min, the nebulizer gas flow rate was 1.0 mL / min, the transmission efficiency was 10.18%, and the residence time was 100 μs; the spray chamber material was quartz, and the nebulizer type was a concentric nebulizer; the AFT voltage was 100 V; and the RPq parameter was 0.45.

[0042] Example 2 Based on Example 1, only the biological sample was changed to urine samples of 30 volunteers, and other conditions remained unchanged.

[0043] Example 1 determines the exposure concentration, maximum frequency exposure size (MFS), and average exposure size (AS) of nano-titanium dioxide in blood as shown in Table 1; Example 2 determines the exposure concentration, maximum frequency exposure size, and average exposure size of nano-titanium dioxide in urine as shown in Table 2.

[0044] Table 1 Exposure concentration, highest frequency exposure size and average exposure size of nano-titanium dioxide in blood

[0045] Table 2 Exposure concentration, highest frequency exposure size and average exposure size of nano-titanium dioxide in urine

[0046] It can be seen from Tables 1 and 2 that the determination method of the present invention is capable of detecting the exposure concentration, the highest frequency exposure size and the average exposure size of nano-titanium dioxide in blood and urine.

[0047] Comparative Example 1 S. Salou, C.-M. Cirtiu, D. Larivière, N. Fleury, Assessment of strategies for the formation of stable suspensions of titanium dioxide nanoparticles in aqueous media suitable for the analysis of biological fluids, Anal Bioanal Chem 412 (2020) 1469-1481. https: / / doi.org / 10.1007 / s00216-020-02412-2. Comparative Example 2 K. Badalova, P. Herbello-Hermelo, P. Bermejo-Barrera, A. Moreda-Piñeiro, Possibilities of single particle-ICP-MS for determining / characterizing titanium dioxide and silver nanoparticles in human urine, Journal of Trace Elements in Medicine and Biology 54 (2019) 55-61. https: / / doi.org / 10.1016 / j.jtemb.2019.04.003. Comparative Example 3 S. Salou, D. Larivière, C.-M. Cirtiu, N. Fleury, Quantification of titanium dioxide nanoparticles in human urine by single-particle ICP-MS, Anal Bioanal Chem 413 (2021) 171-181. https: / / doi.org / 10.1007 / s00216-020-02989-8. Comparative Example 4 M.V. Taboada-López, P. Herbello-Hermelo, R. Domínguez-González, P. Bermejo-Barrera, A. Moreda-Piñeiro, Enzymatic hydrolysis as a sample pre-treatment for titanium dioxide nanoparticles assessment in surimi (crabsticks) by single particle ICP-MS, Talanta 195 (2019) 23–32. https: / / doi.org / 10.1016 / j.talanta.2018.11.023. Comparative Example 5 J. Wojcieszek, J. Jiménez-Lamana, L. Ruzik, M. Asztemborska, M.Jarosz, J. Szpunar, Characterization of TiO2NPs in Radish (Raphanus sativusL.) by Single-Particle ICP-QQQ-MS, Front. Environ. Sci. 8 (2020). https: / / doi.org / 10.3389 / fenvs.2020.00100. The test conditions and results of the present invention and comparative examples 1 to 5 are shown in Table 3.

[0048] Table 3 Test conditions and results of the present invention and comparative examples 1 to 5

[0049] It can be seen from Table 3 that the technical solution of the present invention has a lower detection limit than other test methods.

[0050] Example 3 The method for determining titanium dioxide nanoparticles in biological samples is as follows: (1) Urine samples of 6 female volunteers (samples 1 to 3 are urine samples of female volunteers without makeup, and samples 4 to 6 are urine samples of female volunteers with makeup) were subjected to 90 Hz 24°C water bath ultrasound for 16 min, and then 15 mL was taken into a conical bottom centrifuge tube, diluted 20 times with a 1 wt% PVP-10 aqueous solution diluent, and then ultrasonicated at 90 Hz for 24 min in a 24°C water bath ultrasound to obtain a treated sample; (2) The treated sample obtained in step (1) was measured in a PerkinElmer NexION 5000 by single particle inductively coupled plasma mass spectrometry; wherein the reaction gas of the single particle inductively coupled plasma mass spectrometry was ammonia with a flow rate of 0.55 mL / min; the flow rate of the treated sample was 0.15 mL / min; the RF power was 1500 W, the plasma gas flow rate was 15.5 L / min, the nebulizer gas flow rate was 0.98 mL / min, the transmission efficiency was 9.2%, and the residence time was 100 μs; the spray chamber material was quartz, and the nebulizer type was a concentric nebulizer; the AFT voltage was 100 V; and the RPq parameter was 0.45.

[0051] In Example 3, three of the six female volunteers used sunscreen or makeup every day, and the other three had no habit of using sunscreen or makeup. The exposure levels of titanium dioxide nanoparticles were measured as follows: Figures 1 to 6 shown.

[0052] from Figures 1 to 6 It can be seen that the concentration of titanium dioxide nanoparticles in the urine of the three people who used personal sunscreen or had a habit of makeup was higher than that of the three volunteers who had never used it.

[0053] Example 4 The method for determining titanium dioxide nanoparticles in biological samples is as follows: (1) The titanium dioxide nanoparticles were diluted with a pure aqueous solution to obtain a biological sample with a titanium ion concentration of 1 μg / L. The biological sample was then ultrasonicated in a water bath at 105 Hz and 26°C for 16 min. 15 mL of the biological sample was taken into a conical bottom centrifuge tube and diluted 20 times with a 1 wt% PVP-10 aqueous solution diluent. The biological sample was then ultrasonicated in a water bath at 26°C at 105 Hz for 16 min to obtain a treated sample. (2) The treated sample obtained in step (1) was measured in a PerkinElmer NexION 5000 by single particle inductively coupled plasma mass spectrometry; wherein the reaction gas of the single particle inductively coupled plasma mass spectrometry was ammonia with a flow rate of 0.60 mL / min; the flow rate of the treated sample was 0.25 mL / min; the RF power was 1650 W, the plasma gas flow rate was 16.0 L / min, the nebulizer gas flow rate was 1.01 mL / min, the transmission efficiency was 11%, and the residence time was 100 μs; the spray chamber material was quartz, and the nebulizer type was a concentric nebulizer; the AFT voltage was 100 V; and the RPq parameter was 0.45.

[0054] Based on Example 4, only the AFT voltage was changed, and other conditions remained unchanged. The curves of background equivalent concentration and pulse peak signal intensity changing with AFT voltage are as follows: Figure 7 As shown in the figure, the blank (cps) curve is the curve of the pulse peak signal intensity of the instrument PerkinElmer NexION5000 changing with the AFT voltage (the same below), and the standard (cps) curve is the curve of the pulse peak signal intensity of the biological sample in Example 4 changing with the AFT voltage (the same below).

[0055] Based on Example 4, only the RPq parameter was changed, and other conditions remained unchanged. The curves of background equivalent concentration and pulse peak signal intensity changing with RPq parameters are as follows: Figure 8 shown.

[0056] Based on Example 4, only the ammonia flow rate was changed, and other conditions remained unchanged. The curves of background equivalent concentration and pulse peak signal intensity changing with ammonia flow rate are as follows: Fig. 9 shown.

[0057] from Fig. 9It can be seen that when the AFT voltage is 100 V, the RPq parameter is 0.45, and the ammonia flow rate is 0.60 mL / min, a higher intensity and a more ideal background equivalent concentration (BEC) with less interference can be obtained. 48 The signal of Ti(NH)(NH3)4.

[0058] Titanium-ammonia adduct in Example 4 48 The signal of Ti(NH)(NH3)4 is Fig.10 shown.

[0059] from Fig.10 It can be seen that titanium-ammonia adduct 48 The signal of Ti(NH)(NH3)4 was the strongest, so this substance was selected as the target after mass shift.

[0060] Example 5 The method for determining titanium dioxide nanoparticles in biological samples is as follows: (1) The biological sample is ultrasonicated in a water bath at 110 Hz and 23° C. for 18 minutes, then 15 mL is taken into a conical centrifuge tube, diluted 20 times with a 1 wt % PVP-10 aqueous solution diluent, and then ultrasonicated in a water bath at 23° C. at 110 Hz for 18 minutes to obtain a processed sample; wherein the biological sample is blood; (2) The treated sample obtained in step (1) was measured in a PerkinElmer NexION 5000 by single particle inductively coupled plasma mass spectrometry; wherein the reaction gas of the single particle inductively coupled plasma mass spectrometry was ammonia with a flow rate of 0.60 mL / min; the flow rate of the treated sample was 0.15 mL / min; the RF power was 1680 W, the plasma gas flow rate was 15.8 L / min, the nebulizer gas flow rate was 0.99 mL / min, the transmission efficiency was 12.2%, and the residence time was 100 μs; the spray chamber material was quartz, and the nebulizer type was a concentric nebulizer; the AFT voltage was 100 V; and the RPq parameter was 0.45.

[0061] Comparative Example 6 On the basis of Example 5, the dwell time was changed to 20 μs, and other conditions remained unchanged.

[0062] Comparative Example 7 On the basis of Example 5, the dwell time was changed to 50 μs, and other conditions remained unchanged.

[0063] Comparative Example 8 On the basis of Example 5, the dwell time was changed to 200 μs, and other conditions remained unchanged.

[0064] The pulse peak signal intensities of titanium in Example 5 and Comparative Examples 6 to 8 are as follows: Figures 11 to 14shown.

[0065] from Figures 11 to 14 It can be seen that when the dwell time is 100 μs, higher signal intensity and signal-to-noise ratio can be obtained while maintaining good time resolution, ensuring accurate characterization and quantitative analysis of titanium dioxide nanoparticles.

[0066] Example 6 The method for determining titanium dioxide nanoparticles in biological samples is as follows: (1) The biological sample was ultrasonicated in a water bath at 90 Hz and 28°C for 12 min, and then 15 mL was taken into a conical centrifuge tube, diluted 20 times with a 1 wt% PVP-10 aqueous solution diluent, and then ultrasonicated in a water bath at 28°C at 90 Hz for 12 min to obtain a processed sample; wherein the biological sample was the standard NIST1898, and the MFS size was measured to be 71 nm; (2) The treated sample obtained in step (1) was measured in a PerkinElmer NexION 5000 by single particle inductively coupled plasma mass spectrometry; wherein the reaction gas of the single particle inductively coupled plasma mass spectrometry was ammonia with a flow rate of 0.60 mL / min; the flow rate of the treated sample was 0.30 mL / min; the RF power was 1500 W, the plasma gas flow rate was 16.5 L / min, the nebulizer gas flow rate was 0.98 mL / min, the transmission efficiency was 18%, and the residence time was 100 μs; the spray chamber material was quartz, and the nebulizer type was a concentric nebulizer; the AFT voltage was 100 V; and the RPq parameter was 0.45.

[0067] Comparative Example 9 On the basis of Example 6, the type of diluent was changed, and the diluent was prepared by mixing 0.1wt% PVP-10 and 0.01wt% Triton X-100 at a volume ratio of 1:100, and other conditions remained unchanged.

[0068] Comparative Example 10 On the basis of Example 6, the diluent was changed to 1 wt % n-butanol aqueous solution, and other conditions remained unchanged.

[0069] Comparative Example 11 On the basis of Example 6, the diluent was changed to pure water, and other conditions remained unchanged.

[0070] Example 7 On the basis of Example 6, the biological sample was changed to the standard product US3498 with a size of 30 nm, and other conditions remained unchanged.

[0071] Comparative Example 12 On the basis of Example 6, the type of diluent was changed, and the diluent was prepared by mixing 0.1wt% PVP-10 and 0.01wt% Triton X-100 at a volume ratio of 1:100, and other conditions remained unchanged.

[0072] Comparative Example 13 On the basis of Example 6, the diluent was changed to 1 wt % n-butanol aqueous solution, and other conditions remained unchanged.

[0073] Comparative Example 14 On the basis of Example 6, the diluent was changed to pure water, and other conditions remained unchanged.

[0074] The sizes of the titanium dioxide nanoparticles measured in Examples 6 to 7 and Comparative Examples 9 to 14 are as follows: Fig.15 As shown; the Zeta potential of Examples 6 to 7 and Comparative Examples 9 to 14 at 0 to 120 min is as follows Fig.16 shown.

[0075] from Fig.15 It can be seen that the titanium dioxide nanoparticles have good dispersibility and low size change rate in the diluent polyvinyl pyrrolidone aqueous solution, indicating that the diluent system has excellent performance in long-term dispersion stability.

[0076] from Fig.16 It can be seen that the diluent polyvinyl pyrrolidone aqueous solution has a good dispersion effect (≥±30), which is suitable for high-throughput determination of biological samples, realizes the precise characterization and determination of titanium dioxide nanoparticles, and effectively improves the detection sensitivity and accuracy.

[0077] Example 8 The method for determining titanium dioxide nanoparticles in biological samples (urine with a titanium ion concentration of 0.04 μg / L) is as follows: (1) The biological sample was ultrasonicated in a water bath at 110 Hz and 25°C for 20 min, and then 15 mL was taken into a conical centrifuge tube, diluted 20 times with a 1 wt% PVP-10 aqueous solution diluent, and then ultrasonicated in a water bath at 25°C at 110 Hz for 20 min to obtain a treated sample; (2) The treated sample obtained in step (1) was measured in a PerkinElmer NexION 5000 by single particle inductively coupled plasma mass spectrometry; wherein the reaction gas of the single particle inductively coupled plasma mass spectrometry was ammonia with a flow rate of 0.60 mL / min; the flow rate of the treated sample was 0.30 mL / min; the RF power was 1700 W, the plasma gas flow rate was 15.5 L / min, the nebulizer gas flow rate was 0.98 mL / min, the transmission efficiency was 7%, and the residence time was 100 μs; the spray chamber material was quartz, and the nebulizer type was a concentric circle nebulizer; the AFT voltage was 100 V; and the RPq parameter was 0.45.

[0078] Comparative Example 15 On the basis of Example 8, the frequency of water bath ultrasound during the mixing with the diluent was changed to 80 Hz, while other conditions remained unchanged.

[0079] Example 9 On the basis of Example 8, the frequency of water bath ultrasound during the diluent mixing was changed to 100 Hz, and other conditions remained unchanged.

[0080] Comparative Example 16 On the basis of Example 8, the frequency of water bath ultrasound during the addition of diluent and mixing was changed to 120 Hz, while other conditions remained unchanged.

[0081] The maximum frequency exposure size (MFS) and the number of particles of titanium dioxide nanoparticles determined in Examples 8-9 and Comparative Examples 15-16 are as follows: Fig.17 shown.

[0082] from Fig.17 It can be seen that the determination method is more accurate when the water bath ultrasonic frequency is 100Hz and 110Hz.

[0083] It can be seen from the above embodiments and comparative examples that the method provided by the present invention has high sensitivity, high accuracy and high efficiency.

[0084] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A method for determining titanium dioxide nanoparticles in a biological sample, characterized in that: The following steps are involved: (1) Mixing the biological sample with a diluent to obtain a processed sample; (2) Using single particle inductively coupled plasma mass spectrometry to measure the treated sample obtained in step (1), wherein the reaction gas of the single particle inductively coupled plasma mass spectrometry is ammonia.

2. The method according to claim 1, characterized in that The diluent in step (1) is an aqueous solution of polyvinyl pyrrolidone.

3. The method according to claim 2, characterized in that The mass concentration of the diluent is 1.0-1.5%.

4. The method according to claim 1, characterized in that: The mixing in step (1) is performed under ultrasonic conditions.

5. The method according to claim 4, characterized in that The frequency of the ultrasound is 90-110 Hz, the time of the ultrasound is 12-25 min, and the temperature of the ultrasound is 23-28° C.

6. The method according to claim 1, characterized in that The flow rate of ammonia in step (2) is 0.55-0.65 mL / min.

7. The method according to claim 1 or 6, characterized in that: The flow rate of ammonia in step (2) is 0.60 mL / min.

8. The method according to claim 1, characterized in that The flow rate of the sample processed in step (2) is 0.14-0.30 mL / min.

9. The method according to claim 1, characterized in that: The process parameters of the single particle inductively coupled plasma mass spectrometry in step (2) include: RF power 1500~1700W, plasma gas flow rate 15.5~16.5L / min, nebulizer gas flow rate 0.98~1.02mL / min, transmission efficiency 5~20%, residence time 90~110μs, AFT voltage 90~110V, and RPq parameter 0.

45.

10. The method according to claim 1 or 9, characterized in that: The process parameters of the single particle inductively coupled plasma mass spectrometry in step (2) include: RF power 1600 W, plasma gas flow rate 16 L / min, nebulizer gas flow rate 1.0 mL / min, transmission efficiency 8-15%, residence time 100 μs, AFT voltage 100 V, and RPq parameter 0.45.

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