atomic fluorescence spectrometry/
inductively coupled plasma atomic emission spectrometry
The development of lead ion detection methods introduced in the national standard has been relatively mature, and each method has its own advantages and disadvantages. Atomic absorption methods and electrochemical methods can satisfy the detection of lead ion in most cases. However, for laboratories that do not have such expensive instruments, the dithizone colorimeter is a test method that is easier to achieve in ordinary laboratories. The colorimetric method is the only colorimetric spectrophotometry introduced in the national standard method and its operation is complicated. The toxic and easily manufactured properties of trichloromethane also do not apply to some sites that require rapid testing. Therefore, in addition to the test method recommended by the national standard, a variety of more environmentally friendly, more simple, more accurate emerging detection technologies are also developing in the direction of diversification.
Due to the low content of lead in actual samples and certain matrix interference effect in the analysis process, certain pretreatment and lead enrichment processes are usually required. For example, in the national standard GB/T 5750-2006, the reaction products of dithizone-lead in water samples were extracted by chloroform solution in colorimetric method [ 19 ]. This method belongs to liquid-liquid extraction technology, it has good selective extraction and enrichment effect on lead. In the national standard DZ/T 0064.20-2021, the lead ions in the water samples were enriched by chelating resin and then determined by atomic absorption spectrophotometry [ 21 ], it belongs to solid phase extraction technology. Traditional liquid–liquid extraction technology usually needs to use a large dose of organic reagents, which has a large pollution to the environment and a limited enrichment ratio. Based on this, researchers explored other green, economical and safe extraction methods for trace lead detection
Decentralized liquid-liquid microextraction (DLLME) is a new extraction method developed in recent years. It is different from the traditional liquid-liquid extraction method in the national standard method, it has the advantages of less extraction agent consumption, fast extraction time, and high enrichment efficiency. DDLME technique can be used in combination with atomic absorption method, spectrophotometry, and other analytical techniques to determine trace lead in samples. Zhang et al. [ 26 ] used light solvent octanol as extraction agent, methanol as dispersing agent, and diethyl dithiocarbamate (DDTC) as chelating agent to establish a dispersive liquid–liquid microextraction-graphite furnace atomic absorption spectrometry (LDS-DLLMEGFAAS) method. The method has a concentration of 87 times lead and a detection limit of 0.15 μg/L. It has been successfully applied to the detection of trace Pb in tap water, drinking water, and South Lake water. He et al. [ 27 ] used 8-hydroxyquinoline (8-HQ) as the coordination agent, carbon tetrachloride as the extraction agent and acetone as the dispersible agent to determine trace lead in tea with spectrophotometry, and the detection limit reached 0.045 μg/L. Tang et al. [ 28 ] used 2-[(5-bromo-2-pyrene-)]azo-5-diethylaminophenol as the chelating agent, carbon tetrachloride as the extractant, ethanol as the dispersant. The enrichment ratio was up to 94 times, and the detection limit of the method was 0.1 mg/L. DLLME technology usually requires the use of both extractant and dispersant. However, Franca et al. [ 29 ] for the first time used non-toxic and biodegradable dimethyl carbonate (DMC) as both extractant and dispersive agent for lead determination, and used dithiophosphate as complexing agent, combined with UV spectrophotometry. The enrichment factor of this method was 8.8, and the detection limit was 0.2 mg/L.
Cloud point extraction(CPE) technology is a new environmentally friendly extraction technology that does not use organic solvents. It is an extraction method based on the solubility and turbidity of aqueous solution of surfactant micelles. This method achieves the purpose of separating the target analytes and sample by controlling the change of reaction conditions, such as pH and temperature. Mao et al. [ 30 ] established a method of crown ether double turbidity point extraction (DCH18C6-DCPE) to determine trace lead in environmental water samples and food. Lead was selectively extracted by DCH18C6 to form a hydrophobic complex into L64 enrichment phase, then the L64 enrichment phase obtained by turbidity point extraction was complexed with EDTA solution and extracted into the aqueous phase. The enrichment multiple of this process was 18, the extraction time was 10 min, and the method detection limit was 2.8 μg/L.
Solid phase extraction (SPE) technology has the advantages of simple operation, low organic reagent consumption and low price, and is also widely used in the field of environmental and biological sample analysis. Zhao et al. [ 31 ] prepared a novel amine-functionalized polyacrylonitrile and a self-made solid phase extraction column to enrich lead ions in water and successfully determined the lead content in environmental water by combined with inductively coupled plasma mass spectrometry technology. Under the optimized conditions, 95% adsorption rate can be achieved in only 10 min with high selectivity and a detection limit of 2.5 μg/L. Liang et al. [ 32 ] synthesized lead ion-imprinted polymer microspheres by ion-imprinted polymerization technology. Additionally, it filled the polymer microspheres into solid phase extraction columns to enrich lead ions in the samples. The extraction column has a maximum enrichment ratio of 250 times and can be reused for more than 12 times. Combined with microwave plasma emission spectrometry, the detection limit of this method is 0.26 μg/L under optimal extraction conditions. Khoshhesab et al. [ 33 ] synthesized a magnetic nano-adsorbent nickel ferrite with high adsorption performance for lead ions in water. The extractant can be quickly separated under the external magnet, then eluted with hydrochloric acid solution, and determined by spectrophotometry. The extractant can be reused at least three times. Wang et al. [ 34 ] synthesized manganese tetroxide nanoparticles for solid phase extraction of lead, and combined with inductively coupled plasma mass spectrometry to determine lead content in vegetables, the detection limit of which was 4 ng/L. The extraction column has good stability in a weakly acidic environment and can be reused 60 times. Solid phase extraction technology is mostly in conjunction with on-line technology. In addition to its good selective adsorption performance for lead ions, the reuse performance of extraction column is also one of the important factors to evaluate the applicability of the method. Therefore, it is necessary to increase the reuse times of extraction columns in the development of new extraction columns.
Ionic liquid, as a new functional material, is also widely used in the field of extraction, which has the advantages of non-volatilization, high stability, and design of results. Fan [ 35 ] prepared three ionic liquids with different cationic side chain lengths [CnMIM] ( n = 4, 6, and 8), used them as extractants, and used dithizone as chelating agent. The extraction rate of lead ions was higher than 93.5% under optimized conditions, and the ionic liquids can be back extracted by controlling the pH value.
Due to the unique optical properties, silver/gold/copper and other noble metal nanoparticles have been widely used as chemical probes or sensor probes for the analysis of various components in environmental and food samples in recent years [ 36 , 37 , 38 ]. From this, Shrivas et al. [ 39 ] reported a paper-based lead ion analysis device. The device is modified with polyvinyl alcohol (PVA) coated silver nanoparticles (AgNPs). The red shift of the local surface plasmon resonant absorption band occurs when the lead ion touches AgNPs/PVA (as shown in Figure 1 ). The color intensity of PADs is recorded with a smart phone, then processed with ImageJ software. A new colorimetric method is finally established. The calibration curve has a good linear relationship in the range of 20–1000 μg/L, and the limit of detection (LOD) is 8 μg/L.
Imaging color on PADs at different lead ion concentrations ( a – f ) and the calibration curve between different concentrations of lead from 50 to 1000 μg L −1 against the respective mean color intensity [ 39 ].
Krian [ 40 ] prepared an alumina material coated with 2-Mercaptosuccinic acid (MSA)-capped gold nanoparticles and used the material as a solid extraction agent for lead. The limit of detection was 0.22 μg/L under the optimal conditions. Although the material has a good enrichment and adsorption effect on lead, its specific selective performance for lead is not optimistic, and it is greatly interfered by Zn 2+ , Cl − , and SO 4 2− . So, the accuracy of the material used for testing lead in actual water samples remains to be studied. Zhong et al. [ 41 ] used glutathione (GSH) and gold nanoparticles (AuNP) for the rapid determination of lead. GSH, as a binding agent between lead ion and AuNP, enabled AuNP to selectively bind with lead ion. AuNP rapidly aggregated under the combined action of lead ion and GSH and a rapid color change can be observed. The AuNP solution changed from ruby red to blue within 10 min and the rate of color change was different with different concentrations of lead (as shown in Figure 2 ). The absorbance ratio between the two colors (A610/A520) has a linear relationship within a certain range of lead concentration, achieving a linear calibration curve of up to 500 ppb and a detection limit of 6 ppb. However, the interaction between the thiol (-SH) groups and the lead cation is usually nonspecific and susceptible to interference by other heavy metals. Due to the well reaction and strong specific selectivity between lead ion and phenolic hydroxyl/carboxyl groups, Berlina [ 42 ] et al. synthesized colloidal gold nanoparticles using sodium citrate and sodium tannate as reductants and stabilizers. The corresponding concentration relationship was established by comparing the absorbance changes before and after the interaction between colloidal gold and lead ions at 595 nm. No specific reagent was added to coupling the nanoparticles to the target reactants in this study, and the quantitative limit of the method was 60 ng/mL.
The color of the solution varied with different reaction times [ 41 ].
Although traditional laboratory methods and instruments can achieve accurate quantitative analysis of trace lead in water samples, they often have the disadvantages of complicated operation process, large amount of reagents, expensive analytical instruments, and higher requirements for professional and technical personnel. Paper-based microfluidic technology takes paper as the substrate of microfluidic devices. Various 2D and 3D microfluidic channels can be established through the pore structure and pore size distribution of the paper itself, so that the fluid can be controlled to flow in the pre-designed channel to achieve the effect of detection and analysis. As a low-cost point-of-care diagnostic device, it has the advantages of being easy to carry and a fast analysis speed, which is of great significance for online testing and is widely used in chemistry, biology, medicine, and other fields [ 43 , 44 , 45 ]. Smartphones also provide an attractive platform for analytical devices for different areas, such as rapid diagnostics and environmental monitoring. Since the smartphone camera is a good color imaging sensor, most of the analysis methods on smartphones are based on colorimetry and macroscopic feature imaging. Additionally, the use of the smartphone camera can be further extended by adding add-on accessories.
Nguyen et al. [ 46 ] established a nano-colorimetric method using smart phones for quantitative detection of soluble lead ions in drinking water based on the principle of quantitative reaction between chromate ions and lead ions to produce bright yellow precipitates. The laboratory has designed a smartphone microscope that can operate in both fluorescence and dark-field imaging modes and enables color detection and intensity quantification at the nanometer level with the smartphone microscope. The sum of the intensities of the yellow pixels showed a good linear relationship with the Pb 2+ concentration in deionized water (1.37–175 ppb) and in urban tap water (5–175 ppb) ( Figure 3 a). The same smartphone without the improvement could only detect Pb 2+ at a concentration of more than 35,000 ppb, and these images were highly blurred compared with microscopic images ( Figure 3 b).
( a ) PbCrO 4 sediment imaged by dark-field smartphone microscope with Pb 2+ concentration ranging from 1.375–350 ppb. The brightness and contrast of the PbCrO 4 sediment images at Pb 2+ concentration of 1.375–2.75 ppb was adjusted for display purpose; ( b ) PbCrO 4 sediment taken by the same smartphone without the objective lens. The yellow color of PbCrO 4 can only be detected at a concentration above 35,000 ppb. The images are highly blurred compared to the microscopy images [ 46 ].
Satarpai et al. [ 47 ] prepared a paper-based lead ion enrichment and concentration material using filter paper as the substrate and zirconium silicate as the adsorption material. It was prepared by transferring a solution of zirconium silicate onto filter paper, then drying it. The modified filter paper was cut into suitable small discs and placed in a simple enrichment device (a micro-centrifuge tube equipped with a peristaltic pump) to enrich lead ions in water. Then, the filter paper, after the lead ion enrichment was dried, was placed in a special detection area device and sodium rodiate was added to react with lead ion to produce a pink substance. The higher the concentration of Pb(II), the stronger the color. The lead ion concentration was determined by taking pictures with a smart phone and processing images with ImageJ image processing software. The detection limit of the method was 10 μg/L, which could realize the detection of 10–100 μg/L lead ion in environmental water.
Sahu et al. [ 48 ] prepared a paper colorimeter device based on glucose-functionalized gold nanoparticles (AuNPs/Glu) for simultaneous determination of As(III) and Pb(II). The non-covalent interaction between As(III) and Pb(II) and glucose molecules leads to the aggregation of metal nanoparticles, which causes the color change and red shift of the localized surface plasmon resonance (LSPR) absorption band of AuNPs/Glu in the 200–800 nm region. The red shift (Dl) of the LSPR band of As(III) is 525–660 nm and that of Pb(II) is 525–670 nm. A smart phone and ImageJ image processing software were used to process and determine the concentration of those two ions. The color changes after the reaction of different concentrations of ions and the linear relationship are shown in Figure 4 .
( a ) Circular filter paper strip fabricated with AuNPs/Glu along with the deposition of different concentrations of As(III) with their calibration curve; ( b ) circular filter strip fabricated with AuNPs/Glu along with the deposition of different concentrations of Pb(II) with their calibration curve [ 48 ].
The traditional plasma emission spectrometry and atomic absorption spectrometry for the determination of sample lead content require some pre-treatment processes, such as sample digestion and regular calibration of the working curve, which leads to a large amount of time to test a sample. Su et al. [ 49 ] used energy dispersive X-ray fluorescence spectrometry to determine lead in polymer materials. The test process did not need to destroy the sample, but only needed to crush the large polymeric sample to a particle diameter of less than 4 mm, which greatly saved the sample pre-treatment time and reduced the detection cost. The detection limit of the method was 4.1 μg/g, and the accuracy was good. He et al. [ 50 ] combined a self-designed new type of hydride generator with inductively coupled plasma atomic emission spectrometer and added a self-made pre-stabilizer to the reducing agent to solve the problem of instability of the traditional hydride measurement system and improve the sensitivity of the method. The detection limit of the method can reach 1.0 μg/L, and there is no matrix effect interference. Lehmann et al. [ 51 ] studied CO 2 laser induced spectroscopy for the detection of lead in the classification of industrial recycled glass. Compared with the most advanced X-ray fluorescence technology, the detection limit, detection speed, and detection accuracy of CO 2 laser-induced spectroscopy are comparable, and the hardware of CO 2 laser-induced spectroscopy has a lower price and is expected to replace X-ray fluorescence spectroscopy to realize the detection of lead in glass. Tian et al. [ 52 ] used Fourier transform infrared spectroscopy based on principal component analysis (PCA) and partial least squares (PLS-DA) to study the biochemical changes in plasma during acute lead poisoning (ALP) in rats. The researchers first collected a large number of plasma samples from rats with and without ALP and found that the corresponding biochemical changes between plasma and lead can be used as potential spectral biomarkers for the diagnosis of lead poisoning. This is the first application of FTIR spectroscopy based on stoichiometry. Arif et al. [ 53 ] used a FieldSpec-3 portable handheld ground object spectrometer to measure cadmium (Cd) and lead (Pb) content from 23 roads in the municipality of Chongqing, China. For the Pb content inversion models, the PLS model processed by SG-MSC had the best prediction accuracy. The results of this study are of great value for the portable detection of lead in green space by hyperspectral imaging.
Fluorescent molecules can emit a certain wavelength of fluorescence when they are irradiated by ultraviolet or visible light. Its fluorescence properties change with the change of the environment, so as to realize the effective detection of the tested substance. Fluorescence sensor technology has the advantages of good sensitivity, high selectivity, and short response time. In recent years, fluorescence sensors related to heavy metal detection have also been widely concerned by researchers.
Chen et al. [ 54 ] reported a dual-function biosensor with electrochemical and fluorescent detection that can be used for blood lead detection. In this system, the presence of magnetic ferric oxide allows the sensor to be quickly fixed on the magnetic electrode. The surface of Fe 3 O 4 is modified with hyperbranched polyamide (HPAM) with good fluorescence characteristics, rich amino groups, and cavity structure, which can form coordination bonds with lead ions to rapidly accumulate blood lead ( Figure 5 A). The enriched lead ions precipitate on the electrode surface and generate a current, while limiting the geometric movement of the fluorescence center of HPAM to enhance the fluorescence intensity. Based on this, the system realizes electrochemical and fluorescence dual-function detection of blood lead. The electrochemical detection range was 1.5–4.8 × 10 3 pM and the detection limit was 4.4 pM Figure 5 B. The fluorescence detection range was 0.5–4.8 × 10 3 pM and the detection limit was 1.0 pM ( Figure 5 C).
( A ) Schematic illustration of the synthesis of MHPAM-H NPs and their applications in ( B ) the electrochemical detection and ( C ) the fluorescence detection for blood lead [ 54 ].
Song et al. [ 55 ] synthesized a fluorescent fiber nanocrystal sensor for lead ion detection in aqueous solution, which is composed of fluorescent 1, 8-naphthimide dye covalently combined with cellulose nanocrystal (CNCs). The dye group grafted on the sensor and the adjacent carboxyl group on the surface of CNCs synergistically interact with lead ions in aqueous solution to show selectivity, resulting in a significant enhancement of fluorescence emission intensity. The binding ratio of lead ions to fluorophores on CNCs is 1.2:1 and the detection limit can be as low as 1.5 × 10 −7 mol/L. Qi et al. [ 56 ] designed a fluorescence sensor of H 2 Pc-β-(ZnPor) 2 , a phthalocyanine porphyrin heterotriplet, for the determination of lead ions. This triplet has an efficient intramolecular fluorescence resonance energy transfer process (FRET) from two zinc porphyrin (ZnPor) units to a metal-free phthalocyanine (H 2 Pc) unit. Selective binding of lead ions to H 2 Pc effectively quench the fluorescence emission of the phthalocyanine unit (700 nm) while inhibiting the intramolecular FRET process and enhancing the fluorescence emission of the ZnPor unit (605 and 652 nm). A significant ratio fluorescence response was thus produced ( Figure 6 ).
Lead ion detection mechanism [ 56 ].
Electrochemical analysis has the advantages of good sensitivity, large linear dynamic range, fast analysis time, and low cost. To realize the selectivity test of electrochemical method for lead ion in aqueous solution, a lead selective adsorption film is usually prepared to modify the electrode, then lead determination is carried out under certain conditions. Electrochemical analysis has the advantages of good sensitivity, large linear dynamic range, fast analysis time, and low cost. Under certain detection conditions, the electrochemical method usually realizes the selectivity test of lead ions in aqueous solution by preparing a lead-selective adsorption film to modify the electrode. As the electrode head is vulnerable to the interference of organic compounds, such as passivation and signal weakening, it is extremely important to pay attention to the reuse performance, precision, and anti-interference ability of the electrode while synthesizing high-sensitivity electrode modified films. Nguyen et al. [ 57 ] prepared a platinum nanoflower modified electrode by one-step electrochemical deposition method for simultaneous determination of lead ions and cadmium ions in water. Lead and cadmium ions in the range of 1–100 μg/L can be tested normally. The detection limits of the electrode for lead and cadmium were 0.408 and 0.453 μg/L, respectively. Guo et al. [ 58 ] established a method for determination of lead ions by square wave voltammetry using isoleucine modified glassy carbon electrode working electrode. Under the optimized conditions, the peak current Ip had a good linear relationship with lead ion concentration in the range of 5–50 nmol/L and 0.05–5.0 mmol/L, and the detection limit could be as low as 3.41 nmol/L. Although the newly fabricated electrode has high sensitivity, its reuse performance and anti-interference performance are not further described. In anodic stripping voltammetry, the lead detection signal is easily weakened or eliminated by surfactants and humic acid in environmental water. Grabarczyk et al. [ 59 ] found that adding a certain amount of Amberlite XAD-7 resin to the solution could eliminate the interference of some organic substances, such as surfactants without adsorbing lead ions, so that the electrode could directly detect lead ions in wastewater containing surfactants. A sensitive, rapid, and economical method for determination of lead in environmental water was developed. Silva et al. [ 60 ] used paraffin oil as the binder, cork, and graphite to synthesize a green, low-cost graphite/cork electrode material. Experiments show that the material has the best sensitivity to lead ions when the content of cork is 70% and the content of graphite is 30%. The sensitivity is better in 0.5 M sulfuric acid medium, and the detection limit of the method is 0.3 μM. Although the material is green and easy to synthesize, its sensitivity is relatively low compared with other methods, and acetate ion has a great influence on the determination of lead. Therefore, it can be further optimized. Deswati et al. [ 61 ] established an adsorbent cathodic stripping voltammetry (AdCSV) for the determination of lead and cadmium in seawater. In this method, calcium reagent was used as heavy metal complexing agent to adsorb lead ions and cadmium ions in seawater, then reduced on the surface of the hanging mercury drop electrode. Under the optimal testing conditions, the linear ranges of Pb and Cd were 10–160 ng/mL and 10–190 ng/mL, respectively, and the detection limits were 0.02 ng/mL and 0.05 ng/mL, respectively. The Pb and Cd showed good anti-interference performance against common ions in environmental water, but their re-use performance was unknown.
As the traditional dithizone color method consumes a large test dose, large waste liquid displacement, the masking agent used is highly toxic, and has a complicated operation, people continue to verify, improve, and supplement the methods of lead detection, so there is relatively mature atomic absorption spectrometry, atomic fluorescence spectrometry, electrochemistry, and other methods. Although the traditional method can achieve more accurate determination of lead in different fields, the greener, more efficient, and more portable method is still the main research focus. Among the new methods described in the review, The method based on precious metal nanotechnology has high sensitivity and can realize the detection of trace lead in environmental water samples. Paper-based microfluidic technology provides great convenience for on-site real-time detection, and its advantages of low cost, high sensitivity, non-professionals can use it, and quickly obtain test results make it have a huge development space and potential in the field of analysis and detection. The spectroscopic method is still the most commonly used method in the field of lead detection. It is the first choice in the field of lead detection because of its small amount of test samples, green and stable test links, and high detection accuracy. The electrochemical method also has good sensitivity, large detection linear range, low production cost, and high accuracy, which has become a research hotspot in the field of pre-detection. The summary of lead new measurement method is shown in Table 2 .
Summary of lead new measurement method.
Methods | Concentration Range | Applicable Objects | Advantages | Disadvantages | |
---|---|---|---|---|---|
Precious metal nanotechnology | AgNPs/PVA [ ] MSA-capped GNP-supported alumina [ ] | 20–10,000 μg/L [ ] 0–50 μg/L [ ] | Surface water and industrial waste water [ , ] | High sensitivity | It is difficult to synthesize and has a poor shelf life |
Paper-based microfluidic technology | Chromate method [ ] Sodium rhodizonate method [ ] AuNPs/Glu method [ ] | 1.37–175 μg/L [ ] 10–100 μg/L [ ] 0–1000 μg/L [ ] | Environmental water and industrial waste water [ , , ] | It has low cost, real-time monitoring on site, and can be used by non-specialists | The sensitivity was low, and the paper chip structure design did not meet the market demand |
Spectrometry | CO laser induced spectroscopy [ ] Chemometrics-Based Fourier Transform Infrared Spectroscopy [ ] | >6 wt.-% [ ] | Glass [ ] Blood lead [ ] | High precision, wide application field | Due to the large interference, it is difficult to meet the accurate measurement of different water quality. High cost |
Fluorescent molecular probe | A dual-responsive biosensor [ ] Fluorescent cellulose nanocrystals [ ] | 0.5–4.8 × 10 pM [ ] 2.5 × 10 –5.0 × 10 mol/L [ ] | Blood lead [ ] chemical, environmental, and biological systems [ ]. | Good sensitivity, high selectivity, and short response time | The synthesis is complex and the photostability is unknown |
Electrode | Anodic Stripping Voltammetry [ ] Graphite/Cork sensor [ ] Adsorptive cathodic stripping voltammetry [ ] | 2 × 10 –5.0 × 10 mol/L [ ] 1–25 μmol/L [ ] 10–160 ng/mL [ ] | Waste water [ ] Natural water [ ] Seawater [ ] | Good sensitivity, large linear dynamic range, fast analysis time, and low cost | The electrode membrane is easily inactivated by interfering substances, and the shelf life needs to be improved |
The high sensitivity sensor based on noble metal nanoclusters relies on effective methods to synthesize excellent noble metal nanoclusters probes. The combination between ultra-small size (<2 nm) precious metals and lead ions is more sensitive. Therefore, the synthesis of stable and highly sensitive noble metal nanoclusters is a major difficulty in the field of precious metal nanotechnology in the detection of heavy metals. The design of paper chip structure is related to the detection efficiency, sensitivity, and specific selection performance. Therefore, how to optimize paper wetting conditions and liquid conveying speed to improve sample conveying capacity is the main research direction of this technology, and most of the studies in the review still have a long way to go from market application. Good photostability and high quantum yield have always been the focus of the research of fluorescent molecular probes. The reported synthesis of probe molecules is relatively complex. The design of a Pb 2+ fluorescent probe with simple structure, low cost, good selectivity and high sensitivity has important research value and practical significance. The development of X-ray fluorescence spectroscopy, Fourier transform infrared spectroscopy, and so on are also developing towards the direction of low cost and high precision and are gradually applied in various fields of lead monitoring, but there are few applications in water quality monitoring. The change of environmental conditions, such as temperature and pH, will cause great interference to the spectral absorption and the electronic circuit of the instrument, which makes it difficult to meet the accurate measurement of different water quality. Electrochemical method of sensitization of nanomaterials, more green synthetic raw materials, and other detection of lead ions in water has shown a wider range of application, but electrode film activity and preservation stability are still a major difficulty of electrode method, especially the preservation of nanomaterials is extremely unstable, they will become inefficient due to degeneration, degradation, or aggregation. This will greatly reduce the detection performance of the sensor.
Lead ions can easily enter the human body through contaminated water and food chain. Due to the non-degradability of lead, it is easy to accumulate in animals and plants. In severe cases, lead can lead to systemic diseases in humans, and ultimately pose a great threat to human health. The high content of lead in the environment can reduce the photosynthetic rate of plants and crop production. Therefore, it is imperative to accurately monitor the lead pollution in people’s daily living environment. This paper briefly introduces the harmful effects of lead ions and the emission limits of lead ions in various fields. The national standard detection methods of lead ion, such as atomic absorption spectrophotometry, electrochemical method, inductively coupled plasma mass spectrometry, etc., are introduced. There are many methods for lead ion detection, and their applicable fields and test ranges are also different. Each method has its own advantages and disadvantages. Thus, in the actual test process, we should choose a more suitable test method according to different test conditions. When the content of lead in the sample and the sample volume are small, the spectral and electrochemical methods can be used to determine the content of lead. When the sample quantity is large or there is not enough detection budget, the dithizone color method can be selected for determination. A safer, greener, and more efficient pre-treatment technology is also one of the hot topics in the field of lead ion detection due to the complicated pre-treatment process during sample testing.
With the progress of science and technology, emerging detection technologies, such as the application of precious metal nanotechnology, paper-based microfluidic technology, synthesis technology of new fluorescent molecular probes, and new green and efficient electrochemical technology, also emerge in an endless stream.
Due to the high price of traditional detection technology and the complex extraction technology with a certain toxicity, the research of various new technologies is constantly developing in the direction of more economic, more portable, and more rapid. The future research directions of lead detection can be as follows: first, the direction of higher detection efficiency and measurement accuracy. The second is to reduce the pollutants produced in the experiment and use as few samples as possible to get as high accuracy as possible. The third is to develop towards a wider range of applications, such as air, soil, biomedicine, and so on. Fourth, it can be developed in the direction of reducing equipment costs, realizing real-time monitoring, and more portable and efficient testing. Therefore, the development trend of lead ion detection technology in the future must be lower equipment cost, more portable operation, more rapid and efficient, better stability, and higher accuracy.
We thank the Lohand Water Analysis Urban Enterprised High Technology Research Institute and the Experimental Teaching Center of Zhejiang University for providing the scientific research platform.
This research was funded by the Provincial Natural Science Fund (LGN21C200017), School-Enterprise cooperation project (2023-KYY-513110-0001).
D.W. and Y.H. were equal contributors as the first authors. Investigation, methodology, and writing—original draft, D.W. and Y.H.; writing review and editing, H.C. and X.Y. All authors have read and agreed to the published version of the manuscript.
Not applicable.
Data availability statement, conflicts of interest.
The authors declare no conflict of interest.
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Lead (Pb) is a widespread environmental heavy metal that can damage the cerebral cortex and hippocampus, and reduce the learning and memory ability in humans and animals. In vivo and in vitro models of acute lead acetate exposure were established to further study the mechanism of neurons injury. In this study, 4-week-old female Kunming mice were randomly divided into four groups. Each group was treated with distilled water with different Pb concentrations (0, 2.4, 4.8 and 9.6 mM). Mice were killed, and brain tissues were collected to detect the changes in synaptic plasticity-related protein expression. Furthermore, Neuro-2A cells were treated with 0, 5, 25 and 50 μM lead acetate for 24 h to observe the changes in cell morphology and function. In in vivo experiment, results showed that the expression levels of cytoskeleton-associated and neural function-related proteins decreased in a dose-dependent manner in the mouse brain tissue. In in vitro experiment, compared with the control group, Pb treatment groups were observed with smaller and round cells, decreased cell density and number of synapses. In the Pb exposure group, the survival rate of nerve cells decreased evidently, and the permeability of the cell membrane was increased. Western blot results showed that the expression of cytoskeleton-associated and function-related proteins decreased gradually with increased Pb exposure dose. Confocal laser scanning microscopy results revealed the morphological and volumetric changes in Neuro-2A cells, and a dose-dependent reduction in the number of axon and dendrites. These results suggested that abnormal neural structures and inhibiting expression of synaptic plasticity-related proteins might be the possible mechanisms of Pb-induced mental retardation in human and animals, thereby laying a foundation for the molecular mechanism of Pb neurotoxicity.
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Lead-induced changes of cytoskeletal protein is involved in the pathological basis in mice brain, lead exposure impairs hippocampus related learning and memory by altering synaptic plasticity and morphology during juvenile period, alterations of synaptic proteins in the hippocampus of mouse offspring induced by developmental lead exposure, explore related subjects.
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Arslan A (2021) Extrasynaptic δ-subunit containing GABA A receptors. J Integr Neurosci 30;20(1):173–184. https://pubmed.ncbi.nlm.nih.gov/33834705/
Caldas D, Pestana IA, Almeida MG, Henry FC, Salomão MS, de Souza CM (2016) Risk of ingesting As, Cd, and Pb in animal products in north Rio de Janeiro state, Brazil. Chemosphere 164:508–515
Article CAS Google Scholar
Chen L, Chen H, Yao C, Chang C, Xia H, Zhang C, Zhou Y, Yao Q, Chen K (2015) The toxicity of NaF on BmN cells and a comparative proteomics approach to identify protein expression changes in cells under NaF-stress: impact of NaF on BmN cells. J Hazard Mater 286:624–31
Chen F, Zhou CC, Yang Y, Liu JW, Yan CH (2019) GM1 Ameliorates Lead-Induced Cognitive Deficits and Brain Damage Through Activating the SIRT1/CREB/BDNF Pathway in the Developing Male Rat Hippocampus. Biol Trace Elem Res 190(2):425–436
Chen L, Ning H, Yin Z, Song X, Feng Y, Qin H, Li Y, Wang J, Ge Y, Wang W (2017) The effects of fluoride on neuronal function occurs via cytoskeleton damage and decreased signal transmission. Chemosphere 185:589–594
Choi WS, Kim SJ, Kim JS (2011) Inorganic lead (Pb)- and mercury (Hg)-induced neuronal cell death involves cytoskeletal reorganization. Lab Anim Res 27(3):219–25
Article Google Scholar
Dehmelt L, Halpain S (2004) The MAP2/Tau family of microtubule-associated proteins. Genome Biol 6(1):204
Ding JJ, Zou RX, He HM, Lou ZY, Xu Y, Wang HL (2018) Pb inhibits hippocampal synaptic transmission via cyclin-dependent kinase-5 dependent Synapsin 1 phosphorylation. Toxicol Lett 296:125–131. https://pubmed.ncbi.nlm.nih.gov/30121340/
dos Remedios C G, Chhabra D, Kekic M, Dedova I V, Tsubakihara M., Berry D A, Nosworthy N J (2003) Actin binding proteins: regulation of cytoskeletal microfilaments. Physiol Rev 83(2): 433–73. https://pubmed.ncbi.nlm.nih.gov/12663865/
Flora G, Gupta D, Tiwari A (2012) Toxicity of lead: a review with recent updates. Interdiscip Toxicol 5(2):47–58
Gąssowska M, Baranowska-Bosiacka I, Moczydłowska J, Frontczak-Baniewicz M, Gewartowska M, Strużyńska L, Gutowska I, Chlubek D, Adamczyk A (2016a) Perinatal exposure to lead (Pb) induces ultrastructural and molecular alterations in synapses of rat offspring. Toxicology 373:13–29
Gąssowska M, Baranowska-Bosiacka I, Moczydłowska J, Tarnowski M, Pilutin A, Gutowska I, Strużyńska L, Chlubek D, Adamczyk A (2016b) Perinatal exposure to lead (Pb) promotes Tau phosphorylation in the rat brain in a GSK-3β and CDK5 dependent manner: relevance to neurological disorders. Toxicology 347–349:17–28
Ge Y, Chen L, Sun X, Yin Z, Song X, Li C, Liu J, An Z, Yang X, Ning H (2018a) Lead-induced changes of cytoskeletal protein is involved in the pathological basis in mice brain. Environ Sci Pollut Res Int 25(12):11746–11753
Ge Y, Chen L, Yin Z, Song X, Ruan T, Hua L, Liu J, Wang J, Ning H (2018b) Fluoride-induced alterations of synapse-related proteins in the cerebral cortex of ICR offspring mouse brain. Chemosphere 201:874–883
Ge Y, Song X, Chen L, Hu D, Hua L, Cui Y, Liu J, An Z, Yin Z, Ning H (2019) Cadmium induces actin cytoskeleton alterations and dysfunction in Neuro-2a cells. Environ Toxicol 34(4):469–475
Gulisano W, Maugeri D, Baltrons MA, Fà M, Amato A, Palmeri A, D'Adamio L, Grassi C, Devanand DP, Honig LS, Puzzo D, Arancio O (2018) Role of Amyloid-β and Tau Proteins in Alzheimer's Disease: Confuting the Amyloid Cascade. J Alzheimers Dis 64(s1): S611-S631. https://www.j-alz.com/manuscript-disclosures/17-9935
Gumy LF, Katrukha EA, Grigoriev I, Jaarsma D, Kapitein LC, Akhmanova A, Hoogenraad CC (2017) Map2 defines a pre-axonal filtering zone to regulate kif1-versus kif5-dependent cargo transport in sensory neurons. Neuron 94(2):347–362
Hayashi Y, Nishimune H, Hozumi K, Saga Y, Harada A, Yuzaki M, Iwatsubo T, Kopan R, Tomita T (2016) A novel non-canonical Notch signaling regulates expression of synaptic vesicle proteins in excitatory neurons. Sci Rep 6:23969
Ketschek A, Spillane M, Dun XP, Hardy H, Chilton J, Gallo G (2016) Drebrin coordinates the actin and microtubule cytoskeleton during the initiation of axon collateral branches. Dev Neurobiol 76(10):1092–110
Kumar D, Thakur MK (2017) Anxiety like behavior due to perinatal exposure to Bisphenol-A is associated with decrease in excitatory to inhibitory synaptic density of male mouse brain. Toxicology 378:107–113
Liu Y, Xu YF, Zhang L, Huang L, Yu P, Zhu H, Deng W, Qin C (2017a) Effective expression of Drebrin in hippocampus improves cognitive function and alleviates lesions of Alzheimer's disease in APP (swe)/PS1 (ΔE9) mice. CNS Neurosci Ther 23(7):590–604. https://pubmed.ncbi.nlm.nih.gov/28597477/
Liu Y, Xu Y, Zhang L, Huang L, Yu P, Zhu H, Deng W, Qin C (2017b) Down-Regulated Drebrin Aggravates Cognitive Impairments in a Mouse Model of Alzheimer’s Disease. Int J Mol Sci 18(4):800
Nascimento CRB, Risso WE, Martinez CBDR (2016) Lead accumulation and metallothionein content in female rats of different ages and generations after daily intake of Pb-contaminated food. Environ Toxicol Pharmacol 48:272–277
Neal AP, Guilarte TR (2010) Molecular neurobiology of lead (Pb (2+)): effects on synaptic function. Mol Neurobiol 42(3):151–60
Neelima A, Rajanna A, Bhanuprakash RG, Chetty CS, Suresh C (2017) Deleterious effects of combination of lead and β-amyloid peptides in inducing apoptosis and altering cell cycle in human neuroblastoma cells. Interdiscip Toxicol 10(3):93–98
Ning H, Li C, Yin Z, Hu D, Ge Y, Chen L (2021) Fluoride exposure decreased neurite formation on cerebral cortical neurons of SD rats in vitro. Environ Sci Pollut Res Int 28(37):50975–50982
Ohkawa N, Hashimoto K, Hino T, Migishima R, Yokoyama M, Kano M, Inokuchi K (2007) Motor discoordination of transgenic mice overexpressing a microtubule destabilizer, stathmin, specifically in Purkinje cells. Neurosci Res 59(1):93–100. https://pubmed.ncbi.nlm.nih.gov/17640754/
Paik NJ, Yang E (2014) Role of GABA plasticity in stroke recovery. Neural Regen Res 9(23):2026–8. https://pubmed.ncbi.nlm.nih.gov/25657711/
Ramírez Ortega D, González Esquivel DF, Blanco Ayala T, Pineda B, Gómez Manzo S, Marcial Quino J, Carrillo Mora P, Pérez de la Cruz V (2021) Cognitive impairment induced by lead exposure during lifespan: mechanisms of lead neurotoxicity. Toxics 9(2):23
Shirao T, González-Billault C (2013) Actin filaments and microtubules in dendritic spines. J Neurochem 126(2):155–64
Takizawa H, Hiroi N, Funahashi A (2012) Mathematical modeling of sustainable synaptogenesis by repetitive stimuli suggests signaling mechanisms in vivo. PLoS One 7(12):e51000
Tanabe K, Yamazaki H, Inaguma Y, Asada A, Kimura T, Takahashi J, Taoka M, Ohshima T, Furuichi T, Isobe T, Nagata K, Shirao T, Hisanaga S (2014) Phosphorylation of drebrin by cyclin-dependent kinase 5 and its role in neuronal migration. PLoS One 9(3):e92291
Verstraeten SV, Aimo L, Oteiza PI (2008) Aluminium and lead: molecular mechanisms of brain toxicity. Arch Toxicol 82(11):789–802
Vicini S, Wang JF, Li JH, Zhu WJ, Wang YH, Luo JH, Wolfe BB, Grayson DR (1998) Functional and pharmacological differences between recombinant N-methyl-D-aspartate receptors. J Neurophysiol. 79(2):555–66. https://pubmed.ncbi.nlm.nih.gov/9463421/
Wagner PJ, Park HR, Wang Z, Kirchner R, Wei Y, Su L, Stanfield K, Guilarte TR, Wright RO, Christiani DC, Lu Q (2017) In vitro effects of lead on gene expression in neural stem cells and associations between up-regulated genes and cognitive scores in children. Environ Health Perspect 125(4):721–729
Wu J, Basha MR, Brock B, Cox DP, Cardozo-Pelaez F, McPherson CA, Harry J, Rice DC, Maloney B, Chen D, Lahiri DK, Zawia NH (2008) Alzheimer’s disease (AD)-like pathology in aged monkeys after infantile exposure to environmental metal lead (Pb): evidence for a developmental origin and environmental link for AD. J Neurosci 28:3–9
Xiang Y, Niu Y, Xie Y, Chen S, Zhu F, Shen W, Zeng LH (2021) Inhibition of RhoA/Rho kinase signaling pathway by fasudil protects against kainic acid-induced neurite injury. Brain Behav 11(8): e2266. https://publons.com/publon/10.1002/brb3.2266
Yin Z, Hua L, Chen L, Hu D, Li J, An Z, Tian T, Ning H, Ge Y (2020) Bisphenol-A exposure induced neurotoxicity and associated with synapse and cytoskeleton in Neuro-2a cells. Toxicol In Vitro 67:104911
Yu H, Li T, Cui Y, Liao Y, Wang G, Gao L, Zhao F, Jin Y (2014) Effects of lead exposure on D-serine metabolism in the hippocampus of mice at the early developmental stages. Toxicology 325:189–199
Yu H, Liao Y, Li T, Cui Y, Wang G, Zhao F, Jin Y (2016) Alterations of synaptic proteins in the hippocampus of mouse offspring induced by developmental lead exposure. Mol Neurobiol 53(10):6786–6798
Zarin B, Eshraghi A, Zarifi F, Javanmard SH, Laher I, Amin B, Vaseghi G (2021) A review on the role of tau and stathmin in gastric cancer metastasis. Eur J Pharmacol 908:174312
Zhang XL, Guariglia SR, McGlothan JL, Stansfield KH, Stanton PK, Guilarte TR (2015) Presynaptic mechanisms of lead neurotoxicity: effects on vesicular release, vesicle clustering and mitochondria number. PLoS One 10(5):1–21
Google Scholar
Zhao F, Liao Y, Tang H, Piao J, Wang G, Jin Y (2017) Effects of developmental arsenite exposure on hippocampal synapses in mouse offspring. Metallomics 9(10):1394–1412
Zhou C-C, Gao Z-Y, Wang J, Wu M-Q, Hu S, Chen F, Liu J-X, Pan H, Yan C-H (2018) Lead exposure induces Alzheimers’s disease (AD)-like pathology and disturbes cholesterol metabolism in the young rat brain. Toxicol Lett 296:173–183
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This work was supported by the National Science Foundation of China (32002352), the Nature and Scientific Foundation of Henan Province in China (202300410165), the Key Research Projects in Colleges of Henan province (22A330001 and 22A230007) and the Scientific and Technological Foundation of Henan Province in China (212102110102).
Lingli Chen and Yuye Liu contributed equally to this work.
College of Animal Science and Veterinary Medicine, Henan Institute of Science and Technology, Xinxiang, Henan, 453003, People’s Republic of China
Lingli Chen, Yuye Liu, Penghuan Jia, Hongli Zhang, Zhihong Yin, Dongfang Hu, Hongmei Ning & Yaming Ge
Postdoctoral Research and Development Base, Henan Institute of Science and Technology, Xinxiang, Henan, People’s Republic of China
Lingli Chen, Zhihong Yin & Dongfang Hu
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Lingli Chen contributed to design and data analysis, Yuye Liu wrote the manuscript, Penghuan Jia and Hongli Zhang carried out the experiments and collected the data, Zhihong Yin, Dongfang Hu and Hongmei Ning contributed to revise the manuscript, and Yaming Ge managed the project.
Correspondence to Yaming Ge .
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Chen, L., Liu, Y., Jia, P. et al. Acute lead acetate induces neurotoxicity through decreased synaptic plasticity-related protein expression and disordered dendritic formation in nerve cells. Environ Sci Pollut Res 29 , 58927–58935 (2022). https://doi.org/10.1007/s11356-022-20051-1
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Received : 19 January 2022
Accepted : 29 March 2022
Published : 04 April 2022
Issue Date : August 2022
DOI : https://doi.org/10.1007/s11356-022-20051-1
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1. To prepare 250 ml of M/20 of oxalic acid solution. 2. 3. To determine the molarity and strength of KMnO4 solution by treating with standard solution of Mohr's Salt. 4. To detect acid and Basic radical to given salt (in Lead Acetate). 5. To detect acid and Basic radical to given salt (In Strontium Chloride).
Experiment Reagent And Material Required Reagent. 2% lead acetate solution in water; 40% NaOH; Test Sample/solution; Material Required. Test tubes; Test tube stand; Pipettes; Procedure For Lead Acetate Test. Add 1ml test solution in dry test tube. Similarly, take 1 ml distilled water in another test tube as control. Add 2ml of 40 % NaOH and mix ...
The sulfur-containing amino acid such as cysteine, cysteine, and methionine (sulfhydryl/thiol group) reacts with lead acetate under alkaline conditions to form a brown precipitate. These sulfur-containing amino acids are degraded in strongly alkaline media to release sulfide ion (S 2- ) in the form of H 2 S (hydrogen sulfide).
Test for specific amino acids: 1. Millon'sTest 2.Hopkins-Cole Test 3.SakaguchiTest 4.Lead Acetate (Lead sulfide) Test 5.Folin'sTest Overview All the experiments in this lab are used for the detection of specific amino acids, but they're not specific forprotein as each test also detects specific groups present
Lead Acetate is also known as lead (II) acetate, is a white crystalline chemical compound with the formula Pb (C 2 H 3 O 2) 2. Lead Acetate is poisonous in nature. It is used in making white lead in medicines and as a mordant in dyeing. Lead acetate was first produced in the United States in 1944.
lead acetate solution. 6 Sodium nitroprusside test: Take 1 mL of amino acid solution and add few drops of sodium nitroprusside reagent and mix well. Add few drops of liquor ammonia and mix well. 7 Sullivan and McCarthy's test: Take 1 mL of amino acid solution in a test tube, add few drops of sodium hydroxide (5 N), followed by addition of few ...
Lead. STAFFAN SKERFVING, INGVAR A. BERGDAHL, in Handbook on the Toxicology of Metals (Third Edition), 2007. 2.10 Cancer. Animal experiments have shown a tumorigenic effect of lead (Silbergeld et al., 2000).Hence, soluble lead salts, such as lead acetate and subacetate, have produced kidney and brain tumors, and lead phosphate kidney tumors, in rodents after oral or parenteral administration.
4. Add 3 mL of 95% ethanol to the third tube of egg white solution and 3 mL of 95% ethanol to the third tube of milk, mix each tube well and notice whether any precipitate forms. Record your observations on the Report Sheet. 5. Place another test tube containing egg white solution and one tube containing milk in a boiling water bath for 5 min ...
Following experiments are conducted to test occurrence of sulfate ion. A summarized tests . Testing for Sulfate ion with aqueous barium chloride solution. ... When sodium sulfate is added to the aqueous lead acetate solution, Lead sulfate (PbSO 4), a white precipitate is given. PbSO 4 is ...
Safety: Lead acetate or lead nitrate is very toxic. Disposal: The yellow solid, left over after the experiment should be treated as chemical waste, it should not be disposed of as normal household waste. Preparation of a bright yellow precipitate of PbI 2. Dissolve some potassium iodide in water and put this aside.
Lead(II) acetate is a white crystalline chemical compound with a slightly sweet taste. Its chemical formula is usually expressed as Pb(CH 3 COO) 2 or Pb(OAc) 2, where Ac represents the acetyl group.Like many other lead compounds, it causes lead poisoning.Lead acetate is soluble in water and glycerin.With water it forms the trihydrate, Pb(OAc) 2 ·3H 2 O, a colourless or white efflorescent ...
The lead acetate strip test was successfully adapted to quantify H 2 S release in cell culture and, compared with agar trap, ... In both experiments, CTRL (+) and DATS with stimulators in cell culture significantly increased the amount of released H 2 S in comparison to intact samples (dashed line) or in presence of CBS/CSE inhibitors. However ...
Lead toxicity is an important environmental disease and its effects on the human body are devastating. There is almost no function in the human body which is not affected by lead toxicity. Though in countries like US and Canada the use of lead has been controlled up to a certain extent, it is still used vehemently in the developing countries.
Lead is known to be highly toxic to humans, causing various disorders infetal development. An experiment was conducted to examine the effects of lead acetate on the structural organization of female rat ovaries. The study involved 40 non-linear female rats divided into four groups: a control group, a low-dose group, a moderate-dose group, and a ...
Decomposition of lead(II) acetate. TGA experiments. The decomposition of lead(II) acetate . has been studied for the last 50 years by many authors, 11-15 with the aim of studying the .
More information on the lead acetate test can be found in Odegaard et al. (2005), Rémillard (2007) and Tétreault (2003). Lead acetate test paper. These papers are coated with lead(II) acetate [Pb(CH 3 COO) 2], a white crystalline lead compound that is soluble in water. Lead test papers can be prepared by soaking paper in a solution of lead ...
Lead acetate was obtained from Sigma Chemical Company, Egypt. A total of 24 (2-3 month old) male albino rats of body weight ranging from ... Food and water were supplied ad libitum for all groups during the period of experiment. Each rat was weighed every week and its daily food intake was determined. Feed efficiency was calculated as the ...
Lead acetate, a sweet tasting but highly toxic lead salt, han easily be made without any exotic chemicals. In this video I am showing how it can be made from...
Lead is the most abundant heavy metal in the earth's crust, which has stable chemical properties, excellent ductility, and easy to form alloys with other metals. ... Experiments show that the material has the best sensitivity to lead ions when the content of cork is 70% and the content of graphite is 30%. The sensitivity is better in 0.5 M ...
Lead (Pb) is a widespread environmental heavy metal that can damage the cerebral cortex and hippocampus, and reduce the learning and memory ability in humans and animals. In vivo and in vitro models of acute lead acetate exposure were established to further study the mechanism of neurons injury. In this study, 4-week-old female Kunming mice were randomly divided into four groups. Each group ...