Method for determining lead in whole blood by using alkaline diluent

Abstract

The invention discloses a method for determining lead in whole blood by using an alkaline diluent. A graphite furnace atomic absorption spectrometry is adopted. Wherein the diluent is a mixed solution of sodium hypochlorite and triton X-100, and the mixed solution comprises the following components in percentage by volume: 0.1 to 0.5 percent of sodium hypochlorite and 0.1 to 1.5 percent of triton X-100; the matrix modifier is an ammonium dihydrogen phosphate solution, a palladium nitrate solution or a magnesium nitrate solution. The method disclosed by the invention is high in accuracy, low in detection limit, good in precision and high in analysis speed, cannot damage the graphite tube, and can be better applied to determination of lead in whole blood.

Description

Technical Field

[0001] The invention relates to the technical field of biochemical analysis, and in particular to a method for determining lead in whole blood using an alkaline diluent. Background Art

[0002] Lead is a heavy metal element widely present in the natural environment. In daily life, lead is mainly absorbed from the digestive tract through contaminated hands, skin and clothing. Long-term exposure to high-concentration lead environments may lead to a variety of health problems, such as nervous system damage, kidney damage, cardiovascular disease, etc. Therefore, the monitoring and control of lead is of great significance. The determination of lead in whole blood is an important means to assess human lead exposure. At present, the commonly used methods for whole blood lead determination mainly include atomic absorption spectrometry (AAS), inductively coupled plasma mass spectrometry (ICP-MS) and inductively coupled plasma emission spectrometry (ICP-AES). Although ICP-MS and ICP-AES have high accuracy and sensitivity, the instruments and equipment are expensive and the operation is complicated, which is not conducive to popularization and promotion. As a commonly used analytical method, AAS has the characteristics of high sensitivity, good accuracy and fast detection speed. It can provide reliable test results in a short time and is suitable for rapid screening and analysis of large quantities of samples. At present, AAS technology has been widely used in environmental monitoring, food safety, medical research and other fields, and has strong practicality.

[0003] The pretreatment of the lead sample in whole blood by graphite furnace atomic absorption determination mainly includes acid deproteinization method and direct dilution method. High concentration of nitric acid can digest the blood sample and reduce the phenomenon of carbon deposition in the graphite tube. However, high concentration of acid will damage the graphite tube, and acidic reagents can easily cause protein precipitation, resulting in blockage of the pipeline. Therefore, it is extremely important to establish a graphite furnace atomic absorption determination method for lead in whole blood that can reduce protein aggregation in whole blood and reduce graphite tube loss.

[0004] Selection of sample pretreatment method: When selecting a sample pretreatment method, factors such as sample properties, test purpose, subsequent test method and reporting time should be considered to meet the needs of rapid lead detection. A certain concentration of nitric acid can digest blood samples to reduce the phenomenon of carbon deposition in graphite tubes. The sample pretreatment for the determination of lead in whole blood by graphite furnace atomic absorption is mainly acid digestion. In the acid digestion method, the acid deproteinization method uses 5% nitric acid to deproteinize and centrifuge to take the supernatant for analysis. This method can reduce the interference of the blood sample matrix to a certain extent, but the operation steps are relatively cumbersome and the cost is high. The direct dilution method of acid reagent dilutes the whole blood sample with a mixed solution of Triton X-100 and nitric acid and then determines it. This method has the advantages of simple sample pretreatment and fast detection speed. However, too high a concentration of nitric acid will damage the graphite tube, and proteins are easy to condense in acidic reagents, causing blockage of the pipeline.

[0005] In order to solve the problem of protein aggregation in whole blood in acidic reagents, Wang Kai et al. established a method for determining lead in whole blood by graphite furnace atomic absorption spectrometry, which did not use nitric acid, but only diluted the blood sample with 0.1% Triton X-100 solution. At the same time, in order to reduce the carbon deposition in the graphite tube caused by the lack of acid digestion, Wang Kai et al. added a step of air before the ashing stage to increase oxidation and play a role in carbon removal. However, oxidizing gases will accelerate the loss of graphite tubes and increase the cost of detection. Summary of the invention

[0006] The purpose of the present invention is to provide a method for determining lead in whole blood using an alkaline diluent. The method of the present invention has high accuracy, low detection limit, good precision, fast analysis speed, and will not damage the graphite tube, and can be well applied to the determination of lead in whole blood.

[0007] The method for determining lead in whole blood using an alkaline diluent of the present invention adopts graphite furnace atomic absorption spectrometry;

[0008] The diluent is a mixed solution of sodium hypochlorite and Triton X-100, wherein the content of sodium hypochlorite in the mixed solution is 0.1-0.5% and the content of Triton X-100 is 0.1-1.5% by volume.

[0009] The matrix improver is: ammonium dihydrogen phosphate solution, palladium nitrate solution, or magnesium nitrate solution.

[0010] The measuring conditions of the graphite furnace atomic absorption spectrometer are: wavelength 283.3nm, lamp current 10mA, slit 0.7nm, Zeeman buckling background.

[0011] The conditions of the graphite furnace are set as follows:

[0012]

[0013] Preferably, the diluent is: in a mixed solution of sodium hypochlorite and Triton X-100, by volume percentage, sodium hypochlorite is 0.1%, and Triton X-100 is 0.5%.

[0014] The matrix improver is 10-30 g / L diammonium phosphate solution, 0.8-2 g / L palladium nitrate solution, or 0.8-2 g / L magnesium nitrate solution.

[0015] The method for determining lead in whole blood using an alkaline diluent comprises the following steps of sample processing:

[0016] After the whole blood sample is brought to room temperature and fully mixed, accurately aspirate the blood sample and add it to the diluent, dilute it 20-50 times, mix it evenly, and you have it.

[0017] The method for determining lead in whole blood using an alkaline diluent is performed using a lead standard curve, and the construction of the lead standard curve includes the following steps:

[0018] The concentration of the lead standard application solution is configured to be 30-80 μg / L. The instrument standard curve determination uses the standard addition method. The lead standard application solution is automatically prepared into a standard series of different concentrations in the instrument.

[0019] The invention also discloses the use of a mixed solution of sodium hypochlorite and Triton X-100 as an alkaline diluent for determining lead in whole blood by graphite furnace atomic absorption spectrometry.

[0020] Preferably, in the mixed solution of sodium hypochlorite and Triton X-100, the content of sodium hypochlorite is 0.1-0.5%, and the content of Triton X-100 is 0.1-1.5%, calculated by volume percentage.

[0021] Further preferably, in the mixed solution of sodium hypochlorite and Triton X-100, the sodium hypochlorite is 0.1% and the Triton X-100 is 0.5% by volume.

[0022] The present invention

[0023] The method of the present invention can effectively improve the disadvantage of the traditional graphite furnace atomic absorption spectrometry method for determining the lead content in whole blood, that is, the acidic diluent easily causes protein precipitation in the whole blood. Figure 8 As shown in the figure, test tube A is 0.1% sodium hypochlorite + 0.5% Triton dilution, and test tube B is 1% nitric acid + 1% Triton dilution (national standard method); the figure shows that the sample in test tube A is clear and bright red, while the sample in test tube B is turbid and dark red. Fig. 9 It can be seen that after standing for 3 hours, the sample in test tube A is still clear, while the sample in test tube B has precipitated.

[0024] The method of the invention can ensure the accuracy of lead determination in whole blood by graphite furnace atomic absorption spectrometry, the detection limit is 1.1 μg / L, within the range of 1.1-1000 μg / L, the blood lead content has a good linear relationship with the absorbance value (r=0.9991), the sample spike recovery rate is 96%-104.5%, and the precision (RSD) is 1.0%-7.5%.

[0025] The method of the invention has high accuracy, low detection limit, good precision and fast analysis speed, and can be applied to the determination of lead in whole blood. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 For the blank control of Example 10 Figure 1 ;

[0027] Figure 2 For the blank control of Example 10 Figure 2 ;

[0028] Figure 3 This is the sample test diagram of Example 10, diluent: sodium hypochlorite content is 0.1%, Triton X-100 content is 0.5%;

[0029] Figure 4 This is the sample test diagram of Example 10, diluent: sodium hypochlorite content is 0.5%, Triton X-100 content is 0.5%;

[0030] Figure 5 This is the sample test diagram of Example 10, the diluent: sodium hypochlorite content is 1%, and the content of Triton X-100 is 0.5%;

[0031] Figure 6 This is the sample test diagram of Example 10, the diluent: sodium hypochlorite content is 3%, and the content of Triton X-100 is 0.5%;

[0032] Figure 7 This is the sample test diagram of Example 10, diluent: sodium hypochlorite content is 5%, and Triton X-100 content is 0.5%.

[0033] Figure 8 This is a sample comparison diagram of the diluent of Example 6 and the new configuration of the national standard diluent;

[0034] Fig. 9 for Figure 8 Comparison of the two samples after 3 hours. DETAILED DESCRIPTION

[0035] The present invention is further described below by way of examples. It should be understood that the examples of the present invention are intended to illustrate the present invention rather than to limit the present invention.

[0036] Example 1

[0037] The method for determining lead in whole blood using an alkaline diluent in this embodiment adopts graphite furnace atomic absorption spectrometry;

[0038] The diluent is a mixed solution of sodium hypochlorite and Triton X-100, wherein the content of sodium hypochlorite in the mixed solution is 0.1% and the content of Triton X-100 is 0.1% by volume;

[0039] The matrix improver is: 10g / L diammonium phosphate solution.

[0040] The measurement conditions of graphite furnace atomic absorption spectrometer are: wavelength 283.3nm, lamp current 10mA, slit 0.7nm, Zeeman buckling background;

[0041] The conditions of the graphite furnace are set as follows:

[0042]

[0043] The sample processing process is:

[0044] After the whole blood sample is brought to room temperature and fully mixed, accurately pipette 20 μl of the blood sample into a 1.5 ml sample cup, add 980 μl of diluent, mix well, and you have it.

[0045] The detection is carried out using a lead standard curve, and the construction of the lead standard curve includes the following steps:

[0046] Take 1 ml of 1000 μg / ml lead standard solution, dilute to scale with 1% (V / V) nitric acid in a 100 ml volumetric flask to prepare a 10 μg / ml lead standard intermediate solution; then take 0.3 ml of the lead standard intermediate solution, dilute to scale with 1% (V / V) nitric acid solution in a 100 ml volumetric flask to prepare a 30 μg / L lead standard application solution. Low background human blood (lead content less than the quantitative lower limit) is selected as normal human blood, and the instrument standard curve determination uses the standard addition method. The instrument automatically prepares 0, 7.5, 15, 22.5, 30 μg / L standard series.

[0047] Example 2

[0048] The method for determining lead in whole blood using an alkaline diluent in this embodiment adopts graphite furnace atomic absorption spectrometry;

[0049] The diluent is a mixed solution of sodium hypochlorite and Triton X-100, wherein the content of sodium hypochlorite in the mixed solution is 0.5% and the content of Triton X-100 is 1.5% by volume;

[0050] The matrix improver is: 30g / L diammonium phosphate solution.

[0051] The measurement conditions of graphite furnace atomic absorption spectrometer are: wavelength 283.3nm, lamp current 10mA, slit 0.7nm, Zeeman buckling background;

[0052] The conditions of the graphite furnace are set as follows:

[0053]

[0054] The sample processing process is:

[0055] After the whole blood sample is brought to room temperature and thoroughly mixed, accurately aspirate 30 μl of the blood sample into a 1.5 ml sample cup, add 970 μl of diluent, mix well, and you have it.

[0056] The detection is carried out using a lead standard curve, and the construction of the lead standard curve includes the following steps:

[0057] Take 1 ml of 1000 μg / ml lead standard solution, dilute to scale with 1% (V / V) nitric acid in a 100 ml volumetric flask to prepare a 10 μg / ml lead standard intermediate solution; then take 0.8 ml of the lead standard intermediate solution, dilute to scale with 1% (V / V) nitric acid solution in a 100 ml volumetric flask to prepare an 80 μg / L lead standard application solution. Low background human blood (lead content less than the quantitative lower limit) is selected as normal human blood, and the instrument standard curve determination uses the standard addition method, and the instrument automatically prepares 0, 20, 40, 60, 80 μg / L standard series.

[0058] Example 3

[0059] The method for determining lead in whole blood using an alkaline diluent in this embodiment adopts graphite furnace atomic absorption spectrometry;

[0060] The diluent is a mixed solution of sodium hypochlorite and Triton X-100, wherein the content of sodium hypochlorite is 0.3% and the content of Triton X-100 is 1% by volume in the mixed solution;

[0061] The matrix improver is: 20g / L diammonium phosphate solution.

[0062] The measurement conditions of the graphite furnace atomic absorption spectrometer are: wavelength 283.3nm, lamp current 10mA, slit 0.7nm, Zeeman buckling background;

[0063] The conditions of the graphite furnace are set as follows:

[0064]

[0065] The sample processing process is:

[0066] After the whole blood sample is brought to room temperature and thoroughly mixed, accurately pipette 50 μl of the blood sample into a 1.5 ml sample cup, add 950 μl of diluent, mix well, and you have it.

[0067] The detection is carried out using a lead standard curve, and the construction of the lead standard curve includes the following steps:

[0068] Take 1 ml of 1000 μg / ml lead standard solution, dilute to scale with 1% (V / V) nitric acid in a 100 ml volumetric flask to prepare a 10 μg / ml lead standard intermediate solution; then take 0.5 ml of the lead standard intermediate solution, dilute to scale with 1% (V / V) nitric acid solution in a 100 ml volumetric flask to prepare a 50 μg / L lead standard application solution. Low background human blood (lead content less than the quantitative lower limit) is selected as normal human blood, and the instrument standard curve determination uses the standard addition method. The instrument automatically prepares 0, 12.5, 25, 37.5, 50 μg / L standard series.

[0069] Example 4

[0070] The method for determining lead in whole blood using an alkaline diluent in this embodiment adopts graphite furnace atomic absorption spectrometry;

[0071] The diluent is a mixed solution of sodium hypochlorite and Triton X-100, wherein the content of sodium hypochlorite in the mixed solution is 0.2% and the content of Triton X-100 is 0.5% by volume;

[0072] The matrix improver is: 0.8g / L palladium nitrate solution.

[0073] The measurement conditions of the graphite furnace atomic absorption spectrometer are: wavelength 283.3nm, lamp current 10mA, slit 0.7nm, Zeeman buckling background;

[0074] The conditions of the graphite furnace are set as follows:

[0075]

[0076] The sample processing process is:

[0077] After the whole blood sample is brought to room temperature and thoroughly mixed, accurately pipette 25 μl of the blood sample into a 1.5 ml sample cup, add 975 μl of diluent, mix well, and you have it.

[0078] The detection is carried out using a lead standard curve, and the construction of the lead standard curve includes the following steps:

[0079] Take 1 ml of 1000 μg / ml lead standard solution, dilute to scale with 1% (V / V) nitric acid in a 100 ml volumetric flask to prepare a 10 μg / ml lead standard intermediate solution; then take 0.4 ml of the lead standard intermediate solution, dilute to scale with 1% (V / V) nitric acid solution in a 100 ml volumetric flask to prepare a 40 μg / L lead standard application solution. Low background human blood (lead content less than the quantitative lower limit) is selected as normal human blood, and the instrument standard curve determination uses the standard addition method, and the instrument automatically prepares 0, 10, 20, 30, 40 μg / L standard series.

[0080] Example 5

[0081] The method for determining lead in whole blood using an alkaline diluent in this embodiment adopts graphite furnace atomic absorption spectrometry;

[0082] The diluent is a mixed solution of sodium hypochlorite and Triton X-100, wherein the content of sodium hypochlorite in the mixed solution is 0.4% and the content of Triton X-100 is 0.8% by volume;

[0083] The matrix improver is: 2g / L palladium nitrate solution.

[0084] The measurement conditions of graphite furnace atomic absorption spectrometer are: wavelength 283.3nm, lamp current 10mA, slit 0.7nm, Zeeman buckling background;

[0085] The conditions of the graphite furnace are set as follows:

[0086]

[0087]

[0088] The sample processing process is:

[0089] After the whole blood sample is brought to room temperature and thoroughly mixed, accurately aspirate 35 μl of the blood sample into a 1.5 ml sample cup, add 965 μl of diluent, mix well, and you have it.

[0090] The detection is carried out using a lead standard curve, and the construction of the lead standard curve includes the following steps:

[0091] Take 1 ml of 1000 μg / ml lead standard solution, dilute to scale with 1% (V / V) nitric acid in a 100 ml volumetric flask to prepare a 10 μg / ml lead standard intermediate solution; then take 0.7 ml of the lead standard intermediate solution, dilute to scale with 1% (V / V) nitric acid solution in a 100 ml volumetric flask to prepare a 70 μg / L lead standard application solution. Low background human blood (lead content less than the quantitative lower limit) is selected as normal human blood, and the instrument standard curve determination uses the standard addition method. The instrument automatically prepares 0, 17.5, 35, 52.5, 70 μg / L standard series.

[0092] Example 6

[0093] The method for determining lead in whole blood using an alkaline diluent in this embodiment adopts graphite furnace atomic absorption spectrometry;

[0094] The diluent is a mixed solution of sodium hypochlorite and Triton X-100, wherein the content of sodium hypochlorite in the mixed solution is 0.1% and the content of Triton X-100 is 0.5% by volume;

[0095] The matrix modifier is: 1g / L palladium nitrate solution.

[0096] The measurement conditions of graphite furnace atomic absorption spectrometer are: wavelength 283.3nm, lamp current 10mA, slit 0.7nm, Zeeman buckling background;

[0097] The conditions of the graphite furnace are set as follows:

[0098]

[0099] The sample processing process is:

[0100] After the whole blood sample is brought to room temperature and thoroughly mixed, accurately pipette 50 μl of the blood sample into a 1.5 ml sample cup, add 950 μl of diluent, mix well, and you have it.

[0101] The detection is carried out using a lead standard curve, and the construction of the lead standard curve includes the following steps:

[0102] Take 1 ml of 1000 μg / ml lead standard solution, dilute to scale with 1% (V / V) nitric acid in a 100 ml volumetric flask to prepare a 10 μg / ml lead standard intermediate solution; then take 0.5 ml of the lead standard intermediate solution, dilute to scale with 1% (V / V) nitric acid solution in a 100 ml volumetric flask to prepare a 50 μg / L lead standard application solution. Low background human blood (lead content less than the quantitative lower limit) is selected as normal human blood, and the instrument standard curve determination uses the standard addition method. The instrument automatically prepares 0, 12.5, 25, 37.5, 50 μg / L standard series.

[0103] Example 7

[0104] The method for determining lead in whole blood using an alkaline diluent in this embodiment adopts graphite furnace atomic absorption spectrometry;

[0105] The diluent is a mixed solution of sodium hypochlorite and Triton X-100, wherein the content of sodium hypochlorite in the mixed solution is 0.1% and the content of Triton X-100 is 0.4% by volume;

[0106] The matrix improver is: 0.8g / L magnesium nitrate solution.

[0107] The measurement conditions of the graphite furnace atomic absorption spectrometer are: wavelength 283.3nm, lamp current 10mA, slit 0.7nm, Zeeman buckling background;

[0108] The conditions of the graphite furnace are set as follows:

[0109]

[0110] The sample processing process is:

[0111] After the whole blood sample is brought to room temperature and fully mixed, accurately pipette 20 μl of the blood sample into a 1.5 ml sample cup, add 980 μl of diluent, mix well, and you have it.

[0112] The detection is carried out using a lead standard curve, and the construction of the lead standard curve includes the following steps:

[0113] Take 1 ml of 1000 μg / ml lead standard solution, dilute to scale with 1% (V / V) nitric acid in a 100 ml volumetric flask to prepare a 10 μg / ml lead standard intermediate solution; then take 0.6 ml of the lead standard intermediate solution, dilute to scale with 1% (V / V) nitric acid solution in a 100 ml volumetric flask to prepare a 60 μg / L lead standard application solution. Low background human blood (lead content less than the quantitative lower limit) is selected as normal human blood, and the instrument standard curve determination uses the standard addition method, and the instrument automatically prepares 0, 15, 30, 45, 60 μg / L standard series.

[0114] Example 8

[0115] The method for determining lead in whole blood using an alkaline diluent in this embodiment adopts graphite furnace atomic absorption spectrometry;

[0116] The diluent is a mixed solution of sodium hypochlorite and Triton X-100, wherein the content of sodium hypochlorite is 0.5% and the content of Triton X-100 is 1.3% by volume in the mixed solution;

[0117] The matrix modifier is: 2g / L magnesium nitrate solution.

[0118] The measurement conditions of the graphite furnace atomic absorption spectrometer are: wavelength 283.3nm, lamp current 10mA, slit 0.7nm, Zeeman buckling background;

[0119] The conditions of the graphite furnace are set as follows:

[0120]

[0121] The sample processing process is:

[0122] After the whole blood sample is brought to room temperature and thoroughly mixed, accurately pipette 45 μl of the blood sample into a 1.5 ml sample cup, add 955 μl of diluent, mix well, and you have it.

[0123] The detection is carried out using a lead standard curve, and the construction of the lead standard curve includes the following steps:

[0124] Take 1 ml of 1000 μg / ml lead standard solution, dilute to scale with 1% (V / V) nitric acid in a 100 ml volumetric flask to prepare a 10 μg / ml lead standard intermediate solution; then take 0.5 ml of the lead standard intermediate solution, dilute to scale with 1% (V / V) nitric acid solution in a 100 ml volumetric flask to prepare a 50 μg / L lead standard application solution. Low background human blood (lead content less than the quantitative lower limit) is selected as normal human blood, and the instrument standard curve determination uses the standard addition method. The instrument automatically prepares 0, 12.5, 25, 37.5, 50 μg / L standard series.

[0125] Example 9

[0126] The method for determining lead in whole blood using an alkaline diluent in this embodiment adopts graphite furnace atomic absorption spectrometry;

[0127] The diluent is a mixed solution of sodium hypochlorite and Triton X-100, wherein the content of sodium hypochlorite in the mixed solution is 0.1% and the content of Triton X-100 is 0.5% by volume;

[0128] The matrix modifier is: 1g / L magnesium nitrate solution.

[0129] The measurement conditions of the graphite furnace atomic absorption spectrometer are: wavelength 283.3nm, lamp current 10mA, slit 0.7nm, Zeeman buckling background;

[0130] The conditions of the graphite furnace are set as follows:

[0131]

[0132]

[0133] The sample processing process is:

[0134] After the whole blood sample is brought to room temperature and thoroughly mixed, accurately pipette 50 μl of the blood sample into a 1.5 ml sample cup, add 950 μl of diluent, mix well, and you have it.

[0135] The detection is carried out using a lead standard curve, and the construction of the lead standard curve includes the following steps:

[0136] Take 1 ml of 1000 μg / ml lead standard solution, dilute to scale with 1% (V / V) nitric acid in a 100 ml volumetric flask to prepare a 10 μg / ml lead standard intermediate solution; then take 0.5 ml of the lead standard intermediate solution, dilute to scale with 1% (V / V) nitric acid solution in a 100 ml volumetric flask to prepare a 50 μg / L lead standard application solution. Low background human blood (lead content less than the quantitative lower limit) is selected as normal human blood, and the instrument standard curve determination uses the standard addition method. The instrument automatically prepares 0, 12.5, 25, 37.5, 50 μg / L standard series.

[0137] Example 10

[0138] 1. Selection of diluent concentration: Triton X-100 is ductile and can promote the dissolution of proteins and cell membranes, which is helpful for sample determination. When the volume fraction of Triton X-100 is 0.5%, the method investigates the effect of sodium hypochlorite with volume fractions of 0, 0.1%, 0.5%, 1%, 3% and 5% on the determination of freeze-dried bovine blood lead and cadmium component analysis standard materials (GBW09139, GBW09140), and the results are shown in Table 1. The results show that when the volume fraction of sodium hypochlorite is 0 and 0.1%, the measured values ​​of GBW09139 and GBW09140 are within the reference value range and the background peak area is low. When the volume fraction of sodium hypochlorite is 0.5%, the measured value of GBW09139 is within the reference value range but the background peak area increases. When the volume fraction of sodium hypochlorite is ≥1%, the background peak area of ​​GBW09139 increases significantly, and the measured value is not within the reference range due to the interference of high concentration of chlorine in sodium hypochlorite. When the volume fraction of sodium hypochlorite is ≥0.5%, the measured value of GBW09140 is lower than the reference range and the background peak area increases significantly. After comprehensive consideration, the volume fraction of sodium hypochlorite is selected as 0.1%.

[0139] When the volume fraction of sodium hypochlorite is 0.1%, the influence of volume fractions of 0, 0.1%, 0.5%, 1%, and 1.5% of Triton X-100 on the determination of GBW09139 and GBW09140 is investigated. The results are shown in Table 2. The results show that the volume fraction of Triton X-100 has little effect on the determination value and background peak area of ​​GBW09139. When the volume fraction of Triton X-100 is 0.5%, the determination value of GBW09140 is within the reference value range. When the volume fraction of Triton X-100 is 0, 0.1%, 1%, and 1.5%, the determination value of GBW09140 is lower than the reference value. This is because when the volume fraction of Triton X-100 is too low, the ductility of the sample solution after entering the graphite tube is not enough to affect the determination; when the volume fraction of Triton X-100 increases, the viscosity of the sample solution is too high, so the determination result is affected, and this phenomenon is more significant when measuring high-concentration samples. After comprehensive consideration, 0.5% volume fraction of Triton X-100 was selected as the experimental condition. The final dilution solution was composed of a mixed solution of 0.1% volume fraction of sodium hypochlorite and 0.5% volume fraction of Triton X-100.

[0140] Figure 1-Figure 7 This is the spectrum diagram of the research process.

[0141] Table 1 Effect of volume fraction of sodium hypochlorite

[0142]

[0143]

[0144] Table 2 Effect of volume fraction of Triton X-100

[0145]

[0146] Note: The reference value of GBW09139 is 107±15μg / L, and the reference value of GBW09140 is 318±12μg / L.

[0147] 3. Selection of matrix modifier: In graphite furnace atomic absorption analysis, matrix modifiers such as ammonium dihydrogen phosphate, palladium nitrate and magnesium nitrate are usually used. In the present invention, according to the above-mentioned instrument conditions and sample processing methods, ammonium dihydrogen phosphate, palladium nitrate and magnesium nitrate are used as matrix modifiers for experimental research. It is found that these three matrix modifiers can meet the test requirements. Among them, in the detection process of blood lead, it is found that the lead element can form a very stable covalent bond with palladium nitrate in the ashing stage, so that it can withstand higher ashing temperatures. The experimental results show that under the same conditions, when palladium nitrate is used as a matrix modifier, the resulting peak shape is better and the response value is higher, and the background interference is smaller. Therefore, palladium nitrate is the most preferred as a matrix modifier.

[0148] 4. Selection of instrument conditions: Experiments were conducted at ashing temperatures of 700, 750, 800, 850, 900, 950, and 1000°C. The results showed that when the ashing temperature was between 750 and 900°C, the absorbance values ​​of the samples were all high, and reached the maximum at 850°C; when the ashing temperature was ≥950°C, the absorbance value dropped rapidly, indicating that the ashing loss of lead element was serious at this temperature. According to the principles of signal value, background absorption and stability, the ashing temperature was selected as 850°C. Experiments were conducted at atomization temperatures of 1600, 1650, 1700, 1750, 1800, 1850, 1900, and 2000°C. The results showed that with the increase of atomization temperature, the absorbance value first increased and then slightly decreased; when the atomization temperature was 1750°C, the absorbance value was the largest. Therefore, the atomization temperature was selected as 1750°C.

[0149] 4. Linear range, correlation coefficient and linear equation of the standard working curve: 11 low-concentration samples were measured in parallel under the optimized instrument conditions. The detection concentrations corresponding to 3 times and 10 times the relative standard deviations of the absorbance values ​​were 1.1 and 3.8 μg / L, respectively. In the range of 1.1-1000 μg / L, the blood lead content had a good linear relationship with the absorbance value, with a correlation coefficient of r=0.9991 and a linear equation of y=0.00261x+0.00218.

[0150] 5. Method accuracy, precision and interference experiment: Mixed element standard solutions (including lead, silver, arsenic, barium, beryllium, calcium, cadmium, cobalt, chromium, copper, iron, potassium, magnesium, manganese, molybdenum, sodium, nickel, antimony, selenium, tin, strontium, titanium, thallium, vanadium, aluminum and zinc) of three concentrations of low (10.0 μg / L), medium (200.0 μg / L) and high (400.0 μg / L) were added to the blood lead background samples, and six groups of spikes were added in parallel at each concentration. The calculated spike recovery was 101.6% to 103.5%, and the precision (RSD) was 2.1% to 3.2%. The results are shown in Tables 3 and 4. The mixed standard solution used for spike addition included 25 common elements except lead. The results showed that the RSD of the deviation caused by the above elements in the concentration range of 10 to 400 μg / L on the determination results was less than 10%, indicating that the interference of the above ions at this concentration can be regarded as inhibition.

[0151] Table 3 Accuracy and precision of blood lead method (n=6)

[0152]

[0153] 6. Actual sample test results: 10 blood samples were tested using the experimental method, and the blood lead test results are shown in Table 4. A total of 10 whole blood samples, the blood lead test results ranged from 9.9 to 432.2 μg / L.

[0154] Table 4 Blood sample measurement results (n=3)

[0155]

[0156] The method of the present invention finally selects the optimal solution of a mixed solution of 0.1% sodium hypochlorite and 0.5% Triton X-100 as a sample diluent, directly dilutes the sample 20 times, and uses graphite furnace atomic absorption spectrometry to determine the lead in whole blood, the detection limit is 1.1 μg / L, within the range of 1.1-1000 μg / L, the blood lead content and the absorbance value have a good linear relationship (r=0.9991), the sample spike recovery rate is 96%-104.5%, and the precision (RSD) is 1.0%-7.5%. The method has high accuracy, low detection limit, good precision, fast analysis speed, and can be applied to the determination of lead in whole blood.

[0157] Although the present invention has been described in detail above by means of general description, specific implementation methods and tests, it is obvious to those skilled in the art that some modifications or improvements may be made to the present invention. Therefore, these modifications or improvements made without departing from the spirit of the present invention all fall within the scope of protection claimed by the present invention.

Claims

1. A method for determining lead in whole blood using an alkaline diluent, characterized in that: Graphite furnace atomic absorption spectrometry was used; The diluent is a mixed solution of sodium hypochlorite and Triton X-100, wherein the content of sodium hypochlorite in the mixed solution is 0.1-0.5% and the content of Triton X-100 is 0.1-1.5% by volume. The matrix improver is: ammonium dihydrogen phosphate solution, palladium nitrate solution, or magnesium nitrate solution.

2. The method for determining lead in whole blood using an alkaline diluent as claimed in claim 1, characterized in that: The measuring conditions of the graphite furnace atomic absorption spectrometer are: wavelength 283.3nm, lamp current 10mA, slit 0.7nm, Zeeman buckling background.

3. The method for determining lead in whole blood using an alkaline diluent as claimed in claim 2, characterized in that: The conditions of the graphite furnace are set as follows:

4. The method for determining lead in whole blood using an alkaline diluent as claimed in claim 1, characterized in that: The diluent is: in the mixed solution of sodium hypochlorite and Triton X-100, the sodium hypochlorite is 0.1% and the Triton X-100 is 0.5% by volume.

5. The method for determining lead in whole blood using an alkaline diluent as claimed in claim 1, characterized in that: The matrix improver is 10-30 g / L diammonium phosphate solution, 0.8-2 g / L palladium nitrate solution, or 0.8-2 g / L magnesium nitrate solution.

6. The method for determining lead in whole blood using an alkaline diluent according to claim 1, wherein: The sample processing includes the following steps: After the whole blood sample is brought to room temperature and fully mixed, accurately aspirate the blood sample and add it to the diluent, dilute it 20-50 times, mix it evenly, and you have it.

7. The method for determining lead in whole blood using an alkaline diluent as claimed in claim 1, characterized in that: The detection is carried out using a lead standard curve, and the construction of the lead standard curve includes the following steps: The concentration of the lead standard application solution is configured to be 30-80 μg / L. The instrument standard curve determination uses the standard addition method. The lead standard application solution is automatically prepared into a standard series of different concentrations in the instrument.

8. Use of a mixture of sodium hypochlorite and Triton X-100 as an alkaline diluent in the determination of lead in whole blood by graphite furnace atomic absorption spectrometry.

9. The use according to claim 8, characterized in that: In the mixed solution of sodium hypochlorite and Triton X-100, the content of sodium hypochlorite is 0.1-0.5% and the content of Triton X-100 is 0.1-1.5% by volume.

10. The use according to claim 9, characterized in that: In the mixed solution of sodium hypochlorite and Triton X-100: by volume percentage, the sodium hypochlorite is 0.1% and the Triton X-100 is 0.5%.

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