A method for eliminating silver interference in cadmium-based verification of bis(acetonitrile)dichloropalladium

Abstract

This invention provides a method for verifying the elimination of silver interference in bis(acetonitrile)palladium dichloride based on cadmium. This method involves determining silver interference in bis(acetonitrile)palladium dichloride using mass spectrometry and verifying the elimination of interference based on cadmium. The method includes determining the mass-to-charge ratio of the sample by mass spectrometry and using two methods—design equation calculation and collision reaction—to eliminate silver interference in bis(acetonitrile)palladium dichloride. 108 Pd 1 The method for H interference with Ag. In addition, this method is simple and easy to implement, and can effectively eliminate the influence of organic components on the determination, ultimately ensuring accurate and efficient determination of Ag content in bis(acetonitrile)palladium dichloride. Moreover, the simultaneous determination of cadmium also achieves the effect of eliminating the above-mentioned silver interference.

Description

Technical Field

[0001] This invention belongs to the field of bis(acetonitrile)palladium dichloride material analysis technology, specifically relating to a method for verifying the elimination of silver interference in bis(acetonitrile)palladium dichloride based on cadmium. Background Technology

[0002] Palladium bis(acetonitrile)dichloride is a key reagent in homogeneous catalysis and materials synthesis, playing an irreplaceable role, especially in high-end fields such as drug synthesis and new energy materials. Although silver impurities in palladium bis(acetonitrile)dichloride are usually present in trace amounts (ppm level), the similar chemical properties of silver and palladium can negatively impact the catalytic performance, process stability, and material functionality of the product. Especially in high-end catalysis and materials fields, even trace amounts of Ag can lead to substandard product performance. Therefore, accurately determining the silver impurity content in palladium bis(acetonitrile)dichloride is crucial for adjusting the production process and controlling the Ag impurity content.

[0003] Currently, trace amounts of Ag in palladium compounds are mainly determined using spectroscopic methods and mass spectrometry. However, when using mass spectrometry, the determination of Ag isotopes is limited. 109 Ag will be affected 108 Pd 1 Mass spectrometry interference from H can affect the accuracy of measurement results. Currently, there is no commercially available standard reference for bis(acetonitrile)palladium dichloride, and since bis(acetonitrile)palladium dichloride usually contains a certain amount of Ag impurities, even if a standard reference is found, confirming whether the trace silver interference has been completely eliminated is still difficult. Therefore, eliminating the aforementioned silver mass spectrometry interference and verifying the degree of interference elimination is crucial for obtaining accurate analytical results. Summary of the Invention

[0004] This invention aims to solve the above-mentioned problems and provides a method for eliminating silver interference in bis(acetonitrile)palladium dichloride based on cadmium verification. This method eliminates silver interference in bis(acetonitrile)palladium dichloride through two methods: equation calculation and collision reaction. 108 Pd 1 The method of H interference with Ag was used, and the elimination effect was verified by using simultaneous determination of cadmium.

[0005] The technical solution of the present invention is as follows:

[0006] A method for verifying the elimination of silver interference in bis(acetonitrile)palladium dichloride based on cadmium, the method comprising the following steps: (1) Elimination mass spectrometry determination of silver interference in bis(acetonitrile)palladium dichloride and verification of interference elimination based on cadmium.

[0007] S1. The sample is properly treated to digest bis(acetonitrile)palladium dichloride, and a sample solution of a certain mass concentration is prepared as an analytical solution.

[0008] S2. Prepare a palladium matrix blank solution and a silver standard solution of a certain mass concentration, measure the signal intensity at m / z=109 on a mass spectrometer, and optimize the ammonia flow rate to obtain the optimal ammonia flow rate;

[0009] S3. Prepare a series of mixed standard solutions of Ag and Cd for determination and verification, as well as a Cs internal standard solution for correcting matrix effects;

[0010] S4. Based on the signal intensities at m / z=109, m / z=111, m / z=114, and m / z=118 measured in the sample solution, the following formula (5) is used in the calculation method. During the mass spectrometry determination process, the signal intensity at m / z=109, m / z=111, m / z=114, and m / z=118 in the sample solution is obtained through formula (5). 109 The net signal strength of Ag;

[0011] ………………………………(5)

[0012] S5. On the mass spectrometer, the series of mixed standard solutions and internal standard solutions prepared in step S3 are introduced through a three-way valve. First, under the condition of no collision reaction gas, the signal intensity at the mass-to-charge ratio involved in formula (5) in step S4 is measured. Then, under the optimal ammonia flow rate obtained in step S2, the signal intensity of Ag and Cd at the selected mass-to-charge ratios (m / z=109, m / z=111, m / z=114, m / z=118) of the above series of mixed standard solutions is measured, while the signal intensity of the internal standard is monitored. At the same time, the Ag working curve under the condition of no collision reaction gas and the Ag and Cd working curves under the ammonia flow rate are plotted according to formula (5).

[0013] S6. Introduce the bis(acetonitrile)palladium dichloride sample solution prepared in step S1 into the mass spectrometer, and measure the signal intensity at each mass-to-charge ratio in the sample solution under the same collision-free reaction gas and ammonia flow rate conditions as in step S5.

[0014] S7. Based on the formula (5) in step S4 and the working curves of the series of standard solutions plotted in step S5, the determination results of silver in the bis(acetonitrile)palladium dichloride sample solution in step S6 under non-collision reaction gas conditions and the determination results of silver and cadmium under the same ammonia flow rate are calculated.

[0015] S8. Based on the cadmium determination results of step S7 above, compare the silver determination results under the same ammonia flow rate to verify its accuracy; and based on the silver determination results under the same ammonia flow rate, compare the silver results obtained by formula (5) to verify the accuracy of the calculation equation.

[0016] In step S4 above, formula (5) is obtained as follows:

[0017] In mass spectrometry, firstly, interference signals are subtracted based on the signal intensity at m / z=109 in the bis(acetonitrile)palladium dichloride sample solution. 108 Pd 1 The signal strength of H can be obtained 109 The net signal strength of Ag, i.e., formula (1):

[0018] ………………………………(1)

[0019] Furthermore, in formula (1) 108 Pd 1 H signal strength transfer 110 Pd 1 For H, see formula (2):

[0020] ………………………………(2)

[0021] Furthermore, in formula (2) 110 Pd 1 The relationship between H signal intensity and cadmium signal intensity is shown in formula (3):

[0022] ………………………………(3)

[0023] Furthermore, in formula (3) 114 The Cd signal intensity shifts to m / z=118, as shown in formula (4):

[0024] ………………………………(4)

[0025] Furthermore, substituting equation (4) into equation (3), then into equation (2), and then into equation (1), and iterating in this way, we obtain the final equation required for the computational correction of the Ag signal intensity, namely equation (5):

[0026] ………………………………(5)

[0027] It should be noted that the numerator and denominator values ​​of the coefficients used in formulas (2)-(4) represent isotopic abundances, specifically 26.46 and 11.72, respectively. 108 Pd, 110 Pd abundance: 12.80 and 28.73 respectively 111 Cd, 114 Cd abundance: 0.66 and 24.22 respectively. 114 Sn、 118 Sn abundance.

[0028] In addition, in order to obtain accurate analytical results of trace Ag, when using the calculation method based on formula (5), the signal intensity at m / z=109, m / z=111, m / z=114, and m / z=118 involved in the series of mixed standard solutions and sample solutions needs to be collected simultaneously.

[0029] In step S1, the first step of digesting the sample by appropriate treatment involves reacting the palladium bis(acetonitrile) dichloride sample with strong oxidizing reagents such as concentrated hydrochloric acid and concentrated nitric acid to generate the corresponding palladium salt solution. The generated palladium salt solution is then prepared into a sample solution. The specific preparation method for the analytical solution is as follows: accurately weigh the palladium bis(acetonitrile) dichloride sample to be analyzed, place it in a 50 mL polytetrafluoroethylene beaker, add concentrated hydrochloric acid and concentrated nitric acid (volume ratio 3:1), cover the beaker, heat on a 180°C hot plate for 30 min, remove and allow to cool slightly, add 30% hydrogen peroxide, boil for 5 min, cool to room temperature, transfer to a 100 mL volumetric flask with deionized water, dilute to the mark, and mix well.

[0030] In step S2, the optimization of the ammonia flow rate is obtained as follows: a palladium matrix blank solution with a mass concentration of 1 mg / mL and a silver standard solution with a mass concentration of 40 ng / mL are prepared. Within a certain flow rate range, the ammonia flow rate is changed at intervals of 0.5 mL / min, and the signal intensity of the palladium matrix blank solution and the silver standard solution at m / z=109 is measured respectively. The optimized ammonia flow rate range is 0~10 mL / min, and the preferred flow rate range is 0~8 mL / min.

[0031] Further, in step S2, the optimal ammonia flow rate is obtained as follows: based on the relative relationship between the signal intensities of the palladium matrix blank solution and the silver standard solution obtained above, the equivalent concentration C of Ag in the palladium matrix blank solution under different optimized ammonia flow rates is calculated according to the following formula (6). 空白 Then, based on the equivalent concentration C of Ag... 空白 The optimal ammonia flow rate is selected based on the size of the gas flow to achieve elimination. 108 Pd 1 The purpose of H interference.

[0032] ………………………………(6)

[0033] It should be noted that C 空白 The smaller the value, the more complete the collision reaction, and the lower the corresponding ammonia flow rate for elimination. 108 Pd 1 The better the H interference effect; when in C 空白Under the same conditions, the ammonia flow rate at which the silver standard solution signal intensity is higher is selected to ensure that the mass spectrometry method for determining the silver content in bis(acetonitrile)palladium chloride has better sensitivity.

[0034] In step S2, the palladium-based blank solution is prepared using sponge palladium (w Pd Formulated with ≥99.99% (or higher);

[0035] In steps S2 and S3, the silver standard solution, the Ag and Cd series mixed standard solution, and the Cs internal standard solution are all obtained by stepwise dilution of Ag, Cd, and Cs standard stock solutions with a mass concentration of 100 μg / mL; the Ag and Cd standard stock solutions are respectively prepared by dissolving metallic Ag (w) in nitric acid beforehand. Ag ≥99.99%) and metallic Cd (w Cd It is prepared by dissolving Cs2CO3 (spectrally pure) in nitric acid (≥99.99%). The Cs standard stock solution is prepared by dissolving Cs2CO3 (spectrally pure) in nitric acid.

[0036] In step S3, the standard solution is prepared as follows: based on the fact that the trace Ag mass fraction in bis(acetonitrile)palladium dichloride is less than 0.0010%, the mass concentration range of Ag in the analytical solution is determined according to the sample solution preparation method described in step S1, and a series of mixed standard solutions of Ag and Cd with different concentrations are prepared, with hydrochloric acid and nitric acid (volume ratio of 3:1) as the medium; the internal standard solution is a solution of a certain element (such as Cs) that is not usually present in the sample solution, and a Cs solution with a mass concentration of 100 ng / mL is prepared as the internal standard solution, with 2% nitric acid as the medium.

[0037] In step S5, on a mass spectrometer, under conditions of no collision reaction gas and optimal ammonia flow rate, the signal intensity of a series of mixed standard solutions and bis(acetonitrile)palladium dichloride sample solutions was measured at m / z=109, and the signal intensity at m / z=111, m / z=114 and m / z=118 was also measured; the ammonia gas is a collision reaction gas.

[0038] Furthermore, an internal standard solution was introduced through a three-way valve, and the signal intensity of the internal standard solution was monitored simultaneously.

[0039] Furthermore, the linear correlation coefficient between the Ag working curve under non-collision reaction gas conditions and the Ag and Cd working curves under ammonia flow conditions is not less than 0.999;

[0040] In step S7, the signal intensity of the non-collision reaction gas is processed according to formula (5), and the measurement result of silver under this condition is obtained based on the working curve method.

[0041] In step S8, the determination results of silver and cadmium under the ammonia flow rate conditions obtained according to the working curve method are further used to verify the equation calculation and the elimination of collision reaction interference.

[0042] The beneficial effects of this invention are:

[0043] (1) This method can achieve multiple signal strength transfers through equations and subtract signal strength through calculation. 108 Pd 1 H interference was used to obtain the signal intensity of Ag in bis(acetonitrile)palladium dichloride solution under collision-free reaction gas conditions;

[0044] (2) This method can use a palladium matrix blank solution and silver standard solution of a certain mass concentration to optimize the ammonia flow rate in the range of 0~10 mL / min. The equivalent concentration of the blank solution can be calculated by formula, and the optimal ammonia flow rate can be screened.

[0045] (3) This method can be used to obtain the optimal ammonia flow rate by making interfering ions 108 Pd 1 H reacts with ammonia gas, directly eliminating... 108 Pd 1 H interference, thus accurately determining the Ag content in bis(acetonitrile)palladium dichloride;

[0046] (4) This method can effectively eliminate the influence of organic components on the determination by using hydrochloric acid, nitric acid and hydrogen peroxide in appropriate volume ratios and under suitable temperature conditions to digest the bis(acetonitrile)palladium dichloride sample by the strong oxidizing and acidic properties of the reagents.

[0047] (5) This method can simultaneously measure Ag and Cd under the same ammonia flow rate, and verify the degree of Ag interference elimination by measuring Cd; and further verify the accuracy of the equation calculation method under non-collision reaction gas conditions by verifying the Ag results.

[0048] Therefore, the method for eliminating silver interference in bis(acetonitrile)palladium dichloride based on cadmium verification according to the present invention solves the problem of silver interference in the determination of impurity Ag content in bis(acetonitrile)palladium dichloride sample solution due to... 108 Pd 1 This method addresses the problem of inaccurate measurement results caused by H interference, and also solves the issue that it is often impossible to verify whether the interference elimination is thorough. As demonstrated by the above steps, this method is simple and easy to implement, effectively eliminating the influence of organic components on the determination, ultimately ensuring accurate and efficient determination of Ag content in bis(acetonitrile)palladium dichloride. Furthermore, the simultaneous determination of cadmium also achieves the effect of eliminating the aforementioned silver interference. Attached Figure Description

[0049] Figure 1The working curve of Ag in the example without collision reaction gas is shown.

[0050] Figure 2 The example shows the working curve of Ag when the ammonia flow rate is 5 mL / min.

[0051] Figure 3 The example shows the operating curve of Cd when the ammonia flow rate is 5 mL / min. Detailed Implementation

[0052] The technical solution of the present invention will be further described below through embodiments.

[0053] 1. For the palladium dichloride bis(acetonitrile) sample, accurately weigh 0.10 g (to a precision of 0.0001 g) and place it in a 50 mL PTFE beaker. Add 3 mL of hydrochloric acid and 1 mL of nitric acid. Cover the beaker and heat it on a 180°C hot plate for 30 min. After cooling slightly, add 1 mL of hydrogen peroxide and boil. Cool to room temperature and transfer to a 100 mL volumetric flask with deionized water. Dilute to the mark and mix well.

[0054] 2. Prepare a series of Ag and Cd standard solutions with mass concentrations of 0, 10 ng / mL, 20 ng / mL, 30 ng / mL, and 40 ng / mL by serially diluting the 100 μg / mL Ag and Cd standard stock solutions. The medium is 3% hydrochloric acid and 1% nitric acid.

[0055] Furthermore, a Cs solution with a mass concentration of 100 ng / mL was prepared by serially diluting the 100 μg / mL Cs standard stock solution as an internal standard solution; during instrumental analysis, this internal standard solution was introduced into the injection system through a three-way connector.

[0056] 3. Prepare a 1 mg / mL palladium matrix blank solution and a 40 ng / mL silver standard solution for ammonia flow rate optimization. Within the range of 0–8 mL / min, change the ammonia flow rate at 0.5 mL / min intervals, and measure the signal intensity of the palladium matrix blank solution and the silver standard solution at m / z = 107. Calculate the equivalent concentration C according to formula (6). 空白 The summary results are shown in Table 1.

[0057] According to Table 1, the optimal ammonia flow rate is determined to be 5 mL / min.

[0058] Table 1. Signal intensity variation with ammonia flow rate at m / z=107 and calculated equivalent concentration.

[0059]

[0060] Simultaneously, working curves for Ag and Cd were plotted on a mass spectrometer at an ammonia flow rate of 5.0 mL / min. Figure 2and Figure 3 With Cs as the internal standard for correction, the linear correlation coefficient is greater than 0.999;

[0061] 4. On a mass spectrometer, the signal intensities of a series of standard solutions and bis(acetonitrile)palladium dichloride sample solutions at m / z=109, m / z=111, m / z=114 and m / z=118 were measured in the absence of collision reaction gas, and the corrected signal intensity I of Ag was obtained by formula (5). Ag ;

[0062] Furthermore, based on the corrected I from a series of standard solutions Ag Plot the working curve of Ag for collision-free reactive gases ( Figure 1 );

[0063] Furthermore, according to Figure 1 The mass concentration of Ag in the bis(acetonitrile)palladium dichloride sample solution was calculated from the working curve of Ag when there was no collision reaction gas.

[0064] The above measurements were taken when directly measuring the bis(acetonitrile)palladium dichloride sample solution under a non-collision reaction gas. The signal intensity at each mass-to-charge ratio, the corresponding mass concentration, and the signal intensity I of Ag after processing according to formula (5) were obtained. Ag The mass concentration C of Ag calculated after subtracting interference. Ag See Table 2.

[0065] Table 2

[0066]

[0067] 5. On a mass spectrometer, under an ammonia flow rate of 5 mL / min, the signal intensity at m / z=109 and m / z=111 of the bis(acetonitrile)palladium dichloride sample solution was measured.

[0068] Furthermore, according to Figure 2 and Figure 3 The mass concentrations of Ag and Cd in the bis(acetonitrile)palladium dichloride sample solution were calculated using the working curves. The results are shown in Table 3.

[0069] Table 3

[0070]

[0071] 6. In bis(acetonitrile)palladium dichloride solution 109 Ag received 108 Pd 1 H interference, 111 Cd is affected 110 Pd 1H interference. Table 2 shows that when the ammonia flow rate was 0 mL / min, the Cd value was 0.76 ng / mL; while Table 3 shows that when the ammonia flow rate was 5 mL / min, Cd was not detected in bis(acetonitrile)palladium dichloride. This indicates that the interference from PdH polyatoms has been eliminated using the method of this invention. Therefore, the Cd determination results can verify… 109 The interference experienced by Ag has been eliminated, i.e., C in Table 3. Ag =0.34ng / mL is an accurate analytical result.

[0072] Furthermore, as shown in Table 2, in the absence of collision reaction gas, C is obtained by subtracting the interference signal intensity using formula (5). Ag =0.33 ng / mL, which is considered consistent with the result of 0.34 ng / mL in Table 3. This demonstrates that the method of this invention can effectively eliminate the interference of silver in both the equation calculation and the collision reaction.

[0073] As can be seen from the above embodiments, the calculation equations and ammonia collision reactions designed in this invention have achieved the beneficial effect of effectively eliminating the interference of silver in bis(acetonitrile)palladium dichloride, and the accuracy can also be verified by the simultaneous determination of cadmium.

Claims

1. A method for verifying the elimination of silver interference in bis(acetonitrile)palladium dichloride based on cadmium, wherein the method involves determining silver interference in bis(acetonitrile)palladium dichloride using elimination mass spectrometry and verifying whether the interference has been eliminated based on cadmium, characterized in that, Includes the following steps: S1. The sample is properly treated to digest bis(acetonitrile)palladium dichloride, and a sample solution of a certain mass concentration is prepared as an analytical solution. S2. Prepare a palladium matrix blank solution and a silver standard solution of a certain mass concentration, measure the signal intensity at m / z=109 on a mass spectrometer, and optimize the ammonia flow rate to obtain the optimal ammonia flow rate. S3. Prepare a series of mixed standard solutions of Ag and Cd for determination and verification, as well as a Cs internal standard solution for correcting matrix effects; S4. Based on the signal intensities at m / z=109, m / z=111, m / z=114, and m / z=118 measured in the sample solution, the following formula (5) is used in the calculation method. During the mass spectrometry determination process, the signal intensity at m / z=109, m / z=111, m / z=114, and m / z=118 in the sample solution is obtained through formula (5). 109 The net signal strength of Ag; ………………………………（5） S5. On the mass spectrometer, the series of mixed standard solutions and internal standard solutions prepared in step S3 are introduced through a three-way valve. First, under the condition of no collision reaction gas, the signal intensity at the mass-to-charge ratio involved in formula (5) in step S4 is measured. Then, under the optimal ammonia flow rate obtained in step S2, the signal intensity of Ag and Cd in the above series of mixed standard solutions at the selected mass-to-charge ratios: m / z=109, m / z=111, m / z=114, m / z=118 is measured, and the signal intensity of the internal standard is monitored at the same time. After processing according to formula (5), the Ag working curve under the condition of no collision reaction gas is completed. The Ag and Cd working curves under the ammonia flow rate condition are completed. S6. Introduce the bis(acetonitrile)palladium dichloride sample solution prepared in step S1 into the mass spectrometer, and measure the signal intensity at each mass-to-charge ratio in the sample solution under the same collision-free reaction gas and ammonia flow rate conditions as in step S5. S7. Based on the formula (5) in step S4 and the working curves of the series of standard solutions plotted in step S5, the determination results of silver in the bis(acetonitrile)palladium dichloride sample solution in step S6 under non-collision reaction gas conditions and the determination results of silver and cadmium under the same ammonia flow rate are calculated. S8. Based on the cadmium determination results from step S7 above, compare them with the silver determination results under the same ammonia flow rate to verify their accuracy. The results of silver determination under the same ammonia flow conditions were compared with the results of silver obtained by formula (5) to verify the accuracy of the calculation equation.

2. The method according to claim 1, characterized in that, In step S1, the specific preparation method of the analytical solution is as follows: accurately weigh the palladium dichloride bis(acetonitrile) sample to be analyzed, place it in a 50 mL polytetrafluoroethylene beaker, add concentrated hydrochloric acid and concentrated nitric acid in a volume ratio of 3:1, cover the beaker and heat it on a 180°C hot plate for 30 min, remove it and let it cool slightly, add 30% hydrogen peroxide, boil for 5 min, cool to room temperature, transfer it to a 100 mL volumetric flask with deionized water, dilute to the mark and mix well.

3. The method according to claim 1, characterized in that, In step S2, the optimization of the ammonia flow rate is obtained as follows: a palladium matrix blank solution with a mass concentration of 1 mg / mL and a silver standard solution with a mass concentration of 40 ng / mL are prepared. Within a certain flow rate range, the ammonia flow rate is changed at intervals of 0.5 mL / min, and the signal intensity of the palladium matrix blank solution and the silver standard solution at m / z=109 is measured respectively; the optimized ammonia flow rate range is 0~10 mL / min.

4. The method according to claim 3, characterized in that, In step S2, the optimal ammonia flow rate is obtained as follows: Based on the relative relationship between the signal intensities of the palladium matrix blank solution and the silver standard solution obtained above, the equivalent concentration C of Ag in the palladium matrix blank solution at different ammonia flow rates is calculated according to the following formula (6). 空白 Then, based on the equivalent concentration C of Ag... 空白 The optimal ammonia flow rate is determined by the size of the gas. ………………………………（6）。 5. The method according to claim 1, characterized in that, In step S4, formula (5) is obtained as follows: In mass spectrometry, firstly, interference signals are subtracted based on the signal intensity at m / z=109 in the bis(acetonitrile)palladium dichloride sample solution. 108 Pd 1 The signal strength of H can be obtained 109 The net signal strength of Ag, i.e., formula (1): ………………………………（1） Furthermore, in formula (1) 108 Pd 1 H signal strength transfer 110 Pd 1 For H, see formula (2): ………………………………（2） Furthermore, in formula (2) 110 Pd 1 The relationship between H signal intensity and cadmium signal intensity is shown in formula (3): ………………………………（3） Furthermore, in formula (3) 114 The Cd signal intensity shifts to m / z=118, as shown in formula (4): ………………………………（4） Furthermore, substituting equation (4) into equation (3), then into equation (2), and then into equation (1), and iterating in this way, we obtain the final equation required for the computational correction of the Ag signal intensity, namely equation (5): ………………………………（5） The values ​​of the numerator and denominator in the coefficients used in formulas (2)-(4) are the isotope abundances.

6. The method according to claim 1, characterized in that, In step S5, the linear correlation coefficient between the Ag working curve under non-collision reaction gas conditions and the Ag and Cd working curves under ammonia flow conditions is not less than 0.

999.

7. The method according to claim 1, characterized in that, In step S7, the signal intensity of the non-collision reaction gas is processed according to formula (5), and the measurement result of silver under this condition is obtained based on the working curve method.

8. The method according to claim 1, characterized in that, In step S8, the determination results of silver and cadmium under the ammonia flow rate conditions obtained according to the working curve method are used to verify the equation calculation and the elimination of collision reaction interference.

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