Method for simultaneously determining NaHS and Na2S in PPS slurry mother liquor by high performance liquid chromatography

Abstract

The application discloses a method for simultaneously determining NaHS and Na2S in PPS slurry mother liquor by using high performance liquid chromatography, and comprises the following steps: (1) preparing a sample solution: taking the PPS slurry mother liquor, adding water to constant volume, filtering to obtain a filtrate, and then dividing the filtrate into two parts, one part is added with an equal volume of ultrapure water and recorded as sample solution a1, and the other part is added with an equal volume of a derivatizing agent to perform a derivatization reaction and recorded as sample solution a2; (2) preparing a control solution: respectively taking NaHS and Na2S, dissolving and constant volume by adding water, and reserving after filtering; (3) sample injection and detection: using high performance liquid chromatography, a mobile phase comprises mobile phase A and mobile phase B, the mobile phase A is selected from acetonitrile, and the mobile phase B is selected from a mixed solution comprising an ammonium formate and formic acid buffer solution. The test method is simple and efficient, has good system adaptability and high specificity for the PPS slurry mother liquor, and has high precision, high accuracy and high sensitivity in detection.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of material analysis and detection, and particularly relates to a method for simultaneously determining NaHS and Na2S in PPS slurry mother liquor by using high performance liquid chromatography. BACKGROUND

[0002] PPS (polyphenylene sulfide) is an important special engineering plastic. Due to its excellent performance in chemical corrosion resistance, thermal stability, mechanical properties and other aspects, it is widely used in chemical industry, automobile, electronics, machinery and other fields.

[0003] At present, the synthesis of PPS mainly adopts sodium sulfide method. The reaction is to prepare linear high molecular weight PPS by using sodium hydrosulfide, sodium hydroxide and p-dichlorobenzene as raw materials, and through condensation reaction in a strong polar solvent under high temperature and high pressure conditions. The reaction formula is as follows:

[0004]

[0005] Under this method, the content of raw materials sodium hydrosulfide (NaHS) and sodium sulfide (Na2S) is a key factor for the success of polymerization reaction, and directly affects the yield of PPS. Therefore, by monitoring the content of NaHS and Na2S in PPS polymerization mother liquor, it has important guiding role for monitoring production quality, evaluating PPS performance index and other aspects.

[0006] At present, there is no specific method for detecting the content of NaHS and Na2S in PPS slurry mother liquor. The national standard GB / T23937-2020 mentions using titration method to detect NaHS and Na2S, but this method has a narrow application range and is not suitable for the analysis of NaHS and Na2S in PPS slurry mother liquor. This is because PPS slurry mother liquor is complex and contains a large amount of organic and inorganic alkali, which will seriously interfere with the detection of NaHS and Na2S. In addition, the titration method is complicated and has poor detection sensitivity, so the traditional titration method cannot be used for quantitative analysis of target analytes NaHS and Na2S.

[0007] Compared with titration method, high performance liquid chromatography method has simple test process, high efficiency, high accuracy of test results and good repeatability, so it is more suitable for detection method of monitoring index in production process. However, NaHS and Na2S have similar structures, and the current chromatographic instrument analysis technology cannot separate them. In addition, PPS slurry mother liquor is complex and contains a large amount of impurities, so it is extremely difficult to develop a simple and effective high performance liquid test method for simultaneously determining NaHS and Na2S. SUMMARY

[0008] In view of the above problems existing in the prior art, the application discloses a method for simultaneously determining NaHS and Na2S in PPS slurry mother liquor by using high performance liquid chromatography, and the test method is simple and efficient, and has good system adaptability, high specificity, high precision, high accuracy and high sensitivity.

[0009] The specific technical scheme is as follows:

[0010] A method for simultaneously determining NaHS and Na2S in PPS slurry mother liquor by using high performance liquid chromatography, comprising the following steps:

[0011] (1) preparing a sample solution: taking PPS slurry mother liquor, adding water to constant volume, filtering to obtain filtrate, and then dividing the filtrate into two parts, one part is added with an equal volume of ultrapure water and is recorded as sample solution a1, and the other part is added with an equal volume of a derivatizing agent for derivatization reaction and is recorded as sample solution a2;

[0012] The derivatizing agent is selected from a glyoxal solution.

[0013] (2) preparing a control solution: respectively taking NaHS and Na2S, dissolving and constant volume with water, and filtering for standby;

[0014] (3) sample injection and detection: high performance liquid chromatography is adopted to detect the sample solution and the control solution respectively, and the content of NaHS and Na2S in the sample solution is calculated according to the external standard method with peak area;

[0015] The mobile phase used in the high performance liquid chromatography comprises mobile phase A and mobile phase B, the mobile phase A is selected from acetonitrile, and the mobile phase B is selected from a mixed solution comprising ammonium formate and formic acid buffer solution.

[0016] The method selects specific mobile phase composition for high performance liquid chromatography test, and adds a specific derivatizing agent for derivatization reaction when preparing the sample solution, so that the simultaneous determination of NaHS and Na2S in the PPS slurry mother liquor is realized.

[0017] It is found through experiments that if the composition of the mobile phase A and the mobile phase B in the mobile phase is replaced, the quantitative test of NaHS and Na2S in the PPS slurry mother liquor cannot be satisfied.

[0018] It is also found through experiments that even if the appropriate mobile phase composition is selected, if the added derivatizing agent is replaced with a formaldehyde solution, the test of NaHS and Na2S in the PPS slurry mother liquor cannot be satisfied.

[0019] In step (1):

[0020] The derivatization reaction has a reaction time of 10-15 min and a reaction temperature of 25-35 DEG C.

[0021] It is found through experiments that when the temperature and time of the derivatization reaction reach the above conditions, the derivatization reaction can be completely reacted, thereby ensuring the accurate testing of the content of NaHS and Na2S in the PPS slurry mother liquor.

[0022] Further preferably, the reaction time of the derivatization reaction is 12 min and the reaction temperature is 30°C.

[0023] The filtration is selected from filtration with a PTFE filter membrane.

[0024] In step (2), the pH of the mobile phase B is 3.0-4.0, and the concentration of the mobile phase B is 15-25 mmol / L.

[0025] The filtration is selected from filtration with a PTFE filter membrane.

[0026] In step (3), the elution program of the mobile phase in the high performance liquid chromatography is as follows:

[0027] 0-10 min, isocratic elution, the volume fraction of the mobile phase B in the mobile phase is 87-95%;

[0028] 10-25 min, gradient elution, elution to the volume fraction of the mobile phase B in the mobile phase being 10%;

[0029] 25-29 min, isocratic elution, the volume fraction of the mobile phase B in the mobile phase is 10%;

[0030] 29-30 min, gradient elution, elution to the volume fraction of the mobile phase B in the mobile phase being 87-95%.

[0031] Preferably, the pH of the mobile phase B in the high performance liquid chromatography is 3.0-4.0, and the concentration of the mobile phase B is 15-25 mmol / L.

[0032] 0-10 min, isocratic elution, the volume fraction of the mobile phase A in the mobile phase is 8%, and the volume fraction of the mobile phase B in the mobile phase is 92%;

[0033] 10-25 min, gradient elution, elution to the volume fraction of the mobile phase A in the mobile phase being 90%, and the volume fraction of the mobile phase B in the mobile phase being 10%;

[0034] 25-29 min, isocratic elution, the volume fraction of the mobile phase A in the mobile phase is 90%, and the volume fraction of the mobile phase B in the mobile phase is 10%;

[0035] 29-30 min, gradient elution, elution to the volume fraction of the mobile phase A in the mobile phase being 8%, and the volume fraction of the mobile phase B in the mobile phase being 92%.

[0036] Preferably, the pH of the mobile phase B in the high performance liquid chromatography is 3.0-4.0, and the concentration of the mobile phase B is 15-25 mmol / L.

[0037] Preferably, the flow rate of the mobile phase is 0.8-1.2 mL / min; further preferably 1.0 mL / min.

[0038] Preferably, the chromatographic column is a SAX chromatographic column, and the column temperature is 25-35 DEG C; further preferably the column temperature is 30 DEG C.

[0039] Preferably, the detection wavelength is 210-225 nm; further preferably 218 nm.

[0040] Preferably, the injection volume is 5-25 muL; further preferably 20 muL.

[0041] Compared with the prior art, the present application has the following beneficial effects:

[0042] The present application discloses for the first time a high-performance liquid detection method for simultaneously detecting the contents of NaHS and Na2S in PPS slurry mother liquor, fills the blank in the PPS production field that the contents of raw materials NaHS and Na2S cannot be monitored in the production process, and provides a new idea and method for testing the contents of NaHS and Na2S.

[0043] The high-performance liquid detection method disclosed by the present application has the advantages of good system adaptability, high specificity, high precision, high accuracy, high sensitivity, etc., and the operation process is simple, and the contents of NaHS and Na2S in PPS slurry mother liquor can be quickly determined; this has an important guiding role for monitoring the conversion rate of PPS polymerization reaction and ensuring the production quality of PPS. BRIEF DESCRIPTION OF DRAWINGS

[0044] Figure 1 HPLC chromatogram of the control solution a obtained by using the detection process in Example 1;

[0045] Figure 2 HPLC chromatogram of the control solution b obtained by using the detection process in Example 1;

[0046] Figure 3 HPLC chromatogram of the blank solution obtained by using the detection process in Example 1;

[0047] Figure 4 HPLC chromatogram of the sample solution a1 obtained by using the detection process in Example 1;

[0048] Figure 5 HPLC chromatogram of the sample solution a2 obtained by using the detection process in Example 1;

[0049] Figure 6 Correction chart of NaHS in Example 1;

[0050] Figure 7 Corrected chromatogram of Na2S in Example 1;

[0051] Figure 8 HPLC chromatogram of control solution a obtained by using the detection process in Comparative Example 2;

[0052] Figure 9 HPLC chromatogram of control solution a obtained by using the detection process in Comparative Example 3;

[0053] Figure 10 HPLC chromatogram of control solution a obtained by using the detection process in Comparative Example 4;

[0054] Figure 11 HPLC chromatogram of control solution a obtained by using the detection process in Comparative Example 5. DETAILED DESCRIPTION

[0055] In order to make the objects, features and advantages of the present application more obvious, the following examples are further listed to explain the present application in detail. The following examples are only used to further explain the present application, and cannot be understood as a limitation on the protection scope of the present application. Some non-essential improvements and adjustments made by those skilled in the art according to the principles set forth in the present application all belong to the protection scope of the present application.

[0056] In the following examples, comparative examples and experiments, acetonitrile is chromatographic grade, ammonium formate is chromatographic grade (purity ≥ 99.9%), formic acid is chromatographic grade (purity ≥ 99.9%), glyoxal solution (40% aqueous solution), neutral formaldehyde solution (37%-40% aqueous solution, reagent formaldehyde solution is adjusted to neutral with phenothalin as indicator and sodium hydroxide), water is ultrapure water, sodium sulfide standard (Na2S·9H2O, purity 99.99%), sodium hydrosulfide standard (purity 99.00%). The high performance liquid chromatograph used is a Thermo Fisher Ultimate 3000.

[0057] Example 1

[0058] 1. Chromatographic system

[0059] Chromatographic column: SAX;

[0060] Mobile phase: mobile phase A: acetonitrile; mobile phase B: ammonium formate and formic acid buffer solution;

[0061] Take ammonium formate 1.27 g, accurately weigh, add 900 mL of ultrapure water, stir to dissolve, adjust the pH to 3.5 with formic acid, then transfer to a 1 L volumetric flask, dilute to volume, and filter through a 0.45 μm PTFE filter membrane to obtain mobile phase B;

[0062] Flow rate: 1.0 mL / min;

[0063] Detection wavelength: 218 nm;

[0064] Column temperature: 30℃;

[0065] Injection volume: 20 μL;

[0066] Elution procedure:

[0067] Time (min) Mobile phase A (volume fraction, %) Mobile phase B (volume fraction, %) 0.00 8 92 10 8 92 25 90 10 29 90 10 30 8 92

[0068] 2. Specific steps:

[0069] 2.1 Preparation of sample solution

[0070] Take 15 mL of PPS slurry mother liquor with a pipette, place it in a 100 mL beaker, dissolve it with 50 mL of water, transfer it to a 250 mL volumetric flask, and then dilute it to the mark with water to obtain sample solution a;

[0071] Take 25 mL of sample solution a and place it in a 100 mL beaker, add an equal volume of ultrapure water to obtain sample solution a1;

[0072] Take 25 mL of sample solution a and place it in a 100 mL beaker, add an equal volume of glyoxal solution to carry out derivatization reaction in a constant temperature water bath, set the water bath temperature to 30℃, and the water bath time to 12 min; after the water bath is completed, the derivatized sample is obtained, which is recorded as sample solution a2.

[0073] Take 15 mL of PPS slurry mother liquor with a pipette, place it in a 100 mL beaker, dissolve it with 50 mL of water, transfer it to a 250 mL volumetric flask, and then dilute it to the mark with water to obtain sample solution a;

[0074] According to the preparation steps of sample solution a1 and sample solution a2 above, sample solution b1 and sample solution b2, sample solution c1 and sample solution c2, sample solution d1 and sample solution d2, sample solution e1 and sample solution e2, sample solution f1 and sample solution f2, sample solution g1 and sample solution g2 are obtained in turn.

[0075] 2.2 Preparation of control solution

[0076] Take NaHS about 0.1 g, accurately weigh, dissolve with 50 mL water, transfer to a 100 mL volumetric flask, and dilute to volume with water to obtain the reference solution a of NaHS. Dilute the reference solution a with water to obtain different concentrations of NaHS reference, marked as reference a1#-a6#. The concentrations are 0.4005 mg / L (reference a1#), 0.8010 mg / L (reference a2#), 1.0013 mg / L (reference a3#), 2.0025 mg / L (reference a4#), 4.0050 mg / L (reference a5#), and 8.0100 mg / L (reference a6#).

[0077] Take Na2S·9H2O about 0.3 g, accurately weigh, dissolve with 50 mL water, transfer to a 100 mL volumetric flask, and dilute to volume with water to obtain the reference solution b of Na2S. Dilute the reference solution b with water to obtain different concentrations of Na2S reference, marked as reference b1#-b6#. The concentrations are 50.1005 mg / L (reference b1#), 80.1608 mg / L (reference b2#), 100.2010 mg / L (reference b3#), 120.2412 mg / L (reference b4#), 150.3015 mg / L (reference b5#), and 200.4020 mg / L (reference b6#).

[0078] The blank solution (glyoxal solution), sample solution, and reference solution are analyzed by high performance liquid chromatography method, and the system suitability, accuracy, and sensitivity are verified.

[0079] 3. Verification results of detection method

[0080] 3.1 System suitability

[0081] In this embodiment, the chromatograms of the reference solution a and the reference solution b are shown in Figure 1 , Figure 2 . The retention time of NaHS and Na2S is consistent, both about 6.95 min, and the tailing factors are 1.02 and 1.03, respectively, indicating that under this method, NaHS and Na2S both have good symmetry.

[0082] Take the reference solutions a and b for repeated injection 6 times to investigate the system suitability, and the test results are shown in Table 1.

[0083] Table 1

[0084]

[0085] From the test results of Table 1, the relative standard deviations (RSD) of the retention time and peak area of NaHS and Na2S chromatographic peaks in the 6 standard solution were less than <0.1%, which indicated that the system had good adaptability.

[0086] 3.2 Specificity

[0087] In this embodiment, the chromatograms of the blank solution and sample solution a1 are shown in Figure 3 , Figure 4 respectively. The blank solution had no chromatographic peak at the retention time of about 6.95 min of the target peak NaHS / Na2S. The resolution (R) between the target peak NaHS / Na2S and the adjacent peak was 2.15, which was greater than 1.5.

[0088] In this embodiment, the chromatograms of the blank solution and sample solution a2 are shown in Figure 3 , Figure 5 respectively. The blank solution had no chromatographic peak at the retention time of about 6.95 min of the target peak Na2S. The resolution (R) between the target peak NaHS / Na2S and the adjacent peak was 2.14, which was greater than 1.5.

[0089] It was shown that under this method, the target substance could be completely separated from other impurities. The blank solution would not interfere with the analysis of NaHS and Na2S in the sample solution.

[0090] From the above, it was shown that this method had good specificity and was suitable for the analysis of NaHS and Na2S in the PPS slurry mother liquor.

[0091] 3.3 Linearity and Range

[0092] In this embodiment, the test results of the content and peak area of the sodium hydrosulfide standard solution and the sodium sulfide standard solution are shown in Table 2.

[0093] Table 2

[0094]

[0095] According to the test results in Table 2, taking the concentration of NaHS and Na2S as the abscissa and the peak area as the ordinate, the least squares method was used for linear regression, and the calibration curves of NaHS and Na2S were obtained, as shown in Figure 6 , Figure 7 . The linear regression equation of NaHS was Y=0.7281X-0.062, the linear correlation coefficient R 2 =0.9996, and the linear regression equation of Na2S was Y=0.9336X-0.4002, R 2 =0.9998. The results showed that the method had good linearity and could perform accurate quantitative detection.

[0096] 3.4 Test of the content of NaHS and Na2S in PPS slurry mother liquor

[0097] In this example, the peak area of sample solution a1 obtained at the retention time RT = 6.947 min is A1 (see Figure 2), which represents the sum of the peak areas of NaHS and Na2S in the sample solution. Figure 4 The peak area of sample solution a2 obtained at the retention time RT = 6.943 min is A2 (see Figure 2), which represents the peak area of Na2S in the solution. Figure 5

[0098] According to the linear regression equation of NaHS and Na2S obtained in 3.3 and the test results of sample solution a1 and sample solution a2 in this example, the calculation formula of the content of NaHS and Na2S in PPS slurry mother liquor (unit: mg / L) is shown in the following two formulas, wherein:

[0099]

[0100]

[0101] According to the above calculation formula, the content of NaHS and Na2S in PPS slurry mother liquor can be obtained as shown in Table 3.

[0102] Table 3

[0103]

[0104] 3.5 Precision of the method

[0105] According to the calculation formula in 3.4, the test results of NaHS and Na2S in sample solutions PPS slurry mother liquor 1#, PPS slurry mother liquor 2#, PPS slurry mother liquor 3#, PPS slurry mother liquor 4#, PPS slurry mother liquor 5# and PPS slurry mother liquor 6# are shown in Table 4.

[0106] Table 4

[0107]

[0108] From the test results in Table 4, it can be seen that the content of NaHS in PPS slurry mother liquor is about 30 mg / L, and the content of Na2S is about 3675 mg / L. The relative standard deviation (RSD) of the content of NaHS and Na2S in the 6 test results samples is less than 1%, which indicates that the precision of the method is good.

[0109] 3.6 Accuracy

[0110] ​In order to verify whether the method has good accuracy, the recovery rate of NaHS and Na2S can be investigated by adding control solution of NaHS and Na2S with different concentrations in sample solution, and then evaluated.

[0111] Precisely pipette 25 mL of sample solution a into three different volumetric flasks, and then add 0.25 mL of control solution a1#, 0.25 mL of control solution a3# and 0.25 mL of control solution a6# respectively, to obtain spiked solution a1, spiked solution a2 and spiked solution a3 respectively.

[0112] Precisely pipette 25 mL of sample solution a into three different volumetric flasks, and then add 0.25 mL of control solution a1#, 0.25 mL of control solution a3# and 0.25 mL of control solution a6# respectively, to obtain spiked solution a1, spiked solution a2 and spiked solution a3 respectively.

[0113] According to the test method of sample solution in the present embodiment, the test results of the content and recovery rate of NaHS and Na2S in the above spiked solutions obtained by repeating sampling for 3 times are shown in Tables 5-10.

[0114] Table 5

[0115]

[0116] Table 6

[0117]

[0118] Table 7

[0119]

[0120] Table 8

[0121]

[0122] Table 9

[0123]

[0124]

[0125] Table 10

[0126]

[0127] From the results of Table 5 to Table 10, the recovery of NaHS and Na2S in sample solution a is between 95 to 105%, the recovery of the method is good, which shows that the derivatization reaction in the sample solution preparation process is complete, the matrix of PPS slurry mother liquor and glyoxal solution will not affect the test of NaHS and Na2S, the method is accurate and suitable for the test of NaHS and Na2S in PPS slurry mother liquor.

[0128] 3.7 Sensitivity

[0129] The sensitivity of the test method is evaluated by the detection limit of the method, where the detection limit is the concentration corresponding to 3 times the instrument noise level. By continuously diluting the sample solution, the signal-to-noise ratio of the response signal meets the signal-to-noise ratio of the detection limit. According to the method in this embodiment, the detection limit of the detection method for NaHS in PPS slurry mother liquor is 0.05 mg / L, and the detection limit of Na2S is 0.02 mg / L, which shows that the method has high sensitivity.

[0130] Examples 2-4

[0131] The detection process is basically the same as in Example 1, except that the derivatization reaction time is replaced with 8 min, 10 min and 15 min, respectively, when preparing sample solution a2.

[0132] Examples 1-4 investigate the effect of derivatization reaction time on the test results. The test results of NaHS and Na2S in PPS slurry mother liquor after different derivatization times are shown in Table 11.

[0133] Table 11

[0134]

[0135]

[0136] From the results of Table 11, the derivatization reaction of sodium hydrosulfide and glyoxal gradually increases with the increase of reaction time, until the reaction endpoint is reached. From the test results in the table, the derivatization reaction is complete after 10 min, and the content of NaHS and Na2S in PPS slurry mother liquor hardly changes thereafter. In order to ensure that the derivatization reaction is sufficient and to save the sample pretreatment time to the maximum, the derivatization reaction time is preferably 12 min.

[0137] Examples 5-7

[0138] The detection process is basically the same as in Example 1, except that the derivatization reaction temperature is replaced with 20℃, 25℃ and 35℃, respectively, when preparing sample solution a2.

[0139] The effect of temperature on the derivatization reaction was investigated in Examples 1, 5-7. The test results of NaHS and Na2S in the PPS slurry mother liquor obtained after 12 min of reaction at different derivatization temperatures are shown in Table 12.

[0140] Table 12

[0141]

[0142] As can be seen from the results in Table 12, the derivatization reaction of sodium hydrosulfide and glyoxal increases in rate as the reaction temperature increases. However, too high a temperature can reduce the service life of the instrument and cause loss of glyoxal and water in the sample. As can be seen from the test results in Table 12, the derivatization reaction of sodium hydrosulfide and glyoxal is complete after 12 min at 25°C, and after that, as the derivatization temperature increases, the content of NaHS and Na2S in the PPS slurry mother liquor hardly changes. In order to ensure that the derivatization reaction is complete, there is no loss of substances during derivatization, and the wear of the instrument is minimized, the derivatization temperature is preferably 30°C.

[0143] Examples 8-9

[0144] The detection process is basically the same as in Example 1, except that the flow rate of the mobile phase is replaced by 0.8 mL / min and 1.2 mL / min, respectively.

[0145] Examples 1, 8-9 investigate the effect of flow rate on the test results. The test results of Na2S in the derivatized sample solution a2 under different flow rates are shown in Table 13.

[0146] Table 13

[0147]

[0148] where the response factor = peak area / compound content. As can be seen from the test results in Table 13, as the flow rate increases, the separation degree of the test substance Na2S decreases, the response factor increases slightly, and the tailing factor and theoretical plate number hardly change. The test method is selected to have a high response factor and a high separation degree, and the flow rate is preferably 1.0 mL / min after considering various factors.

[0149] Examples 10-11

[0150] The detection process is basically the same as in Example 1, except that the pH value of the mobile phase B is replaced by 3.0 and 4.0, respectively.

[0151] Example 1, 10-11 The influence of pH of mobile phase B on the test results was investigated. The test results of Na2S in derivatized sample solution a2 under different pH conditions are shown in Table 14.

[0152] Table 14

[0153]

[0154] From the test results in Table 14, it can be seen that as the pH of mobile phase B gradually increases, the response factor of the test substance Na2S decreases, the resolution decreases, the theoretical plate number decreases, and the tailing factor is almost unchanged. On the one hand, the pKa of formic acid is about 3.7, and the buffer capacity of ammonium formate and formic acid buffer solution is the strongest at pH 3.5, on the other hand, low pH mobile phase will reduce the service life of the chromatographic column, in addition, the system indicators such as response factor, resolution, tailing factor and theoretical plate number of the chromatographic peak are not much different when the pH of the mobile phase is 3.0 and 3.5, and considering comprehensively, the pH of the mobile phase B is preferably 3.5.

[0155] Example 12-13

[0156] The detection process is basically the same as in Example 1, except that the column temperature is replaced by 25℃ and 35℃, respectively.

[0157] The influence of column temperature on the test results was investigated. The test results of the sample are shown in Table 15:

[0158] Table 15

[0159]

[0160] From the test results in Table 15, it can be seen that as the column temperature gradually increases, the response factor of Na2S decreases, the resolution decreases, the theoretical plate number decreases, and the tailing factor is almost unchanged. The column temperature of 30℃ is the midpoint of the temperature range, which meets the stability of temperature fluctuation, and is consistent with the derivatization temperature, and considering comprehensively, the column temperature is preferably 30℃.

[0161] Comparative Example 1

[0162] The detection process is basically the same as in Example 1, except that during the derivatization reaction, the glyoxal solution is replaced by a neutral formaldehyde solution, and the blank solution is also replaced by a neutral formaldehyde solution.

[0163] The test results of NaHS and Na2S in PPS slurry mother liquor using different derivatizing agents are shown in Table 16.

[0164] Table 16

[0165]

[0166] From the test results of Table 16, it can be seen that the neutral formaldehyde as the derivatizing agent of the test method not only leads to the chromatographic peaks of NaHS and Na2S in the PPS slurry mother liquor failing to reach the ideal peak shape (the tailing factor is between 0.95-1.05), but also fails to obtain the true content of NaHS and Na2S in the PPS slurry mother liquor. The detection process cannot meet the quantitative test of NaHS and Na2S in the PPS slurry mother liquor.

[0167] Comparative Example 2

[0168] The detection process is basically the same as that of Example 1, except that the mobile phase B is replaced by water.

[0169] Figure 8 The HPLC chromatogram of the control solution a obtained by the detection process in this comparative example is shown in the figure, and the chromatographic peak of the target control solution is not detected. The detection process cannot meet the quantitative test of NaHS and Na2S in the PPS slurry mother liquor.

[0170] Comparative Example 3

[0171] The detection process is basically the same as that of Example 1, except that the mobile phase A is replaced by methanol.

[0172] Figure 9 The HPLC chromatogram of the control solution a obtained by the detection process in this comparative example is shown in the figure, and the retention time of the control solution a is 4.303 min, and the tailing factor is 2.55, which does not meet the requirement that the tailing factor is between 0.95-1.05. Under this detection process, the symmetry of the chromatographic peak is poor, and the quantitative test of NaHS and Na2S in the PPS slurry mother liquor cannot be met.

[0173] Comparative Example 4

[0174] The detection process is basically the same as that of Example 1, except that the mobile phase B is replaced by a water solution of formic acid with pH=3.5.

[0175] Figure 10 The HPLC chromatogram of the control solution a obtained by the detection process in this comparative example is shown in the figure, and the retention time of the control solution a is 4.233 min, and the tailing factor is 8.55, which does not meet the requirement that the tailing factor is between 0.95-1.05. Under this detection process, the symmetry of the chromatographic peak is extremely poor, and the quantitative test of NaHS and Na2S in the PPS slurry mother liquor cannot be met.

[0176] Comparative Example 5

[0177] The detection process is basically the same as that of Example 1, except that the chromatographic column is replaced by C18 (250x4.6mm, 5μm).

[0178] Figure 11 The chromatogram of the control solution a obtained by using the detection process in the present comparative example did not detect chromatographic peaks of NaHS and Na2S. The present detection process cannot meet the quantitative test of NaHS and Na2S in the PPS slurry mother liquor.

[0179] The above examples are the preferred embodiments of the present application, but the embodiments of the present application are not limited to the above examples, and any changes, modifications, substitutions, combinations, simplifications made without departing from the spirit and principles of the present application should be equivalent replacement methods, and are included in the protection scope of the present application.

Claims

1. A method for simultaneous determination of NaHS and Na2S in PPS slurry mother liquor by high performance liquid chromatography, characterized in that, The method comprises the following steps: (1) preparing a sample solution: taking the PPS slurry mother liquor, adding water to constant volume, filtering to obtain a filtrate, and then dividing the filtrate into two parts, one part is added with an equal volume of ultrapure water and is recorded as sample solution a1, and the other part is added with an equal volume of a derivatizing agent for a derivatization reaction and is recorded as sample solution a2; the derivatizing agent is selected from a glyoxal solution; (2) preparing a control solution: taking NaHS and Na2S respectively, dissolving in water, and adding water to constant volume, and then filtering to obtain the control solution; (3) sample injection and detection: the sample solution and the control solution are detected respectively by using a high performance liquid chromatography method, and the contents of NaHS and Na2S in the sample solution are calculated according to an external standard method based on peak areas; the mobile phase used in the high performance liquid chromatography method comprises mobile phase A and mobile phase B, the mobile phase A is selected from acetonitrile, and the mobile phase B is selected from a mixed solution comprising a formic acid ammonium buffer solution, and the pH of the mobile phase B is 3.0-4.0; the elution program of the mobile phase in the high performance liquid chromatography method is as follows: 0-10 min, isocratic elution, the volume fraction of the mobile phase B in the mobile phase is 87-95%; 10-25 min, gradient elution, elution to the volume fraction of the mobile phase B in the mobile phase being 10%; 25-29 min, isocratic elution, the volume fraction of the mobile phase B in the mobile phase is 10%; 29-30 min, gradient elution, elution to the volume fraction of the mobile phase B in the mobile phase being 87-95%; the chromatographic column is a SAX chromatographic column, and the chromatographic column temperature is 25-35℃; the detection wavelength is 210-225 nm.

2. The method for simultaneously determining NaHS and Na2S in PPS slurry mother liquor by high performance liquid chromatography according to claim 1, characterized in that, In step (1): the derivatization reaction is performed at a reaction temperature of 25-35℃ for a reaction time of 10-15 min.

3. The method for simultaneously determining NaHS and Na2S in PPS slurry mother liquor by high performance liquid chromatography according to claim 1, characterized in that, In step (3), the concentration of the mobile phase B in the high performance liquid chromatography method is 15-25 mmol / L.

4. The method for simultaneously determining NaHS and Na2S in PPS slurry mother liquor by high performance liquid chromatography according to claim 1, characterized in that, In step (3), the high performance liquid chromatography method: the flow rate of the mobile phase is 0.8-1.2 mL / min; the injection volume is 5-25 μL.

5. The method for simultaneously determining NaHS and Na2S in a PPS slurry mother liquor by using a high performance liquid chromatography method according to claim 1, characterized in that: in step (1), the filtering is performed by using a PTFE filter membrane; in step (2), the filtering is performed by using a PTFE filter membrane.

6. The method for simultaneously determining NaHS and Na2S in a PPS slurry mother liquor by using a high performance liquid chromatography method according to any one of claims 1-5, characterized in that: 0-10 min, isocratic elution, the volume fraction of the mobile phase A in the mobile phase is 8%, and the volume fraction of the mobile phase B in the mobile phase is 92%; 10-25 min, gradient elution, elution to the volume fraction of the mobile phase A in the mobile phase being 90%, and the volume fraction of the mobile phase B in the mobile phase being 10%; 25-29 min, isocratic elution, the volume fraction of the mobile phase A in the mobile phase is 90%, and the volume fraction of the mobile phase B in the mobile phase is 10%; 29-30 min, gradient elution, elution to the volume fraction of the mobile phase A in the mobile phase being 8%, and the volume fraction of the mobile phase B in the mobile phase being 92%.

7. The method for simultaneously determining NaHS and Na2S in PPS slurry mother liquor by high performance liquid chromatography according to claim 6, characterized in that: the flow rate of the mobile phase is 1.0 mL / min, the pH of the mobile phase B in the mobile phase is 3.5, and the concentration is 20 mmol / L.

8. The method for simultaneously determining NaHS and Na2S in PPS slurry mother liquor by high performance liquid chromatography according to claim 6, characterized in that: the column temperature is 30℃, the detection wavelength is 218 nm, and the injection volume is 20 μL.

9. The method for simultaneously determining NaHS and Na2S in PPS slurry mother liquor by high performance liquid chromatography according to claim 6, characterized in that: the reaction time of the derivatization reaction is 12 min, and the reaction temperature is 30℃.

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