Method for detecting benzene and 1, 2-dichloroethane in activated carbon

Abstract

The invention discloses a method for detecting benzene and 1, 2-dichloroethane in activated carbon and application of the method, aiming at solving the problem that a method for detecting the benzene and the 1, 2-dichloroethane in the activated carbon is lacked at present, and realizing qualitative or quantitative detection of a residual solvent of the benzene or the 1, 2-dichloroethane in the activated carbon so as to ensure the quality of the activated carbon. And the safety of the injection production process is improved. N, N-dimethylformamide or dimethyl sulfoxide is selected as the solvent, so that the toxicity of the test solvent is remarkably reduced. The activated carbon has high adsorption activity on benzene, toluene or ethylbenzene or xylene is used as an internal standard substance for benzene content determination, the desorption effect of N, N-dimethylformamide or dimethyl sulfoxide on activated carbon of different sources is corrected through an internal standard, and the accuracy of a benzene content result can be obviously improved. A headspace sampling method is selected, a mixed solvent of water and N, N-dimethylformamide or dimethyl sulfoxide is used, and the sensitivity of the method is improved through azeotropy of the mixed solvent.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of activated carbon detection, and particularly relates to a method for detecting benzene and 1,2-dichloroethane in activated carbon. BACKGROUND

[0002] Activated carbon can be prepared from various charcoal, various fruit shells and high-quality coal and the like raw materials. If other impurities, especially organic solvents, are mixed in the raw materials during the production of activated carbon, the activated carbon may be adsorbed and retained due to its good adsorption property, and then migrate to the preparation solution during the use of the activated carbon for decolorization. However, the existing detection method for the residual solvents in activated carbon cannot accurately determine and measure, and the existing detection method has low sensitivity. SUMMARY

[0003] To solve the above problems, the present application provides a method for detecting benzene and 1,2-dichloroethane in activated carbon, which is realized by the following technical scheme.

[0004] A method for detecting benzene and 1,2-dichloroethane in activated carbon, comprising the following steps:

[0005] S1, preparation of an internal standard stock solution;

[0006] S2, preparation of a control stock solution;

[0007] S3, determination of specificity, diluting the internal standard stock solution to prepare a blank internal standard solution, diluting the control stock solution and the internal standard stock solution to prepare a control solution, and injecting the prepared blank internal standard solution, control solution and blank solution into a gas chromatograph through headspace sampling for detection;

[0008] S4, determination of the limit of quantification and the limit of detection, diluting the control stock solution to prepare an intermediate stock solution, adding the internal standard stock solution to the intermediate stock solution and diluting to prepare a limit of quantification solution and a limit of detection solution, and injecting the obtained limit of quantification solution and limit of detection solution into the gas chromatograph through headspace sampling for detection;

[0009] S5, determination of linearity and range, mixing and diluting the internal standard stock solution and the control stock solution to prepare a linear working solution, and injecting the linear working solution into the gas chromatograph through headspace sampling for detection;

[0010] S6, accuracy determination, using activated carbon samples to add the linear working solution to prepare a recovery base solution and a spiked recovery test solution, and injecting the recovery base solution and the spiked recovery test solution into the gas chromatograph through headspace sampling for detection;

[0011] S7, the repeatability determination, using activated carbon sample to join the linear working solution to prepare the repeatability test solution, and the repeatability test solution is injected into the gas chromatograph by the way of headspace sampling and detected;

[0012] S8, the benzene and 1,2-dichloroethane determination, the internal standard solution is prepared by diluting the control product stock solution, the test sample solution is prepared by using the activated carbon sample to join the internal standard solution, and the test sample solution is injected into the gas chromatograph by the way of headspace sampling and detected.

[0013] Further, the gas chromatograph adopts DB-WAX chromatographic column, the size of the chromatographic column is 30m*250μm*0.25μm, and the gas chromatograph adopts FID detector.

[0014] Further, the carrier gas in the chromatographic column is any one of nitrogen and helium, the flow rate of the carrier gas is 0.8-2.0ml / min, the initial temperature of the carrier gas is 30-70℃, the holding time is 0-10min, the rate of temperature rise is 10-30℃ / min, and the temperature is raised to 200-250℃.

[0015] Further, the carrier gas is nitrogen, the flow rate of the carrier gas is 1.0ml / min, the initial temperature is 35℃, and the holding time is 9min, then the temperature is raised to 220℃ at the rate of 30℃ / min, and the holding time is 3min.

[0016] Further, the split ratio of the headspace sampling is 5:1-20:1, the equilibrium temperature of the headspace sampling is 75-95℃, the equilibrium time is 10-30min, and the sampling time is 0.5-1.0min.

[0017] Further, the split ratio of the headspace sampling is 10:1, the equilibrium temperature is 80℃, the equilibrium time is 30min, and the sampling time is 1min.

[0018] Further, the volume of the headspace sampling solution is 1-9ml, and the volume of the water added is 9-1ml.

[0019] Further, the volume of the headspace sampling solution is 3ml, and the volume of the water added is 5ml.

[0020] The beneficial effects of the present application are,

[0021] 1. The present invention relates to a method for detecting benzene and 1,2-dichloroethane in activated carbon. The method has strong specificity and employs an internal standard method for determining benzene content and an external standard method for determining 1,2-dichloroethane content. The accuracy of the method is significantly higher than that of existing patents. The present invention can accurately evaluate the benzene and 1,2-dichloroethane contents in activated carbon.

[0022] 2. This invention addresses the lack of sensitivity of existing detection methods by establishing a highly sensitive method for testing benzene and 1,2-dichloroethane in activated carbon. This method meets the Chinese Pharmacopoeia's residual solvent limits for benzene and 1,2-dichloroethane, facilitating the oversight and monitoring of activated carbon safety risks by manufacturers and regulatory authorities. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] In order to more clearly illustrate the technical solution of the present invention, the following is a brief introduction to the drawings required for use in the description of the specific implementation methods. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0024] Figure 1 : A detection flow chart of a method for detecting benzene and 1,2-dichloroethane in activated carbon according to the present invention. DETAILED DESCRIPTION

[0025] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0026] like Figure 1 As shown, the present invention has the following specific embodiments.

[0027] Example:

[0028] A method for detecting benzene and 1,2-dichloroethane in activated carbon comprises the following steps:

[0029] S1. Preparation of internal standard stock solution;

[0030] S2. Preparation of reference substance stock solution;

[0031] S3, specificity determination, take the internal standard stock solution and dilute it to prepare the internal standard solution, take the reference substance stock solution and dilute it to prepare the reference substance solution, and inject the prepared internal standard solution, reference substance solution and blank solution into the gas chromatograph by headspace injection for detection;

[0032] S4, determination of the limit of quantification and the limit of detection, the intermediate stock solution is prepared by diluting the control stock solution, the internal standard stock solution is added to the intermediate stock solution and diluted to prepare the limit of quantification solution and the limit of detection solution, the obtained limit of quantification solution and limit of detection solution are respectively injected into the gas chromatograph for detection by headspace sampling;

[0033] S5, determination of linearity and range, the internal standard stock solution is mixed with the control stock solution and diluted to prepare a linear working solution, the linear working solution is injected into the gas chromatograph for detection by headspace sampling;

[0034] S6, accuracy determination, the recovery blank solution and the spiked recovery test solution are prepared by adding the linear working solution to the activated carbon sample, and the recovery blank solution and the spiked recovery test solution are respectively injected into the gas chromatograph for detection by headspace sampling;

[0035] S7, repeatability determination, the repeatability test solution is prepared by adding the linear working solution to the activated carbon sample, and the repeatability test solution is injected into the gas chromatograph for detection by headspace sampling;

[0036] S8, determination of benzene and 1,2-dichloroethane, the test sample solution is prepared by adding the blank internal standard solution to the activated carbon sample, and the test sample solution is injected into the gas chromatograph for detection by headspace sampling.

[0037] S9, detection method, accurately measure each test solution, add water, cap, seal. Headspace sampling, inject into the gas chromatograph.

[0038] Preferably, the gas chromatograph uses a DB-WAX chromatographic column with a column size of 30m x 250μm x 0.25μm, and the gas chromatograph uses an FID detector.

[0039] Preferably, the carrier gas in the chromatographic column is any one of nitrogen and helium, the flow rate of the carrier gas is 0.8-2.0ml / min, the initial temperature of the carrier gas is 30-70℃, the holding time is 0-10min, the rate of temperature rise is 10-30℃ / min, and the temperature is raised to 200-250℃.

[0040] Preferably, the carrier gas is nitrogen, the flow rate of the carrier gas is 1.0ml / min, the initial temperature is 35℃, and the holding time is 9min, then the temperature is raised to 220℃ at a rate of 30℃ / min and held for 3min.

[0041] Preferably, the split ratio of the headspace injection is 5:1-20:1, the equilibrium temperature of the headspace injection is 75-95℃, the equilibrium time is 10-30 minutes, and the injection time is 0.5-1.0 minutes.

[0042] Preferably, the split ratio of the headspace injection is 10:1, the equilibrium temperature is 80℃, the equilibrium time is 30 minutes, and the injection time is 1 minute.

[0043] Preferably, the precise measurement of each test solution is 1-9 ml, and the volume of water added is 9-1 ml.

[0044] Preferably, the precise measurement of each test solution is 1-9 ml, and the volume of water added is 9-1 ml.

[0045] First, prepare the internal standard stock solution and the reference standard stock solution, and then prepare the blank internal standard solution, the reference standard solution, the limit of quantification solution, the limit of detection solution, the linear working solution, the recovery background solution, the spiked recovery test solution, and the repeatability test solution according to the internal standard stock solution and the reference standard stock solution and the activated carbon sample. Inject the corresponding solutions into the gas chromatograph to determine the specificity, the limit of quantification and the limit of detection, the linearity and range, the accuracy, and the repeatability.

[0046] Example 1

[0047] Specificity

[0048] A method for detecting benzene and 1,2-dichloroethane in activated carbon, comprising: the activated carbon in this embodiment is activated carbon for injection.

[0049] Solvent: N,N-dimethylformamide.

[0050] Internal standard substance: toluene.

[0051] Internal standard stock solution: take an appropriate amount of toluene, accurately weigh and quantitatively dilute with solvent to prepare a solution containing about 10 mg of toluene per 1 ml as the internal standard stock solution.

[0052] Reference standard stock solution: take an appropriate amount of benzene and 1,2-dichloroethane reference standard, accurately weigh and quantitatively dilute with solvent to prepare a solution containing about 10 mg of benzene and 10 mg of 1,2-dichloroethane per 1 ml.

[0053] Blank solution: solvent.

[0054] Blank internal standard solution: accurately measure 0.1 ml of the internal standard stock solution into a 50 ml volumetric flask and dilute to the mark with solvent.

[0055] The control solution was prepared by taking 0.1 ml of the control stock solution and 0.1 ml of the internal standard stock solution into a 50 ml volumetric flask, and diluting to the mark with solvent to obtain a solution containing about 20 μg of benzene, 1,2-dichloroethane and toluene per 1 ml.

[0056] Instrument: Agilent 7890B gas chromatograph and 7697A headspace sampler.

[0057] Chromatographic conditions: DB-WAX chromatographic column (30 m x 250 μm x 0.25 μm) was used; nitrogen was used as the carrier gas, and the carrier gas flow rate was 1.0 ml / min; the programmed temperature was 35°C for 9 min, then increased to 220°C at a rate of 30°C / min, and maintained for 3 min; the injection mode was headspace injection, the equilibrium temperature was 80°C, the equilibrium time was 30 min, the injection port temperature was 230°C, the injection time was 1.0 min, and the split ratio was 10:1; the detector was an FID detector;

[0058] Detection method: 3 ml of the blank solution, the blank internal standard solution and the control solution were precisely taken into a headspace bottle, 5 ml of water was added, the cap was screwed on and the bottle was sealed. The headspace injection was performed, and the gas chromatograph was injected. The results are shown in the table.

[0059] Specificity determination results

[0060]

[0061] Example 2

[0062] Limit of quantification and limit of detection

[0063] The difference between Example 1 and Example 2 is as follows:

[0064] The limit of quantification solution was prepared by taking 0.1 ml of the benzene control stock solution into a 100 ml volumetric flask, and diluting to the mark with solvent to obtain a benzene limit of quantification intermediate stock solution; 1 ml of the 1,2-dichloroethane control stock solution was taken into a 100 ml volumetric flask, and diluting to the mark with solvent to obtain a 1,2-dichloroethane limit of quantification intermediate stock solution; 0.3 ml of the benzene and 1,2-dichloroethane limit of quantification intermediate stock solutions were precisely taken into a 50 ml volumetric flask, 0.1 ml of the internal standard stock solution was added, and the volume was diluted to the mark with solvent to obtain a solution containing about 0.06 μg of benzene, 0.60 μg of 1,2-dichloroethane and 20 μg of toluene per 1 ml, which was used as the limit of quantification solution. 0.1 ml of the benzene and 1,2-dichloroethane limit of quantification intermediate stock solutions were precisely taken into a 50 ml volumetric flask, 0.1 ml of the internal standard stock solution was added, and the volume was diluted to the mark with solvent to obtain a solution containing about 0.02 μg of benzene, 0.2 μg of 1,2-dichloroethane and 20 μg of toluene per 1 ml, which was used as the limit of detection solution. 3 ml of the limit of quantification solution and the limit of detection solution were precisely taken into a headspace bottle, 5 ml of water was added, the cap was screwed on and the bottle was sealed. The headspace injection was performed, and the gas chromatograph was injected.

[0065] Detection method: respectively precision limit solution and detection limit solution 3 ml, placed in the top empty bottle, add water 5 ml, roll cover, seal. Headspace injection, into the gas chromatograph, the results are shown in the table.

[0066] Quantitative limit and detection limit results

[0067]

[0068] Example 3

[0069] Linear and range

[0070] The difference between example 1 and example 2 is that:

[0071] Linear working solution L1: respectively take benzene control product stock solution, 1,2-dichloroethane control product stock solution 0.25 ml, precision take internal standard stock solution 0.1 ml, placed in 50 ml volumetric flask, with solvent quantitative dilution to the scale, make every 1 ml about containing benzene, 1,2-dichloroethane each about 50 ug, internal standard about 20 ug solution.

[0072] Linear working solution L2: respectively take benzene control product stock solution, 1,2-dichloroethane control product stock solution 0.10 ml, precision take internal standard stock solution 0.1 ml, placed in 50 ml volumetric flask, with solvent quantitative dilution to the scale, make every 1 ml about containing benzene, 1,2-dichloroethane each about 20 ug, internal standard about 20 ug solution.

[0073] Linear working solution L3: respectively take benzene control product stock solution, 1,2-dichloroethane control product stock solution 1.0 ml, placed in 10 ml volumetric flask, with solvent quantitative dilution to the scale, precision 0.5 ml, placed in 50 ml volumetric flask, precision take internal standard stock solution 0.1 ml, placed in the same volumetric flask, with solvent dilution to the scale, make every 1 ml about containing benzene, 1,2-dichloroethane each about 10 ug, internal standard about 20 ug solution.

[0074] Linear working solution L4: respectively take benzene control product stock solution, 1,2-dichloroethane control product stock solution 1.0 ml, placed in 10 ml volumetric flask, with solvent quantitative dilution to the scale, precision 0.25 ml, placed in 50 ml volumetric flask, precision take internal standard stock solution 0.1 ml, placed in the same volumetric flask, with solvent dilution to the scale, make every 1 ml about containing benzene, 1,2-dichloroethane each about 5 ug, internal standard about 20 ug solution.

[0075] Linear working solution L5: take 1.0 ml of benzene control stock solution and 1,2-dichloroethane control stock solution respectively, place in a 10 ml volumetric flask, dilute to the mark with solvent, take 0.1 ml accurately, place in a 50 ml volumetric flask, take 0.1 ml of internal standard stock solution accurately, place in the same volumetric flask, dilute to the mark with solvent, prepare a solution containing about 2 μg of benzene and 1,2-dichloroethane and about 20 μg of internal standard per 1 ml.

[0076] Detection method: take 3 ml of linear working solution L1-L5 and the limit of quantification solution under Example 2 respectively, place in a headspace bottle, add 5 ml of water, roll the cap, seal. Headspace injection, inject into a gas chromatograph, take the concentration as the X axis, take the ratio of benzene peak area to toluene peak area as the Y axis, fit the benzene linear equation. Take the concentration as the X axis, take the 1,2-dichloroethane peak area as the Y axis, fit the 1,2-dichloroethane linear equation. The results are shown in the table.

[0077] Linear determination results

[0078] Linear equations Range (μg / ml) Correlation coefficient (R) benzene Y=0.0576X+0.0005 0.067～55.5 0.99999 1,2-Dichloroethane Y=6.3647X-1.0963 0.601～2.002 0.99994

[0079] Example 4

[0080] Accuracy

[0081] The difference from Example 1 is that:

[0082] Low concentration recovery solution: accurately weigh about 0.25 g of activated carbon sample, accurately add 5 ml of L5 linear working solution under Example 3, shake vortex for 60 seconds, centrifuge at 10000 rpm for 10 minutes, prepare 3 parallel samples.

[0083] Medium concentration recovery solution: accurately weigh about 0.25 g of activated carbon sample, accurately add 5 ml of L4 linear working solution under Example 3, shake vortex for 60 seconds, centrifuge at 10000 rpm for 10 minutes, prepare 3 parallel samples.

[0084] High concentration recovery solution: accurately weigh about 0.25 g of activated carbon sample, accurately add 5 ml of L3 linear working solution under Example 3, shake vortex for 60 seconds, centrifuge at 10000 rpm for 10 minutes, prepare 3 parallel samples.

[0085] Recovery blank solution: accurately weigh about 0.25 g of activated carbon sample, accurately add 5 ml of blank internal standard solution, shake vortex for 60 seconds, centrifuge at 10000 rpm for 10 minutes.

[0086] Detection method: Respectively, precision take recovery background solution and standard addition recovery test solution each 3 ml, in the top empty bottle, add water 5 ml, roll cover, seal. Headspace injection, into the gas chromatograph, with the linear equation of example 3 linear and range item to calculate the recovery background solution and each concentration standard addition solution concentration, recovery rate calculation formula as follows, the results are shown in the table.

[0087]

[0088] Benzene recovery rate

[0089]

[0090] 1,2-Dichloroethane recovery rate

[0091]

[0092]

[0093] Example 5

[0094] Repeatability

[0095] The difference from example 1 is that:

[0096] Repeatability test solution: precision take about 0.25 g of activated carbon sample, precision add 5 ml of L4 linear working solution under the linear item of example 3, shake vortex 60 seconds, centrifuge 10 minutes at 10000 revolutions per minute, prepare 6 copies in parallel.

[0097] Detection method: Respectively, precision take supernatant of repeatability test solution each 3 ml, in the top empty bottle, add water 5 ml, roll cover, seal. Headspace injection, into the gas chromatograph, with the linear equation of example 3 linear and range item to calculate the solution repeatability results, the results are shown in the table.

[0098] Repeatability determination results

[0099]

[0100] Example 6

[0101] Application of benzene and 1,2-dichloroethane determination

[0102] The difference from example 1 is that:

[0103] Test solution: precision take about 0.25 g of activated carbon sample, precision add 5 ml of blank internal standard solution, shake vortex 60 seconds, centrifuge 10 minutes at 10000 revolutions per minute.

[0104] Detection method: precisely pipette 3 ml of the supernatant of the test sample solution into a headspace bottle, add 5 ml of water, roll the cap, seal. Inject the headspace into a gas chromatograph, calculate the content of benzene and 1,2-dichloroethane in the activated carbon sample by the linear equation in the linear range item of Example 3, the calculation formula is as follows, and the results are shown in the table.

[0105]

[0106] Determination results of benzene and 1,2-dichloroethane (%)

[0107] Sample 1 Sample 2 Sample 3 Sample 4 Sample 5 Sample 6 benzene Not detected 0.01 0.02 0.03 0.003 0.08 1,2-Dichloroethane Not detected Not detected Not detected Not detected 0.05 Not detected

[0108] The preferred embodiments of the present application disclosed above are only used to help explain the present application. The preferred embodiments do not describe all the details and limit the present application to the specific embodiments. Obviously, many modifications and variations can be made according to the content of the present application. The present application is selected and specifically described in order to better explain the principles and practical applications of the present application, so that those skilled in the art can well understand and utilize the present application. The present application is limited by the claims and their full scope and equivalents.

Claims

1. A method for detecting benzene and 1,2-dichloroethane in activated carbon, characterized in that: The following steps are involved: S1. Preparation of internal standard stock solution; S2. Preparation of reference substance stock solution; S3. Determination of specificity: dilute the internal standard stock solution to prepare a blank internal standard solution, and dilute the reference substance stock solution and the internal standard stock solution to prepare a reference substance solution. The prepared blank internal standard solution, reference substance solution, and blank solution are injected into a gas chromatograph by headspace injection for detection; S4, determination of the limit of quantitation and the limit of detection, preparing an intermediate stock solution by diluting the reference substance stock solution, adding the internal standard stock solution to the intermediate stock solution and diluting the solution to prepare a limit of quantitation solution and a limit of detection solution, and injecting the obtained limit of quantitation solution and limit of detection solution into a gas chromatograph by headspace injection for detection; S5, linearity and range determination, mixing and diluting the internal standard stock solution and the reference substance stock solution to prepare a linear working solution, and injecting the linear working solution into a gas chromatograph by headspace injection for detection; S6. Accuracy determination: using the activated carbon sample to add the linear working solution to prepare a recovery background solution and a spiked recovery test solution, the recovery background solution and the spiked recovery test solution are respectively injected into a gas chromatograph by headspace injection for detection; S7, repeatability determination, using the activated carbon sample to add the linear working solution to prepare a repeatability test solution, and injecting the repeatability test solution into the gas chromatograph by headspace injection for detection; For the determination of S8, benzene and 1,2-dichloroethane, the activated carbon sample was added with the internal standard solution to prepare the test solution, and the test solution was injected into the gas chromatograph by headspace injection for detection. S9. Preparation of headspace injection solution: Add water to each test solution to prepare headspace injection solution, roll-cap the headspace injection solution, seal it, and then inject the headspace into the gas chromatograph.

2. The method for detecting benzene and 1,2-dichloroethane in activated carbon according to claim 1, wherein: The gas chromatograph adopts a DB-WAX chromatographic column with a column size of 30m×250μm×0.25μm, and the gas chromatograph adopts a FID detector.

3. The method for detecting benzene and 1,2-dichloroethane in activated carbon according to claim 2, wherein: The carrier gas in the chromatographic column is any one of nitrogen and helium, the flow rate of the carrier gas is 0.8-2.0 ml / min, the starting temperature of the carrier gas is 30°C-70°C, the holding time is 0-10 min, and the heating rate is 10°C / min-30°C / min, so that the temperature is raised to 200°C-250°C.

4. The method for detecting benzene and 1,2-dichloroethane in activated carbon according to claim 3, wherein: The carrier gas was nitrogen, the carrier gas flow rate was 1.0 ml / min, the initial temperature was 35° C., maintained for 9 minutes, then heated to 220° C. at 30° C. / min and maintained for 3 minutes.

5. The method for detecting benzene and 1,2-dichloroethane in activated carbon according to claim 1, wherein: The split ratio of the head space injection is 5:1 to 20:1, the equilibrium temperature of the head space injection is 75° C. to 95° C., the equilibrium time is 10 min to 30 min, and the injection time is 0.5 min to 1.0 min.

6. The method for detecting benzene and 1,2-dichloroethane in activated carbon according to claim 5, wherein: The split ratio of the headspace injection was 10:1, the equilibrium temperature was 80° C., the equilibrium time was 30 min, and the injection time was 1 min.

7. The method for detecting benzene and 1,2-dichloroethane in activated carbon according to claim 1, wherein: The headspace sampling solution is precisely measured to a volume of 1-9 ml of each test solution, and the volume of water added is 9-1 ml. The cap is rolled and sealed. Headspace sampling.

8. The method for detecting benzene and 1,2-dichloroethane in activated carbon according to claim 6, wherein: For the headspace sampling solution, precisely measure each test solution to a volume of 3 ml and add water to a volume of 5 ml. Cap the tube and seal.

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