CN115201382A - Method for detecting sample containing diaminotoluene - Google Patents
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Abstract
The invention relates to the field of detection, in particular to a method for detecting a sample containing diaminotoluene. The detection method provided by the invention comprises the following steps: dissolving a sample containing diaminotoluene by using an organic solvent to obtain a sample to be detected, and detecting; wherein the sample containing diaminotoluene is in a non-molten state. The method provided by the invention does not need to heat or melt the sample containing diaminotoluene, has low pollution and high detection speed. Experiments show that samples containing diaminotoluene are successfully detected by the detection method provided by the invention, and Measurement System Analysis (MSA) is carried out on the detection results, the Standard Deviation (SD) and the research variation (SV%) of the detection method provided by the invention are obviously reduced, the precision and the stability of the analysis results are improved compared with the existing detection method, the analysis time is greatly shortened, diaminotoluene steam pollution is avoided, and the occupational health of inspectors is ensured.
Description
Technical Field
The invention relates to the field of detection, in particular to a method for detecting a sample containing diaminotoluene.
Background
Diaminotoluene (TDA) has a melting point of 99 ℃, exists in a liquid form in the production process, samples are taken by a liquid sampling method during inspection, the samples are brought into a laboratory to be solidified, sand bath heating is needed in the laboratory, a needle head is generally inserted into a plug of a sampling bottle to be communicated with the atmosphere in order to avoid the pressure bearing and bursting of the bottle during the heating process, and thus TDA steam can be volatilized into the laboratory. Because TDA is the main materials of dyestuff, its permeability is extremely strong, is polluted by TDA and can causes regional yellow gradual blacking, and along with TDA's infiltration diffusion, the contaminated area can constantly enlarge moreover, even heat in the fume chamber, the contaminated area also can diffuse wall and whole room.
Diaminotoluene has irritant effects on mucous membranes, respiratory tracts and skin, and can cause poisoning by inhalation, ingestion or percutaneous absorption, and also can cause eczema and erysipelas-like crust. The poisoning is manifested by bronchitis, tracheitis, asthma, etc.; IARC carcinogenicity review: people may be carcinogenic, so laboratory environments contaminated with TDA are extremely hazardous to laboratory personnel. Therefore, it is necessary to reduce or even avoid TDA contamination of the laboratory, and it is a major problem in the industry.
Disclosure of Invention
In view of the above, the technical problem to be solved by the present invention is to provide a method for detecting a sample containing diaminotoluene, which does not require heating or melting of the sample containing diaminotoluene, and has low contamination and high detection speed.
The invention provides a method for detecting a sample containing diaminotoluene, which comprises the following steps: dissolving a sample containing diaminotoluene by using an organic solvent to obtain a sample to be detected, and detecting; wherein the sample containing diaminotoluene is in a non-molten state.
According to the method, firstly, a sample containing diaminotoluene is dissolved by using an organic solvent to obtain a sample to be detected, wherein the sample containing diaminotoluene is in a non-molten state. Specifically, a sample containing diaminotoluene is dissolved in an organic solvent within 0min to 5min to obtain a sample to be tested, and the sample containing diaminotoluene is in a non-molten state. The sample containing diaminotoluene is in a liquid state or a solid-liquid mixed state.
The sample containing the diaminotoluene is a relatively common industrial diaminotoluene product, contains various isomers, exists in a liquid state in the production process, can be solidified into a solid at normal temperature, and is detected by heating and melting the sample in the prior art.
The sample containing diaminotoluene begins to solidify at normal temperature, and the shorter the time for dissolving the sample with the organic solvent, the better the sample containing diaminotoluene is, so as to avoid the sample containing diaminotoluene being difficult to dissolve completely after solidification. In the invention, a sample containing diaminotoluene is dissolved in an organic solvent within 0min to 5min, preferably within 0min to 1 min.
The method selects the organic solvent with stable property to dissolve the sample containing the diaminotoluene, and the organic solvent is stable at normal temperature or under heating, does not change and is not easy to react with other substances in the system. The organic solvent is at least one selected from dichloromethane, methanol, absolute ethyl alcohol, acetone, N-dimethylformamide and dimethyl sulfoxide, and is preferably selected from dichloromethane.
The present invention employs a volume of the organic solvent to dissolve a volume of sample containing diaminotoluene. The volume ratio of the diaminotoluene-containing sample to the organic solvent is 5 to 15.
According to the invention, after a sample containing diaminotoluene is dissolved by an organic solvent to obtain a sample to be detected, the sample to be detected is detected. Specifically, the method detects the sample to be detected, and corrects the detection result of the sample to be detected to obtain the detection result of the sample containing diaminotoluene; the correction processing method comprises a correction factor method or a background deduction method; the correction factor method comprises an internal standard method, an external standard method or a normalization method; the detection method comprises chromatography, polarography and Karl Fischer method.
After a sample containing diaminotoluene is dissolved by an organic solvent to obtain a sample to be detected, detecting the sample to be detected by adopting a gas chromatography to obtain a detection result of the sample to be detected; detecting the standard sample to obtain a correction factor; and correcting the detection result of the sample to be detected through the correction factor.
Specifically, after a sample containing diaminotoluene is dissolved by an organic solvent to obtain a sample to be detected, setting the working conditions of a gas chromatograph, and injecting the sample to be detected into the gas chromatograph according to the sample injection amount of 0.5-1.0 muL to carry out detection to obtain the detection result of the sample to be detected; injecting a standard sample into the gas chromatograph according to the same sample injection amount as the sample to be detected for detection to obtain a detection result of the standard sample; obtaining a correction factor through the detection result of the standard sample, and correcting the detection result of the sample to be detected through the correction factor to obtain the detection result of the sample containing diaminotoluene; the chromatographic column of the gas chromatograph is a capillary chromatographic column, and the carrier gas of the gas chromatograph is N 2 (ii) a The chromatographic column of the gas chromatograph is HP-5 (Crosslinked 5% PH ME Siloxane), and the specification of the chromatographic column is 30m multiplied by 0.32mm multiplied by 0.25 mu m.
When the gas chromatography is adopted to detect the sample to be detected, the working conditions of the hue chromatograph can be changed according to different detection items. When the invention carries out component determination on the sample containing diaminotoluene, the working conditions of the gas chromatograph are as follows: the temperature of a sample inlet is 230-270 ℃, and preferably 240-260 ℃; the temperature of the detector is 280-320 ℃, preferably 290-310 ℃; the column front pressure is 8psi to 12psi; the column flow rate is 1.5 mL/min-2.0 mL/min; the auxiliary airflow speed is 25 mL/min-35 mL/min; the hydrogen flow rate is 25 mL/min-35 mL/min; the air flow rate is 300 mL/min-500 mL/min; the split ratio is 40 to 60:1, preferably 45 to 55:1; the gas chromatograph adopts programmed heating, and the programmed heating comprises the following steps: the initial temperature is 90-110 ℃ for 0 min-1 min, the temperature is increased to 120-140 ℃ at the speed of 8-11 ℃/min for 3 min-7 min, and the temperature is increased to 265-285 ℃ at the speed of 27-33 ℃/min for 1 min-3 min.
When the invention is used for measuring the tar content in the sample containing diaminotoluene, the working conditions of the gas chromatograph are as follows: the temperature of the injection port is 290-330 ℃, and the preferred temperature is 300-320 ℃; the temperature of the detector is 290-330 ℃, preferably 300-320 ℃; the front column pressure is 8psi to 12psi; the column flow rate is 1.5-mL/min-2.0 mL/min; the auxiliary airflow speed is 25 mL/min-35 mL/min; the hydrogen flow rate is 25 mL/min-35 mL/min; the air flow is 300 mL/min-500 mL/min; the split ratio is 20 to 40:1, preferably 29 to 39:1; the gas chromatograph adopts programmed heating, and the programmed heating comprises the following steps: the initial temperature is maintained at 90-110 ℃ for 0-1 min, the temperature is raised to 240-260 ℃ at the speed of 13-16 ℃/min for 0-1 min, and the temperature is raised to 270-290 ℃ at the speed of 1.5-3.5 ℃/min for 8-12 min.
The sample to be detected is detected by adopting a gas chromatography, and the selection of the standard sample is different according to the content of ortho-position isomers in the sample containing diaminotoluene. When the content of ortho-isomer (OTD) of the sample containing diaminotoluene is 0% -5%, the standard sample is obtained by dissolving the following components in 100mL of the organic solvent by mass: 0.005 g to 0.015 g, 2.0 to 3.0g of 2.4-TDA, 0.5 to 1.0g of 2.6-TDA and 0.020 to 0.030 g of 3.4-TDA. When the content of ortho-isomer (OTD) of the sample containing diaminotoluene is 5% -100%, the standard sample is obtained by dissolving the following mass composition in 100mL of the organic solvent: 0.020 g to 0.030 g, 2.0 to 3.0g of 2.4-TDA, 0.5 to 1.0g of 2.6-TDA, and 2.0 to 3.0g of 3.4-TDA.
The method adopts the gas chromatography to detect the sample to be detected, and corrects the detection result of the sample to be detected through the correction factor to obtain the detection result of the sample containing diaminotoluene. In the detection result of the sample to be detected, each component has its own correction factor. The invention adopts a normalization method to correct the detection result of the sample to be detected, and specifically comprises the following steps: the correction factor of each component in the detection result of the sample to be detected is obtained by dividing the self percentage of each component in the detection result of the standard sample by the self characteristic peak area percentage; and the detection result of the sample to be detected is corrected by multiplying the correction factor of each component by the characteristic peak area percentage of each component.
After a sample containing diaminotoluene is dissolved by an organic solvent to obtain a sample to be detected, detecting the sample to be detected by adopting a polarography to obtain a detection result of the sample to be detected; detecting the standard sample to obtain a standard curve; and correcting the detection result of the sample to be detected through the standard curve.
Specifically, after a sample containing diaminotoluene is dissolved by an organic solvent to obtain a sample to be detected, the sample to be detected is diluted by DMF, the DMF and a buffer solution are mixed according to a volume ratio of 50; and detecting the standard sample by using the same method, obtaining a standard curve by using an external standard method, obtaining a correction factor by calculating the reciprocal of the slope of the standard curve, and correcting the detection result of the sample to be detected by using the correction factor to obtain the detection result of the sample containing the diaminotoluene. The measurement conditions of the polarograph are as follows: the dropping rate of mercury is 1-3 drops/s; the nitrogen blowing time is 500s to 800s; the scanning range is + 0.1V-1.0V.
The pH of the buffer solution is 3~5, preferably 4. The preparation method of the buffer solution comprises the following steps: adding 400 mL-600 mL of high-purity water, 1.5 mL-2.0 mL of acetic acid, 2 mL-2.5 mL of 86% phosphoric acid, 1.6 g-2.3 g of boric acid and 30-50 mL of 1mol/L sodium hydroxide solution into a 1.0L volumetric flask, diluting to a scale mark with high-purity water, and shaking uniformly. The standard sample comprises the following components by mass: 20 g-40 g TDA;1 g to 5g of dinitrotoluene; 1 g to 10 g of dimethylformamide and 58 g to 78 g of water.
According to the method, after a sample containing diaminotoluene is dissolved by an organic solvent to obtain a sample to be detected, the sample to be detected and the organic solvent are detected by a Karl Fischer method, and the detection result of the sample to be detected is corrected according to the detection result of the organic solvent.
Specifically, after a sample containing diaminotoluene is dissolved by an organic solvent to obtain a sample to be detected, a Karl-type furnace with set working conditions is used for detecting the moisture content of the sample to be detected, the moisture content of the organic solvent is continuously detected, and the detection result of the sample to be detected is subtracted from the detection result of the organic solvent through calculation to obtain the detection result of the sample containing diaminotoluene. The working conditions of the Karl furnace are as follows: high-purity nitrogen with the content of more than or equal to 99.999 percent is adopted, the flow rate of a rotor flow meter is 0 mL/min-1000 mL/min, the concentration of the Karl reagent is 3 mg/mL or 5mg/mL, and the set heating temperature of the Karl furnace is 100-150 ℃, preferably 110 ℃.
After a sample containing diaminotoluene is dissolved by an organic solvent to obtain a sample to be measured, firstly setting the working conditions of a Karschner furnace, opening a nitrogen valve, adjusting the flow of a flow purging gas circuit of a rotor flow meter for 10min to 20 min, and adding 30mL of anhydrous methanol into an evacuated measuring cup for pre-titration; weighing the mass of an empty sampling bottle, adding a sample to be tested into the sampling bottle, and weighing the mass of the sampling bottle added with the sample to be tested; putting the sampling bottle added with the sample to be detected into a sample tray of a Karl Fischer furnace for detecting the water content to obtain a detection result of the sample to be detected; detecting the moisture content of the organic solvent by the same method to obtain a detection result of the organic solvent; and deducting the detection result of the organic solvent from the detection result of the sample to be detected through calculation to obtain the detection result of the sample containing the diaminotoluene.
The invention provides a method for detecting a sample containing diaminotoluene, which comprises the following steps: dissolving a sample containing diaminotoluene by using an organic solvent to obtain a sample to be detected, and detecting; wherein the sample containing diaminotoluene is in a non-molten state. The method provided by the invention does not need to heat or melt the sample containing diaminotoluene, has low pollution and high detection speed. Experiments show that samples containing diaminotoluene are successfully detected by the detection method provided by the invention, and Measurement System Analysis (MSA) is carried out on the detection results, the Standard Deviation (SD) and the research variation (SV%) of the detection method provided by the invention are obviously reduced, the precision and the stability of the analysis results are improved compared with the existing detection method, the analysis time is greatly shortened, diaminotoluene steam pollution is avoided, and the occupational health of inspectors is ensured.
Drawings
FIG. 1 is a graph showing the compositional determination of a TDA sample;
FIG. 2 is a polar diagram of dinitrotoluene measurement of TDA material.
Detailed Description
The invention discloses a method for detecting a sample containing diaminotoluene. Those skilled in the art can modify the process parameters appropriately to achieve the desired results with reference to the disclosure herein. It is expressly intended that all such similar substitutes and modifications which would be obvious to one skilled in the art are deemed to be included in the invention. While the methods and applications of this invention have been described in terms of preferred embodiments, it will be apparent to those of ordinary skill in the art that variations and modifications in the methods and applications described herein, as well as other suitable variations and combinations, may be made to implement and use the techniques of this invention without departing from the spirit and scope of the invention.
The invention is further illustrated by the following examples:
example 1
1 clean, high temperature resistant 30mL special sample vial was prepared, analytically pure methylene chloride reagent and disposable 10mL syringe.
Sampling on a semi-closed sampling system, wherein the specific operation method comprises the following steps: screwing a special sampling bottle onto the sampling point takes a sample which occupies one third of the volume of the special sampling bottle, namely about 10mL of sample.
After the sampling is finished, taking down the sampling bottle, screwing on the bottle cap with the rubber mat, extracting 10mL of dichloromethane by using an injector and injecting the dichloromethane into the sampling bottle, enabling the total amount of liquid in the special sampling bottle to reach about two thirds of the volume of the bottle, shaking up and dissolving, pasting a label, putting the sample into a clean special sample conveying box and bringing the sample into a laboratory. Before the sample box is taken into a laboratory, the outer wall of the sample box is ensured to be free from material pollution, otherwise, the sample box can be taken into the laboratory after being wiped by a clean rag; and putting the sample into a special ventilation cabinet for TDA samples to be detected after the sample enters a laboratory.
Example 2
The components of the TDA sample obtained above were measured by gas chromatography, and the order of appearance of peaks was: toluidine, 2,3-TDA and 3,4-TDA (ortho isomer of diaminotoluene, i.e., ortho-toluenediamine, abbreviated as OTD in English), 2,5-TDA, 2,4-TDA and 2,6-TDA (meta-isomer of diaminotoluene, i.e., meta-toluenediamine, abbreviated as MTD in English) were quantified by the normalization method. The method is suitable for measuring toluidine, OTD and MTD in TDA materials.
Preparing pure dichloromethane as a reagent, and taking o-toluidine, m-toluidine, p-toluidine, 2.4-TDA, 2.6-TDA and 3.4-TDA as reference reagents; the instrument was prepared as follows: a gas chromatograph equipped with FID and split/no-split sample inlets, the gas chromatograph equipped with 30m 0.32mm 0.25 μm specification HP-5 (Crosslinked 5% PH ME Siloxane) capillary chromatography column and 10 μ L microsyringe; the chromatographic conditions were as follows:
column temperature: initial temperature 100 ℃, initial holding time: 0. the heating rate is as follows: 10 ℃/min, final temperature: 130 ℃ and final temperature holding time: 5min, heating rate: 30 ℃/min, final temperature: 275 ℃ and final temperature holding time: 2 min, injection port temperature: 250 ℃, detector temperature: 300 ℃, pre-column pressure: 10psi, carrier gas: n is a radical of 2 Column flow rate: 1.8mL/min, flow rate of auxiliary gas: 30mL/min, hydrogen flow: 30mL/min, air flow: 400mL/min, split ratio: 50:1
Preparing a standard sample according to the components of the standard sample shown in the table 1, wherein the standard sample A is used for measuring a sample with low content of ortho-position isomer; standard sample B was used for samples with high amounts of ortho isomers. The prepared standard sample is added with 100mL dichloromethane for dissolution, and the percentage content of each component (not containing dichloromethane) is calculated according to the total mass:
TABLE 1
The components of the TDA sample obtained above were measured according to the following procedure:
1) Setting the conditions of a gas chromatograph according to the chromatographic conditions;
2) The TDA sample obtained above 8-10 drops were taken and placed in a glass vial, 10mL of the methylene chloride described in this example was added to dissolve the sample, and the mixture was mixed to obtain a dissolved sample.
3) 0.6 μ L of the dissolved sample was injected into a gas chromatograph.
4) The same procedure was followed as for the standard.
The component measurement results of the TDA sample are obtained according to the steps, and as shown in FIG. 1, FIG. 1 is a component measurement diagram of the TDA sample; the results were calculated as follows:
calculation of response factor: f i =M i /A i (ii) a The percentage content of the components is calculated as follows: x i =F i ×A i ；
In the formula: a. The i Is the area percentage of the i component in the standard sample;
F i a response factor that is a component i;
M i is the percentage content of the component i in the standard sample;
A i is the area percentage of the i component;
X i is the percentage content of the component i.
Example 3
The tar in the TDA sample obtained above is measured by gas chromatography, and the peak appearance sequence is as follows: toluidine, TDA, tar were quantified by calibration normalization.
Preparing chromatographically pure dichloromethane; the instrument was prepared as follows: a gas chromatograph equipped with a 30m 0.32mm 0.25 μm standard HP-5 (Crosslinked 5% PH ME Siloxane) capillary chromatography column and a 10 μ L microsyringe; the chromatographic conditions were as follows:
column temperature: initial temperature 100 ℃ and initial holding time: 0. the heating rate is as follows: 15 ℃/min, final temperature: 250 ℃ and final temperature holding time: 5min, heating rate: 2.5 ℃/min, final temperature: 280 ℃ and final temperature holding time: 10min, injection port temperature: 310 ℃ and detector temperature: 310 ℃ and pre-column pressure: 10psi, carrier gas: n is a radical of 2 Column flow rate: 1.8mL/min, assist gas flow rate: 30mL/min, hydrogen flow: 30mL/min, air flow: 400mL/min, split ratio: 26:1
The tar in the TDA sample obtained above was measured according to the following procedure:
(1) Setting the conditions of a gas chromatograph according to the chromatographic conditions;
(2) The TDA sample obtained above 8-10 drops were taken and placed in a glass vial, 10mL of the methylene chloride described in this example was added to dissolve the sample, and the mixture was mixed to obtain a dissolved sample.
(3) And injecting 1.0 muL of the dissolved sample to a gas chromatograph to obtain a measurement result.
(4) The same procedure was followed as described for the standard in example 1.
The results were calculated as follows:
calculation of response factor: f i =M i /A i ；
The percentage content of the components is calculated as follows: x i =F i ×A i ；
In the formula: a. The i Is the area percentage of the i component in the standard sample;
F i a response factor that is a component i;
M i is the percentage content of the component i in the standard sample;
A i is the area percentage of the i component;
X i is the percentage content of the component i.
Example 4
The trace water in the TDA sample is measured by adopting a Karl furnace-Karl Fischer combination method, and the principle is that the moisture in the TDA sample or the mixture of TDA and ODCB is measured at a certain temperatureDistilled off, charged with nitrogen (N) 2 ) As a carrier, carrying the carrier into a Karl Fischer titration cup for titration; the method is suitable for measuring the moisture in TDA and TDA/ODCB, and the content range is 0-0.75%.
The instruments and reagents required are as follows: karl fischer instrument: a cassette furnace-Karl Fischer titrator combination, high-purity nitrogen gas: not less than 99.999%, rotor flow meter: 0-1000 mL/m, anhydrous methanol: analytical pure, karl reagent: 3 or 5mg/mL.
The experimental procedure was as follows:
1) Turning on a Karl Fischer instrument power supply and a Karl Fischer furnace power supply, and setting the heating temperature to be 110 ℃;
2) Opening a nitrogen valve, and adjusting the rotor flow meter to enable the flow rate to reach 60 mL/min to purge the gas circuit for 10 minutes;
3) Adding 30mL of anhydrous methanol into the emptied measuring cup, and starting pre-titration;
4) Weighing empty sampling bottle mass m 0 Weighing the mass m of the resample bottle 1 ；
5) 2g (accurate to 0.0002 g) of sample is weighed by a syringe and injected into a sample bottle special for a dry Karl furnace;
6) Putting the sample bottles in the step 5) into a sample tray of a Karl-type furnace;
7) Setting a Karl Fischer analyzer to determine the water content x in the sample 1 ；
8) 2g (to the nearest 0.0002 g) of methylene chloride was weighed into a dry sample bottle dedicated to the Karl oven using a syringe;
9) Putting the sample bottle into a sample tray of a Karl-type furnace;
10 Set a Karl Fischer analyzer, measure the water content x of the dichloromethane, and calculate to obtain the result.
After the analysis is finished, immediately cleaning the special sample bottle for the Ka-shi furnace by using dichloromethane, drying the special sample bottle in a 110 ℃ drying oven, and putting the special sample bottle into a dryer for later use; the sample bottle cap is cleaned by dichloromethane, wiped by clean filter paper and put into a dryer for standby.
The results were calculated as follows:
x={( m 1 - m 0 )* x 1 -13.25* x 0 )} / ( m 1 - m 0 -13.25)；
in the formula: x is the water content in the TDA sample, mg/kg;
x 0 water content in dichloromethane, mg/kg;
x 1 the water content in the sample, mg/kg, was determined for the Karl furnace;
m 0 weighing the mass g of an empty sampling bottle;
m 1 weighing the mass g of a heavy sampling bottle;
the number 13.25 is the mass of 10mL of dichloromethane, g;
example 5
Polarography is adopted to carry out polarography on reducible substance (-NO) in TDA sample obtained in the way 2 ) The measurement is carried out according to the principle that the amount of dinitrotoluene in a sample is represented by the increase value of electrode potential measured by a polarograph, and the content of dinitrotoluene is calculated according to the increase value of polarographic wave height; suitable for the determination of low concentrations of Dinitrotoluene (DNT) in TDA or solutions thereof.
The following instruments and reagents were prepared: a polarograph, high-purity nitrogen, volumetric flasks of 10mL and 100mL, and sample injectors of 100 muL and 1000 muL; dimethylformamide (DMF), analytically pure, high purity water, dinitrotoluene, oxygen adsorbent (triton X-100), and buffer solution with pH of 4; the preparation method of the buffer solution with the pH of 4 comprises the following steps: to a 1.0L volumetric flask were added about 500mL of high purity water, 1.83mL of acetic acid, 2.15mL of 86% phosphoric acid, 1.98g of boric acid and 40mL of 1mol/L sodium hydroxide solution, diluted to the mark with high purity water, and shaken well.
Obtaining a DNT correction factor F by:
(1) The following components were weighed: 30g of TDA (a mixture of 2.4-TDA and 2.6-TDA in a mass ratio of 80: 20), 65g of high purity water, 2.0g of DNT and 3.0g of DMF, and the total weight of the weighed raw materials is 100g, and 2.0% of DNT correction mother liquor is prepared by weighing the raw materials to be accurate to 0.1 mg.
(2) And (2) weighing 0.5g, 1.0g, 2.0g, 3.0g and 5.0g of the DNT correction mother liquor prepared in the step (1), wherein the weighing needs to be accurate to 0.1mg, diluting the DNT correction mother liquor to 100mL by using DMF respectively, and weighing respectively to prepare the DNT standard series liquid. Calculating the DNT content in the DNT standard series liquid according to the following formula:
X(mg/kg)=m×c×10000/(m+m 1 )
in the formula:
x is DNT standard series concentration, mg/kg;
c is the concentration of DNT mother liquor,%;
m is the mass of DNT mother liquor, g;
m 1 mass of DMF, g.
(3) The prepared DNT standard series liquid was subjected to measurement according to the sample analysis procedure, and the wave height (. Mu.A) values of-0.5V, -0.7V, -0.85V were recorded.
(4) The amount of DNT measured, a, was calculated according to the following formula, in μ g:
A=X×m
in the formula:
a is the measured mass of DNT, μ g;
x is the concentration of DNT standard, mg/kg;
m is the mass of the DNT standard, g.
(5) A standard curve was obtained by plotting the amount of DNT A (. Mu.g) against the total wave height H.
(6) The inverse of the slope of the standard curve was calculated to give the DNT correction factor F in μ g/μ a.
Reducible substance (-NO) in the TDA sample obtained as described above was subjected to the following procedure 2 ) And (3) carrying out measurement:
(1) Ensuring that the sample is uniformly mixed, and if solids appear, placing the sample in a water bath for heating and melting, and uniformly mixing.
(2) Weighing empty sampling bottle mass m 0 Weighing the mass m of the heavy sampling bottle 1 ；
(3) 0.8g of sample is weighed into a 10mL volumetric flask using a 1mL syringe and diluted to the mark with DMF.
(4) A10 mL mixed solution of DMF at a volume ratio of 50.
(5) And sucking the 500 mu L of well-treated sample by using a sample injector, and adding the sample into a polarographic pool.
(6) Setting the measurement conditions of a polarograph, wherein the measurement conditions comprise that mercury dropping is carried out in a mercury dropping mode of 2 drops/s, nitrogen blowing time is 600s, and the scanning range is +0.1V to-1.0V.
(7) Testing under the conditions in the step (6), repeatedly measuring for 2 times, and respectively recording the polarographic wave height (mu A) measured at-0.5V, 0.7V and 0.85V; the results are shown in FIG. 2, and FIG. 2 is a polar spectrum of dinitrotoluene in TDA material; record the polarographic wave height, μ A, measured at-0.5V, -0.7V, -0.85V.
The results were calculated as follows:
(1) The DNT wave height is measured, and the calculation formula is as follows: h = H 1 +h 2 +h 3 ；
(2) Calculating the DNT content, wherein the calculation formula is as follows: x = (H × F/m) × { (m) 1 -m 0 )/(m 1 -m 0 -13.25)}；
In the formula: h is DNT polarographic wave height and the unit is uA; h is 1 The polarographic wave height measured at-0.5V is in units of muA; h is 2 The agent spectrum wave height measured under-0.7V is measured in the unit of mu A; h is 3 The polarographic wave height measured at-0.85V, unit is muA; x is the DNT content in the sample, and the unit is mg/kg; f is a DNT correction factor and has the unit of mu g/mu A; m is the sample mass, and the unit is g; m is a unit of 0 Weighing the mass of an empty sampling bottle in unit of g; m is 1 Weighing the mass of a heavy sampling bottle in g;13.25 is the mass of 10mL of dichloromethane in g.
Example 6
The reducible DNT (unhydrogenated-NO) was carried out on the filtered sample of the DNT hydrogenation reaction using the method of the present invention and the method of the prior art, respectively 2 ) The results of the analysis of tar and DNT are shown in table 2, and table 2 is a comparison of the sample analysis data after DNT hydrogenation filter. Wherein the prior art method is as follows:
(1) sampling and sample pretreatment: sampling about 100g by using a 150mL high-temperature-resistant glass bottle, placing the sample on a sand bath at 140 ℃ in a laboratory for melting and shaking up to obtain a melted and uniformly mixed sample solution, and inserting two needles into a bottle cap to prevent the glass bottle from cracking due to pressure holding.
(2) Determination of reducible DNT: and (2) inserting the sample solution in the step (1) into a 10mL syringe, repeatedly pumping in and out, and preheating the syringe. Then, enough of the melt-mixed sample was withdrawn, and 0.8g was weighed into a 10mL volumetric flask and diluted to the mark with DMF. A 10mL mixed solution of DMF of 50. And sucking the well-treated sample by using a sample injector, and adding the sample into the polarographic pool. Setting the polarograph measuring conditions to be the same as the conditions in the example 5, carrying out mercury dropping in a mercury dropping mode of 2 drops/s, carrying out nitrogen blowing time of 600s, scanning the range of +0.1V to-1.0V, repeating the measurement for 2 times, and respectively recording the polarographic wave height and muA measured by-0.5V, -0.7V and-0.85V. The DNT content was calculated by a correction factor.
(3) Determination of tar in TDA: and (2) inserting the sample solution in the step (1) by using a syringe, repeatedly pumping in and out, and preheating the syringe. Then, 4-5 drops of the melted and uniformly mixed sample are taken to be dropped into a small glass bottle, 10mL of dichloromethane is added to dissolve and uniformly mix the sample, the determination condition of a chromatograph is set to be the same as the determination condition of the tar in the TDA of the embodiment 3, and 1.0 muL of dissolved sample is injected into a gas chromatograph to obtain the tar content in the TDA.
TABLE 2 comparison of sample analytical data after DNT hydrogenation filter
Example 7
Measuring water, tar, toluidine, OTD, 2.5-TDA and MTD of a TDA product according to the method of the invention, and measuring according to the method of the prior art, wherein the test results are shown in Table 3, and Table 3 is the comparison of analysis data of TDA samples of the product. Wherein the prior art method is as follows:
(1) sampling and sample pretreatment: sampling about 100g by using a 150mL high-temperature-resistant glass bottle, placing the sample on a sand bath at 140 ℃ in a laboratory for melting and shaking up to obtain a melted and uniformly mixed sample solution, and inserting two needles into a bottle cap to prevent the glass bottle from cracking due to pressure holding.
(2) Determination of trace water: opening the Karl furnace, and setting the temperature of the Karl furnace to be 110 ℃; opening a nitrogen valve, and adjusting the rotor flow meter to enable the flow rate to reach 160 mL/min; adding 30mL of anhydrous methanol into the emptied measuring cup, and starting pre-titration till the end of the pre-titration; and (3) inserting the sample solution in the step (1) into a 10mL syringe, repeatedly pumping in and out, and preheating the syringe. Then, enough of the molten, homogenized sample was withdrawn, a mass (about 1 ml) of the molten, homogenized MTD sample was rapidly added to the sample bottle, and its mass (g) was weighed; putting the sample bottles into a sample tray of a Karl-type furnace; and (5) starting measurement, and automatically giving an analysis result (mu g/g) by a Karl Fischer apparatus.
(3) Determination of tar in TDA: and (2) inserting the sample solution in the step (1) by using a syringe, repeatedly pumping in and out, and preheating the syringe. And then, dropping 4-5 drops of the melted and uniformly mixed sample into a small glass bottle, adding 10mL of dichloromethane for dissolving and uniformly mixing, setting the measuring condition of a chromatograph to be the same as the measuring condition of the tar in the TDA in the method, and injecting 1.0 mu L of the dissolved sample into a gas chromatograph to obtain the content of the tar in the TDA.
(4) Determination of the TDA component: and (3) inserting the sample solution in the step (1) by using a syringe, repeatedly pumping in and out, and preheating the syringe. Then, 4-5 drops of the melted and uniformly mixed sample are taken to be put into a small glass bottle, 10mL of dichloromethane is added for dissolution, and the mixture is uniformly mixed; setting the determination conditions of a chromatograph to be the same as the determination conditions of the tar in the TDA in the method, and injecting 0.6 mu L of a dissolved sample into the gas chromatograph to obtain the content of each component in the TDA.
TABLE 3 TDA product analysis data comparison
As can be seen from the above data, the analysis results of the method of the present invention after the sampling and analysis method is improved are completely consistent with the analysis results of the method of the prior art, the analysis time is greatly reduced because the sample is not heated and melted on a sand bath, and importantly, the laboratory has no diaminotoluene steam pollution, thereby ensuring the occupational health of the inspectors.
Example 8
The method of the invention is evaluated in accuracy and precision, samples are respectively taken from a TDA product storage tank by using the method of the prior art and the method of the invention for 10 days continuously, the numbers are respectively 1 to 10 and (1) to the capacitor, and the samples measured by the method of the prior art are firstly heated and melted by sand bath and then analyzed; the samples determined according to the method of the invention are directly subjected to sample analysis after sampling. Designing a sample analysis sequence by Minitab, respectively measuring water content of two groups of 10 samples by two skilled assay personnel by using a Karman-Karl Fischer combined method by adopting an MSA method, and analyzing the MTD content by using chromatography, wherein the results are shown in the following tables 4 and 5, the results are shown in the table 4, the results are obtained by designing and analyzing the samples by Minitab by using a TDA sampling and analyzing method in the prior art, and the results are shown in the table 5, the results are obtained by designing and analyzing the samples by Minitab by using the TDA sampling and analyzing method in the invention:
TABLE 4
TABLE 5
The results of the moisture measurements on the TDA samples of the prior art and the method of the invention were analyzed for MSA using a reproducibility and reproducibility analysis (R & R analysis, also called XBR/R analysis) in which the number of distinguishable classes in the results of the prior art method was 7 and the number of distinguishable classes in the results of the method of the invention was 10, as shown in Table 6:
TABLE 6
MSA analysis was performed using the method R & R (XBR/R) method on the results of the above-described prior art method and the TDA sample MTD content measurement of the method of the present invention, wherein the number of distinguishable classes in the results of the prior art method was 3, and the number of distinguishable classes in the results of the method of the present invention was 5, and the results are shown in Table 7:
TABLE 7
R & R study analysis using the xabar/R method using the Minitab tool for the prior art method and the method of the invention is shown in table 8, table 8 is the R & R study results for the different sampling analysis methods:
TABLE 8
As can be seen from Table 8, when the TDA sample is sampled and analyzed by the method of the invention, SD and SV% are both obviously reduced, which shows that the stability of the sample is obviously improved and the precision of the analysis result is improved.
The above description is only for the preferred embodiment of the present invention, but the scope of the present invention is not limited thereto, and any person skilled in the art should be considered as the technical solutions and the inventive concepts of the present invention within the technical scope of the present invention.
Claims (9)
1. A method for detecting a sample containing diaminotoluene, comprising the steps of:
dissolving a sample containing diaminotoluene by using an organic solvent to obtain a sample to be detected, and detecting;
the sample containing diaminotoluene is in a non-molten state;
the volume ratio of the diaminotoluene-containing sample to the organic solvent is 5 to 15.
2. The detection method according to claim 1,
dissolving a sample containing diaminotoluene in an organic solvent within 0min to 5 min.
3. The detection method according to claim 1, wherein the organic solvent is at least one selected from the group consisting of dichloromethane, methanol, absolute ethanol, acetone, N-dimethylformamide, and dimethylsulfoxide.
4. The detection method according to claim 1, wherein the detection method is as follows:
and detecting the sample to be detected by adopting a gas chromatography to obtain a detection result of the sample to be detected, detecting the standard sample to obtain a correction factor, and correcting the detection result of the sample to be detected by the correction factor.
5. The detection method according to claim 4, wherein the gas chromatography employs a temperature programming;
the temperature programming is as follows: maintaining the initial temperature at 90-110 ℃ for 0-1 min, heating to 120-140 ℃ at the speed of 8-11 ℃/min for 3-7 min, and heating to 265-285 ℃ at the speed of 27-33 ℃/min for 1-3 min;
alternatively, the first and second electrodes may be,
the initial temperature is maintained at 90-110 ℃ for 0-1 min, the temperature is raised to 240-260 ℃ at the speed of 13-16 ℃/min for 0-1 min, and the temperature is raised to 270-290 ℃ at the speed of 1.5-3.5 ℃/min for 8-12 min.
6. The detection method according to claim 4, wherein the chromatographic conditions of the gas chromatography are:
the temperature of a sample inlet is 240-260 ℃; the temperature of the detector is 290-310 ℃; the flow dividing ratio is 45 to 55;
alternatively, the first and second electrodes may be,
the temperature of a sample inlet is 300-320 ℃; the temperature of the detector is 300-320 ℃; the flow split ratio is 20 to 30.
7. The detection method according to claim 1, wherein the detection method is as follows:
and detecting the sample to be detected by adopting a polarography to obtain a detection result of the sample to be detected, detecting a standard sample to obtain a standard curve, and correcting the detection result of the sample to be detected through the standard curve.
8. The detection method according to claim 7, wherein the condition of polarography is:
dropping rate of mercury: 1 to 3 drops/s;
nitrogen blowing time: 500 s-800 s;
scanning range: + 0.1V-1.0V.
9. The detection method according to claim 1, characterized in that the method of detection is:
and detecting the sample to be detected by adopting a Karl Fischer method, detecting the organic solvent, and correcting the detection result of the sample to be detected according to the detection result of the organic solvent.
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