CN112577921A - Method for detecting alkyl nitrate - Google Patents
Method for detecting alkyl nitrate Download PDFInfo
- Publication number
- CN112577921A CN112577921A CN202011496359.4A CN202011496359A CN112577921A CN 112577921 A CN112577921 A CN 112577921A CN 202011496359 A CN202011496359 A CN 202011496359A CN 112577921 A CN112577921 A CN 112577921A
- Authority
- CN
- China
- Prior art keywords
- alkyl nitrate
- detecting
- calibration
- alkyl
- volume
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
- -1 alkyl nitrate Chemical compound 0.000 title claims abstract description 75
- 229910002651 NO3 Inorganic materials 0.000 title claims abstract description 71
- 238000000034 method Methods 0.000 title claims abstract description 25
- 238000002414 normal-phase solid-phase extraction Methods 0.000 claims abstract description 29
- 239000012482 calibration solution Substances 0.000 claims abstract description 25
- 239000002283 diesel fuel Substances 0.000 claims abstract description 25
- 239000012085 test solution Substances 0.000 claims abstract description 12
- 239000002904 solvent Substances 0.000 claims abstract description 7
- 239000000126 substance Substances 0.000 claims abstract description 5
- QGJOPFRUJISHPQ-UHFFFAOYSA-N Carbon disulfide Chemical compound S=C=S QGJOPFRUJISHPQ-UHFFFAOYSA-N 0.000 claims description 36
- 230000005526 G1 to G0 transition Effects 0.000 claims description 18
- OKKJLVBELUTLKV-UHFFFAOYSA-N Methanol Chemical compound OC OKKJLVBELUTLKV-UHFFFAOYSA-N 0.000 claims description 18
- 238000011088 calibration curve Methods 0.000 claims description 17
- 238000002835 absorbance Methods 0.000 claims description 14
- 238000000605 extraction Methods 0.000 claims description 11
- YMWUJEATGCHHMB-UHFFFAOYSA-N Dichloromethane Chemical compound ClCCl YMWUJEATGCHHMB-UHFFFAOYSA-N 0.000 claims description 9
- SPWVRYZQLGQKGK-UHFFFAOYSA-N dichloromethane;hexane Chemical compound ClCCl.CCCCCC SPWVRYZQLGQKGK-UHFFFAOYSA-N 0.000 claims description 9
- 238000005406 washing Methods 0.000 claims description 8
- 239000012046 mixed solvent Substances 0.000 claims description 7
- 230000003287 optical effect Effects 0.000 claims description 7
- 238000005259 measurement Methods 0.000 claims description 6
- VLKZOEOYAKHREP-UHFFFAOYSA-N n-Hexane Chemical compound CCCCCC VLKZOEOYAKHREP-UHFFFAOYSA-N 0.000 claims description 6
- 229910017604 nitric acid Inorganic materials 0.000 claims description 6
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 claims description 4
- 230000001419 dependent effect Effects 0.000 claims description 4
- 238000012417 linear regression Methods 0.000 claims description 4
- 238000005070 sampling Methods 0.000 claims description 4
- 239000000741 silica gel Substances 0.000 claims description 4
- 229910002027 silica gel Inorganic materials 0.000 claims description 4
- 238000001704 evaporation Methods 0.000 claims description 3
- 238000011068 loading method Methods 0.000 claims description 3
- 238000002156 mixing Methods 0.000 claims description 2
- 238000012856 packing Methods 0.000 claims description 2
- 239000012071 phase Substances 0.000 claims description 2
- 239000003495 polar organic solvent Substances 0.000 claims description 2
- 238000001228 spectrum Methods 0.000 claims description 2
- 238000001514 detection method Methods 0.000 abstract description 13
- 150000004945 aromatic hydrocarbons Chemical class 0.000 abstract description 4
- 229930195734 saturated hydrocarbon Natural products 0.000 abstract description 4
- 231100000331 toxic Toxicity 0.000 abstract description 4
- 230000002588 toxic effect Effects 0.000 abstract description 4
- 238000004458 analytical method Methods 0.000 abstract description 3
- 239000000243 solution Substances 0.000 description 10
- NNKQLUVBPJEUOR-UHFFFAOYSA-N 3-ethynylaniline Chemical compound NC1=CC=CC(C#C)=C1 NNKQLUVBPJEUOR-UHFFFAOYSA-N 0.000 description 9
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 4
- IOLCXVTUBQKXJR-UHFFFAOYSA-M potassium bromide Chemical compound [K+].[Br-] IOLCXVTUBQKXJR-UHFFFAOYSA-M 0.000 description 4
- HEMHJVSKTPXQMS-UHFFFAOYSA-M Sodium hydroxide Chemical compound [OH-].[Na+] HEMHJVSKTPXQMS-UHFFFAOYSA-M 0.000 description 3
- 238000006243 chemical reaction Methods 0.000 description 3
- 239000003153 chemical reaction reagent Substances 0.000 description 3
- 238000011049 filling Methods 0.000 description 3
- 150000002430 hydrocarbons Chemical class 0.000 description 3
- 238000002360 preparation method Methods 0.000 description 3
- NHJNEVDNUSFTSG-UHFFFAOYSA-N 1,5-dimethylcyclohexa-2,4-dien-1-ol Chemical compound CC1=CC=CC(C)(O)C1 NHJNEVDNUSFTSG-UHFFFAOYSA-N 0.000 description 2
- IQUPABOKLQSFBK-UHFFFAOYSA-N 2-nitrophenol Chemical compound OC1=CC=CC=C1[N+]([O-])=O IQUPABOKLQSFBK-UHFFFAOYSA-N 0.000 description 2
- GRYLNZFGIOXLOG-UHFFFAOYSA-N Nitric acid Chemical compound O[N+]([O-])=O GRYLNZFGIOXLOG-UHFFFAOYSA-N 0.000 description 2
- QAOWNCQODCNURD-UHFFFAOYSA-N Sulfuric acid Chemical compound OS(O)(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-N 0.000 description 2
- 239000002253 acid Substances 0.000 description 2
- WUKWITHWXAAZEY-UHFFFAOYSA-L calcium difluoride Chemical compound [F-].[F-].[Ca+2] WUKWITHWXAAZEY-UHFFFAOYSA-L 0.000 description 2
- 229910001634 calcium fluoride Inorganic materials 0.000 description 2
- 238000001035 drying Methods 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 238000002329 infrared spectrum Methods 0.000 description 2
- 238000002386 leaching Methods 0.000 description 2
- 238000012986 modification Methods 0.000 description 2
- 230000004048 modification Effects 0.000 description 2
- 238000006396 nitration reaction Methods 0.000 description 2
- 229910052757 nitrogen Inorganic materials 0.000 description 2
- 230000035945 sensitivity Effects 0.000 description 2
- 238000000926 separation method Methods 0.000 description 2
- 238000000935 solvent evaporation Methods 0.000 description 2
- 230000003595 spectral effect Effects 0.000 description 2
- 238000002798 spectrophotometry method Methods 0.000 description 2
- 238000012360 testing method Methods 0.000 description 2
- CIWBSHSKHKDKBQ-JLAZNSOCSA-N Ascorbic acid Chemical compound OC[C@H](O)[C@H]1OC(=O)C(O)=C1O CIWBSHSKHKDKBQ-JLAZNSOCSA-N 0.000 description 1
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical group [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 1
- 239000004215 Carbon black (E152) Substances 0.000 description 1
- NHTMVDHEPJAVLT-UHFFFAOYSA-N Isooctane Chemical compound CC(C)CC(C)(C)C NHTMVDHEPJAVLT-UHFFFAOYSA-N 0.000 description 1
- 230000002411 adverse Effects 0.000 description 1
- 238000003556 assay Methods 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 238000004364 calculation method Methods 0.000 description 1
- 238000012937 correction Methods 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- JVSWJIKNEAIKJW-UHFFFAOYSA-N dimethyl-hexane Natural products CCCCCC(C)C JVSWJIKNEAIKJW-UHFFFAOYSA-N 0.000 description 1
- 238000002474 experimental method Methods 0.000 description 1
- 210000004907 gland Anatomy 0.000 description 1
- 229930195733 hydrocarbon Natural products 0.000 description 1
- 230000007062 hydrolysis Effects 0.000 description 1
- 238000006460 hydrolysis reaction Methods 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 239000011159 matrix material Substances 0.000 description 1
- 239000000203 mixture Substances 0.000 description 1
- 239000011541 reaction mixture Substances 0.000 description 1
- 238000011084 recovery Methods 0.000 description 1
- 238000011160 research Methods 0.000 description 1
- NESLWCLHZZISNB-UHFFFAOYSA-M sodium phenolate Chemical compound [Na+].[O-]C1=CC=CC=C1 NESLWCLHZZISNB-UHFFFAOYSA-M 0.000 description 1
- 239000007790 solid phase Substances 0.000 description 1
Images
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N21/00—Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light
- G01N21/17—Systems in which incident light is modified in accordance with the properties of the material investigated
- G01N21/25—Colour; Spectral properties, i.e. comparison of effect of material on the light at two or more different wavelengths or wavelength bands
- G01N21/31—Investigating relative effect of material at wavelengths characteristic of specific elements or molecules, e.g. atomic absorption spectrometry
- G01N21/35—Investigating relative effect of material at wavelengths characteristic of specific elements or molecules, e.g. atomic absorption spectrometry using infrared light
- G01N21/3577—Investigating relative effect of material at wavelengths characteristic of specific elements or molecules, e.g. atomic absorption spectrometry using infrared light for analysing liquids, e.g. polluted water
Abstract
The invention relates to the technical field of chemical analysis, in particular to a method for detecting alkyl nitrate. The detection method of the alkyl nitrate comprises the following steps: preparing a series of alkyl nitrate calibration solutions, and detecting the series of alkyl nitrate calibration solutions by using infrared rays to obtain a calibration formula; carrying out solid phase extraction on the vehicle diesel oil containing the alkyl nitrate to form a test solution to be detected; and detecting the test solution to be detected by utilizing infrared, obtaining the volume fraction of the alkyl nitrate according to a calibration formula, and then calculating the content of the alkyl nitrate according to the formula. The detection method does not need to react with alkyl nitrate, and does not adopt corrosive and toxic solvents, so that the detection method is simpler, more convenient and safer. Meanwhile, the method has high selectivity, can eliminate the influence of components such as saturated hydrocarbon, aromatic hydrocarbon and the like in the diesel oil on detection, and ensures the accuracy and precision of the detection result.
Description
Technical Field
The invention relates to the technical field of chemical analysis, in particular to a method for detecting alkyl nitrate.
Background
Alkyl nitrates have a good cetane number improving effect and are predominant in the market. However, the alkyl nitrate may affect the color and stability of the diesel oil for vehicles, and form an association with an acid type lubricity improver in the diesel oil to block an engine filter, thereby resulting in unsmooth oil supply to the engine. In addition, the determination of carbon residue in the vehicle diesel oil is influenced by adding the alkyl nitrate into the vehicle diesel oil, so the content of the alkyl nitrate needs to be controlled and determined when the vehicle diesel oil is blended and the production research is carried out.
At present, ultraviolet spectrophotometry (SH/T0559 + 1993, ASTM D4046-2014, ISO 13759 + 1996) is mainly adopted for determining the content of the alkyl nitrate in the vehicle diesel oil, the determination principle is that the alkyl nitrate in a sample is hydrolyzed in sulfuric acid solution to generate nitric acid, meanwhile, m-dimethylphenol is added to carry out nitration reaction with the nitric acid generated by hydrolysis, then, generated nitrophenol is extracted from a nitration reaction mixture by isooctane, the nitrophenol reacts with sodium hydroxide to obtain yellow phenol sodium salt, and after the absorbance is determined by spectrophotometry at the wavelength of 452nm, the content of the alkyl nitrate is calculated according to the slope of a calibration working curve. The defects of the existing determination method are mainly as follows: 1. the operation steps of preparation of a calibration solution and sample pretreatment reaction extraction are complicated, and the analysis manual operation period is long; 2. in the step of sample pretreatment, reaction and extraction, corrosive strong acid and toxic and highly volatile m-dimethylphenol are required to be used, so that the adverse effects on the physical health of operators and the laboratory environment are caused; 3. the type of alkyl nitrate added needs to be well understood before detection, and if a calibration solution is used that contains a different alkyl nitrate than the sample being analyzed, the assay results will be disturbed.
In view of this, the invention is particularly proposed.
Disclosure of Invention
The invention aims to provide a method for detecting alkyl nitrate. The detection method does not need to react with alkyl nitrate, and does not adopt corrosive and toxic solvents, so that the detection method is simpler, more convenient and safer. Meanwhile, the method has high selectivity, can eliminate the influence of components such as saturated hydrocarbon, aromatic hydrocarbon and the like in the diesel oil on detection, and ensures the accuracy and precision of the detection result.
The invention is realized by the following steps:
in a first aspect, the present invention provides a method for detecting alkyl nitrate, comprising: preparing a series of alkyl nitrate calibration solutions, detecting the series of alkyl nitrate calibration solutions by using infrared rays, and obtaining the following calibration formula:
carrying out solid phase extraction on the vehicle diesel oil containing the alkyl nitrate to form a test solution to be detected;
detecting the test solution to be detected by utilizing infrared, substituting absorbance obtained by detecting the test solution to be detected into a calibration formula, and calculating to obtain qmThen, the content of the alkyl nitrate is calculated according to the following formula:
In an alternative embodiment, the sample cell may be a fixed thickness sample cell made of potassium bromide or calcium fluoride, and a total specular reflection (ATR) accessory may be used if the sensitivity allows.
In an alternative embodiment, the conditions for detection using infrared include: the spectrum scanning range is 4000-400 cm-1The optical distance of the sample cell is 0.1-0.5 mm, and the resolution is 4cm-1The scanning frequency is 32, and the measurement wave number is 1620-1640 cm-1Or 1270-1285 cm-1。
In an alternative embodiment, the calibration formula is a calibration formula obtained by taking the absorbance a as a dependent variable and taking the volume fraction q of the alkyl nitrate as an independent variable as a calibration curve and performing linear regression;
preferably, if the correlation coefficient R of the calibration curve is2If the content of the nitric acid alkyl ester is less than 0.99, repeating the step of detecting the series of nitric acid alkyl ester calibration solutions to obtain a calibration formula;
preferably, the step of preparing a series of alkyl nitrate calibration solutions comprises: mixing and dissolving a standard product of alkyl nitrate and carbon disulfide to obtain a series of calibration solutions with different concentrations.
In an alternative embodiment, the stationary phase used for the solid phase extraction is a normal phase stationary phase, preferably silica gel.
In an alternative embodiment, the loading volume per unit mass of the stationary phase is 0.5 to 10mL/g, preferably 3 mL/g.
In an alternative embodiment, the step of solid phase extraction comprises: and after the sample is loaded, washing the solid-phase extraction column by using a normal hexane-dichloromethane mixed solvent, and then washing the solid-phase extraction column by using an extraction solvent to obtain the test solution to be detected.
In an alternative embodiment, the volume ratio of n-hexane to dichloromethane in n-hexane-dichloromethane is 0-1: 1.
In an alternative embodiment, the extraction solvent is a polar organic solvent, preferably methanol.
In an alternative embodiment, the capacity of the solid phase extraction column is 1-60ml and the packing capacity of the stationary phase is 0.5-30 g.
In an alternative embodiment, the step of forming the test solution to be tested comprises: and concentrating the extract obtained by solid phase extraction and fixing the volume.
Preferably, the concentration and volume fixing step comprises: and collecting the extract in a colorimetric tube, evaporating at 40-60 ℃ under normal pressure until the volume is fixed to remove the extractant, and then fixing the volume to the scale mark of the colorimetric tube by using carbon disulfide.
The invention has the following beneficial effects: the invention effectively separates the saturated hydrocarbon and the aromatic hydrocarbon components in the vehicle diesel oil by adopting the solid phase extraction method under the condition of ensuring higher recovery rate of the components to be detected, thereby eliminating the interference of hydrocarbon substances on the detection. And the advantages of infrared detection are combined, so that the alkyl nitrate in the diesel oil can be quickly, simply and conveniently quantified on the basis of not using corrosive and toxic reagents, the selectivity, the precision and the accuracy are high, and the alkyl nitrate with low content can be detected.
Drawings
In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings needed to be used in the embodiments will be briefly described below, it should be understood that the following drawings only illustrate some embodiments of the present invention and therefore should not be considered as limiting the scope, and for those skilled in the art, other related drawings can be obtained according to the drawings without inventive efforts.
FIG. 1 is a schematic diagram of a solid phase extraction column;
FIG. 2 shows that the carbon disulfide calibration solution and diesel oil with different alkyl nitrate contents are 1300-1250 cm-1Comparison of infrared spectra over the range;
FIG. 3 shows carbon disulfide calibration solutions with different alkyl nitrate contents and diesel oil at 1660-1610 cm-1Comparison of infrared spectra over the range;
FIG. 4 shows the concentration of isooctyl nitrate-carbon disulfide solution at 1275cm-1A calibration curve plotted against absorbance;
FIG. 5 shows the concentration of isooctyl nitrate in carbon disulfide solution at 1632cm-1Absorbance of (d) was plotted as a calibration curve.
Detailed Description
In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below. The examples, in which specific conditions are not specified, were conducted under conventional conditions or conditions recommended by the manufacturer. The reagents or instruments used are not indicated by the manufacturer, and are all conventional products available commercially.
The embodiment of the invention provides a method for detecting alkyl nitrate, which can quickly and efficiently detect the alkyl nitrate by combining solid-phase extraction and infrared, without complicated steps such as sample pretreatment reaction and the like and without adopting harmful reagents, and comprises the following steps:
(1) preparation of calibration solutions: a series of (at least 4) carbon disulfide calibration solutions of known exact concentrations of alkyl nitrate were prepared by adding a quantity of an alkyl nitrate standard to carbon disulfide.
(2) And (3) spectrogram measurement: respectively injecting the calibration solution into sample pools with optical distances of 0.1-0.5 mm, recording infrared spectrograms of the sample pools with air spectrograms as backgrounds, wherein the spectral scanning range is 4000-400 cm-1Resolution of 4cm-1The number of scans was 32. The sample cell can be selected from a sample cell with a fixed thickness and made of potassium bromide or calcium fluoride, and a mirror total reflection (ATR) accessory can be selected under the condition that the sensitivity allows.
(3) Calibration formula: using a calibration solution at 1620-1640 cm-1Or 1270-1285 cm-1The absorbance A at (A) was plotted as a dependent variable and the volume fraction q of the alkyl nitrate was plotted as an independent variable, and a linear regression was performed. The calibration formula is shown in formula (1).
In the formula:
a-absorbance;
l is the optical path length of the sample cell used, mm;
q-volume fraction of alkyl nitrate,%;
a-the slope of the calibration curve;
b-intercept of the calibration curve on the y-axis.
Correlation coefficient R of calibration curve2Below 0.99, the calibration procedure should be repeated. The accuracy of the correction formula is guaranteed, and the accuracy of the final result is improved.
(4) Preparing a solid phase extraction column: and uniformly filling a certain mass of dry stationary phase in the extraction column. The solid phase extraction column comprises a sample inlet, a gland, an extraction column, a sieve plate, a stationary phase, a sample outlet and the like, and has the function of effectively separating saturated hydrocarbon and aromatic hydrocarbon components in the automobile diesel containing the alkyl nitrate from the alkyl nitrate, wherein the stationary phase with stronger polarity is selected correspondingly, and dry silica gel is preferred. The upper part of the solid phase extraction column can be connected with an injector to pressurize so as to accelerate the leaching speed, and an automatic solid phase extractor meeting the separation condition can also be used for separation. The capacity of the solid phase extraction column can be 1-60mL, and the filling amount of the stationary phase is selected according to the column capacity and can be 0.5-30 g.
(5) Sample extraction: a test tube is arranged at the lower end of a sample outlet of the solid phase extraction column, a certain volume of the vehicle diesel oil sample containing the alkyl nitrate is accurately transferred and injected into the solid phase extraction column. And after the hydrocarbon compound completely flows out, washing the stationary phase by using a proper amount of n-hexane-dichloromethane mixed solvent, and after the n-hexane-dichloromethane mixed solvent completely flows out, introducing nitrogen into the column to blow the column for drying. And then, placing a colorimetric tube at the lower end of a sample outlet of the solid-phase extraction column, and washing the stationary phase by using a proper amount of methanol to ensure that the alkyl nitrate completely flows out. The volume ratio of n-hexane to dichloromethane in the n-hexane-dichloromethane mixed solvent may be 0-1: 1. The sampling amount of diesel oil and the usage amount of the leaching solvent are determined according to the filling amount of the stationary phase, and the loading volume of the stationary phase per unit mass can be between 0.5 and 10mL/g, preferably 3 mL/g.
(6) Solvent evaporation: and evaporating the solution collected in the colorimetric tube at the normal pressure of 40-60 ℃ until the volume is fixed so as to remove the methanol.
(7) And (3) sample determination: adding carbon disulfide into the colorimetric tube to the scale mark, covering the colorimetric tube with a cover, shaking up, measuring the solution after constant volume according to the same method in the step (2) to obtain absorbance, carrying out calculation in the formula (1) on the absorbance obtained by side amount to obtain qm, and calculating the content of alkyl nitrate in the sample according to the formula (2).
In the formula:
qm-calculating the volume fraction of alkyl nitrate obtained, mm, from the calibration curve;
Vcthe volume of the sample is determined in the colorimetric tube to be mL;
V0sampling volume of diesel oil for the vehicle to be detected, mL.
The features and properties of the present invention are described in further detail below with reference to examples.
Example 1
In the embodiment, isooctyl nitrate is added by taking straight-run diesel oil (180-350 ℃ cut segment) as a matrix, and the feasibility of the method is verified according to the precision and the accuracy of the measurement result, and the specific implementation steps are as follows.
(1) Preparation of calibration solutions: in six 10mL volumetric flasks were added 0. mu.L, 2. mu.L, 5. mu.L, 10. mu.L, 20. mu.L and 50. mu.L of isooctyl nitrate, respectively. After carbon disulfide is used for constant volume, calibration solutions with the volume fractions of isooctyl nitrate of 0%, 0.02%, 0.05%, 0.1%, 0.2% and 0.5% are obtained.
(2) And (3) spectrogram measurement: injecting the calibration solution into a sample cell with an optical path of 0.5mm, recording an infrared spectrogram of the calibration solution by taking an air spectrogram as a background, wherein the spectral scanning range is 4000-400 cm-1Resolution of 4cm-1The number of scans was 32. The scanning results are shown in fig. 2 and 3.
(3) Calibration formula: respectively with a calibration solution at 1275cm-1And 1632cm-1The absorbance of (d) was plotted as a dependent variable and the volume fraction of isooctyl nitrate was plotted as an independent variable, and linear regression was performed. The calibration curves are shown in fig. 4 and 5, respectively, and the calibration formulas are shown in formula (3) and formula (4), respectively.
A＝2.3284q+0.001,R2＝0.9999 (3)
A＝4.6854q+0.3601,R2＝0.9999 (4)
(4) Preparing a solid phase extraction column: 1g of dry silica gel was uniformly packed in a 5mL extraction column, the structure of which is shown in FIG. 1.
(5) Sample extraction: a test tube is arranged at the lower end of a sample outlet of the solid phase extraction column, 2mL of the vehicle diesel oil sample with 0.2 percent of isooctyl nitrate prepared in advance is accurately transferred and injected into the solid phase extraction column. And after the hydrocarbon compound completely flows out, washing the stationary phase by using 5mL of n-hexane-dichloromethane mixed solvent, and after the n-hexane-dichloromethane mixed solvent completely flows out, introducing nitrogen into the column to blow the column for drying. Then, a 10mL colorimetric tube is arranged at the lower end of the sample outlet of the solid-phase extraction column, and 5mL methanol is used for washing the stationary phase to ensure that the isooctyl nitrate completely flows out.
(6) Solvent evaporation: the solution collected in the cuvette was evaporated to a fixed volume at 60 ℃ at normal pressure to remove methanol.
(7) And (3) sample determination: adding carbon disulfide to scale marks in colorimetric cylinderThen, the mixture was shaken well with a lid, and the volume-fixed solution was measured in the same manner as in the step (2), and q was calculated from the formula (3) and the formula (4), respectivelymAnd calculating the content of isooctyl nitrate in the sample according to the formula (2). The experiment was repeated three times, and the measurement results are shown in table 1.
TABLE 1 determination of isooctyl nitrate content in additized diesel
According to the results, the content of the alkyl nitrate in the diesel oil can be accurately determined by adopting the method for detecting the alkyl nitrate provided by the embodiment of the invention.
The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention, and various modifications and changes may be made by those skilled in the art. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.
Claims (10)
1. A method for detecting alkyl nitrate, characterized by comprising: preparing a series of alkyl nitrate calibration solutions, detecting the series of alkyl nitrate calibration solutions by using infrared rays, and obtaining the following calibration formula:
subjecting the vehicle diesel containing alkyl nitrate to solid phase extraction to form the testA test solution; detecting the test solution to be detected by utilizing infrared, substituting absorbance obtained by detecting the test solution to be detected into a calibration formula, and calculating to obtain qmThen, the content of the alkyl nitrate is calculated according to the following formula:
wherein the content of the first and second substances,
-volume fraction of alkyl nitrate in diesel oil to be tested,%; q. q.sm-calculating the volume fraction of alkyl nitrate obtained, mm, from the calibration curve; vcThe volume of the sample is determined in the colorimetric tube to be mL; v0Sampling volume of diesel oil for the vehicle to be detected, mL.
2. The method for detecting an alkyl nitrate according to claim 1, wherein the conditions for detecting an alkyl nitrate by infrared include: the spectrum scanning range is 4000-400 cm-1The optical distance of the sample cell is 0.1-0.5 mm, and the resolution is 4cm-1The scanning frequency is 32, and the measurement wave number is 1620-1640 cm-1Or 1270-1285 cm-1。
3. The method for detecting alkyl nitrate according to claim 1, wherein the calibration formula is a calibration formula obtained by performing linear regression using absorbance a as a dependent variable and alkyl nitrate volume fraction q as an independent variable as a calibration curve;
preferably, if the correlation coefficient R of the calibration curve is2If the content of the nitric acid alkyl ester is less than 0.99, repeating the step of detecting the series of nitric acid alkyl ester calibration solutions to obtain a calibration formula;
preferably, the step of preparing a series of alkyl nitrate calibration solutions comprises: mixing and dissolving a standard product of alkyl nitrate and carbon disulfide to obtain a series of calibration solutions with different concentrations.
4. The method for detecting alkyl nitrate according to claim 1, wherein the stationary phase used in the solid phase extraction is a normal phase stationary phase, preferably silica gel.
5. The method for detecting alkyl nitrate according to claim 4, wherein the loading volume per unit mass of the stationary phase is 0.5 to 10mL/g, preferably 3 mL/g.
6. The method for detecting alkyl nitrate according to claim 1, wherein the step of solid-phase extraction comprises: and after the sample is loaded, washing the solid-phase extraction column by using a normal hexane-dichloromethane mixed solvent, and then washing the solid-phase extraction column by using an extraction solvent to obtain the test solution to be detected.
7. The method for detecting an alkyl nitrate according to claim 6, wherein the volume ratio of n-hexane to dichloromethane in n-hexane-dichloromethane is 0-1: 1.
8. The method for detecting alkyl nitrate according to claim 6, wherein the extraction solvent is a polar organic solvent, preferably methanol.
9. The method for detecting alkyl nitrate according to claim 6, wherein the capacity of the solid phase extraction column is 1 to 60ml, and the packing capacity of the stationary phase is 0.5 to 30 g.
10. The method for detecting alkyl nitrate according to claim 1, wherein the step of forming a test solution to be detected comprises: concentrating the extract obtained by solid phase extraction and fixing the volume;
preferably, the concentration and volume fixing step comprises: and collecting the extract in a colorimetric tube, evaporating at 40-60 ℃ under normal pressure until the volume is fixed to remove the extractant, and then fixing the volume to the scale mark of the colorimetric tube by using carbon disulfide.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202011496359.4A CN112577921A (en) | 2020-12-17 | 2020-12-17 | Method for detecting alkyl nitrate |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202011496359.4A CN112577921A (en) | 2020-12-17 | 2020-12-17 | Method for detecting alkyl nitrate |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN112577921A true CN112577921A (en) | 2021-03-30 |
Family
ID=75135736
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202011496359.4A Pending CN112577921A (en) | 2020-12-17 | 2020-12-17 | Method for detecting alkyl nitrate |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN112577921A (en) |
Citations (11)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6140647A (en) * | 1997-12-19 | 2000-10-31 | Marathon Ashland Petroleum | Gasoline RFG analysis by a spectrometer |
| CN1591004A (en) * | 2003-08-29 | 2005-03-09 | 中国石油化工股份有限公司 | Method of analyzing diesel oil hydrocarbon composition using solid phase extraction and mass chromatogrophy |
| CN102621084A (en) * | 2012-03-14 | 2012-08-01 | 合肥工业大学 | Method for measuring soil ammonium nitrogen |
| CN104749298A (en) * | 2013-12-30 | 2015-07-01 | 中国石油化工股份有限公司 | Solid phase extraction column for separating different hydrocarbon components in diesel oil and application method |
| CN104833652A (en) * | 2015-04-15 | 2015-08-12 | 北京理工大学 | Method for rapidly analyzing content of cellulose nitrate in mixed material |
| CN105778981A (en) * | 2014-12-23 | 2016-07-20 | 中国石油天然气股份有限公司 | Solid phase extraction and enrichment method of nitrogen-containing compounds in diesel fuel |
| US20170225149A1 (en) * | 2014-09-25 | 2017-08-10 | Carbon Nano Engineering Systems Corporation | Solid phase extraction column, preparation method therefor, and pre-processing method of chemical sample based on solid phase extraction column |
| CN109632698A (en) * | 2018-12-21 | 2019-04-16 | 内蒙古航天红峡化工有限公司 | A kind of NG/BTTN is plasticized the rapid detection method of nitric acid ester content in adhesive |
| CN109839448A (en) * | 2017-11-28 | 2019-06-04 | 中国石油天然气股份有限公司 | The method of phenolic compound in solid-phase extraction column and Solid phase extraction separation diesel oil |
| US10379033B1 (en) * | 2016-06-06 | 2019-08-13 | University Of Puerto Rico | Coupling of thin layer chromatography (TLC) to quantum cascade laser spectroscopy (QCLS) for qualitative and quantitative field analyses of explosives and other pollutants |
| CN111965180A (en) * | 2020-08-28 | 2020-11-20 | 中国石油化工股份有限公司 | Quantitative detection method for alkyl nitrate in diesel oil |
-
2020
- 2020-12-17 CN CN202011496359.4A patent/CN112577921A/en active Pending
Patent Citations (11)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6140647A (en) * | 1997-12-19 | 2000-10-31 | Marathon Ashland Petroleum | Gasoline RFG analysis by a spectrometer |
| CN1591004A (en) * | 2003-08-29 | 2005-03-09 | 中国石油化工股份有限公司 | Method of analyzing diesel oil hydrocarbon composition using solid phase extraction and mass chromatogrophy |
| CN102621084A (en) * | 2012-03-14 | 2012-08-01 | 合肥工业大学 | Method for measuring soil ammonium nitrogen |
| CN104749298A (en) * | 2013-12-30 | 2015-07-01 | 中国石油化工股份有限公司 | Solid phase extraction column for separating different hydrocarbon components in diesel oil and application method |
| US20170225149A1 (en) * | 2014-09-25 | 2017-08-10 | Carbon Nano Engineering Systems Corporation | Solid phase extraction column, preparation method therefor, and pre-processing method of chemical sample based on solid phase extraction column |
| CN105778981A (en) * | 2014-12-23 | 2016-07-20 | 中国石油天然气股份有限公司 | Solid phase extraction and enrichment method of nitrogen-containing compounds in diesel fuel |
| CN104833652A (en) * | 2015-04-15 | 2015-08-12 | 北京理工大学 | Method for rapidly analyzing content of cellulose nitrate in mixed material |
| US10379033B1 (en) * | 2016-06-06 | 2019-08-13 | University Of Puerto Rico | Coupling of thin layer chromatography (TLC) to quantum cascade laser spectroscopy (QCLS) for qualitative and quantitative field analyses of explosives and other pollutants |
| CN109839448A (en) * | 2017-11-28 | 2019-06-04 | 中国石油天然气股份有限公司 | The method of phenolic compound in solid-phase extraction column and Solid phase extraction separation diesel oil |
| CN109632698A (en) * | 2018-12-21 | 2019-04-16 | 内蒙古航天红峡化工有限公司 | A kind of NG/BTTN is plasticized the rapid detection method of nitric acid ester content in adhesive |
| CN111965180A (en) * | 2020-08-28 | 2020-11-20 | 中国石油化工股份有限公司 | Quantitative detection method for alkyl nitrate in diesel oil |
Non-Patent Citations (2)
| Title |
|---|
| 张疆兵;: "傅立叶变换红外光谱仪在测定柴油中脂肪酸甲酯中的应用", 中国石油和化工标准与质量, no. 01, pages 45 * |
| 林春花;雷志伟;谢贤清;夏剑辉;廖维林;杨绍明;: "固相萃取-阴离子交换色谱法测定硝酸异辛酯合成后残留的混酸含量", 分析试验室, no. 12, pages 1378 - 1381 * |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| Van De Voort et al. | Quantitative determination of moisture in lubricants by Fourier transform infrared spectroscopy | |
| CN111948322A (en) | Method for detecting organic tin in water body | |
| CN102072893B (en) | Fluorescent detection method of benzo (a) pyrene in edible oil | |
| CN112577921A (en) | Method for detecting alkyl nitrate | |
| CN109187831A (en) | Using the method for 9 kinds of alcohol compound contents in GC-MS Rapid Simultaneous Determination alcohol | |
| CN114166974B (en) | Method for detecting triethylamine in soil and sediment by gas chromatography-mass spectrometry | |
| CN113189230A (en) | Verifying liquid CO2Method for detecting presence or absence of benzo (a) pyrene in sample | |
| López-Anreus | Simultaneous vapour phase Fourier transform infrared spectrometric determination of butyl acetate, toluene and methyl ethyl ketone in paint solvents | |
| Ludvík et al. | Determination of water in acetonitrile, propionitrile, dimethylformamide and tetrahydrofuran by infrared and near-infrared spectrometry | |
| Yuki et al. | Analysis of serum iron by gel permeation high-performance liquid chromatography | |
| RU2285917C1 (en) | Method of determining hydrogen sulfide and light mercaptans in crude oil, petroleum derivatives, and gas condensate | |
| Harrison et al. | Detection, determination and identification of furfuraldehyde in hydrocarbon oil | |
| Mirzaeva et al. | Extraction–photometric determination of dimedrol and papaverine in pharmaceutical dosage forms | |
| RU2810686C1 (en) | Determination of methanol and diethylene glycol in process liquids of process of drying full natural gas by gas chromatography method in conditions of interfering factor of gas condensate | |
| US4499190A (en) | Method of detecting sulfur dioxide | |
| RU2172944C2 (en) | Method of determining water levels in crude oils, condensates, and petroleum products | |
| CN112881546B (en) | Detection method of diglycolamine residue | |
| CN114839290B (en) | Method for screening colored organic substances in water body | |
| CN114088686B (en) | Method for real-time nondestructive determination of chlorine content in chlorinated paraffin | |
| López-Anreus et al. | Determination of Paint Solvents by Vapour Phase Fourier Transform Infrared Spectrometry. | |
| RU2307341C2 (en) | Method of detecting methanol in gas condensate | |
| CN109521120B (en) | Quantitative determination of DNTF content by GC-AED independent calibration curve method (CIC method) | |
| RU2670726C9 (en) | Ir-spectrometric method of determination of non-hydrocarbon cutting fluid in compressed air | |
| CN109358021A (en) | A kind of method of tert-butyl peroxide ether content in infrared spectroscopic determination diesel oil | |
| Nomura et al. | Application of total reflection X-ray fluorescence spectrometry to drug analysis |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination |