Method for detecting composition of additive in mechanical oil

Abstract

The invention provides a method for detecting the composition of an additive in mechanical oil. The detection method comprises the following steps: adding a recovery rate indicator into the mechanical oil to be detected, and sequentially extracting and concentrating to obtain an extracting solution; carrying out gel chromatographic separation on the extract liquor to obtain a to-be-detected solution; the method comprises the following steps: respectively carrying out liquid chromatography-mass spectrometry detection on a to-be-detected liquid and an additive standard substance by using ion sources ESI < + > and ESI <->, and calculating through a standard curve equation to obtain a quantitative result of the additive composition in the mechanical oil; wherein the mechanical oil to be tested is gear oil and / or hydraulic oil. By using liquid chromatography-dual mass spectrometry, namely simultaneously using ion sources ESI < + > and ESI <-> to perform mass spectrometry on the standard substance additive and the mechanical oil to be detected, hundreds of additives in the mechanical oil can be quantified at the same time, health risks and pollution sources existing in a large mechanical operation area can be accurately evaluated, and the method has the advantages of being short in time consumption, high in throughput, high in sensitivity and the like. The device can be popularized and used in a large range.

Description

Technical Field

[0001] The invention relates to the technical field of mining, and in particular to a method for detecting the composition of additives in mechanical oil. Background Art

[0002] The greases used in mining production are mainly gear oil and hydraulic oil. To protect the function of mechanical operation, synthetic additive chemicals such as antioxidants and lubricants are added. Although these additives are conducive to the convenience of industrial production, some additives have been listed as environmental pollutants and may enter the environment during use, causing environmental pollution. Therefore, analyzing the composition of additives in gear oil and hydraulic oil, that is, fingerprints, plays an important role in tracing the source of pollutants in environmental media such as water bodies.

[0003] However, there is no relevant analysis method for the composition of many additives in gear oil and hydraulic oil. In addition, the research on the analysis of organic pollutants in oils is mainly focused on edible oils, and the composition of edible oils is different from that of gear oil and hydraulic oil. It is not suitable for the detection of mechanical oils such as gear oil and hydraulic oil. In addition, the detected components are limited and fingerprint spectra cannot be obtained. Therefore, providing a method that can comprehensively analyze the composition of additives in gear oil and hydraulic oil is of great significance for the sustainable production of mining environment. Summary of the invention

[0004] The main purpose of the present invention is to provide a method for detecting the composition of additives in mechanical oil, so as to solve the problem that the composition of additives in gear oil and hydraulic oil cannot be comprehensively analyzed in the prior art.

[0005] In order to achieve the above-mentioned purpose, according to the first aspect of the present invention, there is provided a method for detecting the composition of additives in mechanical oil, characterized in that the detection method comprises: adding a recovery indicator to the mechanical oil to be tested, extracting and concentrating in sequence to obtain an extract; subjecting the extract to gel chromatography separation to obtain a liquid to be tested; using ion sources ESI+ and ESI- to perform liquid chromatography-mass spectrometry detection on the liquid to be tested and an additive standard, respectively, and obtaining a quantitative result of the additive composition in the mechanical oil by calculating through a standard curve equation; wherein the mechanical oil to be tested is gear oil and / or hydraulic oil.

[0006] By applying the technical solution of the present invention, by utilizing liquid chromatography-dual mass spectrometry, that is, simultaneously utilizing ion sources ESI+ and ESI- to perform mass spectrometry on standard additives and the machine oil to be tested, hundreds of additives in the machine oil can be quantified simultaneously, which is beneficial for accurately assessing the health risks and pollution sources in large-scale machinery operation areas (such as mining areas). It has the advantages of short time consumption, high throughput, and wide applicability, and can be promoted for large-scale use. DETAILED DESCRIPTION

[0007] It should be noted that, in the absence of conflict, the embodiments and features in the embodiments of the present application can be combined with each other. The present invention will be described in detail below in conjunction with the embodiments.

[0008] As mentioned in the background technology, there is no comprehensive detection method for the complex additive components in gear oil and / or hydraulic oil in the prior art, and the additive components therein may cause pollution to mining. How to obtain more accurate and comprehensive qualitative and quantitative results of complex additives in mechanical oil is of great significance to the sustainable mining construction of mining areas.

[0009] In a first typical embodiment of the present application, a method for detecting the composition of additives in mechanical oil is provided, the detection method comprising: adding a recovery indicator to the mechanical oil to be tested, extracting and concentrating in sequence to obtain an extract; subjecting the extract to gel chromatography separation to obtain a liquid to be tested; using ion sources ESI+ and ESI- to perform liquid chromatography-mass spectrometry detection on the liquid to be tested and an additive standard, respectively, and obtaining a quantitative result of the additive composition in the mechanical oil by calculating the standard curve equation; wherein the mechanical oil to be tested is gear oil and / or hydraulic oil.

[0010] The present application uses ion sources ESI+ and ESI- to perform liquid chromatography-mass spectrometry detection on different compound structures, respectively, and can obtain qualitative and quantitative results with better response and more accurate response. The present application uses a variety of additive standards for liquid chromatography-mass spectrometry detection, and further accurately indicates the mass spectrometry parameters of the additive standards by adding recovery rate indicators, so as to obtain more comprehensive parameters of additives that may be present in gear oil and / or hydraulic oil, which can provide support for the liquid chromatography-mass spectrometry detection results of the mechanical oil to be tested, and obtain more accurate qualitative and quantitative results.

[0011] In order to obtain more comprehensive qualitative and quantitative data of various additives in mechanical oils, as many comprehensive types of additives as possible are involved, including antioxidants, UV stabilizers, plasticizers, photoinitiators, retarders and flame retardants. In a preferred embodiment, the additive standard includes the compounds shown in the following table (the abbreviations, full names and corresponding CAS numbers of the additives are shown in Table 1):

[0012] Table 1:

[0013]

[0014]

[0015]

[0016]

[0017]

[0018]

[0019]

[0020] In order to further improve the detection accuracy of the additive in the mechanical oil to be tested, adding an isotope-labeled recovery indicator to the sample can significantly reduce the matrix effect and improve the accuracy and sensitivity of the detection. In a preferred embodiment, the recovery indicator includes: ATBC-d3, BzP-d10, BzP-d10, BEHA-d8, DOcTPh, DBzPh-d4, DEPh-d4, DEPh, DHxPh-d4, DprPh-d4, DiBPh-d4, DBPh-d4, DPePh-d4, mBPh-d4, mEHPh-d4, mBzPh-d4, d-TPHP, d-TBP, d-TCEP, d-TDCPP, d-TEP, BBOEP-d8, BCIPP-d12, BDCPP-d10, BEHP-d34, DBP-d18, DoCP-d14 or DPHP-d10.

[0021] Different additives have different physicochemical properties, and the types of applicable recovery rate indicators are also different. Different compounds need to be selected as the recovery rate indicators of the corresponding additives. The specific types of recovery rate indicators corresponding to each additive are shown in Table 2 below.

[0022] Table 2:

[0023]

[0024]

[0025]

[0026]

[0027]

[0028]

[0029]

[0030]

[0031] In order to prepare a sample suitable for liquid chromatography-mass spectrometry detection, in a preferred embodiment, the mass ratio of the machine oil to be tested to the recovery indicator is 1:100000000-500000000. The machine oil to be tested is a mixture, containing impurities and components that actually need to be detected.

[0032] In order to further extract the components of relevant additives in the mechanical oil to be tested and remove some irrelevant impurities, in a preferred embodiment, the extraction includes: recording the mechanical oil to be tested with the recovery indicator added as a mixed liquid; adding a first organic solvent to the mixed liquid, and performing ultrasonic extraction and centrifugation in sequence to obtain a first extracted clear liquid; preferably, the first organic solvent includes saturated acetonitrile with n-hexane; preferably, the mass ratio of the mixed liquid to the first organic solvent is 1:20; preferably; preferably, the ultrasonic extraction time is 10 minutes.

[0033] To obtain a sample solution with clear solvent composition, in a preferred embodiment, the concentration includes: nitrogen blowing and concentrating the first extract to complete dryness, dissolving it with a second organic solvent to obtain an extract, preferably, the second organic solvent includes n-hexane.

[0034] In order to further obtain a purer sample containing additives, the extract needs to be further separated and purified. In a preferred embodiment, the gel chromatography column for gel chromatography separation is a 50 cm×1.5 cm glass column; preferably, the glass column is filled with biobads filler.

[0035] In a preferred embodiment, gel chromatography separation includes: activating a gel chromatography column; adding an extract to the activated gel chromatography column for elution to obtain a liquid to be tested; preferably, activating the gel chromatography column includes: adding a third organic solvent to the gel chromatography column for activation for 6-8 hours; preferably, the volume of the third organic solvent is 50 mL; preferably, the third organic solvent includes a mixed solution of dichloromethane and n-hexane.

[0036] In order to further obtain a sample with a relatively pure content to be tested, in a preferred embodiment, elution includes: eluting the extract with a third organic solvent to obtain an eluent; nitrogen blowing and concentrating the eluent to completely dry it, dissolving it with a fourth organic solvent, adding an internal standard compound, and obtaining a liquid to be tested; preferably, the fourth organic solvent includes methanol; preferably, the volume of the fourth organic solvent is 50 μL. This application uses the peak value of the internal standard with a known content as a reference in the preparative liquid chromatography-mass spectrometry detection to calculate the peak content of the subsequent mechanical oil to be tested. In a preferred embodiment, the internal standard compound includes: methidathion-d10 (CAS No. 287397-86-8), bisphenol A-d16 or perfluorooctanoic acid. Preferably, the mass ratio of the mechanical oil to be tested to the internal standard compound is 1:100000000-500000000.

[0037] In order to obtain more accurate qualitative and quantitative results of additives, in a preferred embodiment, the chromatographic column for liquid chromatography-mass spectrometry detection is Omega 3μm PS C18 100A-LC Column, specification is 100×3.0mm; preferably, the conditions of liquid chromatography are as follows: column temperature: 40°C, mobile phase: phase A is 0.02mM ammonium acetate aqueous solution, phase B is methanol, gradient program is: 0-2min, mobile phase B volume fraction is 10%; 2-6min, mobile phase B volume fraction is 70%, 6-22min, mobile phase B volume fraction is 99%, 22-22.1min, mobile phase B volume fraction is 10%, and maintained for 3min; flow rate is 0.4mL / min, injection volume is 5μL.

[0038] In order to obtain more accurate qualitative and quantitative results of the additive, in a preferred embodiment, the conditions of mass spectrometry detection are respectively a first detection condition and a second detection condition. Preferably, the first detection condition is: electrospray ion source, ion temperature is 550°C, detection mode is positive ion detection mode; nebulization gas pressure: nitrogen, pressure level is 55psi; Preferably, the second detection condition is: electrospray ion source, ion temperature is 550°C, detection mode is negative ion detection mode; nebulization gas pressure: nitrogen, pressure level is 55psi.

[0039] By performing mass spectrometry on the additive standard, the specific parameters of the qualitative ion pair and the quantitative ion pair of the additive standard with known components (i.e., the precursor ion (Q1), the reaction ion (Q3), the declustering voltage and the collision energy in the first mass spectrometry parameter value and the second mass spectrometry parameter value as shown in Table 3) are obtained. The first mass spectrometry parameter value and the second mass spectrometry parameter value are used to set the corresponding numerical values ​​during the mass spectrometry detection of the mechanical oil sample to be tested, so as to observe whether the corresponding peak exists, so as to determine whether the mechanical oil to be tested contains the corresponding additive. In addition, the peak area of ​​the internal standard compound with a known content is used to further confirm the content of the detected additive. In a preferred embodiment, the mass spectrometry parameter values ​​of the additive standard are shown in the following table:

[0040] Table 3:

[0041]

[0042]

[0043]

[0044]

[0045]

[0046]

[0047]

[0048] The present application is further described in detail below in conjunction with specific embodiments. These embodiments should not be construed as limiting the scope of protection claimed in the present application.

[0049] Example 1

[0050] In this embodiment, four types of gear oils and two types of hydraulic oil samples collected from a coal mining area were selected and mixed, and the mixture was used for subsequent testing of the additive composition.

[0051] Reagents and materials:

[0052] The additive standards used in this application include 48 flame retardants, 35 antioxidants, 25 UV stabilizers, 77 plasticizers, 15 photoinitiators and 4 retarders, all purchased from AccuStandard, Sigma-Aldrich, Wellington Laboratories, Canada or Toronto Research Chemicals, Canada. In addition, there are 28 isotope-labeled recovery indicators and 3 internal standards. Detailed information on the types of additive standards, isotope-labeled recovery indicators and internal standard compounds is shown in Tables 2 and 4.

[0053] Table 4:

[0054]

[0055] Sample pretreatment and instrument analysis:

[0056] Take 0.1 g of a mixture of gear oil and hydraulic oil, add 1-5 ng of 28 corresponding isotopic recovery indicators as shown in Table 2, add 3 ml of the first organic solvent (n-hexane saturated acetonitrile), ultrasonically extract for 10 min, centrifuge at 4000 rpm for 3 min (repeat twice), then concentrate to dryness with nitrogen blowing, and dissolve with 1 ml of the second organic solvent n-hexane to obtain an extract.

[0057] The extract was loaded into an activated gel chromatography column (50 cm × 1.5 cm glass column, filled with biobads filler and activated for 6 hours with 50 ml of the third organic solvent (dichloromethane: n-hexane, 1:1)), and an elution solvent (dichloromethane: n-hexane, 1:1) was added for elution. The collected 65 ml of the eluate was concentrated again, re-dissolved with 50 μl of the fourth organic solvent, methanol, and 1.5 ng of each of the three internal standard compounds was added to obtain the solution to be tested.

[0058] Liquid chromatography-mass spectrometry (LC-MS) was used to quantitatively analyze the additive standards, where the liquid chromatography parameters were set as shown in Table 5 and the mass spectrometry parameters were set as shown in Table 6. According to the properties of the standard products, the content was determined by internal standard method, and the first mass spectrometry parameters and second mass spectrometry parameters of various additive standards were obtained as shown in Table 3, providing data support for the subsequent qualitative analysis of the mechanical oil to be tested.

[0059] Among them, a series of measures were taken to ensure the quality of analysis, and a laboratory blank sample was set in each batch of oil samples. Some compounds were detected in the laboratory blank, but they were all far lower than the sample concentration. The limit of quantification (LOQ) of the method is defined as the compound concentration corresponding to a response that is 10 times the standard deviation of the noise. If the LOQ is lower than the lowest concentration of the quantitative standard curve or the background contamination value in the blank, the higher of the latter is used. The LOQs of all compounds range from 0.018 to 12.8 ng / g.

[0060] Table 5:

[0061]

[0062] Table 6:

[0063] Ion source type Ion temperature Detection Mode Atomizing air pressure pressure The first test condition Electrospray 550℃ Positive ion detection Nitrogen 55psi Second test condition Electrospray 550℃ Negative ion detection Nitrogen 55psi

[0064] Analysis results:

[0065] The mechanical oil to be tested was subjected to liquid chromatography-mass spectrometry using the same experimental conditions as the above-mentioned additive standards.

[0066] A total of 36 additives were detected in the mixture of hydraulic oil and gear oil in the tested mechanical oil, of which UV stabilizers accounted for 86.04% of the total concentration, followed by flame retardants (7.82%), plasticizers (4.56%), and antioxidants (1.58%). The concentrations (ng / g) of each target compound are shown in Table 7.

[0067] Table 7:

[0068]

[0069]

[0070] From the above description, it can be seen that the above-mentioned embodiments of the present invention achieve the following technical effects: by using the liquid chromatography-mass spectrometry detection method of the present application, combined with the mass spectrometry parameters of the additive standard mentioned in the present application, the content of various additives in gear oil and hydraulic oil can be detected efficiently and accurately. And by using recovery indicators and internal standards, the accuracy and reliability of detection are improved. At the same time, through further purification by gel chromatography columns, impurities in the sample are effectively removed, ensuring the purity of the target compound, thereby improving the accuracy and selectivity of detection.

[0071] In addition, the detection method of the present application is applicable to hundreds of different types of additives, has wide applicability and flexibility, and provides strong technical support for the quality control of mechanical oils and additive research, which is of great significance to the sustainable production of mining areas.

[0072] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A method for detecting the composition of additives in mechanical oil, characterized in that: The detection method comprises: Adding a recovery rate indicator to the machine oil to be tested, extracting and concentrating in sequence to obtain an extract; The extract is subjected to gel chromatography separation to obtain a liquid to be tested; Using ion sources ESI+ and ESI- to perform liquid chromatography-mass spectrometry detection on the test liquid and the additive standard, respectively, and obtaining the quantitative result of the additive composition in the mechanical oil by calculating the standard curve equation; Wherein, the mechanical oil to be tested is gear oil and / or hydraulic oil.

2. The detection method according to claim 1, characterized in that: The additive standards include the compounds shown in the following table:

3. The detection method according to claim 1, characterized in that: The recovery indicators include: ATBC-d3, BzP-d10, BzP-d10, BEHA-d8, DOcTPh, DBzPh-d4, DEPh-d4, DEPh, DHxPh-d4, DprPh-d4, DiBPh-d4, DBPh-d4, DPePh-d4, mBPh-d4, mEHPh-d4, mBzPh-d4, d-TPHP, d-TBP, d-TCEP, d-TDCPP, d-TEP, BBOEP-d8, BCIPP-d12, BDCPP-d10, BEHP-d34, DBP-d18, DoCP-d14 or DPHP-d10.

4. The detection method according to claim 1, characterized in that: The mass ratio of the tested mechanical oil to the recovery rate indicator is 1:100000000-500000000; Preferably, the extraction comprises: The machine oil to be tested with the recovery rate indicator added thereto is recorded as a mixed liquid; Adding a first organic solvent to the mixed solution, performing ultrasonic extraction and centrifugation in sequence, to obtain a first extraction clear solution; Preferably, the first organic solvent comprises n-hexane saturated acetonitrile; Preferably, the mass ratio of the mixed liquid to the first organic solvent is 1:20; Preferably, the ultrasonic extraction time is 10 min; Preferably, the concentration comprises: nitrogen blowing and concentrating the first extraction clear liquid to complete dryness, and dissolving it with a second organic solvent to obtain the extraction liquid; Preferably, the second organic solvent comprises: n-hexane.

5. The detection method according to claim 4, characterized in that: The gel chromatography column for the gel chromatography separation is a 50 cm×1.5 cm glass column; Preferably, the glass column is filled with biobads filler.

6. The detection method according to claim 5, characterized in that: The gel chromatography separation comprises: activating the gel chromatography column; Adding the extract to the activated gel chromatography column for elution to obtain the liquid to be tested; Preferably, activating the gel chromatography column comprises: adding a third organic solvent to the gel chromatography column and activating for 6-8 hours; Preferably, the volume of the third organic solvent is 50 mL; Preferably, the third organic solvent comprises a mixed solution of dichloromethane and n-hexane.

7. The detection method according to claim 6, characterized in that: The elution comprises: eluting the extract with the third organic solvent to obtain an eluate; The eluate is concentrated by nitrogen blowing to complete dryness, dissolved by a fourth organic solvent, and an internal standard compound is added to obtain the solution to be tested; Preferably, the internal standard compound includes: methidathion-d10, bisphenol A-d16 or perfluorooctanoic acid; Preferably, the fourth organic solvent comprises methanol; Preferably, the volume of the fourth organic solvent is 50 μL.

8. The detection method according to claim 1, characterized in that: The chromatographic column for carrying out the liquid chromatography-mass spectrometry detection is Omega 3μm PS C18 100A-LC Column, size: 100×3.0mm; Preferably, the conditions of the liquid chromatography are as follows: Column temperature: 40°C, mobile phase: phase A is 0.02 mM ammonium acetate aqueous solution, phase B is methanol, gradient program: 0-2 min, mobile phase B volume fraction is 10%; 2-6 min, mobile phase B volume fraction is 70%, 6-22 min, mobile phase B volume fraction is 99%, 22-22.1 min, mobile phase B volume fraction is 10%, and keep for 3 min; The flow rate was 0.4 mL / min and the injection volume was 5 μL.

9. The detection method according to claim 1, characterized in that: The mass spectrometry detection conditions are respectively the first detection condition and the second detection condition; Preferably, the first detection condition is: electrospray ion source, ion temperature is 550°C, detection mode is positive ion detection mode; atomization gas pressure: nitrogen, pressure level is 55psi; Preferably, the second detection condition is: electrospray ion source, ion temperature is 550° C., detection mode is negative ion detection mode; atomization gas pressure: nitrogen, pressure level is 55 psi.

10. The detection method according to claim 1, characterized in that: The mass spectrometry parameter values ​​of the additive standards are shown in the following table:

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