CN104807902B - The detection method of benzyldithio toluene and antioxidant in insulating oil - Google Patents
The detection method of benzyldithio toluene and antioxidant in insulating oil Download PDFInfo
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- CN104807902B CN104807902B CN201510209935.5A CN201510209935A CN104807902B CN 104807902 B CN104807902 B CN 104807902B CN 201510209935 A CN201510209935 A CN 201510209935A CN 104807902 B CN104807902 B CN 104807902B
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Abstract
The invention discloses the detection method of active sulfur and antioxidant in a kind of insulating oil, this detection method adopts gas chromatogram to detect, and comprises the steps: that (1) prepares standard solution; (2) sample pre-treatments; (3) measure. The present invention establishes chromatography of gases-electron capture detector (GC-ECD) accurate quantitative analysis and measures the method for benzyldithio toluene (DBDS) in insulating oil, GC-ECD method is in insulating oil 2 simultaneously, 6-toluene di-tert-butyl phenol (T501) also has good detection by quantitative effect, and this method can realize single injected sampling just can measure DBDS and T501 in insulating oil simultaneously.
Description
Technical field
The present invention relates to technical field of analysis and detection, particularly relate to the detection method of active sulfur and antioxidant in a kind of insulating oil.
Background technology
In recent years, there occurs the transformer fault that in many causes insulating oil, active sulfur causes both at home and abroad, the safe operation of electrical network is caused significant damage. Active sulfur refers to the element sulphur of the metal sulfide that can react under certain condition or unstable sulfide with metal, and metal is had stronger corrosivity by them. Active sulfur mainly has elemental sulfur, hydrogen sulfide, mercaptan and some micromolecular sulfide, they and copper metal reaction generate light blue and Dark grey deposit cuprous sulfide, this material is a kind of semiconductive material, penetrate into and Oil-Paper Insulation causes insulation breakdown so that transformer insulated hydraulic performance decline, greatly affect the safe and stable operation of transformator.
Benzyldithio toluene (DBDS) is the topmost active sulfur of transformer oil most typically, and it was found that is formed in the transformer oil of cuprous sulfide and all contains this material.At present, except mercaptan (R-SH) was once carried out except correlational study as the active sulfur in insulating oil by ABB AB, other unit is that DBDS launches research as the main corrosion sulfur in insulating oil mostly. Require that the DBDS content in transformer oil is less than 5mg/kg in the world, therefore that the detection by quantitative of active sulfur in transformer oil is very necessary also highly significant.
2,6-toluene di-tert-butyl phenols (T501) are a kind of antioxidants being added in insulating oil, it is therefore an objective to for the antioxygenic property of reinforced insulation oil. GB/T7595-2008 " in operation transformer oil quality " defines the content of T501 in fresh oil and reclaimed oil and is not less than 0.3%-0.5%, run oil and should be not less than 0.15%, then need to add lower than this regulation, therefore in actual production, also typically require the content of the T501 detected in insulating oil. At present, in detection insulating oil, the method for T501 has: spectrophotography, liquid chromatography and infrared spectrometry.
Therefore the detection method finding a kind of active sulfur that can simultaneously detect in insulating oil and antioxidant can save substantial amounts of manpower and materials, be greatly improved detection efficiency, has important practical application meaning.
Summary of the invention
Based on this, it is an object of the invention to provide the detection method of active sulfur and antioxidant in a kind of insulating oil.
Concrete technical scheme is as follows:
The detection method of benzyldithio toluene and antioxidant in a kind of insulating oil, adopts gas chromatogram to detect, comprises the steps:
(1) standard solution is prepared
Precision weighs benzyldithio toluene, adds transformator blank oil, prepares the benzyldithio toluene standard solution of desired concn;
Precision weighs the standard substance of antioxidant, adds transformator blank oil, prepares the antioxidant standard solution of desired concn;
Precision weighs Diphenyl disulfide ether, adds isobutyltrimethylmethane., prepares the interior mark liquid of desired concn;
(2) sample pre-treatments
Precision weighs standard solution or insulating oil testing sample, and in adding, mark liquid, adds isobutyltrimethylmethane., and vibration obtains standard solution sample or need testing solution;
(3) measure
Chromatographic condition: post case initial temperature is 80-90 DEG C, is warming up to 275-285 DEG C with the speed of 9-11 DEG C/min, keeps 10-15min; Detector temperature is 338.0-342.0 DEG C, and injector temperature is 248.0-252.0 DEG C; Carrier gas is the high pure nitrogen of purity 99.99%, adopts the split ratio of 20:1, and make-up gas flow is 55-65ml/min, and chromatographic column flow is 0.648ml/min;
Accurate absorption standard solution sample, injection gas chromatography, measure to obtain standard curve;
Accurate need testing solution of drawing, injection gas chromatography, measure, to obtain final product.
Wherein in an embodiment, described antioxidant is 2,6-toluene di-tert-butyl phenols.
Wherein in an embodiment, described chromatographic condition is: post case initial temperature is 90 DEG C, is warming up to 280 DEG C with the speed of 10 DEG C/min, keeps 10min; Detector temperature is 340.0 DEG C, and injector temperature is 250.0 DEG C; Carrier gas is the high pure nitrogen of purity 99.99%, adopts the split ratio of 20:1, and make-up gas flow is 60ml/min, and chromatographic column flow is 0.648ml/min.
Wherein in an embodiment, with described gas chromatogram with the use of detector be electron capture detector.
Wherein in an embodiment, in step (2), the filter element used in described filtration step is 0.22 ��m.
Beneficial effects of the present invention is as follows:
(1) present invention establishes gas chromatography-electron capture detector (GC-ECD) accurate quantitative analysis and measures the method for benzyldithio toluene (DBDS) in insulating oil, (method is in insulating oil 2 for GC-ECD simultaneously, 6-toluene di-tert-butyl phenol (T501) also has good detection by quantitative effect, this method can realize single injected sampling just can measure DBDS and T501 in insulating oil simultaneously, save a large amount of manpower and materials, improve detection efficiency, there is important practical application meaning.
(2) in the method mensuration insulating oil, DBDS and T501 has good accuracy, and recovery of standard addition is all between 90%-110%; Having good repeatability, within the relative standard deviation 6.3% of 5 measurement results of DBDS, the relative standard deviation of 5 measurement results of T501 is within 6.2%.
(3) GC-ECD method measures the detection limit of DBDS in insulating oil and quantitative limit is 0.05mg/kg and 0.1mg/kg respectively, measures detection limit and quantitative limit respectively 2.5mg/kg and the 10mg/kg of T501 in insulating oil.
Accompanying drawing explanation
Fig. 1 is the gas chromatogram of DBDS, T501 and DPDS;
Fig. 2 is the standard curve of DBDS;
Fig. 3 is the standard curve of T501.
Detailed description of the invention
By the following examples the application is further elaborated.
1.1 instrument and equipments
Gas chromatograph: Agilent7890A; Chromatographic column, 5% phenyl polysiloxane of 30m �� 0.25mm �� 0.1 ��m and 95% methyl polysiloxane fix phase; Electron capture detector; Agilent chromatographic work station; Analytical balance, is accurate to 0.001g.
1.2 reagent
NynasNytroLibra blank oil (transformator blank oil), without test substance; Benzyldithio toluene (DBDS), analytical pure; Isobutyltrimethylmethane., analytical pure; Diphenyl disulfide ether (DPDS), analytical pure; 2,6-toluene di-tert-butyl phenols (T501), analytical pure.
1.3 processs of the test
1.3.1 standard solution preparation
With analytical balance precise DBDS and T501 solid, making solvent with NynasNytroLibra blank oil, being configured to DBDS content be 1000mg/kg, T501 content is the stock solution of 10000mg/kg. Continue with NynasNytroLibra blank oil dilution stock solution, the standard solution of preparation desired concn. In 6 kinds of standard solution of preparation, DBDS concentration is 5mg/kg, 50mg/kg, 100mg/kg, 200mg/kg, 400mg/kg and 600mg/kg respectively, the concentration of T501 respectively 50mg/kg, 500mg/kg, 1000mg/kg, 2000mg/kg, 4000mg/kg and 6000mg/kg. With marking liquid in the DPDS that isobutyltrimethylmethane. compound concentration is 50mg/kg. Standard solution and interior mark liquid are saved in Brown Glass Brown glass bottles and jars only and seal and be placed in shady place.
1.3.2 sample treatment
Take out 0.25g oil sample in centrifuge tube with analytical balance, add mark liquid in 0.25gDPDS, then be diluted to 5g with isobutyltrimethylmethane., after shaking up, extract 1.5ml solution with 5ml syringe, stand-by with injecting in sample injection bottle after 0.22 ��m of filter element filtering.
2 result of the tests and discussion
2.1 qualitative tests
Regulate and instrument parameter is set, when instrument parameter is: initial temperature is 90 DEG C, being increased to 280 DEG C with the speed of 10 DEG C/min, keeping 10min; Detector temperature 340.0 DEG C, injector temperature is 250.0 DEG C; Carrier gas is purity is the high pure nitrogen of 99.99%, adopt the split ratio of 20:1, make-up gas flow is 60ml/min, chromatographic column flow is 0.648ml/min, after gas chromatogram and ECD detector are stable, solution injection instrument after filtering is detected, it is determined that the retention time of DBDS, T501, DPDS, as shown in Figure 1. From fig. 1, it can be seen that the appearance time of T501 was at about 10.6 minutes, the appearance time of DPDS is at about 14.9min, and the appearance time of DBDS is at about 16.5min, and three kinds of material peak shapes are good, separate substantially, it is possible to carry out respectively quantitatively.
2.2 quantitative tests
By the standard solution for preparing by 1.3.2 step process, then the titer of variable concentrations is analyzed, records the response value that each solubility is corresponding. By linear fit response value-concentration, obtain the standard curve of DBDS and T501 as shown in Figures 2 and 3.The relative coefficient that the relative coefficient of DBDS standard curve is 0.9998, T501 standard curve is 0.9925, illustrates that dependency is good, it is possible to effectively DBDS and T501 in detection insulating oil.
In order to verify the accuracy of this method further, prepare the titer of three parts of concentration known according to test procedure 1.3, be labeled as sample 1 (DBDS concentration is 80mg/kg, T501 concentration is 800mg/kg), sample 2 (DBDS concentration is 150mg/kg, T501 concentration is 1500mg/kg) and sample 3 (DBDS concentration is 350mg/kg, T501 concentration is 3500mg/kg). These 3 samples are measured 5 times respectively, and measurement result is as shown in table 1.
Table 1 is analyzed from DBDS and the T501 response rate of dosing
As can be seen from Table 1, for DBDS and the T501 in autogamy sample 1,2 and 3, its recovery of standard addition is all between 90%-110%, and this illustrates that the method has good accuracy, it is possible to effectively detect DBDS and the T501 content in insulating oil. Simultaneously, in order to illustrate that this method measures the accuracy of low concentration DBDS, two samples that concentration is 2mg/kg and 8mg/kg are also prepared, parallel assay three times, measurement result is 2.11mg/kg, 1.87mg/kg, 1.98mg/kg and 8.15mg/kg, 8.43mg/kg, 8.65mg/kg respectively, meansigma methods is 1.99mg/kg and 8.41mg/kg respectively, and this illustrates that GC-ECD method also has fairly accurate mensuration ability for the DBDS sample of low concentration.
Draw oil sample from 4 operating transformers 4 parts, be labeled as sample 4 to sample 7. Carrying out sample treatment according to step 1.3.2 and measure the concentration of DBDS and T501 in sample, each sample parallel measures 5 times, and test result is in Table 2. From table 2 it can be seen that within the relative standard deviation 6.3% of the 5 of DBDS measurement results, the relative standard deviation of 5 measurement results of T501, within 6.2%, illustrates that this method measures the repeated fine of DBDS and the T501 in operating transformer oil.
The repeatability analysis of table 2DBDS and T501
The determination of 2.3 detection limits and quantitative limit
Detection limit refers to the Cmin or content that produce certain element required for an analysis signal that can be reliably detected, and quantitative limit then refers to the actual limit that can reach of quantitative analysis. IUPAC (IUPAC) advises, determines the detection limit of mass spectrometer with signal to noise ratio 2:1 or 3:1. Meanwhile, the general sample introduction concentration corresponding by 10 times of signal to noise ratios or sample size represent quantitative limit.
2.3.1DBDS detection limit and quantitative limit
Prepare the titer that concentration is 1mg/kg and 2mg/kg, test its signal to noise ratio respectively 5.1 and 14.8, titer for both concentration, from the sample handling processes of 1.3.2 it is known that, actual sample introduction concentration is equivalent to dilute 20 times, thus may determine that detection is limited to 0.05mg/kg, quantitative limit is 0.1mg/kg.
2.3.2T501 detection limit and quantitative limit
The signal to noise ratio of 50mg/kg titer is the signal to noise ratio of 4.6,200mg/kg titers is 15.6, it is thus determined that detection is limited to 2.5mg/kg, is quantitatively limited to 10mg/kg.
3 conclusions
(1) present invention establishes a kind of accurate quantitative analysis and measures the method for DBDS in insulating oil, T501 in insulating oil is also had good detection by quantitative effect by the method simultaneously, this method can realize single injected sampling just can measure DBDS and T501 in insulating oil simultaneously, can use manpower and material resources sparingly in a large number, improve detection efficiency, there is important practical application meaning.
(2) in the method mensuration insulating oil, DBDS and T501 has good accuracy, and recovery of standard addition is all between 90%-110%;Having good repeatability, within the relative standard deviation 6.3% of 5 measurement results of DBDS, the relative standard deviation of 5 measurement results of T501 is within 6.2%.
(3) GC-ECD method measures the detection limit of DBDS in insulating oil and quantitative limit is 0.05mg/kg and 0.1mg/kg respectively, measures detection limit and quantitative limit respectively 2.5mg/kg and the 10mg/kg of T501 in insulating oil.
Each technical characteristic of embodiment described above can combine arbitrarily, for making description succinct, the all possible combination of each technical characteristic in above-described embodiment is not all described, but, as long as the combination of these technical characteristics is absent from contradiction, all it is considered to be the scope that this specification is recorded.
Embodiment described above only have expressed the several embodiments of the present invention, and it describes comparatively concrete and detailed, but can not therefore be construed as limiting the scope of the patent. It should be pointed out that, for the person of ordinary skill of the art, without departing from the inventive concept of the premise, it is also possible to making some deformation and improvement, these broadly fall into protection scope of the present invention. Therefore, the protection domain of patent of the present invention should be as the criterion with claims.
Claims (5)
1. the detection method of benzyldithio toluene and antioxidant in an insulating oil, it is characterised in that adopt gas chromatogram to detect, comprise the steps:
(1) standard solution is prepared
Precision weighs benzyldithio toluene, adds transformator blank oil, prepares the benzyldithio toluene standard solution of desired concn;
Precision weighs the standard substance of antioxidant, adds transformator blank oil, prepares the antioxidant standard solution of desired concn; Described antioxidant is 2,6-toluene di-tert-butyl phenol;
Precision weighs Diphenyl disulfide ether, adds isobutyltrimethylmethane., prepares the interior mark liquid of desired concn;
(2) sample pre-treatments
Precision weighs standard solution or insulating oil testing sample, and in adding, mark liquid, adds isobutyltrimethylmethane., and vibration obtains standard solution sample or need testing solution;
(3) measure
Chromatographic condition: post case initial temperature is 80-90 DEG C, is warming up to 275-285 DEG C with the speed of 9-11 DEG C/min, keeps 10-15min; Detector temperature is 338.0-342.0 DEG C, and injector temperature is 248.0-252.0 DEG C; Carrier gas is high-purity helium of purity 99.99%, adopts the split ratio of 20:1, and make-up gas flow is 55-65ml/min, and chromatographic column flow is 0.648ml/min;
Accurate absorption standard solution sample, injection gas chromatography, measure to obtain standard curve;
Accurate need testing solution of drawing, injection gas chromatography, measure, to obtain final product.
2. detection method according to claim 1, it is characterised in that described chromatographic condition is: post case initial temperature is 90 DEG C, is warming up to 280 DEG C with the speed of 10 DEG C/min, keeps 10min; Detector temperature is 340.0 DEG C, and injector temperature is 250.0 DEG C; Carrier gas is high-purity helium of purity 99.99%, adopts the split ratio of 20:1, and make-up gas flow is 60ml/min, and chromatographic column flow is 0.648ml/min.
3. the detection method according to any one of claim 1-2, it is characterised in that with described gas chromatogram with the use of detector be electron capture detector.
4. the detection method according to any one of claim 1-2, it is characterised in that the detection limit of benzyldithio toluene and quantitative limit respectively 0.05mg/kg and 0.1mg/kg.
5. the detection method according to any one of claim 1-2, it is characterised in that the detection limit of described antioxidant and quantitative limit respectively 2.5mg/kg and 10mg/kg.
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| CN105974042A (en) * | 2016-07-20 | 2016-09-28 | 黑龙江省电力科学研究院 | Reversed phase high performance liquid chromatography method for determining content of dibenzyl disulfide in insulating oil |
| CN106248912B (en) * | 2016-07-21 | 2018-04-03 | 广东电网有限责任公司电力科学研究院 | A kind of characterizing method of transformer oil ageing |
| CN107367559B (en) * | 2017-07-19 | 2019-10-01 | 云南电网有限责任公司电力科学研究院 | The detection method of oxidation preventive content in a kind of insulating oil |
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