JPH1038878A - Quantitative testing method of peripheral oil kind in light oil - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable quantitative test of peripheral oil type to be calculated from an calibration curve by mixing a light oil sample with a specific rate of dilution agent, alkali solution, and alcohol solution, extracting coumarin in the light oil, exciting ultraviolet ray, and measuring fluorescent intensity. SOLUTION: A test tube 3 in which light oil samples are put is set in a sample chamber 2 of a fluorescence spectrophotometer 1, ultraviolet rays are applied to the samples from a excitation light source chamber 5, and fluorescent intensity of fluorescent light generated from the samples is measured by a fluorescent measuring chamber 6. The sample chamber 2 has an excitation light source window 7 and a fluorescent intensity measuring window 8, and a stirrer 9 is provided at a bottom part of the sample test tube 3. Diluent n-dodecane is diluted with an approx. 4 to 8 volume relevant to an approx. 1 volume of samples, mixed by adding an approx. 4 to 6 volume of alkali solution and an approx. 6 to 10 volume of alcohol solution, shaked, and left statically, and coumarin in the light oil is extracted in solution and hydrolyzed. The extraction solution is excited by ultra-violet rays of approx. 360nm, and mixture rate of the coumarin-added oil in the light oil is calculated from fluorescent intensity of approx. 500nm specific to coumarin based on calibration curve.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for quantitatively determining the type of peripheral oil in light oil and a quantitative test apparatus therefor.

[0002]

2. Description of the Related Art Conventionally, the Agency for Natural Resources and Energy of the Ministry of International Trade and Industry has decided to add coumarin to oil types around gas oil, Detailed rules have been established. From the standpoint of normalizing the distribution order of diesel oil by preventing tax evasion of the diesel oil tax, the Agency adds 1 ppm of coumarin to diesel oil around oil (kerosene and heavy oil A) with a certain degree of accuracy to mix it with diesel oil. We are developing a system that allows for quick and simple checks of the information. Conventional coumarin analysis methods include a simple measurement method used as primary screening on the road and the like, and a quantitative analysis method that uses a spectrofluorometer in a laboratory or the like to quantify coumarin and determine the mixing ratio of coumarin-added oil from a calibration curve. Two methods are mainly used. In the current quantification method, 20 ml of a sample is diluted with 180 ml of n-dodecane, a predetermined amount of an alkali solution and an alcohol solution having a predetermined concentration prepared in advance are added, and the mixture is vigorously shaken to extract coumarin in the sample into the alkali layer. 5 ml of this alkaline solution
Was diluted 10-fold with water, and then diluted 36 times using a spectrofluorometer.
The fluorescence intensity at 500 nm when irradiated with ultraviolet light at 0 nm is measured, and the mixing ratio of the coumarin-added oil to the sample is calculated based on the calibration curve prepared from the standard solution. As a conventional simple measuring method, a sample of 20 ml is taken in a screw-mouth test tube, a predetermined amount of an alkali solution and an alcohol solution having a predetermined concentration prepared in advance are added and shaken vigorously to extract coumarin in the sample into an alkali layer. I do. The alkali layer is irradiated with ultraviolet light for a certain period of time using a fluorescent colorimetric juice, and a separately prepared colorimetric standard solution (containing 0.035 mg / l of coumarin) is compared with a green fluorescent hue and luminance unique to coumarin and visually observed. This is a method for discriminating light oil around mixed light oil types.

[0003]

However, the current quantitative analysis method described above has a poor operability because the extraction operation is performed with a total of nearly 250 ml of an alkaline solution or an organic solvent in a 500 ml separating funnel. The operation was complicated, such as diluting the alkaline solution with water even after extracting the alkaline solution into the alkaline solution, and the analysis required time and skill. Even if the analysis was successful, the separatory funnel after the measurement was muddy with alkaline solution and oil, so it was necessary to take some time to wash the instruments or leave them for a while with the stopper still on. There was a problem that the alkali was hardened at the mouth of the separating funnel and the stopper could not be removed, and the expensive separating funnel had to be discarded. Therefore, there is a demand for a method and an apparatus for quantifying the workability with good reproducibility in a short time.

[0004]

Means for Solving the Problems In order to solve the above-mentioned problems, the present inventors have conducted intensive studies and found that a diluent, an alkali solution and an alcohol solution were used in a specific ratio with respect to a light oil sample.
Coumarin in light oil is extracted into an aqueous solution, excited by ultraviolet light of a specific wavelength, the fluorescence intensity of coumarin is measured, and a quantitative test of the peripheral oil type in light oil can be performed from a specific formula obtained from a calibration curve. The inventors have found that the above-mentioned problems can be solved, and have reached the present invention. That is, (1) a light oil sample of the present invention is diluted with a diluent n-dodecane in a test tube for quantification, an alkali solution and an alcohol solution are added thereto, mixed and shaken, and then allowed to stand, and coumarin contained in the light oil is diluted. Is extracted into an aqueous solution, hydrolyzed, and the extract is excited by ultraviolet light of 360 nm, and the mixing ratio of the coumarin-added oil in the light oil is calculated from the following calibration curve by the fluorescence intensity of 500 nm specific to coumarin. Quantitative test method of peripheral oil type in light oil, characterized by calculating and measuring

[0005]

(Equation 2)

(2) Diluent n-
(1) The quantitative test method described in (1), which is used in a ratio of 4 to 8 volumes of dodecane, 4 to 6 volumes of alkali solution and 6 to 10 volumes of alcohol solution, (3) 6 volumes of diluent n-dodecane per 1 volume of light oil sample, (1) The quantitative test method described in (1), which is used at a ratio of 5 volumes of an alkali solution and 8 volumes of an alcohol solution, and (4) a mixing and shaking time of 1 to 5 minutes, preferably 3 minutes.
The quantitative test method according to (1), wherein
(5) A spectrofluorimeter equipped with a quantitative test tube with a built-in stirrer, a device for irradiating ultraviolet light of 360 nm for isomerizing a coumarin hydrolyzate in an aqueous solution of the test tube, and a fluorescent intensity of 500 nm And a device for calculating the mixing ratio of the coumarin-added oil from the general formula obtained from the calibration curve. Quantitative test equipment, (6)
The light oil according to (5), wherein the spectrofluorometer comprises a sample chamber, an excitation-side wavelength selector for irradiating the sample chamber with ultraviolet light, and a fluorescence measurement chamber for measuring the fluorescence intensity from the sample chamber. (7) Quantitative test tube is a screw hole, flat bottom cylindrical glass tube, length 1
5-18, 1.5-2.0 cm in diameter (5)
The present invention relates to the quantitative test apparatus described above.

According to the present invention, coumarin contained in a sample oil is concentrated into an extract, hydrolyzed with an alkali, and cis-
-O-Hydroxycinnamic acid is converted to a trans-form which emits fluorescence by irradiating ultraviolet rays, and then quantitatively analyzed by measuring the fluorescence intensity. At this time, the sample oil also contains a substance (originating fluorescent substance) that emits fluorescence that interferes with the measurement of fluorescence from trans-o-hydroxycinnamic acid. It is necessary to prevent the influence of this derived fluorescent substance as much as possible. The conditions required for the extract in the above steps are as follows: (1) Coumarin is extracted faster and at a higher concentration. (2) The coumarin in the extract is rapidly hydrolyzed. (3) The derived fluorescent substance is not extracted. (4) Separation of the extract and the sample oil is fast. And the like. As a mixed extract satisfying these conditions, the following (A) alkaline solution, (B) alcohol solution,
(C) A hydrocarbon liquid is used. These, (A),
(B) and (C) are composition liquids having excellent performance which have been used and studied in the conventional coumarin determination method. (A) Alkaline liquid: 10 g of sodium hydroxide and 20 g of sodium nitrate were added to water to make 100 ml.
Potassium hydroxide can be used instead of sodium hydroxide, and potassium nitrate, sodium chloride, potassium chloride, or a solution obtained by variously combining them can be used instead of sodium nitrate. (B) Alcohol solution: a mixture of 4 parts of 1-butyl alcohol and 3 parts of ethyl alcohol, but a mixture of methyl alcohol, ethyl alcohol, various combinations of propyl alcohol and butyl alcohol, and a simple mixture of butyl alcohol One composition can be used. (C) Hydrocarbon liquid: n-dodecane is used.
In addition to dodecane, a hydrocarbon compound having no derived fluorescence of about C _{9 to} C ₁₃ can be used alone or in combination. In the present invention, the mixing ratio of the (A) alkali liquid, (B) alcohol liquid and (C) hydrocarbon liquid is important.

As shown in Table 1, various ratios of the liquid B and the liquid C can be used with respect to 1 part of the sample oil. Solution A acts on the hydrolysis of coumarin, and two or more parts can be used for one part of the sample oil.
Part is appropriate. About the ratio of B liquid and C liquid,
When the mixing ratio of the liquid (n-dodecane) is increased, the separation between the extract liquid phase and the sample oil phase is accelerated, but the influence of the fluorescent substance derived from the extract is increased. In addition, when the amount of the liquid B (alcohol liquid) is increased, the influence of the originating fluorescent substance can be greatly reduced, but on the contrary, the time of liquid phase separation becomes longer. From the viewpoint of the speed and accuracy of analysis, good results were obtained when the composition was as shown in Run4. That is, sample oil 1 part C liquid (n-dodecane) 6 parts B liquid (alcohol liquid) 8 parts A liquid (alkali liquid) 5 parts

[0009]

[Table 1]

In the present invention, a light oil sample is measured with a spectrofluorometer 1 having a structure as shown in FIG. A test tube 3 containing a sample is placed in a test tube holder in the sample chamber 2, and the sample in the test tube is irradiated with ultraviolet rays from an excitation light source (ultraviolet) chamber 5. The fluorescence intensity of the fluorescence generated from the sample irradiated with the ultraviolet rays is measured in the fluorescence measurement chamber 6. The sample chamber 2 has an excitation light irradiation window 7 and a fluorescence intensity measurement window 8. A stirrer 9 is provided at the bottom of the test tube 3. In the present invention, a screw mouth type flat bottom test tube shown in FIG. 2 is preferably used as the test tube. This screw-mouthed flat bottom test tube has a length of 15
１８18 cm, 1.5-2.0 cm in diameter, preferably 16.5 cm in length and 1.8 cm in diameter. For this screw-mouthed flat bottom test tube, the reagent ratio, isomerization conditions,
The shaking time was examined and the linearity was confirmed. As a result of the examination, the reagent ratio shown in Table 1 was 20 m in total amount of the reagent.
Sample: n-dodecane (solution C): alkaline solution (solution A): alcohol solution (solution B) 1: 6: 5: 8 m
l. However, the sample amount and the alkaline solution amount are 1 ml and 5 m
l and subtract 1 from 20 ml.
The ratio of n-dodecane to alcohol solution was examined for 4 ml. From the experiments, it was found that the separation time was slightly shorter when the amount of n-dodecane was larger, and the influence of the derived fluorescence was smaller when the amount of alcohol solution was larger. However, it was practically impossible to increase both in a limited amount of solution. Therefore, the ratio of the reagents was selected such that the influence of the derived fluorescence was equivalent to that of the current quantitative analysis method. As a result of studying the isomerization conditions, the bandwidth was 10 nm for both the excitation side and the fluorescence side, and the isomerization time was 5 minutes. The size of the stirrer was set to 1 mm × 5 mm made of iron in consideration of disposable use in the future. If the intensity of the stirrer is low, the isomerization will not be completed in 5 minutes, and if the intensity is too high, the fluorescence intensity may decrease. Therefore, check the optimal intensity scale of the stirrer in advance for each device. Is required. According to the examination result of the shaking time, the extraction efficiency was 97% or more if the shaking time was 3 minutes, and the extraction efficiency was 80% or more if the shaking time was 1 minute. As a result, a shaking time of 3 minutes was adopted. However, when time reduction was necessary, the reproducibility was good even if the shaking time was 1 minute. Therefore, if the reproducibility is confirmed in advance by strictly observing the shaking time, the shaking time may be 1 minute. it is conceivable that. In the confirmation of the linearity, the correlation coefficient r = 0.999 between the coumarin fluorescence intensity and the mixing ratio even under the condition that the shaking time is 1 minute.
A strong correlation of 9 is confirmed.

Based on the measurement conditions shown in Table 2, this time, the separation time, the isomerization time, the derived fluorescence, the confirmation of the quantitative property, and the comparison with the current quantitative analysis method (B) were measured for 30 kinds of the simulated samples. The practicality of the quantitative test method of the invention was examined. In addition, the analysis method flow chart of the quantitative test method (A) of the present invention and the current quantitative analysis method (B) is as shown in FIG. The test samples were as follows. * Test sample: A sample in which 10 types of coumarin 1 ppm added kerosene, LSA heavy oil, and ultra-LSA heavy oil were mixed into light oil at various mixing ratios. As a result, the following became clear. In the confirmation of the separation time, it was confirmed that the separation was almost completed in 1.5 minutes. In the confirmation of the isomerization time, isomerization was completed in 96 minutes or more in 3 minutes. In checking the fuel-derived fluorescence, it was examined whether the type of oil contaminated affected the fluorescence intensity. However, the value was little different from that of the n-dodecane-based standard sample. Seems small. In the confirmation of the quantitativeness, a strong correlation of a correlation coefficient r = 0.9999 was obtained between the mixing ratio and the fluorescence intensity with almost no influence of the fluorescence derived from the base oil or the mixed oil. For comparison with the current quantitative analysis method, the simulation method of the present method and the quantitative test method of the present invention were carried out on 27 simulated samples in which 9 types of light oil peripheral oil types (kerosene, heavy oil A) were mixed at 10% in 3 types of light oil. Analysis was performed by two methods to determine the mixing ratio. As shown in Table 3, the values are almost the same, and it can be said that the quantitative test method of the present invention is equivalent to the current quantitative analysis method. As described above, the quantitative test method of the present invention not only can obtain the same measurement results as the current quantitative analysis method, but also has advantages over the current quantitative method in view of simplicity, small sample size, and reduction in measurement time. You can see that.

[0012]

[Table 2]

[0013]

[Table 3]

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION The quantitative test method of the present invention can be performed according to the following procedure. 1. Apparatus and reagents to be used (1) Apparatus a. Spectrofluorimeter b. Shake meter (3) Reagents a. Alkaline liquid [Composition: sodium nitrate / sodium hydroxide = 10 g /
20 g (content in 100 ml of aqueous solution)] b. Alcohol solution (composition: 1-butanol / ethanol = 4/3) c. Coumarin standard solution for preparing a calibration curve (coumarin concentration 0.8
mg / l) (composition: coumarin / aromatic solvent / n-dodecane) d. 1. n-dodecane Preparation of a standard sample for preparing a calibration curve (when a coumarin standard solution having a coumarin concentration of 0.8 ppm is used) (1) Preparation of a 0% sample 7 ml of an n-dodecane solution is collected with a pipettor and placed in a flat bottom test tube. 8 ml of the alcohol solution is collected with a pipettor and placed in the flat-bottom test tube. Take 5 ml of the alkaline solution with a pipettor and place it in the flat-bottom test tube. Put in the stirrer piece. (2) Preparation of 20% sample 0.25 ml of coumarin standard solution is collected with a pipettor and placed in a flat bottom test tube. 6.75 ml of n-dodecane solution is collected with a pipettor and placed in the flat-bottom test tube. 8 ml of the alcohol solution is collected with a pipettor and placed in the flat-bottom test tube. Take 5 ml of the alkaline solution with a pipettor and place it in the flat-bottom test tube. Put in the stirrer piece. (3) Preparation of 40% sample A 0.5 ml coumarin standard solution is collected with a pipettor and placed in a flat bottom test tube. Take 6.5 ml of n-dodecane solution with a pipettor and place in the flat bottom test tube. 8 ml of the alcohol solution is collected with a pipettor and placed in the flat-bottom test tube. Take 5 ml of the alkaline solution with a pipettor and place it in the flat-bottom test tube. Put in the stirrer piece. (4) Preparation of 80% sample Take 1 ml of coumarin standard solution with a pipettor and put it in a flat bottom test tube. Take 6 ml of n-dodecane solution with a pipettor and place in the flat bottom test tube. 8 ml of the alcohol solution is collected with a pipettor and placed in the flat-bottom test tube. Take 5 ml of the alkaline solution with a pipettor and place it in the flat-bottom test tube. Put in the stirrer piece. (5) Shaking with a shaker and standing still The flat-bottom test tube of (1) to (4) in 2 was attached to the shaker,
Shake for 3 minutes. Each flat-bottom test tube is attached to a test tube stand, and allowed to stand for 5 minutes. Table 4 shows these calibration curve preparation samples.

[0015]

[Table 4]

3. Preparation of calibration curve Each of the flat-bottom test tubes is sequentially mounted on a spectrofluorometer, and a calibration curve is prepared. From the calibration curve, the following general formula, which is a linear regression formula, is obtained by the least squares method.

[0017]

(Equation 3)

4. Preparation of Quantitative Test Sample 1 ml of the test sample is collected with a pipettor and placed in a flat bottom test tube. Take 6 ml of n-dodecane solution with a pipettor and place in the flat bottom test tube. 8 ml of the alcohol solution is collected with a pipettor and placed in the flat-bottom test tube. Take 5 ml of the alkaline solution with a pipettor and place it in the flat-bottom test tube. Put in the stirrer piece. The flat bottom test tube is attached to a shaker and shaken for 3 minutes. The above flat-bottom test tube is attached to a test tube stand, and left still for 5 minutes. 5. Measurement of fluorescence intensity The flat-bottom test tube prepared in 4 was attached to a spectrofluorometer,
The fluorescence intensity x is measured and substituted into the above-mentioned linear regression equation obtained from the calibration curve to determine the mixing ratio of peripheral oil species.

[0019]

[Example 1]

1. Preparation of Calibration Curve A sample for preparing a calibration curve is equivalent to 0%, 20%, 40%, and 80% of the peripheral oil type mixing ratio (hereinafter referred to as mixing ratio) (coumarin content ratio 0 ppm, 0.2 ppm, 0.4 ppm). , 0.8
ppm) of each n-dodecane solution was collected in a flat bottom test tube (hereinafter referred to as a test tube) shown in FIG.
Dodecane solution 6ml, alcohol solution 8ml, alkali solution 5
ml, add a stirrer and cover. Each test tube is mounted on a shaker shown in FIG. 3 and shaken horizontally at a speed of 240 times / min or more for 3 minutes to hydrolyze coumarin in oil and extract it into an alkaline layer. After shaking, stand in a test tube stand 5
Let stand for minutes and separate into oil layer, alcohol layer and alkali layer. After the separation, the test tube was attached to the sample chamber of the spectrofluorometer shown in FIG.
Cis-o-Hydroxycinnamic acid is isomerized, and the time-dependent change in the fluorescence intensity at 500 nm (FIGS. 5 to 8) is monitored, and the end of the isomerization is confirmed when the fluorescence intensity becomes constant. 0%, 20%, after completion of isomerization
Fluorescence intensity is measured for peaks at 500 ± 10 nm for each of 40% and 80%, and the calibration curve (FIG. 9) is created by plotting the mixing ratio on the horizontal axis and the fluorescence intensity on the vertical axis. As shown in FIG. 10, isomerization by irradiation with ultraviolet rays at 360 nm is performed for about 3 minutes or more. The fluorescence intensity is measured at a fluorescence wavelength of 500 nm as shown in FIG. Table 5 shows the data for preparing the calibration curve.

[0020]

[Table 5]

A linear regression equation is obtained by substituting the above data, and is as follows.

[0022]

(Equation 4)

2. As an example of actual measurement of the peripheral oil type contamination rate of a sample gas oil, measurement of gas oil containing about 10% of kerosene is performed. 1 ml of sample gas oil was collected in a test tube, and 6 ml of n-dodecane solution, 8 ml of alcohol solution, and 5 m of alkali solution were collected.
1 is added, a stirrer is put in, and the lid is put. The test tube is mounted on a shaker and shaken horizontally at a speed of 240 times / min or more for 3 minutes to hydrolyze coumarin in the sample and extract it into an alkali layer. After shaking, stand in a test tube stand and let stand for 5 minutes to separate into an oil layer, alcohol layer and alkali layer. After the separation, the test tube was attached to the sample chamber of the spectrofluorometer, and the alkali layer was irradiated with ultraviolet light of 360 nm for 5 minutes to isomerize cis-o-hydroxycinnamic acid, and the change over time of the fluorescence intensity at 500 nm. Is monitored, and the gas oil mixing ratio of the sample is calculated from the calibration curve of FIG. 1 from the value at which the fluorescence intensity becomes constant. Measurement data Fluorescence intensity of sample gas oil: x = 112.6 is substituted into a calibration curve (formula). 112.6 = 9.729C + 3.085 C = 11.3% Therefore, the peripheral oil type contamination rate is 11.3% . .

[0024]

According to the present invention, the amount of reagent used is smaller than that of the conventional method, a sample can be prepared using only a test tube, and the test tube can be extracted in a short time by using a screw bottom flat bottom test tube and a stirrer. The effect of the method is extremely good, and the preparation of the calibration curve and the measurement of the sample at the time of measurement, for example, are 1/2 to 1 of the conventional method.
/ 3 hours.

[Brief description of the drawings]

FIG. 1 is a schematic structural diagram of a spectrofluorometer of the present invention.

FIG. 2 is a schematic external view of a flat bottom test tube.

FIG. 3 is an analysis method flow chart of a quantitative test method (A) of the present invention and a conventional quantitative analysis method (B).

FIG. 4 is a schematic external view of a shaker.

FIG. 5 is a graph showing the change over time in fluorescence intensity during isomerization at a peripheral oil species contamination rate of 0%.

FIG. 6 is a graph showing the change over time in the fluorescence intensity during isomerization at a peripheral oil species contamination rate of 20%.

FIG. 7 is a graph showing the change over time in fluorescence intensity during isomerization at a peripheral oil species contamination rate of 40%.

FIG. 8 is a graph showing a change over time in fluorescence intensity during isomerization at a peripheral oil species contamination rate of 80%.

FIG. 9 is a graph of a calibration curve.

FIG. 10 is a graph showing the change over time in the fluorescence intensity at the time of isomerization of a sample light oil (light oil containing about 10% of kerosene).

FIG. 11 is a graph of the fluorescence wavelength at the time of fluorescence intensity in the spectrum measurement of a sample light oil (light oil mixed with about 10% of kerosene).

[Explanation of symbols]

 1. Spectrofluorometer 2. 2. Sample chamber section Test tube 4. Test tube holder 5. 5. Excitation light source (ultraviolet ray) section 6. Fluorescence measurement room 7. Excitation light irradiation window 8. Fluorescence intensity measurement window Stirrer 10. Test tube lid 11. Shaker 12. Test tube fixing base 13. Timer 14. Switch 15. Speed adjustment dial

Claims (7)

[Claims] 1. A gas oil sample is diluted with a diluent n-dodecane in a test tube for quantification, an alkali solution and an alcohol solution are added thereto, mixed and shaken, and then allowed to stand, and the coumarin contained in the gas oil is dissolved in an aqueous solution. Extract and hydrolyze it, and
m, the coumarin-added oil in the light oil is calculated and measured based on the general formula obtained from the following calibration curve, based on the fluorescence intensity of 500 nm specific to coumarin. Quantitative test method for surrounding oil types. (Equation 1) 2. The quantitative test method according to claim 1, wherein 4 to 8 volumes of diluent n-dodecane, 4 to 6 volumes of alkaline solution and 6 to 10 volumes of alcohol solution are used per 1 volume of the gas oil sample. 3. The quantitative test method according to claim 1, wherein the diluent is used in a ratio of 6 volumes of a diluent, 5 volumes of an alkaline solution and 8 volumes of an alcohol solution per 1 volume of a light oil sample. 4. The quantitative test method according to claim 1, wherein the mixing and shaking time is 1 to 5 minutes, and then the mixture is allowed to stand for 4 to 6 minutes. 5. An apparatus for irradiating 360 nm ultraviolet light for isomerizing a coumarin hydrolyzate in an aqueous solution of a test tube, comprising a spectrofluorometer equipped with a quantitative test tube having a built-in stirrer, and a 500 nm 2. A peripheral oil in light oil for a quantitative test method of peripheral oil in gas oil according to claim 1, comprising a device for measuring fluorescence intensity and a device for calculating the mixing ratio of coumarin-added oil from a general formula obtained from a calibration curve. Seed quantitative test equipment. 6. A spectrofluorometer comprising a sample chamber, an excitation-side wavelength selector for irradiating the sample chamber with ultraviolet light, and a fluorescence measurement chamber for measuring the intensity of fluorescence from the sample chamber. Item 6. A quantitative test device for peripheral oil types in light oil according to item 5. 7. The quantitative test tube is a cylindrical glass tube having a screw mouth and a flat bottom, having a length of 15 to 18 and a diameter of 1.5 to 2.0.
The quantitative testing device for peripheral oil types in light oil according to claim 5, wherein