GB/T 12902-2026Analytical methods for turpentine (English PDF)

5.5 Apparatus for determining initial boiling point and distillate volume fraction

5.5.1 Manual Distillation Range Measurement Apparatus It conforms to the requirements of SH/T 0121.A schematic diagram of the device is shown in Figure 1, and the reducing cylinder is shown in Figure

2.The main components meet the following requirements. Require.

a) Engler distillation flask. capacity 100mL, total height 215mm, outer diameter 70mm, inner diameter of neck 16mm.

b) Thermometer. Rod-type partial immersion mercury thermometer with an expansion chamber, immersion depth 100mm, distance between the bottom of the mercury bulb and the top of the expansion chamber. The graduation should be less than 30mm from the bottom of the mercury bulb, starting at 140mm from the bottom. The graduation range is 140°C to.200°C. 0.5°C, maximum error ±0.5°C, scale length 140mm±10mm, thermometer total length 300mm±10mm, mercury bulb Diameter 4.5mm~6.0mm, height 10mm, rod diameter 6.5mm (maximum not exceeding 7.5mm).

c) Graduated cylinders with varying diameters. 100mL capacity, graduations from 5mL to 84mL in 1mL increments, and graduations from 84mL to 100mL in... The graduation value is

0.2 mL. The distance from the 100 mL mark to the edge of the graduated cylinder mouth is approximately 60 mm.

d) Heat source. Heating rate is adjustable.

5.5.2 Fully Automated Distillation Range Analyzer It meets the requirements of SH/T 0121.

5.6 Other Instruments

5.6.1 Colorimeter. The technical requirements for artificial daylight colorimeters and corresponding lighting sources shall comply with the provisions of GB/T 9761.

5.6.2 Colorimetric tubes. flat-bottomed, 100mL capacity, fitted with optically clear ground glass stoppers. All colorimetric tubes should have consistent color and thickness. The 275mm~295mm range should be marked with graduation lines. The graduation lines of the colorimetric tubes used in the same measurement should not differ by more than ±3mm.

5.6.3 Glass test tube. transparent, colorless, cylindrical, with an inner diameter of

10.65 mm and a length of 114 mm.

5.6.4 Alkaline burette. 10 mL capacity,

0.05 mL graduation.

5.6.5 Erlenmeyer flask. 250mL capacity.

5.6.6 Analytical balance. accuracy not less than 0.0001g.

5.6.7 Barometer. accuracy not less than

0.1 kPa.

According to the sampling rules specified in GB/T 12901, at least 1000 mL of sample shall be taken from the same batch of products, mixed thoroughly, and divided equally. Divide into two portions. one for testing, and the other in a dark glass bottle or other container with equivalent storage conditions, sealed and stored as a sample. for future reference.

7.1 Appearance Measurement

7.1.1 Test Procedure Inject the turpentine sample into a clean, dry colorimetric tube (5.6.2), shake it, and observe it under diffused light in a horizontal visual manner.

7.1.2 Results Observe whether the sample is transparent, water-free, and free of impurities and suspended matter.

7.2.1 Visual inspection method

7.2.1.1 Scope of Application Applicable to color determination of premium, first-grade and second-grade turpentine oil products.

7.2.1.2 Test Procedure Same as 7.1.1.

7.2.1.3 Results Observe whether the sample is colorless.

7.2.2 Platinum-Cobalt Colorimetric Method

7.2.2.1 Scope of Application Applicable to color determination of premium, first-grade and second-grade turpentine oil products.

7.2.2.2 Test Procedure It shall be implemented in accordance with the provisions of GB/T 9282.1-2008.

7.2.2.3 Results The sample color is indicated by the color of the best-matching platinum-cobalt standard colorimetric solution, i.e., the platinum-cobalt color number. If the sample color falls between the two standards... For colorimetric solutions, the larger color number is used.

7.2.3 Gardner colorimetric method

7.2.3.1 Scope of Application Applicable to color determination of heavy turpentine products.

7.2.3.2 Test Procedure It shall be implemented in accordance with the provisions of GB/T 9281.1-2008.

7.2.3.3 Results The sample color is indicated by the color code of the best-matching Gardner standard solution. If the sample color falls between the two standard solutions, the color code of the better-matching Gardner standard solution is used. The color code is indicated by a larger value. If a more precise description of the color is needed, it can be reported as darker or lighter than the standard solution color code, such as the sample color being between 5 and 6. Between 6 and 6, it can be reported as 5 or 6-.

7.3 Relative density determination

7.3.1 Test Procedure Perform the procedure according to GB/T 4472.The hydrometer method is generally used. In case of disputes requiring arbitration, the density bottle method shall be used to determine the results. For reference only. Among them, the temperature correction factor for the density of resin turpentine oil per degree Celsius is krho = 0.00082, and the temperature correction factor for the density of heavy turpentine oil per degree Celsius is... Temperature correction factor krho = 0.00069.Two parallel tests were conducted under the same conditions.

7.3.2 Results The arithmetic mean of the results of two parallel trials is taken as the final result, and reported to three decimal places. The difference between the values should not exceed 0.001.

7.4 Refractive Index Measurement

7.4.1 Test Procedure It shall be performed in accordance with the provisions of GB/T 6488.Among them, the temperature correction factor kn for the refractive index of resin turpentine oil per degree Celsius is... The refractive index of heavy turpentine has a temperature correction factor of kn = 0.00042 per degree Celsius. Two parallel tests were conducted under the same conditions. test.

7.4.2 Results The arithmetic mean of the results of two parallel trials is taken as the final result, and reported to four decimal places. The difference in values should not exceed 0.0003.

7.5 Measurement of Optical Rotation

7.5.1 Test Procedure Perform the test according to GB/T 14454.5.Conduct two parallel tests under the same conditions.

7.5.2 Results The arithmetic mean of the results of two parallel trials is taken as the final result, and reported to two decimal places. The difference between the values should not exceed 0.08.

7.6 Acid value determination

7.6.1 Test Procedure Weigh 10g of turpentine oil sample (accurate to 0.01g) and place it in a 250mL Erlenmeyer flask (5.6.5). Add 30mL of neutral ethanol. (4.4) and 2-3 drops of 10 g/L phenolphthalein indicator (4.3), titrated with

0.02 mol/L potassium hydroxide-ethanol standard solution (4.6) until faintly red. The color was applied and remained unchanged for 30 seconds. Two parallel tests were conducted under the same conditions.

7.6.2 Results The acid value (wa) of turpentine oil is expressed as the mass of potassium hydroxide (KOH) consumed to neutralize 1 gram of turpentine oil, in milligrams per gram (mg/g).

7.7.1 Test Procedure

7.7.1.1 Gas Chromatograph Setup Typical conditions for gas chromatography analysis of turpentine oil component content determination. vaporization chamber and detector temperature 260°C; flow rate 67 mL/min; Split ratio 50.1; injection volume 1.0 µL; initial temperature 70°C, held for 2 min, then increased to 100°C at 2°C/min and 4°C/min respectively. Temperature increased to.200°C, then increased to 250°C at a rate of 10°C/min. Typical conditions for gas chromatography analysis of the component content determination of turpentine oil. vaporization chamber and detector temperature 280°C; flow rate 67 mL/min; Split ratio 50.1; injection volume 1.0 µL; initial temperature 70°C, held for 2 min, then increased to 140°C and 10°C/min at 3°C/min respectively. Heat to 210°C, then increase the temperature to 270°C at a rate of 2°C/min.

Note. The gas chromatography analysis conditions are not mandatory and are for reference only. Adjustments should be made according to the specific instrument used.

7.7.1.2 Preparation of turpentine oil samples The sample can be injected as is, or it can be diluted before injection (e.g., diluted with anhydrous ethanol or methanol to prepare a concentration of 50 mg/mL to 100 mg/mL). (solution).

7.7.1.3 Preparation of Heavy Turpentine Oil Samples Weigh a certain amount of sample, add methanol to prepare a solution of 50 mg/mL to 100 mg/mL, and add 2 to 3 drops of 10 g/L phenolphthalein. Indicator (4.3), add 5% tetramethylammonium hydroxide-methanol solution (4.9) dropwise until the solution turns light red.

7.7.1.4 Sample Injection Analysis The prepared samples were subjected to gas chromatography analysis. Two parallel experiments were conducted under the same conditions. Typical gas chromatography results of turpentine oil from different pine species were presented. Chromatograms and analytical data are provided in Appendices A through E.

7.7.2 Results

7.7.2.1 Qualitative Analysis The qualitative determination of each component in turpentine oil can be achieved using one of the following methods.

a) Compare the chromatograms obtained from the analysis of turpentine oil samples with the gas chromatograms and fractions of turpentine oil from various pine species provided in Appendices A to E. The analytical data were compared to qualitatively identify each component. When analyzing the same sample using chromatographic columns with stationary phases of different polarities, the chromatographic results showed... The number of peaks, retention time (elution order), and relative content of components typically vary. Therefore, in the analysis of turpentine oil components... When comparing the results of fraction determination, data should be based on those obtained using chromatographic columns with the same or similar polarity stationary phases to ensure accuracy. Comparability of analytical results. The chromatograms and data provided in Appendices A to E were obtained using a 5% phenyl/95% stationary phase column. Methyl polysiloxane is a weakly polar chromatographic column.

b) Use other chemical substance qualitative analysis techniques to qualitatively analyze each component.

7.7.2.2 Quantitative Analysis The content of each component in turpentine oil was calculated using the chromatographic peak area normalization method. The results are relative contents, expressed as a percentage (%). It is usually performed using a gas chromatography workstation data processing system. Calculated according to formula (2).

7.7.2.3 Repeatability and Reproducibility When there is doubt about the results of component content determination, repeatability and reproducibility tests should be performed. For example, using turpentine oil samples (alpha-pinene content)... Based on three independent determinations (80.1%, beta-pinene content 6.5%, limonene/beta-phellandrene content 3.4%), given repeatability and reproducibility... The sexual information is as follows:

a) Repeatability standard deviation. 0.12% for alpha-pinene, 0.06% for beta-pinene, and 0.06% for limonene/beta-phellandrene;

b) Repeatability limits (95% confidence level). 0.34% for alpha-pinene, 0.17% for beta-pinene, and 0.17% for limonene/beta-phellandrene;

c) Reproducibility standard deviation. 0.35% for alpha-pinene, 0.38% for beta-pinene, and 0.06% for limonene/beta-phellandrene;

d) Reproducibility limits (95% confidence level). 0.98% for alpha-pinene, 1.06% for beta-pinene, and 0.17% for limonene/beta-phellandrene.

7.8.1 Manual determination method

7.8.1.1 Temperature Correction Record the atmospheric pressure at room temperature, calculate the initial boiling point and distillate volume percentage at the specified temperature of 170°C under standard atmospheric pressure. The thermometer used for measurement should indicate a temperature reading.

7.8.1.2 Device Installation The installation diagram of the apparatus is shown in Figure 1 (5.5.1). Measure 100 mL of turpentine oil sample using a clean, dry graduated cylinder of varying diameter, and add Engler... Add 1-2 dry boiling stones to the distillation flask (the sample should not enter the side arm of the flask); tightly insert the cork with the thermometer into the flask. In the mouth of the flask, align the axis of the thermometer with the axis of the flask; place the flask on the asbestos pad of the support, and plug the side arm with a cork to the top of the condenser. The connection should be tight, with the length extending into the condenser tube being 25mm~30mm, but it should not contact the inner wall; place the graduated cylinder with the measured sample in the condenser. The end of the condenser tube serves as the receiver for the distillate, and is covered with perforated cardboard. The portion of the condenser extending into the graduated cylinder should be at least 25 mm, but more than 100 mL. Scale lines.

7.8.1.3 Measurement Procedure Connect the cooling water, turn on the heater, and control the heating rate. The time from the start of heating to the distillation of the first drop of liquid should be 7 to 10 minutes. Record this time. The thermometer reading observed when the first drop of liquid drips from the bottom of the condenser is recorded, and after calibration, it becomes the initial boiling point. Continue distillation at a rate of 4-5 mL per minute (approximately 2 drops/s), controlling the cooling water flow rate to maintain the distillate temperature within the room temperature range. Ensure consistent temperature. When the thermometer reading reaches 170°C (after calibration), immediately separate the Engler distillation flask from the condenser and turn off the heating to stop distillation. Distillation. Once all the liquid in the condenser has been poured into a graduated cylinder of varying diameter, the volume in milliliters of liquid in the graduated cylinder is the percentage of distilled volume. Two parallel experiments were conducted under the same conditions.

7.8.2 Automated Measurement Method The boiling range test was conducted using a fully automated distillation range analyzer conforming to SH/T 0121, following the instrument's instruction manual. Two tests were performed under identical conditions. Parallel experiments. The initial boiling point and distillate volume percentage can be determined automatically, but in case of disputes requiring arbitration, the results from the manual determination method shall prevail. As the standard.

7.8.3.1 Calculation of temperature correction value Deltat

3 The approximate value of the turpentine boiling point temperature (Deltat3) converted to standard atmospheric pressure (101.3 kPa), in degrees Celsius (°C), is given. According to the temperature and pressure correction coefficient (Kp) shown in Table 1, it is calculated using formula (3).

7.8.3.2 Calculation of Actual Distillation Termination Temperature The distillation termination temperature (tc) read during actual measurement was converted to a distillation range temperature of 170°C under standard atmospheric pressure (101.3 kPa). The obtained temperature value, in degrees Celsius (°C), is calculated according to formula (4).

7.8.3.3 Calculation of Initial Boiling Point The initial boiling point (t0) of turpentine oil is expressed as the initial boiling point temperature under standard atmospheric pressure (101.3 kPa), in degrees Celsius (°C). Formula (5) is used for calculation.

7.8.3.4 Calculation of Distillate Volume Percentage The volume percentage (phid) of turpentine oil distilled off is defined as the percentage of the volume of turpentine oil distilled off at 170°C (corrected) relative to the volume of the sample. Fractions are represented as % and calculated according to formula (6).