Determination Method for Relative Density of Undecylenic Acid Undecylenic acid, also known as 10undecylenoic acid, is an organic compound with the molecular formula C₁₁H₂₀O₂. It is a pale yellow to yellow liquid at room temperature and atmospheric pressure. When cooled, it forms milky white crystalline masses with a characteristic odor. It is miscible with ethanol, chloroform, fatty oils, or volatile oils in all proportions, and insoluble in water. It is widely used in the synthesis of perfumes, pharmaceutical antifungal agents, and other products. Experimental Purpose As a physical constant, relative density can objectively reflect the intrinsic quality of undecylenic acid and is one of the important indicators for evaluating its efficacy and safety. Reflect purity and consistency: According to the Relative Density Test (Method 0601) in the Chinese Pharmacopoeia, the relative density of undecylenic acid is 0.910–0.913 g/cm³ at 25 °C. By measuring its relative density, it can be determined whether the undecylenic acid sample is adulterated. ③ Assist in authenticity identification: Combined with other physical constants such as refractive index and iodine value, relative density helps to verify whether the sample is genuine undecylenic acid. ④ Ensure compliance in industrial applications: In perfumes, pharmaceuticals (e.g., antifungal preparations), and cosmetics, the concentration and purity of undecylenic acid directly affect product safety and efficacy. Relative density is a key parameter for raw material acceptance. The experiment is performed according to Method 3 (Oscillating Density Meter Method) for the Relative Density Test (0601) in the Chinese Pharmacopoeia 2020.The ST217A Automatic Pharmaceutical Relative Density Meter (Shengtai Instrument) complies with this method and is therefore used for the test. Experimental Apparatus ①ST217B Automatic Touchscreen Pharmaceutical Relative Density Meter ② Auxiliary items: purified water, stirring rod, beaker, etc. Experimental Procedures ① Inspect the instrument: Verify that the power supply, sensor, temperature control system (e.g., Peltier thermostat), Ushaped oscillating tube, and other components are functioning normally. ② Clean the measuring cell: Wash the Ushaped tube or sample cell with anhydrous ethanol or distilled water, then dry it to avoid interference from residues. ③ Calibrate the instrument: Inject pure water at 25 °C (density = 0.997043 g/mL) into the measuring cell, remove air bubbles, press the “Calibrate” key, and allow the instrument to complete calibration automatically. Then take out the measuring cell and clean it. ④ Sample introduction: Filter to remove bubbles and impurities. Start the automatic program; the builtin sampling pump completes sampling, cleaning, and drying automatically. Results are output within 2–10 minutes. ⑤ Read the results and repeat the test 1–3 times. Experimental Results and Analysis According to the requirement of the Chinese Pharmacopoeia 0601 Relative Density Test, the relative density of undecylenic acid at 25 °C shall be 0.910–0.913 g/cm³.The values obtained in three replicate tests all fall within the specified range, meeting the standard requirements.

Test Method for Rheological Properties of Wheat Flour Dough Wheat flour dough is a semi-solid mixture with elasticity, extensibility, and plasticity. It is formed by mixing wheat flour and water in a certain proportion and kneading so that proteins absorb water to form a gluten network. It serves as the basic raw material for making pasta products such as bread, steamed buns, noodles, etc. Experimental Purpose 1.Evaluate flour processing quality and classificationThe primary purpose of the experiment is to determine which pasta products the wheat flour is suitable for through rheological curves. Based on the stability time and softening degree measured by the farinograph, it is possible to clearly distinguish strong gluten flour (suitable for bread), medium gluten flour (suitable for steamed buns and noodles), and weak gluten flour (suitable for biscuits and cakes).The longer the stability time, the stronger the mixing resistance of the dough, making it more suitable for bread requiring longtime fermentation. This method can be used for special flour screening, as different pasta products have distinctly different requirements for dough properties. 2.Predict the final quality of pasta productsThere is a significant correlation between the rheological properties of dough and the quality of baked or steamed products, and the experimental data have strong predictability. 3.Guide the optimization of production process parametersThe experimental results can provide specific operational basis for actual production and avoid blind adjustment based on experience. 4.Monitor raw material stability and breeding selection Batch stability monitoring: For flour processing plants, regular testing of rheological properties can monitor quality fluctuations of different batches of wheat flour to ensure product standardization. Reference for wheat breeding: In agricultural research, rheological indicators are important criteria for screening highquality wheat varieties. By analyzing the alveograph properties (such as tenacity P, extensibility L, and strength W) of dough from different varieties, breeding experts can directionally cultivate new wheat varieties suitable for specific processing requirements. Experimental Apparatus Sample:Wheat flour dough Apparatus: ST139 Electric Farinograph，conforming to ISO 55302 Experimental Procedures Sample weighing and water addition calculation Based on 14% moisture basis, weigh 300 g of pretreated wheat flour sample, accurate to 0.1 g.Estimate the water absorption of the wheat flour and calculate the required water volume. Water absorption (%) = (Water addition + Wheat flour weight − 300) / 3(Taking the 300g flour mixing bowl as an example, water addition is in mL.) The final maximum consistency of the dough shall be 500 ± 20 BU.If the curve in the preliminary test exceeds 500 BU, the water addition is insufficient; otherwise, it is excessive. The water addition can be adjusted according to the relationship: 20 BU ≈ 0.6%–0.8% water absorption. Kneading and curve recording Pour the weighed wheat flour into the 300g mixing bowl of the farinograph. Start the mixing bowl at a speed of 63 ± 2 r/min.Complete water addition within 25 seconds to ensure rapid mixing of water and flour.Timing starts from the beginning of water addition. The instrument automatically records the change in resistance of the dough to the mixing arms during kneading and generates a farinogram curve. The conventional test lasts for 20 minutes. The test time can be appropriately extended for special analysis, but the integrity of data collection must be ensured.During the test, closely observe curve changes. If abnormal fluctuations occur, check the instrument status or sample condition. Parallel test setup Each batch of samples shall be tested in at least 2 parallel tests.The allowable error of parallel tests is no more than ±1.5%.If the relative deviation exceeds 5%, the test shall be repeated to ensure data reliability. Experimental Results and Analysis The five wheat flours show significant differences in rheological properties and can be classified into four categories: strong gluten, mediumstrong gluten, medium gluten, and weak gluten according to farinograph parameters.The experimental results meet the requirements of GB/T 146142019.They can provide a scientific basis for raw material acceptance, quality control, and product development in flour enterprises, as well as data support for raw material selection and process optimization in pasta production enterprises.  

  Overview   Liquid hydrocarbons are important chemical raw materials widely used in the production and processing of chemical products such as ethylene, propylene and liquefied petroleum gas. The trace water contained in them will directly affect product quality and the safe operation of production equipment, and may also lead to side reactions in subsequent chemical reactions and catalyst deactivation. Accurate determination of trace water in liquid hydrocarbons is a key link in quality control and safety management of chemical production, and flash vaporization sampling technology is the core pretreatment method to achieve accurate determination of trace water in liquid hydrocarbons.   Experimental Objective   By determining the trace water content in liquid hydrocarbons, we can accurately judge whether liquid hydrocarbon raw materials meet the purity requirements of the production process, and avoid production problems such as equipment corrosion and reaction inefficiency caused by excessive moisture content. This determination is carried out in accordance with GB/T3727-2003 Determination of Trace Water in Industrial Ethylene and Propylene. The SH201 Flash Vaporization Sampler is specially designed for the pretreatment of liquid hydrocarbon samples, which is perfectly compatible with this national standard method. It can convert liquid hydrocarbons into gaseous samples with isocomposition, constant temperature and constant pressure, providing accurate pretreatment guarantee for trace water determination.   Experimental Samples: Liquid hydrocarbons (ethylene/propylene/liquefied petroleum gas, etc.)     Experimental Instruments 1. SH201 Flash Vaporization Sampler 2. Auxiliary equipment: Karl Fischer Moisture Titrator/Dew Point Meter, sampling cylinder, stainless steel tube/polytetrafluoroethylene tube, analytical balance, etc.   Operating Procedures 1. Place the SH201 Flash Vaporization Sampler in a fume hood, connect the vent port and injection port, and connect the injection port to a Karl Fischer Moisture Titrator/Dew Point Meter with the pipelines as short as possible. 2. Connect the downward outlet of the sampling cylinder to the instrument port and tighten it, fully open the cylinder outlet valve to ensure that the liquid sample directly enters the instrument. At the same time, connect the instrument power supply and ensure good earthing of the ground wire. 3. Turn on the instrument, enter the preheating interface to set the vaporization temperature (≥60℃). After 15 minutes of preheating and temperature constant, adjust the flow rate (1.5-2 L/min for routine analysis) and injection volume (5-15 L, the lower the moisture content, the larger the injection volume) on the parameter setting interface. 4. After the Karl Fischer Moisture Titrator/Dew Point Meter reaches the end point, press the instrument's injection key to start the injection and determination. The instrument will automatically control the flow rate and record the cumulative injection volume. 5. When the set injection volume is reached, the instrument will automatically switch to the vent state. The Karl Fischer Moisture Titrator/Dew Point Meter will complete the determination and display the water content. Input the actual injection volume to calculate the final moisture concentration, and the test report can be printed directly. 6. After the completion of one set of determinations, the next set of parallel determinations can be started directly without turning off the instrument. 5 parallel results are required for routine determinations.   Data Analysis and Result Evaluation   The trace water content in standard liquid hydrocarbon samples was determined by pretreatment with the SH201 Flash Vaporization Sampler combined with determination by a Karl Fischer Moisture Titrator. The instrument achieves isocompositional vaporization during the vaporization process, without water adsorption, freezing or concentration deviation. The repeatability error of the determination results meets the requirements of the national standard, and the basic error is controlled within ±5%. The measured value of trace water content accurately reflects the actual moisture content of liquid hydrocarbons, which can provide reliable and accurate data support for the quality judgment of liquid hydrocarbon raw materials in chemical production.

Overview     Cereals and oilseeds are core raw materials for agricultural production and food processing, and their quality is directly related to food safety, storage security and market value. The content of impurities and imperfect grains is a key index for evaluating the quality of cereals and oilseeds. Excessive impurities will reduce the utilization rate of raw materials and affect the processing technology, while imperfect grains are prone to mildew and deterioration during storage, and also lower the edible and processing quality. Therefore, accurate determination of impurities and imperfect grains in cereals and oilseeds is an essential operation in the links of grain purchase, storage and processing.   Experimental Purpose     To accurately determine the quality grade of cereals and oilseeds by screening and detecting the content of impurities and imperfect grains in them, so as to provide a scientific quality basis for grain purchase, storage management and processing production. This test is carried out in accordance with the national standard GB5494-85 Inspection of Cereals and Oilseeds - Method for Inspection of Impurities and Imperfect Grains. The ST134 Computerized Sieve Shaker is a special screening and testing equipment developed in accordance with this standard, which can realize the standardized and automatic screening of cereals and oilseeds. Experimental Samples and Instruments   Experimental Samples   Tested cereal/oilseed samples   Experimental Instruments ST134 Electric Sieve Shaker (including matched grain sieves) Auxiliary accessories such as sample trays and brushes   Operating Procedures Select the corresponding specifications of grain sieve layers in accordance with national standards according to the type of cereals and oilseeds to be tested, and assemble them in order. Take 500g of the tested sample and pour it into the assembled grain sieve, cover the sieve lid, place the sieve into the equipment tray and tighten the pull rods to ensure the sieve layers are stable and firm. Connect the power supply of the ST134 Computerized Sieve Shaker and press the start switch. The instrument will operate automatically according to the program, performing forward sieving for 60 seconds and reverse sieving for 60 seconds before stopping automatically, with planar rotary sieving realized throughout the process. For continuous testing of multiple groups of samples, pour out the sieved samples, put new samples in and fasten the sieve layers again, then press the start switch once more without turning off the power supply. After the test is completed, loosen the pull rods to take out the sieve layers, pour the over-sieve and under-sieve materials into sample trays respectively, and sort and measure the impurities and imperfect grains in accordance with national standard regulations. Data Analysis and Result Evaluation     Through the standardized sieving of the ST134 Computerized Sieve Shaker, impurities and imperfect grains in cereals and oilseeds can be effectively separated from intact grains. The content ratio of impurities and imperfect grains calculated by measurement after sorting fully meets the test accuracy requirements of the national standard GB5494-85. The instrument features stable operation, uniform sieving amplitude and precise control of forward and reverse rotation time, which effectively avoids the errors of manual sieving. The test results can be directly used as a valid basis for determining the quality grade of cereals and oilseeds, and it is suitable for batch testing needs in various scenarios such as agricultural breeding, grain purchase and grain and oil processing.

Determination of Grain Bulk Density Overview   Grain bulk density refers to the mass of grain per unit volume in its natural state, expressed in grams per liter (g/L). It serves as a core indicator for grading grain, evaluating grain quality and kernel plumpness, and directly reflects the kernel density, plumpness and uniformity of grain. Bulk density is adopted as one of the key judgment criteria for the grade classification of various grains including wheat, corn, legumes and millet. Accurate determination of grain bulk density is of great practical guiding significance for grain purchasing, storage, processing and trade pricing.   Experimental Purpose   By testing the bulk density value of grain, its quality grade and kernel plumpness can be accurately determined, so as to provide scientific data support for grain purchasing, storage grading and processing screening. This grain bulk density determination is conducted in accordance with the relevant standard methods for grain quality inspection. The ST128 Electronic Bulk Density Meter is a professional instrument specially designed for grain bulk density testing, which is applicable to the bulk density measurement of small-particle grains (wheat, millet) and large-particle grains (corn, legumes), meeting the professional requirements of grain inspection.   Experimental Samples and Instruments     Experimental Sample: Wheat (replaceable with corn, legumes, millet and other grains) Experimental Instruments: ST128 Electronic Bulk Density Meter Auxiliary tools such as sample leveling implement Operating Procedures Connect the power supply of the ST128 Electronic Bulk Density Meter and turn on the power switch at the rear of the cabinet. Press the Zero key to reset the display to zero. Place the volume cylinder and exhaust hammer on the pan of the electronic scale, press the Tare key to complete the taring operation, and then remove them. Mount the volume cylinder on the plastic base and place it on a horizontal workbench, insert the insert plate, place the exhaust hammer flat, and fit the middle cylinder in position; pour the prepared grain sample into the grain cylinder, fill it up and level it off, then fit the grain cylinder onto the middle cylinder. Open the hopper switch to allow the grain to fall freely. After all the samples have fallen into the volume cylinder, close the switch and pull out the insert piece quickly. After the exhaust hammer and samples settle down, reinsert the insert plate, and remove the grain cylinder and the middle cylinder in sequence. Pour off the excess sample on the insert piece of the volume cylinder, pull out the insert piece, and place the volume cylinder stably on the electronic scale. After the weight is stabilized (the word Stable is displayed on the left side of the screen), read the value. If the test result needs to be saved, press the Print key to print the detection data. For continuous testing of multiple groups of samples, press the Zero key to reset the display to zero, and then repeat the above steps to complete the subsequent measurements. Note: When measuring large-particle grains such as corn and legumes, remove the hopper slider; when measuring small-particle grains such as wheat and millet, install the hopper slider in position before the test.   Data Analysis and Result Evaluation   The bulk density of the wheat sample tested by the ST128 Electronic Bulk Density Meter is 780 g/L, which meets the national grade standard for high-quality wheat (bulk density ≥750 g/L). The instrument has a measurement division value of 1 g and a volume cylinder volume accuracy of 1000±1.5 ml, with the detection error controlled within the allowable range specified in the grain bulk density testing standards, featuring accurate data and good repeatability. The results of multiple repeated tests on large-particle grains such as corn and legumes show that the instrument has small measurement deviation, is suitable for the bulk density testing of grains with different particle sizes, and is characterized by easy operation and reliable results. It can meet the requirements of batch and rapid determination in grain purchasing, storage inspection and other application scenarios.

Test Method for Brookfield Viscosity of Gelatin Gelatin is a natural protein extracted from the bones or skins of animals (such as cattle and pigs). It has no fixed structure, but is soluble in hot water and forms a gel upon cooling. It is commonly used as a thickener in food products (e.g., jelly, yogurt) and also has numerous applications in the pharmaceutical and cosmetic industries. Experimental Purpose The main objective of testing the Brookfield viscosity of gelatin is to quantify the flow characteristics of gelatin in aqueous solution, which is a core indicator for evaluating gelatin quality and directly relates to its suitability in food, pharmaceutical and other fields. Generally, a higher viscosity indicates a larger molecular weight and better quality of gelatin, enabling the formation of a firmer gel. Quality Control: To ensure that gelatin complies with specific industrial standards (e.g., pharmaceutical or food grade) and prevent substandard products from entering the market. Performance Prediction: To predict the performance of gelatin in practical applications (such as jelly setting and capsule formation) based on viscosity values. Research & Development and Comparison: To provide a scientific basis for new product development and the performance comparison of different batches of gelatin. Experimental Sample and Instruments Experimental Sample: Gelatin Experimental Instruments: ST-19A Digital Display Brookfield Viscometer, compliant with QB 2354 Experimental Procedures 1.Instrument Calibration：Turn on the super thermostat to stabilize the water temperature in the viscometer jacket at 60 ± 0.1℃. Check that the capillary tube is clean and free from residual air bubbles. 2.Solution Transfer：Pipette 10 mL of the gelatin solution and quickly pour it into the viscometer funnel, ensuring the liquid level is 2–3 cm above the upper graduation mark. Tap the wall of the funnel gently to remove air bubbles, then adjust the liquid level precisely to the upper graduation mark. 3.Viscosity Measurement：Start the stopwatch and record the time (t, in seconds) for the solution to flow from the upper graduation mark to the lower graduation mark of the capillary tube. Repeat the measurement three times and take the average value to reduce errors. Experimental Results The Brookfield viscosity of the Type A bone gelatin is 3.3 mPa·s, which is higher than the required value of 3.2 mPa·s for Type A gelatin. Therefore, this sample meets the standard for pharmaceutical gelatin.