In the storage and processing of traditional Chinese medicinal materials, sulfur fumigation technology is often used to achieve the goals of mold prevention, insect prevention, bleaching, etc. However, this process can result in residual sulfur dioxide in traditional Chinese medicine, and excessive intake can cause damage to the respiratory, gastrointestinal, and nervous systems of the human body. To ensure medication safety, General Rule 2331 of Part IV of the Pharmacopoeia of the People's Republic of China specifies the detection methods and limit standards for sulfur dioxide residues in traditional Chinese medicinal materials and decoction pieces. The YJ-2331-4B sulfur dioxide residue analyzer developed by Yiyan Shanghai is a professional testing equipment based on this standard, providing efficient and accurate technical support for quality control of traditional Chinese medicinal materials.

1、 Core requirements of Pharmacopoeia 2331 standard: Testing principles and technical specifications

The Pharmacopoeia 2331 standard specifies the "distillation acid-base titration method" (the first method) as the main detection method for detecting sulfur dioxide residues in Chinese medicinal materials. Its core principle and technical process impose strict requirements on the detection equipment, which is also the design basis of YJ-2331-4B analyzer

Detection principle anchoringAccording to the standard, sulfite substances (such as sodium sulfite, sodium bisulfite, etc.) in traditional Chinese medicine can be converted into sulfur dioxide gas after acid treatment; Using nitrogen as a carrier gas, sulfur dioxide gas is introduced into an absorption bottle containing hydrogen peroxide, which oxidizes it to sulfate ions; Finally, the acid-base titration method is used to titrate the generated sulfuric acid with sodium hydroxide standard solution, and the residual amount of sulfur dioxide is calculated based on the volume of standard solution consumed. This principle requires that the detection equipment must have a complete functional chain of "distillation nitrogen blowing absorption titration assistance", and each link must meet the accuracy control requirements.

Technical specification detailsThe standard specifies clear limits on key parameters during the detection process, such as controlling the heating rate during distillation to avoid incomplete release of sulfur dioxide due to sample boiling; The nitrogen flow rate needs to be stable within a specific range (usually 0.5-1.0L/min) to ensure carrier gas efficiency and prevent dispersion of the absorption liquid; The cooling system needs to ensure rapid condensation of distilled steam to prevent loss of sulfur dioxide during transportation. At the same time, the standard requires synchronous processing of blank samples and parallel samples to reduce systematic errors and ensure the repeatability and accuracy of detection results.

IIYiyan Intelligent ManufacturingYJ-2331-4B measuring instrument: technical design and performance advantages in accordance with pharmacopoeia standards

Yiyan Intelligent ManufacturingThe YJ-2331-4B measuring instrument, as a professional equipment that benchmarks against the Pharmacopoeia 2331 standard, deeply matches the standard requirements in terms of structural design, functional configuration, and parameter control. At the same time, it improves detection efficiency and operational convenience through technological innovation.

（1） Accurate adaptation of core functions to pharmacopoeia standards

Distillation module: high borosilicate material+micro boiling temperature control to ensure complete release of sulfur dioxide

The pharmacopoeia requires that the distillation process should achieve sufficient conversion and escape of sulfur dioxide in the sample. The distillation module of YJ-2331-4B uses high borosilicate glass material to make distillation flasks (with a standard specification of 1000ml, which meets the requirements of standard sample volume). This material has strong heat resistance (can withstand temperature fluctuations from 0-200 ℃), high chemical stability, and avoids reacting with acid to contaminate the sample; At the same time, the instrument is equipped with a micro boiling heating control system, with a temperature control range covering 0-200 ℃. The heating power can be adjusted according to the characteristics of different Chinese medicinal materials (such as roots, flowers, and leaves), accurately maintaining the sample in a micro boiling state. This not only prevents sulfur dioxide loss caused by boiling, but also avoids incomplete conversion caused by insufficient heating, which meets the distillation efficiency requirements of the pharmacopoeia.

Nitrogen blowing module: precise flow control, matched with carrier gas efficiency standards

The nitrogen blowing system is a key link in the "sulfur dioxide transmission" in pharmacopoeia testing. YJ-2331-4B is equipped with a nitrogen main interface on the host and independent high-precision flow meters for the four distillation units. The single hole nitrogen flow rate can be adjusted separately. This design can meet the requirements of pharmacopoeia for the stability of nitrogen flow rate - operators can accurately control the flow rate of each group within 0.5-1.0L/min according to standard specifications, ensuring that sulfur dioxide gas is fully loaded into the absorption bottle and avoiding parallel sample detection errors caused by uneven flow rate. In addition, the instrument supports external nitrogen generators or nitrogen cylinders, adapting to different laboratory gas source configurations to enhance flexibility in use.

Cooling module: efficient circulation temperature control, reducing sulfur dioxide loss

The pharmacopoeia requires that distillation steam be rapidly condensed to prevent sulfur dioxide from being lost in transmission pipelines due to high temperatures. YJ-2331-4B adopts the cooling method of "external cooling water circulation machine (built-in optional)" instead of traditional tap water cooling, which not only avoids the unstable cooling effect caused by tap water pressure fluctuations, but also achieves convenient operation through one click shutdown and one click water replenishment functions. The design of the built-in cooling circulation system can also improve the condensation efficiency, allowing the distilled steam to quickly cool down before entering the nitrogen blowing pipeline, ensuring stable transmission of sulfur dioxide in gas form, in line with the technical requirements of the pharmacopoeia for "lossless transmission".

Multi unit synchronous processing: meets the detection requirements of parallel and blank samples

The pharmacopoeia emphasizes that the test results need to be validated through blank controls and parallel samples to reduce systematic errors. YJ-2331-4B is equipped with 4 sets of distillation units, which can process 3-5 samples (including blank samples and parallel samples) simultaneously, meeting the requirements of "synchronous control detection" according to the standard. For example, when testing a batch of Angelica sinensis samples, 1 set of blank samples (no samples added, only reagents added) and 2 sets of parallel samples (different samples from the same batch) can be set simultaneously. Through synchronous distillation and nitrogen blowing, the time difference error caused by different batches of processing can be effectively avoided, and the repeatability and reliability of detection data can be improved.

（2） Performance Upgrade: Balancing Standard Compliance and Operational Practicality

In addition to complying with the core requirements of the pharmacopoeia,Yiyan Intelligent ManufacturingYJ-2331-4B further optimizes the detection experience in detail design and enhances the practicality of technology application:

Heating control: dual guarantee of safety and precisionThe instrument adopts a sealed infrared ceramic heating sleeve with good heat collection and no open flame, which not only reduces the energy consumption of traditional heating methods (rated power 2450W, compatible with 220V/50HZ conventional power supply), but also prevents equipment damage caused by sample leakage; At the same time, the heating device supports independent temperature control and heating countdown functions. After reaching the set time, it automatically stops heating and beeps to remind, avoiding overheating caused by personnel negligence and ensuring the safety and standardization of the detection process.

Operation interface: Full touch screen interaction reduces the thresholdThe instrument adopts a LCD touch screen as the display and control interface, with intuitive and easy to understand human-computer interaction. Operators can directly set parameters such as heating temperature, nitrogen blowing time, cooling system switch, etc. through the touch screen, without the need for complex button debugging. Even beginners can quickly grasp the operation process, reduce detection errors caused by operational errors, and meet the laboratory's demand for "convenient operation".

Security Design: Avoiding Experimental RisksThe instrument is equipped with leakage protection device and anti dry burning design. When there is leakage in the circuit or water shortage in the heating sleeve, the equipment will automatically shut down to avoid the risk of electric shock or equipment burnout; The external dimensions of 930mm × 520mm × 850mm are designed to ensure a reasonable layout of the four distillation units, as well as to facilitate placement on the laboratory workstation, balancing safety and spatial adaptability.

3、 Practical application scenario: providing technical support for quality control of traditional Chinese medicinal materials

Yiyan Intelligent ManufacturingThe YJ-2331-4B analyzer is designed based on the pharmacopoeia 2331 standard technology, making it widely applicable in the production, scientific research, supervision and other scenarios of traditional Chinese medicine

Chinese medicine production enterprises: raw material entry and finished product factory inspectionWhen purchasing Chinese herbal medicine raw materials, the Chinese herbal medicine decoction piece factory can use this instrument to quickly detect the residual sulfur dioxide content and screen raw materials that meet the pharmacopoeia limit (such as yam, Achyranthes bidentata and other varieties with a limit of 400mg/kg, and American ginseng, saffron and other varieties with a limit of 10mg/kg); Before the finished product leaves the factory, parallel sample testing can also be used to verify product quality and avoid market recall risks caused by excessive residue.

Research Institute: Process Optimization and Methodology ValidationWhen researchers are studying "sulfur free processing techniques" (such as microwave drying, ozone mold prevention, etc.), they can use the YJ-2331-4B analyzer to compare the differences in sulfur dioxide residue between traditional sulfur fumigation and new processes, providing data support for process optimization; At the same time, the high-precision performance of the instrument can also be used for methodological validation (such as precision and accuracy testing), meeting the requirements of scientific research papers for data reliability.

Regulatory agencies: Market sampling and quality supervisionWhen conducting random inspections in the Chinese herbal medicine market, drug regulatory authorities can carry the instrument (or batch process samples in the laboratory) to quickly complete the testing of multiple batches of samples, timely detect products that exceed the standard, and ensure the quality and safety of the Chinese herbal medicine market.

4、 Conclusion: The synergy between standards and equipment strengthens the safety defense line of traditional Chinese medicine

The 2331 standard of the Pharmacopoeia of the People's Republic of China provides technical guidelines for the detection of sulfur dioxide residues in traditional Chinese medicinal materialsYiyan Intelligent ManufacturingThe YJ-2331-4B measuring instrument transforms "pharmacopoeia standards" into "practical detection capabilities" through precise functional design and performance optimization that meet standard requirements. The instrument not only integrates core functions such as distillation, nitrogen blowing, and cooling, but also effectively improves detection efficiency and data accuracy through multi unit synchronous processing, precise parameter control, and convenient operation design, providing reliable technical tools for traditional Chinese medicine production enterprises, research institutes, and regulatory agencies.

Against the backdrop of increasingly strict quality control of traditional Chinese medicine,Yiyan Intelligent ManufacturingThe collaborative application of YJ-2331-4B analyzer and Pharmacopoeia 2331 standard will further promote the standardization and normalization of sulfur dioxide residue detection in traditional Chinese medicine, help the industry shift from "post detection" to "pre prevention", ultimately ensuring consumer medication safety and promoting high-quality development of the traditional Chinese medicine industry.