Freeze drying machines play a crucial role in the field of inspection and testing technology, and their core value lies in achieving sample stabilization and standardization through low-temperature dehydration.
In microbiological testing, freeze-drying machines are used for long-term preservation of standard and quality control strains, ensuring the stability of their genetic characteristics and biological activity, and guaranteeing the accuracy and traceability of test results. In food, environmental, and forensic testing, when faced with samples with high moisture content and easy spoilage, freeze-drying technology can effectively remove moisture, prevent the degradation of the tested components, and make the samples into uniform and stable powders, greatly facilitating subsequent grinding and weighing, providing an ideal pre-treatment solution for precision analysis such as chromatography and mass spectrometry. In addition, many heat sensitive bioactive reagents (such as enzymes, antigens, and antibodies) are also freeze-dried to produce stable freeze-dried powder reagents, which extend their shelf life and facilitate transportation and storage.
1、 Application in Microbial and Pathogen Detection
01. Long term storage of standard and quality control strains
Used for storing standard strains and virus strains provided by ATCC and other institutions, as well as laboratory owned quality control strains. The freeze-drying process causes the metabolic activity of microorganisms to stop and enter a dormant state, which can maintain their genetic and biological characteristics unchanged for a long time (several years or even decades). The advantage of freeze-drying is that it avoids strain variation, contamination, or death caused by repeated passages, ensuring the accuracy, comparability, and traceability of test results.
02. Preparation of diagnostic reagents and culture media
Many bioactive reagents (such as enzymes, antibodies, antigens) and selective culture medium components are thermally unstable. Through freeze-drying technology, it can be made into a stable dry powder reagent that can be transported and stored at room temperature or 4 ℃. When used, it only needs to be redissolved, with almost no loss of activity and potency.
The expiration date of the reagent has been extended by vacuum freeze-drying, which facilitates transportation and storage, and ensures the quality stability of the detection kit.
03. Preprocessing of clinical test samples
For the detection of certain viruses, bacteria, or toxins, samples (such as feces, tissues, sputum) can be freeze-dried first to concentrate the target substance, remove interfering water, and inactivate most pathogens, reducing the biosafety risks of subsequent testing.
Concentrating the target substance can improve detection sensitivity and enhance operational safety.
2、 Application in food and agricultural product testing
1. Sample pretreatment and preparation:
Food and agricultural products (such as meat, vegetables, and fruits) have high moisture content and complex ingredients, making direct detection difficult. Freeze drying can: ● remove moisture: accurately calculate the content of nutrients (protein, fat, vitamins) or pollutants (pesticide residues, heavy metals, fungal toxins) based on dry weight, resulting in more precise data. Stable sample: prevent the sample from spoiling and deteriorating during storage and grinding, and maintain the initial state of the tested component. Homogenization: After freeze-drying, the sample becomes brittle and easily ground into a uniform fine powder, making the sampling more representative and reducing errors. This operation provides stable and uniform standard samples for subsequent chromatography, mass spectrometry, and spectroscopic analysis.
2. Vitamin and functional ingredient testing:
Many vitamins, such as vitamin C and vitamin B, are sensitive to heat, light, and oxygen. Freeze drying can be completed in a low temperature and low oxygen environment, maximizing the protection of the activity of these unstable components and ensuring the authenticity of the test results.
3、 Application in environmental monitoring
01. Water sample analysis
Detect trace or trace pollutants such as heavy metals, persistent organic pollutants (POPs), algal toxins, antibiotics, etc. in water bodies.
The volume of water samples is usually large (upgraded), while the concentration of target pollutants is extremely low. Direct analysis is very difficult. Through freeze-drying, a large amount of water in the water sample can be removed, allowing pollutants to accumulate in the residual solids. Subsequently, by dissolving the residual solid in a small amount of solvent, a concentrated test solution can be obtained, greatly improving the sensitivity and accuracy of the analysis. Compared to traditional heating and concentration methods such as rotary evaporation, freeze-drying is carried out at low temperatures, which can effectively prevent the decomposition and loss of volatile and heat sensitive pollutants (such as certain pesticides and polycyclic aromatic hydrocarbons).
02. Soil and sediment samples
Analyze organic pollutants, microbial communities, volatile organic compounds (VOCs), etc. in soil/sediment.
Moisture standardization: Remove free moisture from the sample to standardize its weight, facilitating accurate calculation of pollutant concentration (based on dry weight) and avoiding errors caused by moisture fluctuations. Stable storage: Freeze drying can greatly inhibit microbial activity, prevent sample biodegradation during storage and transportation, and ensure the originality of pollutant content. This is crucial for ecological surveys that require long-term, large-scale sample collection. Easy to grind and homogenize: The dried sample is more easily ground into a uniform fine powder, improving the repeatability of subsequent extraction and analysis.
Biological samples used for biological monitoring, such as plant leaves, fish, shellfish, etc., to analyze the pollutants enriched in their bodies.
Similar to water samples, sample dehydration, stabilization, and pollutant enrichment are achieved through freeze-drying. Meanwhile, freeze-drying can effectively maintain the tissue structure of the sample, facilitating targeted analysis of different tissue parts in the future.
4、 Application in forensic and toxicology analysis
1. Preservation of biological samples：
Application: Forensic biological samples such as blood, urine, and tissue contain DNA, proteins, drugs, and their metabolites. Freeze drying can store these samples stably for a long time, preventing DNA degradation and drug breakdown, providing the possibility for case re examination and evidence preservation. Advantages: Preserving the originality and validity of evidence, supporting the scientific and impartial nature of judicial appraisal.2. Preparation of standard samples:Application: Analytical standards for toxins are usually expensive and unstable. Freeze drying technology can be used to prepare stable standard dry powder, ensuring the accuracy of quantitative analysis.
5、 Application in drug analysis and quality control
01. Preparation of drug standards
Many biopharmaceutical products, such as protein drugs, vaccines, and antibiotics, require freeze-drying to maintain their biological activity and chemical stability for quality control and content determination.
02. Pre treatment of unstable samples
When analyzing complex preparations containing thermosensitive components (such as certain traditional Chinese medicine injections and biological samples), if it is necessary to concentrate the tested components, freeze-drying is a milder choice than heating and evaporation. It can avoid the decomposition of the analyte during the concentration process, ensuring the accuracy of the analysis results.
The core value of freeze-drying machines in the field of inspection and testing lies in their two major functions of "stability" and "concentration":
Stabilization: By removing moisture and performing at low temperatures, it can maximize the biological activity, chemical composition, and physical structure of the sample, providing a "time capsule" for detection, making the results comparable and traceable. Concentration: By removing the solvent, it can effectively increase the relative concentration of the target analyte, thereby improving the sensitivity and accuracy of detection. Therefore, freeze-drying machine is a fundamental and supportive equipment in modern analytical laboratories, especially in inspection and testing institutions related to microbiology, food, environment, forensic and pharmaceutical fields.