How to Collect and Preserve Samples

Overview

Sample collection is usually referred to as sampling. It is a way of sampling and a scientific research method. The first step of our experimental process is sample collection, which is also very important. For the accuracy of our experimental results, we must correctly select the sampling method and container and implement the sampling operation procedures.

Sample collection

Sample collection refers to taking a certain number of representative samples from the sample library to be tested as materials for detection and analysis. In the process of analysis and measurement, only by collecting reasonable and correct samples, can we obtain useful data and correct and reliable conclusions. There are four principles for sample collection: representativeness principle, typicality principle, timeliness principle and procedure principle.

Sample Preservation

During the period from sample collection to sample analysis and determination, due to the changes of space and time, some physical parameters and chemical components in the sample may change, resulting in detection failure or inaccurate data. How to reduce these changes and ensure the reliability and accuracy of the test results, we need to take certain measures to test or store them properly as soon as possible.
·There are three common storage methods:

1. Sealed preservation method
   Samples containing water or volatile shall be placed in closed containers to prevent weathering and volatilization; For the samples that need to be stored dry, it can also effectively prevent the invasion of exogenous air and water from polluting the samples.
   
2. Chemical preservation
   Some substances are added to the sample to ensure the stability of the sample. Common additive biological inhibitors, acid (alkali), can effectively prevent biological effects, prevent the change of physical properties of samples, etc. It should be noted that the added substances should not interfere with the determination of other components.
   
3. Cold storage
   Placing the sample in a dark place or refrigerator can effectively inhibit the biological activities in the sample, prevent the sample from deterioration caused by exogenous microorganisms, and slow down the physical and chemical speed of the sample itself.

The collection and preservation of samples is the most critical part in the whole process of sample analysis and detection. How to collect correct samples, prevent pollution and prevent the loss of tested components is particularly important. According to different samples, different analysis items and analysis methods, we can use different sampling methods and preservation methods to sample and preserve samples.

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