Commonly Used Sample Preservation Techniques for Laboratory Water – Table 5 (Microbiological Analysis)

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Common Water Sample Preservation Techniques

The table lists the requirements for water sample preservation techniques. The preservation time, container material selection, and application of preservation measures all depend on the components and properties of the sample. However, real-world water samples vary greatly; therefore, the requirements listed in the table are not absolute guidelines. Each analyst should verify the applicability of these requirements in their specific work, and the sample collection and preservation methods should be clearly specified when developing analytical method standards.

Furthermore, if there are incompatibilities between the analytical method to be used and the protective agent and container material, it is often necessary to take several samples from the same water body and analyze them using different preservation methods to determine the most suitable protection method and container.

Common Sample Preservation Techniques – Table 5

(This table only contains general requirements for sample preservation. Due to the complex properties of natural water and wastewater, the stability of each type of sample treated according to the following methods needs to be verified before analysis.)

1. Items to be tested

2. Container Category

3. Saving Method

4. Location Analysis

5. Storage time

6. Recommendations

micro

born

thing

point

Analysis

Total bacterial count, total coliform count, fecal coliforms, fecal streptococci, Salmonella, Shigella, etc.

Sterilization Container G

Refrigerate at 2-5℃

laboratory

As soon as possible (surface water, sewage, and drinking water).

When taking chlorinated or bromine-treated water samples, before disinfecting the sample bottles, add 0.1 mL of 10% (m/m) sodium thiosulfate (Na₂S₂O₃) per 125 mL to eliminate the inhibitory effect of chlorine or bromine on bacteria. For water samples with heavy metal content higher than 0.01 mg/L, add 0.3 mL of 15% (m/m) EDTA per 125 mL volume before container disinfection.

Note: ①P – Polyethylene; C – Borosilicate glass. ②A "-" indicates that no preservation measures are taken.

References

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