What type of sample preservation method is commonly used for biochemical analyses?

The use of cooling the sample in an ice bath or employing chemical preservatives is standard practice for preserving samples for biochemical analyses. This method is effective in slowing down biological processes and enzyme activities that could degrade the sample or alter its biochemical composition. Cooling helps maintain the integrity of the sample by reducing the metabolic activity of microorganisms, thereby minimizing the risk of contamination and degradation.

Chemical preservatives also play an essential role in stabilizing the sample by either inhibiting microbial growth or neutralizing enzymes that could interfere with the analysis. This ensures that the biochemical properties of the sample remain consistent from the time of collection to the time of analysis, allowing for accurate and reliable results.

While freezing samples at -20 degrees Celsius can be useful in certain contexts, it may not be the best preservation method for all biochemical analyses, as some compounds can be unstable at such temperatures. The addition of alcohol could prevent bacterial growth but might not be appropriate for all types of samples. Stirring samples at room temperature is generally not advisable as it could lead to changes in concentration and introduce contamination. Thus, cooling with ice or chemical preservatives is the widely accepted method for maintaining sample integrity in biochemical analyses.