Final answer:
According to Michael McBride from Idexx, before starting your analysis, the sample should be centrifuged (option B). Centrifugation helps to separate the cellular components from plasma or serum in biological samples, which is vital for many types of laboratory analyses, including compound quantification by HPLC.
Step-by-step explanation:
Before starting your analysis, according to Michael McBride from Idexx, it is important to centrifuge the sample. Centrifugation is a common laboratory procedure used to separate components of a complex mixture, which in the context of biological samples, such as blood or urine, separates the cellular components from the plasma or serum. It is essential for certain analyses as it can affect the accuracy and reliability of the test results.
For instance, when working with blood samples, after collection, they are usually centrifuged to obtain plasma. The plasma is then often quenched with methanol immediately before analysis, like in a procedure involving High-Performance Liquid Chromatography (HPLC). In the case of urine samples, these may not require preparation prior to analysis. On the other hand, if you were performing a procedure such as PCR or restriction digestion, the sample may require different forms of preparation, such as being briefly centrifuged to ensure all the reaction mixture is at the bottom of the tube.
Therefore, in most biological sample preparations, centrifugation is a crucial step. It is the process of using the centrifugal force generated by a spinning rotor to separate components of different densities within a sample, for example, separating blood cells from plasma in blood samples.