Mini Case Study: Experimental Design in Metabolomics
Case: A research group wants to investigate the metabolic differences between
healthy and diseased plant leaves. They collect 3 diseased samples from one plant,
and 3 healthy samples from another plant. The samples were stored at room
temperature for 24 hours before moved to a freezer at –20°C. The samples were
stored at –20°C for 2 months before metabolome extraction. They performed
metabolome extraction for the disease samples and healthy samples separately on
different days. The last step of the extraction procedure used MS-grade water to redissolve the metabolites and the same MS-grade water was used as blank to control
the quality of extraction. They plan to only analyze the extracted plant samples with
the blank using a LC-MS method of selection.
Questions:
1. Identify five design flaws in this study and analyze what negative outcomes are
expected.
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2. Suggest how you would redesign the experiment to improve reliability and
interpretability.
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