For an upcoming experiment, an immunoassay (ELISA) protocol calls for a complicated series of dilution steps for your blood specimen. Calculate the final dilution factor after the following steps:
Add 1 liter of blood to four liters of water, then take 1 ounce of that solution and add it to 9 ounces of water. Finally, take 3 mls of that dilution and add it 567 mls of water.
Although the procedure described in this question is unusual for an actual laboratory experiment, the complicated dilution scheme described is a real exam question. Why would instructors ask this type of question if it is not similar to what you might actually do in the laboratory? For one simple reason -- the different ways of describing dilution steps, and the different units used in each of the steps really test your understanding of dilution factors and solution preparation. Let's take a look at what the question is asking, then find the solution.
Part 1: Understanding the question
"For an upcoming experiment, an immunoassay (ELISA) protocol calls for a complicated series of dilution steps for your blood specimen." -- This information sets the context for the question, but is not relevant to the final answer. Whether you are diluting blood, buffer, urine, or vodka, the method used to calculate a dilution factor is exactly the same. Similarly, whether you are performing the dilution for an immunoassay, a chemical reaction, a titration, or to bake a cake, the method used to calculate a dilution factor is ...
In about 800 words, this solution provides a detailed step by step solution which outlines how to calculate the final dilution factor. In addition to a full solution, the answer to this problem includes sections on understanding the question, the definition of the dilution factor, exam tips, the importance of units, and examples of incorrect answers and how to avoid them.