Yes. It's used in chemistry and biology all the time. It just means a sample from a larger volume of something. For example, "add 10 mL aliquots of the buffer solution to each of the test tubes."
I've encountered "aliquot" in the Navy as a nuclear power plant chemist. When calibrating a certain piece of equipment, the procedure tells you to measure out 4 50 ml aliquots of chloride standard solution.