A kit for transporting a sample from a first location to a second location comprises at least one container for holding the sample; an extraction solution disposed in the at least one container for dissolving a chemical of the sample; and an internal standard disposed in the at least one container for calibrating a quantitative measurement of the chemical. A system for assaying an amount of a chemical on a tuber comprises a sampling means for collecting a tuber sample from the tuber; a kit comprising: at least one container for holding the tuber sample; an extraction solution for dissolving the chemical on the tuber sample; an internal standard for calibrating the chemical of the tuber; and a separation means for measuring an amount of the chemical in the extraction solution.
