Measurements?

The X Scale is a measurement scale for Y of Z. The maximum rating of a substance on the X scale may be 16,000,000 units (given to pure W). In the traditional method for determining Y, an alcohol extract of the W oil from a measured amount of Z is added incrementally to a solution of sugar in water until the Y is just detectable by a panel of (usually five) tasters; the degree of dilution gives its measure on the X scale. Modern methods however use sophisticated high-performance liquid chromatography to determine the W content by quantitative analysis. X, Y, Z, W?