to the first solution to form a second solution, measuring the fluorescence of the second solution wavelength of 600-700 nm, and correlating any change fluorescence between the first and second solutions to the concentration of methamphetamine in the sample, wherein the compound of Formula (1) is: ##STR12## wherein R1, R2, R3 and R4 each are a C1-6 alkyl group and X is an anion,and wherein the com