or batch number or to determine the authenticity of for example orange juice apple juice or lemon juice the relative amounts of water can be compared in a standard sample standard and a suspect sample using for example the naphthylamine light emissive dyes sulfonated naphthylamines such as 2 p toludinylnaphthalene 6 sulfonate 2 6 tns and 1 anilino 8 naphthalenesulfonate 1 8 ans shift light emission wavelength in water the relative amount of shift depends on the amount of water in a sample for example in water the spectral sensitivity is substantially shifted to longer wavelengths and the light emission quantum yield and decay times decrease multi variant analysis can be used to analyze the light emission results of each product sample with each light emissive compound typically the results are interpreted in comparison to light emission from a standard product sample treated in the same way or a u201c fingerprint u201d all samples can be analyzed for the presence of key ingredient using a light emissive compound containing a single light emissive compound or a combination of light emissive compounds the largest and smallest mean values are determined for each set of product samples using four independent measurements made of the same sample n 4 the.