A portable, tabletop fluid sampling device simplifies spectral analysis to produce an accurate but inexpensive chromatic fingerprint for fluid samples. In one embodiment, the sampling device uses an array of variable wavelength LED emitters and photodiode detectors to measure Rayleigh scattering of electromagnetic energy from the fluid sample contained in a cuvette. Either the fluid itself, or particles suspended in the fluid can then be identified by performing spectral pattern matching to compare results of a spectral scan against a library of known spectra. A wide range of applications include substance identification, security screening, authentication, quality control, and medical diagnostics.