Total reflection X-ray fluorescence spectroscopy (TXRF) could complement IR and Raman spectroscopy. Spectroscopy, together with infrared (IR), Raman, 2D-fluorescence, amino acids supplier for nutraceuticals and complete reflection X-ray fluorescence combined with multivariate information analysis, are sometimes considered. When extra extensive fingerprinting or investigative work is required, several strategies may be helpful, together with chromatography or inductively coupled plasma mass spectrometry (ICP-MS). High- or extremely-excessive-efficiency liquid chromatography is commonly used in the reverse part mode with aqueous or water-soluble samples.