The carotenoids are prepared either by extraction from natural sources or by chemical synthesis. Samples are supplied in sealed ampoules, under nitrogen, to ensure stability. Usually purity (HPLC, % area) is ≥ 95%. Although the ampoules are labelled as 1 mg or 13 mg, these values are approximate. We guarantee, however, that the actual content will be not less than the stated amount. Whenever possible, they are supplied in crystalline form with the exception of (E/Z)-phytoene and (E/Z)-phytofluene which are oily at ambient temperature. All compounds are fully characterized and analytical data (HPLC, UV/Vis spectra) as a Data Sheet, as well as a Safety Data Sheet (SDS or MSDS) are provided with the samples.