Lutein standard at 5, 15 and 25 ng were used in HPTLC quantification procedure for free lutein, with densitometry at 450 nm from food supplements, but Marigold flower petals are excellent sources of lutein as they contain high levels of lutein (of the order 4500 mg/lb) and no significant levels of other carotenoids. known concentrations of lutein standard between 5 and 40 ppm by HPLC analysis may be useful. Details are in attached article;

Study on the Different Methods of Preparation of Lutein from Supercritical Fluid Processed Lutein Esters. J Nutr Food Sci 2:154. doi:10.4172/2155-9600.1000154

for a linearity curve anything between 50 nanogram to 500 nanogram is advisable as per ICH guidelines.

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