QUANTITATIVE ESTIMATION OF CAROTINOIDS 261 



Summary 



The quantitative estimation of carotinoids in plant and animal tis- 

 sues must be carried out by colorimetric methods. Standard 0.2 per 

 cent potassium dichromate solution serves for the color comparison 

 with carotin, xunthophyll and fucoxanthin solutions. The quantitative 

 relations between the standard and the pigments mentioned are de- 

 scribed and charted in this chapter. The methods are also described in 

 detail for preparing plant and animal tissues for the analysis as well 

 as the separation of the individual carotinoids mentioned when present 

 together in the plant extracts. Data are given showing the results of 

 applying the methods to various plant and animal tissues. 



No method has yet been devised for estimating lycopin quantita- 

 tively. A suitable standard must first be found and a method discov- 

 ered for separating lycopin from carotin. 



