§ 134. EBYTHROPIIYLL, CHLOROPHYLLAN, ETC. 115 



After acidulating the alcoholic extract witlti hydrochloric acid 

 and diluting with a little- ■water, the chlorophyll may be removed 

 by shaking with benzene, xanthophyll remaining in the alcoholic 

 liquid. Under these circumstances, however, the chlorophyll is 

 unfortunately always accompanied by fatty matter, etc. 



§ 1 33. Estimaiion of 'Chlorophyll. — Should it appear desirable t& 

 isolate the chlorophyll for the purpose of weighing (cf. § 37), 

 advantage ipight possibly be taken of an observdition made by 

 Sachsse,* viz., that a benzene solution of chlorophyll, on standing 

 for a few days over metallic sodium, deposits a, green mass 

 capable of being filtered off from the golden-yellow solution. 

 With the exception of its containing sodium, it agrees with 

 chlorophyll in most of its more important characters, although, 

 of cpurse, it no longer represents that substance in an unaltered 

 state. It dissolves' in water, but is completely precipitated by 

 sulphate of eoppei. The copper compound thus formed may, 

 however,, be contaminated with: carbonate. From it the colouring 

 matter may be isolated by suspending in alcohol, passing a current 

 of sulphuretted' hydrogen through the mixture, arid evaporating 

 the alcoholic filtrate. The residue may be weighed. 



§ 134. ErytKrophyll, XJUorophyUan, etc. — By 'first freeing grasis 

 from wax by treatment with ether, and then exhausting with 

 alcohol, Hoppe-Seyler^ succeeded in isolating, from unaltered 

 chlorophyll a greenish- white colouring matter, sparingly soluble 

 in alcohol, crystallizing in four-sided plates, and appearing, red by 

 transmitted light This substance seems to be identical with 

 Bougarel's* erythrophyll. Hoppe-Seyler also separated -a second 

 substance, which was more easily soluble in hot alcohol, crystallized 

 in needles, and appeared darit green by reflected, but brown by 

 transmitted, light. This body, which he terms chloropkyllan, 

 agrees with the so-called chlorophyll in most of its properties, 

 especially the spfectrum, in which, however,, the bands in the 

 yellow and green are somewhat deeper than they are in the 

 ordinary chlorophyll-spectrum (§§ 148 and 20). Hoppe-Seyler 

 thinks it possible to' make approximate estimations of chlorophyll 

 by titration with spectroscopic end-reaction.* Gautier has also 



i Chem. Centralblatt, 121, 1878 ; 741, 1880. 



2 Ber. d. d. chem. Ges. xii. 1655, 1879 ; xiii. 1244, 1880 (Journ. Chem. Sac- 

 xxxvjii.-53, 894). 



3 Bulletin de la Soe. Chhni xxvii. 442, 1879 (Journ. Chem. Soc. xxxu. 790). 

 * For the chlorophyll contained In certain Florideae, see Pringaheimi loc. cil. ; 



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