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7736024 
Journal Article 
H-1 NMR Quantitative Determination of Chlorophyll alpha in the Spirulina Biomass 
Belykh, D; Zainullina, EN; Startseva, OM 
2020 
1 
Macroheterocycles
ISSN: 1998-9539 
Editorial Office 
13 
3 
260-268 
Russian 
WOS:000596543800012 
A method for determining the mass fraction of chlorophyll a in the spirulina biomass — the feedstock for the prepara-tion of chlorophyll a derivatives — using1H NMR spectroscopy without preliminary separation of the extract components is proposed (the extract was obtained by exhaustive extraction with a mixture of chloroform and ethanol). Because of the relative lability of chlorophyll a for its determination the demetallation was performed under mild conditions (action on the extract by 10 % hydrochloric acid) with formation of more stable pheophytin a, which served as a deri-vate for the determination of chlorophyll a. The chlorophyll a mass fraction in the studied raw materials was calculated based on the amount of pheophytin a in the extract. The content of pheophytin a in the extract analyzed for calculating of the chlorophyll a mass fraction in the air-dry biomass of spirulina was determined by the internal standard method. The 4-nitrobenzaldehyde was used as an internal standard. The ratio of the amount of pheophytin a and 4-nitrobenz-aldehyde added to the extract was determined by the signal integrated intensities of protons of the internal standard and protons in the meso-positions of the pheophytin a molecule. It was shown that, to increase the accuracy of deter-mination, preliminary removal of a part of the lipid components by extraction with hexane is useful. The mass fraction of chlorophyll a in the raw material studied was ω(chl) = 0.81 ± 0.05 %. The result obtained corresponds to the data on the preparative yields of pheophytin a and methylpheophorbide a obtained from the same spirulina sample (the yields of these compounds can be used to judge the lower boundary of the content of chlorophyll a in the raw material). The proposed technique can be adapted for other types of raw materials containing chlorophyll a or its derivatives. © ISUCT Publishing. 
Chlorophyll a; pheophytin a; spirulina; quantification; quantitative analysis by H-1 NMR