食品の防黴に関する研究

(第4報) Polarographによる食品中のVitamin K₃の定量

抄録

Vitamin K₃ can be determined polarographically in a buffered solution containing 0.1 N potassium chloride and 20 per cent of isopropanol. The polarogram (Fig. 1.) shows the well defined reduction wave at -0. 25 volt vs. S. C. E. (at pH 7.0), under this condition the wave heights are proportional to the concentration of vitamin K₃ (Fig. 5.).
For the determination of vitamin K₃ in food products, the wave heights of polarograms of sample solutions prepared as follows are measured; A:the ether extract from the food product is dissolved in 2 volume of isopropanol and then 3 volume of 1/3 _N potassium chloride aqueous solution and 5 volume of MCILVAINE'S buffer solution (pH 7.0) are added to this solution; B:the same, sample added with known concentration of standard vitamin K₃ is treated as above. Then the vitamin K₃ in the food product can be calculated with the following equation.
a=b×α/β-α
a:vitamin K₃ in food product,
b:added standard vitamin K₃,
α: wave height of A solution,
β: wave height of B solution.
If the polarogram shows irregular form as Fig. 4., the two sample solutions must be filtered with dry filter paper.