Determination of vitamin K1 in emulsified nutritional supplements by solid-phase extraction and high-performance liquid chromatography with postcolumn reduction on a platinum catalyst and fluorescence detection.
Determination of small amounts of vitamin K1 (0.8 microg/g) in nutritional supplements with high fat content (20 mg/g) was performed by solid-phase extraction and high-performance liquid chromatography (HPLC) with fluorescence detection after reduction on a platinum oxide catalyst. The concentration ratio of plant oils to vitamin K1 (0.8 microg/g) was about 25,000:1. A sample solution was applied to a solid-phase extraction cartridge and vitamin K1 was eluted with ethanol, followed by HPLC. The proposed method was simple, rapid (analysis time: ca. 12 min), sensitive [detection limit: ca. 0.1 pg per injection (100 microl) at a signal-to-noise ratio of 3:1], highly selective and reproducible [relative standard deviation: ca. 1.3%. (n=5)]. The calibration graph of vitamin K1 was linear in the range of 0-2 pg per injection (100 microl). Recovery of vitamin K1 was over 90% by the standard addition method.
Iwase
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Ajinomoto Co., Inc., Central Research Laboratories, Kawasaki, Japan.
D002384:Catalysis; D002851:Chromatography, High Pressure Liquid / Q000379:methods*; D019587:Dietary Supplements / Q000032:analysis*; D004492:Edetic Acid / Q000737:chemistry; D004655:Emulsions; D006863:Hydrogen-Ion Concentration; D010984:Platinum / Q000737:chemistry; D013050:Spectrometry, Fluorescence; D013431:Sulfates / Q000737:chemistry; D010837:Vitamin K 1 / Q000032:analysis*
D004655:Emulsions; D013431:Sulfates; C012036:sodium sulfate; D010984:Platinum; D010837:Vitamin K 1; D004492:Edetic Acid