An X-ray fluorescence spectrometric method for the determination of vitamin B₁₂ in vitamin formulations is described. The method is based on the measurement of Co, the only metallic constituent of vitamin B₁₂. The method is simple, has no spectral interference from any element except Fe and is applicable to both solid and aqueous (dissolved solids) phases. It has a limit of the detection of 2.8 μg/g for Co and 64 μg/g for vitamin B₁₂ in solid pharmaceuticals and 2.0 μg/g for Co and 46 μg/g for vitamin B₁₂ in the liquid (aqueous) counterparts. Several commercial vitamin tablets containing vitamin B₁₂ in 1500–3000 μg/g range are analysed with an accuracy of ~10%. Taking advantage of the water-soluble nature of vitamin B₁₂, some tablets have also been analysed after the ultrasonic extraction of vitamin B₁₂ in aqueous medium. Phosphorous, another distinguishing constituent of vitamin B₁₂, is not found suitable for determining the vitamin due to elevated background and spectral interferences.

描述了一种用于测定维生素制剂中维生素 B ₁₂的 X 射线荧光光谱法。该方法基于对钴的测量，钴是维生素 B ₁₂的唯一金属成分。该方法简单，不受除 Fe 之外的任何元素的光谱干扰，适用于固相和水相（溶解固体）。它具有检测的2.8微克/克为Co和64的用于维生素B微克/ g的极限₁₂在固体药物和2.0微克/克为Co和46微克/克为维生素B ₁₂中的液体（水）的对应。几种含有维生素 B _{12 的}市售维生素片在 1500–3000 μg/g 范围内进行分析，准确度约为 10%。利用维生素 B ₁₂的水溶性特性，在水介质中超声提取维生素 B ₁₂后，还对一些片剂进行了分析。磷是维生素 B _{12 的}另一种显着成分，由于背景和光谱干扰升高，因此不适合用于测定维生素。