From each homogenized sample 25 g were taken in duplicate for the study of iron, copper, zinc and manganese content, and 10 g for sodium, potassium, calcium and magnesium.

• 取25克微粒分布均匀的双份样品（不确定是双份还是同样的另外一份），用来研究铁、铜、锌和锰的含量，再取10克微粒分布均匀的双份样品用来研究钠、钾、钙和镁的含量。