Riffle division method: a riffle is a kind of non-mechanical sample divider, which is usually fed manually.The sample is divided into 2 equal parts by riffle, with one retained and one rejected.

• 二分器缩分法：二分器系非机械式样品缩分器，通常用手工给料，样品通过二分器被分成二等份，一份保留，另一份弃去。