METHOD FOR COLLECTING PRECIOUS METALS FROM SOLUTION CONTAINING PRECIOUS METAL IONS, EXTRACTANT OR ADSORBENT USED THEREFOR, AND BACK EXTRACTANT OR DESORBENT

To provide a method for recovering a precious metal from a solution containing precious metal ions, an extracting agent or adsorbent used therefor, and a back-extracting agent or desorbent. An extracting agent or adsorbent in which precious metal ions are extracted or adsorbed, is brought into contact with a back-extracting agent or desorbent containing a sulfur-containing amino acid derivative represented by the following formula (I): wherein R 1 is a methyl group, an ethyl group, a vinyl group, a C 3-8 linear, branched or cyclic hydrocarbon group, or a C 6-14 aromatic hydrocarbon group, R 2 's are each independently a hydrogen atom, a methyl group, an ethyl group, a vinyl group, a C 3-8 linear, branched or cyclic hydrocarbon group or a C 6-14 aromatic hydrocarbon group, and n is 0 or 1, to obtain a solution containing the precious metal ions, which is subjected to a reduction treatment to obtain a precious metal.