shift reagent

例句：

1. 1.The shift reagent was used to detect the presence of heavy metals in the sample.
   换位试剂被用来检测样品中重金属的存在。
2. 2. The chemical shift reagent was used to determine the molecular structure of the compound.
   化学位移试剂被用来确定化合物的分子结构。
3. 3. The shift reagent was used to analyze the chemical composition of the sample.
   换位试剂被用来分析样品的化学成分。