次硫酸盐

例句：

1. 1. This chemical is used as a preservative in food processing.
   这种化学物质在食品加工中用作防腐剂。
2. 2. The compound is commonly found in fertilizers and insecticides.
   这种化合物通常存在于肥料和杀虫剂中。
3. 3. In the laboratory, it's often used to test for contamination by heavy metals.
   在实验室里，它常用于检测重金属污染。