Sorbitol is a sugar alcohol commonly used as a sweetener and humectant in food and pharmaceutical products. It is important to ensure that sorbitol used in these products is of high purity. Impurities in sorbitol can include residual chemicals from the manufacturing process, such as formaldehyde and heavy metals, as well as microbial contamination. These impurities can have negative effects on the quality and safety of the final product, making it important to carefully monitor and control the sorbitol purification process.