Question

What types of species can be separated by HPLC but not by GC?

Short answer

The inorganic ions and thermally unstable species are only separated by HPLC but not by GC.

Step-by-step solution

Step 1. Given information 

State the types of species separated by HPLC but not by GC.

Step 2. Explanation

The higher performance liquid chromatography is responsible for providing a higher resolution as compared to the gas chromatography. The substances, which are non-volatile such as inorganic ions, and the materials which are unstable, are separated by the higher performance liquid chromatography. The gas chromatography is unable to separate these types of substances and materials due to having poor resolution.

Therefore, the inorganic ions and thermally unstable species are only separated by HPLC but not by GC.