The potassium sulfate-copper sulfate combined catalyst has the following advantages:

1. Significant catalytic effect: At a constant temperature of 420°C, digesting one test sample takes only 40 minutes, which is twice as fast as the potassium sulfate-copper sulfate combined catalyst.

2. No side reactions interfere with the nitrogen determination process, resulting in more accurate measurement data.

3. Convenient to use: The product is in tablet form. Only one tablet needs to be picked with tweezers for digesting each sample, eliminating the hassle of repeated weighing with a balance.

Note: It should not be handled directly with hands, as sweat may contaminate the tablets. Therefore, only tweezers should be used for handling.

4. Clear indication of reaction completion: The digest turns colorless and transparent.