A simple method to distinguish the quality of polyacrylamide: at present, it is impossible to distinguish by observing powder solids. To make a complete difference, a dissolution comparison experiment must be done: take the same quality of solids to make liquids of equal concentration (such as one thousandth), and mix well as much as possible. With the passage of time (about half an hour), the solid is almost completely dissolved, the concentration and viscosity of the high molecular weight solution are significantly higher than those of the low molecular weight product. High-purity products usually have high transparency, while inferior products have low transparency, often with a certain degree of white.