Nephelometry measurements are most directly influenced by which property of particles in suspension?

• A. Color of the solution
• B. Particle size distribution
• C. Solute concentration
• D. Temperature of the solution

Answer: (B)

Nephelometry is all about light scattered by particles in suspension. The amount and pattern of that scattered light are governed primarily by how big the particles are and how their sizes are distributed. Larger particles scatter more light, and a range of sizes (a broad distribution) means different particles contribute different amounts of scattering, changing the overall signal the detector sees. Color or solute concentration mainly affect how light is absorbed rather than scattered, and temperature can tweak refractive index slightly, but these have a much smaller direct impact on the nephelometric signal. So the feature that most directly shapes the measurement is the particle size distribution.