Abstract Narrow-bore fused-silica liquid chromatography columns with I.D. ≦ 500 μm and packed with ≦ 10-μm particles in lengths from 10 cm to a few meters can be efficiently prepared. A 1-m fused-silica column with 110.000 theoretical plates can be packed with 3-μm C 18 bonded-phase particles. Narrow-bore microparticle-packed columns can be used in conjunction with a constant-pressure piston pump a splitter injector and an on-column UV absorbance detector. A 45 cm x 300 μm I.D. column packed with 3-μm C 18 bonded-phase particles allows baseline separation of an Environmental Protection Agency priority pollutant mixture cointaining sixteen polynuclear aromatic hydrocarbons. The use of the effect of solvent modifier(s) in the sample solution to improve solute resolution, peak detection and column selectivity and to reduce analysis time of the narrow-bore microparticle-packed-column high-performance liquid chromatography is proposed and demonstrated. The practical importance of the solvent effect in narrow-bore packed-column high-performance liquid chromatography is also discussed.