Refers collectively to techniques  in which a column of smaller than  conventional inner diameter is used for  separation. The term micro-HPLC most often  is used for HPLC in columns with inner  diameters smaller than 0.5 mm; micro-HPLC  is used in high-sensitivity analysis when the  sample amount is limited and with certain  ionization techniques in LC–MS in which  the volume of solvent flowing into the ionization source must be minimized.

The term "micro-HPLC" was found in the following pages:

LC-ICP-MS: The most often used hyphenated system for speciation analysis | EVISA's News