isocratic analysis

in chromatography
https://doi.org/10.1351/goldbook.I03268
A procedure in which the composition of the mobile phase remains constant during the elution process.
Source:
PAC, 1993, 65, 819. 'Nomenclature for chromatography (IUPAC Recommendations 1993)' on page 826 (https://doi.org/10.1351/pac199365040819)