A solution that maintains constant  pH by resisting changes in pH from dilution or addition of small amounts of  acids and bases. 

The term "buffer" was found in the following pages:

Selenium Speciation in Fortified Vegetables | EVISA's News
Link database: EPA-EAD: Method 1636: Hexavalent Chromium by Ion Chromatography
Instrument database: Bio-Rad Laboratories - BioLogic LP System
Instrument database: Jasco Inc. - PU-2089 quaternary low pressure gradient pump
New Agilent HPLC column for routine determination of arsenic species in human urine by HPLC-ICP-MS | EVISA's News
Rapid automated arsenic speciation analysis by inductively coupled plasma mass spectrometry | EVISA's News
Ultra-sensitive speciation analysis of inorganic platinum-chloride complexes in platinum-based drugs by HPLC-ICP-MS | EVISA's News
Material database: Sigma-Aldrich - Auxiliary reagent for AAS: Cesium chloride Lanthanum chloride
Instrument database: Jasco Inc. - PU-2080 Isocratic HPLC pump
Instrument database: Prince Technologies B.V. - PrinCE-C 650 and 660 Capillary Electrophoresis Systems
Instrument database: Prince Technologies B.V. - PrinCE 400 Series Capillary Electrophoresis System
A highly selective and robust HPLC-ICP-MS arsenic speciation method for urine analysis | EVISA's News
Instrument database: RECIPE Chemicals + Instruments GmbH - IP3000 Isocratic HPLC Pump
Instrument database: Bio-Rad Laboratories - QuadTec UV/vis Detector
Company database: Exaxol Corporation
Instrument database: SPEX CertiPrep - 2000 Geno/Grinder
CE-ICP-MS for speciation analysis | EVISA's News
Material database: Sigma-Aldrich - Auxiliary reagent for AAS: Aluminum nitrate cesium chloride
Instrument database: Gilson, Inc - GX-271 ASPEC™ SolidPhase Extraction system
All about Chromatography - Resources related to Chromatography | EVISA's News