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:

New Agilent HPLC column for routine determination of arsenic species in human urine by HPLC-ICP-MS | EVISA's News
Instrument database: Teledyne CETAC Technologies - CEI-100 Capillary Electrophoresis Interface for ICP-MS
Instrument database: Jasco Inc. - PU-2080 Isocratic HPLC pump
A highly selective and robust HPLC-ICP-MS arsenic speciation method for urine analysis | EVISA's News
Instrument database: Carl Zeiss AG - LIBRa 200 FE
Instrument database: Tecan - Power Washer 384
Company database: Exaxol Corporation
Instrument database: Prince Technologies B.V. - PrinCE 550 and 560 Capillary Electrophoresis System
Instrument database: Bio-Rad Laboratories - QuadTec UV/vis Detector
Instrument database: RECIPE Chemicals + Instruments GmbH - GP3000 Gradient HPLC Pump
Instrument database: Bruker Daltonics - esquire4000
Instrument database: Jasco Inc. - PU-2089 quaternary low pressure gradient pump
New Strategy for Speciation Analysis of Gadolinium retained in Bone after Application of MR Contrast Agents | EVISA's News
Link database: EPA-ORD: Method 218.6: Hexavalent Chromium in Water by Ion Chromatography
Material database: Sigma-Aldrich - Auxiliary reagent for AAS: Aluminum nitrate cesium chloride
Instrument database: Waters Corporation - 3100 Mass Detector
Instrument database: RECIPE Chemicals + Instruments GmbH - IP3000 Isocratic HPLC Pump
Instrument database: Agilent Technologies Inc. - Capillary Electrophoresis System
Species transformation during speciation analysis | EVISA's News
Instrument database: Labomatic instruments AG - HD-3000 HPLC triple piston gradient pump