Any one of a group of three quantities characterizing the composition of a mixture and defined as one of mass, amount of substance (chemical amount), or number divided by volume, giving, respectively, mass, amount (of substance), or number concentrations.

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

FDA Approves Chromium Claim | EVISA's News
Material database: RECIPE Chemicals + Instruments GmbH - ClinChek 8842 Whole blood, lyophilized, trace elements level III: LOT 445
Adisseo obtains FDA approval on pure organic selenium feed additive | EVISA's News
Regulating Mercury Emissions from Power Plants: Will It Protect Our Health? | EVISA's News
Material database: JRC - Joint Research Centre - ERM-BB422 - Fish muscle
Material database: Food Analysis Performance Assessment Scheme (FAPAS) - Test Material T1862 (Canned Meat)
Is methyl mercury limiting the delight of seafood ? - To answer this question is a challenge for elemental speciation analysis | EVISA's News
Instrument database: PerkinElmer Inc. - FIMS-400-Mercury Analyzer
Material database: National Institute for Environmental Studies (NIES) - NIES CRM 15: Scallop
Instrument database: Varian Inc. (Part A) - 500-MS LC Ion Trap
Link database: Chromium VI in cement: new COSHH Regulations
Material database: The Food and Environment Research Agency (FAPAS) - Test Material T07135 (Vegetable Puree)
Instrument database: LUMEX Ltd. - RA-915+/PYRO-915
Tracing Gadolinium-based Contrast Agents from Wastewater, via Surface Water to Drinking Water | EVISA's News
Determination of tungsten species in natural waters by HPLC-ICP-MS | EVISA's News
Link database: FLUXY/MHEDYN: Modelling of dynamic environmental processes
Determination of chromium species in tanned leather samples | EVISA's News
Material database: National Institute of Standards and Technology (NIST) - SRM 679 - Brick Clay
Instrument database: PerkinElmer Inc. - SMS 100 Automated Mercury Analyzer
Material database: Institute of Environmental Health Monitoring (IEHS) - GBW 09133 Bovine Blood