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:

Material database: National Institute of Standards and Technology (NIST) - SRM 2910b - Hydroxyapatite
Link database: Mercury in Crude Oil Refined in the United States
Material database: Food Analysis Performance Assessment Scheme (FAPAS) - Test Material T07128 (Canned Fish)
Instrument database: SPECTRO Analytical Instruments Inc. - SPECTRUMA GDA 750
Instrument database: Teledyne Instruments Leeman Labs Inc. - Hydra AF Mercury Analyzer
Arsenic concentration in groundwater may be affected by bacteria | EVISA's News
Material database: RECIPE Chemicals + Instruments GmbH - ClinChek 8883 Control blood plasma, lyophilised, trace elements level I
Material database: IAEA - MEL International Atomic Energy Agency - IAEA-433 Trace Elements and Methylmercury in Marine Sediment
Instrument database: Organomation Assosciates Inc. - ROT-X-TRACT-LC Extractor for Sample Preparation
Link database: HSE: MDHS29/2 Beryllium and beryllium compounds in air
Detection of Gd-based contrast agent in the skin of a patient eight years after administration | EVISA's News
Material database: The Food and Environment Research Agency (FAPAS) - Test Material T07151 (Powdered Rice)
Arsenic speciation in different parts of the rice plant | EVISA's News
Instrument database: Agilent Technologies Inc. - 7800 ICP-MS
Arsenic species in rice: A new Australian reference material | EVISA's News
Material database: The Food and Environment Research Agency (FAPAS) - Test Material T07158 (Chilli powder)
Material database: IRMM - Institute for Reference Materials and Measurements - ERM-CA400 - Total Mercury in Seawater
Link database: USGS Method I-1232:Chromium, hexavalent, dissolved, water, FLAA
Instrument database: Dionex Corporation - RF 2000 Fluorescence Detector
Instrument database: Nippon Instruments Corporation - EMP-1A Mercury Gas monitor