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: Institute of Environmental Health Monitoring (IEHS) - GBW 09142 Selenium in Lyophilized Bovine Blood
Instrument database: Teledyne Instruments Leeman Labs Inc. - Hydra AA Mercury Analyzer
Instrument database: Waters Corporation - GCT Premier
Material database: International Atomic Energy Agency (IAEA) - IAEA-413 Major, Minor and Trace Elements in Algae
EU directive 2003/53/EC on chromium in cement | EVISA's News
Material database: Food Analysis Performance Assessment Scheme (FAPAS) - Test Material T07112 (Canned Crab Meat)
Arsenic-eating bacteria rewrite evolutionary history | EVISA's News
Link database: Chemical Fact Sheet: Mercury
Man is significantly contaminating oceans with mercury | EVISA's News
The behavior of Gd-based contrast agents during wastewater treatment | EVISA's News
Material database: QUASIMEME - Tributyltin-ethyl
Material database: IRMM - Institute for Reference Materials and Measurements - ERM-BB422 - Fish muscle
Linking atmospheric mercury to methylmercury in fish | EVISA's News
Material database: IRMM - Institute for Reference Materials and Measurements - BCR-713 - Wastewater effluent
Material database: The Food and Environment Research Agency (FAPAS) - Test Material T07134 (Powdered Rice)
Material database: RECIPE Chemicals + Instruments GmbH - ClinChek 8881 Blood Serum Control lyophilised, trace elements level II: LOT 544
Instrument database: Thermo Scientific - ELEMENT XR
As 2006: Natural Arsenic in Groundwaters of Latin America | EVISA's Agenda of Events
Fractionation as a first step towards speciation analysis | EVISA's News
Instrument database: Buck Scientific - 205 AAS