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 Research Council of Canada (NRC - CNRC) - KRIK-1 Cricket Flour Certified Reference Material
Arsenic speciation in different parts of the rice plant | EVISA's News
Material database: IRMM - Institute for Reference Materials and Measurements - ERM-CZ120 Fine dust (PM10 like)
Directory of scientists: Holger Hintelmann
Material database: RECIPE Chemicals + Instruments GmbH - ClinChek 8880 Blood Serum Control lyophilised, trace elements level I: LOT 544
Material database: Food Analysis Performance Assessment Scheme (FAPAS) - Test Material T07138 (Milk Powder)
Application of Mass Spectrometry to Speciation Analysis in the Life Sciences | EVISA's Agenda of Events
Preservation of arsenic speciation in natural water samples for up to three months | EVISA's News
Material database: International Atomic Energy Agency (IAEA) - IAEA-314 226Ra, Th and U in Stream Sediment
Material database: QUASIMEME - Tributyltin monochloride
Material database: JRC - Joint Research Centre - ERM-CC141 - Loam Soil
More nutritious food helps reduce methylmercury in the aquatic food chain | EVISA's News
Instrument database: Nippon Instruments Corporation - RA3110/RA3210/RA3310/RA3320 Reducing-vaporization mercury measuring equipment
Link database: CBI: Sweden legislation: Packaging and packaging waste
Accurate determination of arsenic and its species by internal standardization for quantification by ICP-MS | EVISA's News
Link database: FDA: Elemental Analysis Manual: Section 4.10: HPLC-ICP-MS Determination of Four Arsenic Species in Fruit Juice
Material database: National Institute for Environmental Studies (NIES) - CRM 29: Water hyacinth
Material database: IAEA - MEL International Atomic Energy Agency - IAEA-405 - Trace Elements and Methylmercury in Estuarine Sediment
Material database: National Institute of Standards and Technology (NIST) - SRM 2910b - Hydroxyapatite
Material database: Ecochemistry Laboratory at the University of Canberra - Australian Rice Flour Reference Material