Glossary

Terms used on this site. Cleaning trade and laboratory vocabulary are usually different words for the same idea. Both appear here.

§ 1Defined terms

Concentrate(Stock (lab)): The supplied product before dilution.
Stock solution(Concentrate (trade)): A high-strength solution prepared in advance, diluted on use.
Working solution(Bucket (trade)): The diluted, ready-to-use mix.
Diluent: The liquid added to dilute; usually water.
v/v: Volume in volume. ml of solute per 100 ml of total solution.
w/v: Weight in volume. g of solute per 100 ml of total solution.
w/w: Weight in weight. g of solute per 100 g of total solution.
Molarity (M): Moles of solute per litre of solution.
Molality (m): Moles of solute per kg of solvent. Temperature-independent.
ppm: Parts per million. 1 ppm ≈ 1 mg per litre of water.
BS EN 1276: Quantitative suspension test for the bactericidal activity of chemical disinfectants. UK trade standard.
BS EN 14476: Quantitative suspension test for the virucidal activity of chemical disinfectants.
C₁V₁=C₂V₂: Dilution identity. Concentration times volume is conserved on dilution.
Serial dilution: A sequence of equal-factor dilutions, used to reach very low concentrations accurately.
Pearson's square: Two-by-two arithmetic for blending two strengths to a target.
Available chlorine: Oxidising capacity of a chlorine compound, expressed as ppm or % w/v Cl₂.
QAC: Quaternary ammonium compound. A surfactant family used as a disinfectant.
SDS: Safety Data Sheet. Manufacturer document with hazard, handling and first-aid information.