Faced with a particular customer problem, the laboratory must first set the analytical requirement which defines a method that solves that problem. The main requirements are the following

• Scope - determination of a parameter (concentration of an analyte) in matrices,,,
• Measuring interval - also called range
• Precision - we often focus on a requirement on within-lab reproducibility s(Rw)
• Trueness - expressed as a requirement on maximum bias
• Ruggedness
• Measurement uncertainty

General requirement and specific for the environmental sector can be found here.