matrix effect
  1. (in analytical chemistry) The combined effect of all components of the sample other than the analyte on the measurement of the quantity. If a specific component can be identified as causing an effect then this is referred to as interference.
    matrix (in analysis)
    PAC, 1989, 61, 1657. (Nomenclature for automated and mechanised analysis (Recommendations 1989)) on page 1660 [Terms] [Paper]
  2. (in surface analysis) Effects which cause changes in Auger-electron, photoelectron, secondary ion yield, or scattered ion intensity, the energy or shape of the signal of an element in any environment as compared to these quantities in a pure element. (a) Chemical matrix effects: changes in the chemical composition of the solid which affect the signals as described above. (b) Physical matrix effects: topographical and/or crystalline properties which affect the signal as described above.
    PAC, 1979, 51, 2243. (General aspects of trace analytical methods—IV. Recommendations for nomenclature, standard procedures and reporting of experimental data for surface analysis techniques) on page 2247 [Terms] [Paper]