Pesticides

Pesticide standards labelled with stable isotopes — deuterium, carbon-13 or nitrogen-15 — for use as internal standards in residue analysis by LC-MS/MS and GC-MS/MS.

An isotope-labelled internal standard has the same physicochemical properties as the analyte but a different mass, so it compensates for both losses during sample preparation and matrix effects during ionisation. It is the most practical way to keep accuracy stable at µg/kg levels. See also pesticide reference standards.