6-component certified reference material (CRM) internal standard mix. Ready to use for QuEChERS extractions—no dilutions necessary. Contains PCB 18, 50 µg/mL; PCB 28, 50 µg/mL; PCB 52, 50 µg/mL; Triphenylmethane, 10 µg/mL; Triphenylphosphate, 20 µg/mL; Tris(1,3-dichloroisopropyl)phosphate, 50 µg/mL in acetonitrile. Must be refrigerated at 10C or colder.