High-performance liquid chromatographic method for determination of DDT and its degradation products in rat plasma, liver and brain: validation and application to a pharmacokinetic study

A sensitive and reliable high-performance liquid chromatographic (HPLC) met hod, using a solid-phase extraction (SPE), was established and validated fo r determination of p,p'-DDT [1,1,1-trichloro-2,2-bis(4-chlorophenyl)ethane] and its metabolite p,p'-DDE [1,1-(2,2-dichioroethanylidene)-bis(4-chlorobe nzene)] in rat plasma, liver and brain. After being diluted with water, pla sma, liver and brain samples were applied to a solid-phase extraction C-18 cartridge. The extraction containing p,p'-DDT and p,p'-DDE from the cartrid ge were cleaned-up using a Florisil Sep-Pak cartridge. The samples were ana lyzed by HPLC using UV detection at 238 nm. The limit of detection for p,p' -DDT and p,p'-DDE was 0.1 mg kg(-1) liver or brain and 0.1 mg l(-1) plasma. For six replicate samples at 40, 4 and 0.2 mg kg(-1), intra-day precision values were within 4.9% for plasma, 6.4% for liver, and 9.7% for brain. Int er-day precision values at 4 mg kg(-1) were within 8.2% for plasma and tiss ues. The method performances were shown to be selective for p,p'-DDT and p, p'-DDE, and linear over the range 0.04-12 mg kg(-1) (mg l(-1) for plasma). The absolute recoveries of p,p'-DDT and p,p'-DDE in rat plasma and tissues were over 92%. The method was proved to be applicable to the pharmacokineti c study of DDT in rats after a single oral administration. (C) 2000 Elsevie r Science B.V. All rights reserved.