Previous　studies　have　indicated　that　highly　brominated　diphenyl　ethers　may　be　oxidatively　metabolized　to　OH-PBDEs　and　accumulated　in　human　serum.　However,　identification　of　such　metabolites　has　been　hampered　by　a　lack　of　reference　standards.　In　the　present　study,　we　have　developed　a　systematic　approach　for　the　preparation　of　Br-7-Br-9　OH-PBDEs　with　various　substitution　patterns.　The　approach　involved　a　coupling　reaction　between　5-fluoro-2-nitroaniline　and　a　methoxyphenol　or　aminomethoxy-phenol　to　produce　diphenyl　ethers,　subsequent　bromination　of　these　diphenyl　ethers,　removal　of　the　amino/nitro　groups,　and/or　conversion　of　amino/nitro　groups　to　bromo　substituents.　The　amino　group　was　the　key　to　our　approach;　it　facilitated　regioselective　bromination　on　the　phenyl　rings　and　could　then　be　removed　or　readily　replaced　by　a　bromo　substituent.　In　total,　25　MeO-PBDEs　and　20　OH-PBDEs　were　successfully　synthesized,　demonstrating　the　feasibility　and　versatility　of　this　approach.　The　characteristics　of　the　mass　spectrometric　fragmentations　of　the　MeO-PBDEs　have　been　investigated　and　are　discussed　herein.　In　addition,　the　relative　retention　times　of　these　MeO-PBDEs　relative　to　BDE-118　on　three　columns　with　different　polarities　have　been　determined.　(C)　2013　Elsevier　Ltd.　All　rights　reserved.