A　new　method　for　determination　of　iron(III)　has　been　developed　using　a　kind　of　rhodamine　B　derivative　fluorescent　probe,　rhodamine　amide　(RHA),　in　acidic　HAc-NaAc　buffer　solution.　In　this　approach,　the　heavy　atom　effect　of　I　3-　was　applied　to　quench　the　fluorescence　of　RHA.　When　iron(III)　and　KI　coexisted　in　HAc-NaAc　buffer　solution,　iron(III)　reacted　with　the　excess　KI　to　produce　I3-　that　quenched　the　fluorescence　of　RHA　through　the　formation　of　a　non-fluorescence　compound.　The　results　showed　that　the　fluorescence　intensity　decrease　of　RHA　presented　a　good　linear　relationship　with　the　iron(III)　concentrations　in　the　range　from　0.5　to　5.0　μmol　L-1　with　the　correlation　coefficient　of　0.9970,　and　the　detection　limit　was　0.3　μmol　L-1　iron(III).　The　approach　was　applied　to　determination　of　iron(III)　in　water　samples,　and　the　recovery　was　found　to　be　from　80.7%　to　100.　8%.　©　2012　Elsevier　B.V.　All　rights　reserved.