This　paper　describes　the　use　of　head-column　field-enhanced　sample　stacking　for　on-line　sample　concentration　in　MEKC;　the　method　has　been　applied　to　the　determination　of　C1-C9　aliphatic　amines　after　their　pre-capillary　derivatization　with　3-(4-carboxybenzoyl)　quinoline-2-carboxaldehyde　(CBQCA).　The　optimum　derivatization,　on-line　concentration　and　separation　conditions　for　these　aliphatic　amines　were　investigated　in　detail.　The　optimized　molar　ratio　of　CBQCA　to　amines　was　found　to　be　120:1,　and　50　mmol/L　borate　buffer　(pH　9.5)　was　used　for　derivatization　in　order　to　achieve　high　efficiency.　Nine　imidazole　aliphatic　amines　were　baseline　separated　within　12　min　by　using　50　mmol/　L　of　sodium　borate　(pH　9.5)　and　15　mmol/L　of　SDS　as　running　buffer.　Under　the　optimum　conditions,　the　detection　limits　of　these　nine　aliphatic　amines　ranged　from　1.2　to　3.8　pmol/L.　S/N　=　3,　which　was　about　49-173-fold　lower　than　those　of　conventional　sample　injections.　After　validation,　the　developed　method　was　applied　to　the　determination　of　C1-C9　aliphatic　amines　in　river　water　with　the　average　recoveries　of　86.7-105%.　©　2009　Wiley-VCH　Verlag　GmbH　&　Co.　KGaA,　Weinheim.