Surface-enhanced　Raman　spectroscopy　(SERS),　as　a　nondestructive　and　fast　detection　technique,　is　a　promising　alternative　approach　for　arsenic　detection,　particularly　for　in　situ　applications.　SERS-based　speciation　analysis　according　to　the　fingerprint　SERS　signals　of　different　arsenicals　has　the　potential　to　provide　a　superior　technique　in　species　preservation　over　the　conventional　chromatographic　separation　methods,　albeit　with　some　difficulties　due　to　the　similarity　in　SERS　patterns.　In　this　study,　we　explored　a　novel　SERS　method　for　arsenic　speciation　by　using　the　separation　potential　of　the　coffee　ring　effect　on　negatively　charged　silver　nanofilms　(AgNFs).　Four　arsenic　species,　including　arsenite　(AsIII),　arsenate　(AsV),　monomethylarsonic　acid　(MMAV),　and　dimethylarsinic　acid　(DMAV),　were　measured　for　fingerprint　SERS　signals　in　solution　and　on　the　films.　Significant　enhancement　of　SERS　signals　on　the　dried　coffee　ring　stains　by　the　AgNFs　were　observed　except　for　AsIII,　and　more　importantly,　arsenicals　migrated　varying　distances　during　coffee　ring　development,　promoting　better　speciation.　Sodium　dodecyl　sulfate　was　then　introduced　into　the　droplet　to　reduce　the　droplet　surface　tension,　facilitating　the　migration　of　solution　into　the　peripheral　region.　Under　the　combined　interactions　of　arsenicals　with　the　AgNFs,　solvent,　and　surfactant,　enhanced　separation　between　arsenicals　was　observed　as　a　result　of　the　formation　of　two　concentric　rings.　Combining　the　SERS　fingerprint　signals　and　physical　separation　of　arsenicals　on　the　surface,　arsenic　speciation　was　achieved　using　the　AgNFs　substrate-based　SERS　technology,　demonstrating　the　potential　of　the　coffee　ring　effect　for　rapid　separation　and　analysis　of　small　molecules　by　SERS.　©　2019　American　Chemical　Society.