Adenosine　triphosphate　(ATP),　a　universal　energy　currency　and　biomarker　of　cellular　viability,　undergoes　dynamic　fluctuations　critical　for　neurological　health,　food　safety,　and　clinical　diagnostics.　Real-time　monitoring　of　ATP　in　cerebrospinal　fluid　(CSF)　remains　challenging　due　to　limited　sample　volumes,　ultralow　concentrations　and　matrix　complexity.　Current　analytical　platforms　often　struggle　to　balance　separation　efficiency,　detection　sensitivity,　and　real-time　capability.　Surface-enhanced　Raman　scattering　(SERS)　offers　single-molecule　sensitivity,　but　specificity　remains　a　concern,　especially　when　distinguishing　ATP　from　its　metabolites　such　as　adenosine　diphosphate　(ADP)　and　adenosine　monophosphate　(AMP).　Traditional　liquid　chromatography-SERS　(LC-SERS)　platforms　are　limited　by　memory　effects　from　nanoparticle　aggregation,　insufficient　hotspot　density　of　conventional　substrates,　nonspecific　adsorption　of　interfering　molecules,　and　peak　broadening　caused　by　packed-bed　columns,　hindering　their　application　in　complex　biological　matrices.　Herein,　we　introduce　a　novel　micro　high-performance　liquid　chromatography-SERS　(mu　HPLC-SERS)　platform　featuring　a　Mg2+-regulated　dual-capture　mechanism　for　online　ATP　monitoring.　This　platform　utilizes　an　amino-silica　monolith　(ASM)　with　a　bimodal　pore　structure　for　rapid　permeation　and　efficient　ATP　entrapment.　It　integrates　an　affinity-based　SERS　detection　segment　and　an　electrostatic　pre-enrichment　segment.　The　detection　segment　features　a　1　cm　SERS　aptasensor,　functionalized　with　ATP　aptamer-modified　gold　nanoparticles,　which　captures　ATP　through　Mg2+-triggered　conformational　changes,　enabling　dynamic　detection　under　flow　conditions.　The　10　cm　pre-enrichment　column　selectively　retains　ATP　via　phosphate-amine　interactions　in　Mg2+-free　conditions,　effectively　excluding　metabolites　like　ADP　and　AMP　due　to　their　fewer　phosphate　groups.　This　results　in　high　specificity　and　enhanced　sensitivity,　with　a　limit　of　detection　of　1.03　x　10-11　mol/L.　Validated　in　mouse　models,　this　study　introduces　a　microplatform　that　integrates　online　enrichment,　separation,　and　SERS　detection,　offering　a　novel　solution　for　real-time　monitoring　of　ATP　levels　in　CSF.　This　advancement　ensures　precise　online　ATP　quantification　in　complex　matrices　under　continuous　flow,　paving　the　way　for　applications　in　food　safety,　clinical　diagnostics,　and　personalized　medicine.