To　date,　hydroxyapatite　(HAP)　based　monoliths　were　mainly　fabricated　by　directly　doping　of　HAP,　which　suffered　from　less　effective　coverage　of　HAP.　Herein,　a　HAP　surface-functionalized　monolithic　column　(HAP@PDA@UF)　has　been　prepared　by　in-situ　biomineralization　and　applied　as　sorbent　for　selective　in-tube　solid　phase　microextraction　of　zoleronic　acid　and　risedronic　acid.　A　polydopamine　coating　was　first　generated　on　the　surface　of　the　parent　urea-formaldehyde　resin　monolith;　and　then　HAP　microcrystals　were　further　grew　on　the　polydopamine　coating　to　achieve　this　preparation.　SEM,　EDAX,　FTIR,　XPS　and　mercury　intrusion　method　were　utilized　for　the　characterization　of　the　HAP@PDA@UF　monolith,　and　provided　evidences　of　this　successful　preparation.　The　selective　extraction　mechanism　of　the　HAP@PDA@UF　monolith　was　investigated　by　the　optimization　of　methanol　percentage　in　the　sampling　solution,　phosphate　concentration　in　the　eluent.　Other　crucial　factors,　including　sampling　and　elution　flow　rate,　and　collection　time　span,　were　also　optimized　for　the　desired　SPME　performance.　Under　the　optimal　conditions,　the　proposed　method　showed　low　LODs　of　0.1　μg/mL,　satisfactory　recoveries　of　79.6%-92.5%　with　RSDs　less　than　2.7%,　and　good　reproducibility　with　RSD　less　than　6.9%,　which　demonstrated　the　excellent　application　of　the　HAP@PDA@UF　monolith,　and　its　potential　as　a　promising　selective　sorbent　for　bisphosphonates.　©　2021　Elsevier　B.V.