A　method　combining　magnetic　solid-phase　extraction　(MSPE)　and　ultra-high-pressure　liquid　chromatography-tandem　mass　spectrometry　(UHPLC-MS/MS)　was　developed　for　the　analysis　of　aristolochic　acids　I　(AAI)　in　mouse　serum　and　tissues.　The　magnetic　covalent　organic　frameworks　(MNP@COF)-based　MSPE　exhibited　high　adsorption　capacity　towards　AAI　(93.1　mg/g)　in　optimal　conditions.　After　MSPE　extraction,　AAI　was　separated　with　C18　column　using　gradient　elution　and　quantified　(m/z　342.21　→　298.13)　by　UHPLC-MS/MS　with　monitor　reaction　monitoring　(MRM)　mode.　This　MSPE-based　UHPLC-MS/MS　method　was　validated　with　respected　to　lower　limit　of　quantification　(LLOQ),　linearity,　recovery,　precision　and　accuracy　of　intra-　and　inter-day,　and　matrix　effect.　Good　calibration　linearities　at　the　range　of　1–500　ng/L　for　AAI　in　biological　matrices　(serum,　kidney,　and　liver)　with　high　correlation　coefficient　(R2)　＞　0.9970,　and　high　enrichment　factors　(mean　values　from　1038　to　1045)　were　obtained.　This　method　was　highly　sensitive　to　determine　AAI　with　LLOQ　within　the　range　of　4.62–5.24　ng/L　in　extracted　serum,　kidney,　and　liver　samples.　Recoveries　at　5,　50,　100　and　300　ng/L　in　biological　samples　ranged　from　93.2　to　104.0%,　and　intra-　and　inter　day　accuracy　and　precision　(defined　as　bias　and　coefficient　of　variation,　respectively)　were　below　±　15%.　The　method　was　successfully　applied　in　the　analysis　of　biological　samples　collected　from　mice　exposed　with　AAI　with　concentrations　range　of　0.007–0.041　μg/L　for　consecutive　four　days.　The　established　method　might　be　applied　for　the　investigation　of　risk　assessment　and　toxicity　induced　by　long-time　use　of　AAI-containing　herbs　or　dietary　supplements.　©　2021　Elsevier　B.V.