MgAl2O4@MoSe2 nanocomposite was used to separate-preconcentrate bismuth ions for micro solid phase extraction (μ-SPE). FT-IR, SEM, XRD, SEM-Mapping and SEM-EDX were used to find out about the functional groups, surface morphology, surface area, elemental composition, and crystalline structure of MgAl2O4@MoSe2. Analytical parameters, such as pH, adsorbent dose, sample volume, eluent concentration and volume, vortex time, and matrix effect, were optimized to get the best recovery values. Under optimized experimental conditions and by using FAAS measurements, analytical parameters were calculated, such as the limit of detection, the limit of quantification, the preconcentration factor, the enhancement factor (EF), the relative standard deviation, the sample volume, and the eluent volume as 0.012 μg L-1, 0.04 μg L-1, 10, 8.69, 5.5, 30 mL, and 3.0 mL, respectively. The validation of the presented procedure was checked by the analysis of certified reference materials and the addition-recovery test to real samples. The presented method was applied to the determination of bismuth contents of natural water, food, and cosmetic products. Two certified reference materials (CRMs) (NCS ZC 73028 Rice and NCS ZC 73036 Green tea) were used for the validation of the presented method.