Objective To apply multiple techniques for the combined characterization of commercially available calcined Magnetitum decoction slices and to explore the quality evaluation methods for calcined Magnetitum decoction slices. Methods Eleven batches of commercially available calcined Magnetitum decoction slices were collected. Quality inspections were carried out in accordance with the 2025 edition of the Chinese Pharmacopoeia (volume I). Thermal analysis (TA), X-ray diffraction (XRD), X-ray fluorescence (XRF), and Fourier transform infrared spectroscopy (FTIR) were utilized to characterize the thermal stability, phase composition, elemental composition, and infrared structure of the samples. Inductively coupled plasma mass spectrometry (ICP-MS) was used to determine the contents of heavy metals and harmful elements in the samples. The theoretical maximum residue limit value L and the target hazard quotient (THQ) were calculated to evaluate the health risks. Results The content determination results of 11 batches of commercially available calcined Magnetitum decoction slices were qualified, but the appearance of 4 batches of slices had a quality issue of being too red, which did not meet the requirements of the 2025 edition of the Chinese Pharmacopoeia (volume I). TA results indicated significant differences in the thermal stability of the 11 batches of commercially available calcined Magnetitum decoction slices. Five batches showed a slow weight loss trend; four batches presented weight loss steps in the temperature range of 420—580 ℃; two batches first showed weight gain and then weight loss steps in the 420—580 ℃ range. XRD results showed that the commercially available calcined Magnetitum decoction slices mainly consisted of three phases: Fe₃O₄, SiO₂, and Fe₂O₃, with significant differences in the relative diffraction intensity of Fe₂O₃. XRF results demonstrated that the commercially available calcined Magnetitum decoction slices were mainly composed of elements such as Fe, Si, Al, Mg, P, K, and Ca, and the relative contents of Fe and Si reached 90%. FTIR results showed that the commercially available calcined Magnetitum decoction slices exhibited characteristic absorption peaks of Si-O asymmetric stretching vibration, Si-O-Si symmetric stretching vibration, and Si-O bending vibration in the three wavelength bands of 1 250—1 100, 800—600, and 600—300 cm^-1, respectively, and an absorption peak of Fe-O stretching vibration appeared in the 540—570 cm^-1 band. ICP-MS results indicated that among 11 batches of commercially available calcined Magnetitum decoction slices, three batches exhibited mercury (Hg) content exceeding the limit L with a THQ greater than 1; One batch showed lead (Pb) content exceeding the limit L with THQ > 1. Conclusion The quality of calcined Magnetitum decoction slices was evaluated based on the 2025 edition of the Chinese Pharmacopoeia and multiple techniques, with the aim of providing a reference for improving the quality control of calcined Magnetitum decoction slices.

calcined Magnetitum  /  X-ray diffraction  /  thermal analysis technology  /  Fourier transform infrared spectroscopy  /  inductively coupled plasma mass spectrometry  /  quality evaluation  /  health risk assessment