Abstract: Purposes: To provide a kind of accurate, fast, simple, and direct reading method for calcium content in Pyracantha fortuneana fruit, for its functional compositions in scientific study. Methods: To measure the calcium content in Pyracantha fortuneana fruit by calcium-selective electrode—direct reading concentration method. The experiment studied the TISAB (total ionic strength adjustment buffer), the optimal scope of pH and the recovery, precision, and detection limit of this method. Results: The linear range is 0.731～4017mg/L, the detection limit 1.21×10-2mg/L, the recovery is 92.36%～108.50%, and the RSD% is 1.6%(n=6). Conclusions: This method is fast and simple for the determination of the calcium in Pyracantha fortuneana fruit. The cost is low and the result is satisfatory.

Key words: ion-selective electrode, direct-reading method, calcium, Pyracantha fortuneana fruit