| Objective To study the dissolution characteristics of calcium phosphate composite particles (HA:TCP=3:7) in TRIS buffer solution. Methods A series of standard Ca2+ solutions with increasing concentration are prepared, and the working curve of Ca2+ ion solution was drawn. The composite calcium phosphate particles (HA:TCP=3:7) in the pH value for 7.4 TRIS buffer solution, sampling once per hour (initial samples were collected every 3 min), extracted from the supernatant by high speed centrifugation, measured at each time point of the concentration of Ca2+ extraction liquid by inductively coupled plasma mass spectrometry. The dissolution curve of Ca2+ concentration on soaking time was drawn. Results ①The linear equation of the working curve of Ca2+ ionic solution is y=4043.9x+23783, and the correlation coefficient R is 0.9999. The detection limit is 0.0063 μg/mL, and the quantitative limit is 0.021 μg/mL. ② After the initial immersion within 0.5 h, the concentration of Ca2+ increased with time dramatically, marked a turning point at 0.5 h. From 0.5 h to 2 h, the concentration of Ca2+ ion increased with time, but the rate of increase decreased obviously compared with the first 0.5 h. After 20 h, the dissolution reached the basic balance. ③ The dissolution process of calcium phosphate composite particles can be divided into 3 stages, the first is the dissolution process of Ca2+ ion concentration increased rapidly, the second stage is the competition process of Ca2+ dissolution with HA or CaHPO4·2H2O deposition, the third stage is the stable process of Ca2+ ion concentration will no longer increase. Conclusion The dissolution of composite calcium phosphate particles (HA:TCP=3:7) in TRIS buffer solution has a certain regularity, and the concentration of Ca2+ ions dissolved in 24h is about 1200 μg/L. |
