Micro-Raman and FTIR studies of synthetic and natural apatites
Micro-Raman and FTIR studies of synthetic and natural apatites
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DOI：
10.1016/j.biomaterials.2007.02.028
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发表时间：
2007-07-01
期刊：
影响因子：
14
通讯作者：
Leventouri, Theodora
中科院分区：
文献类型：
--
作者：
Antonakos, Anastasios;Liarokapis, Efthymios;Leventouri, Theodora
用显微拉曼光谱和红外光谱对B型合成碳羟基磷灰石(CHAP)、天然碳氟磷灰石(CFAP)和硅取代羟基磷灰石(SiHAp)进行了研究。研究发现，在碳酸盐磷灰石(CAPS)中以B型碳酸盐取代为主的同时，也检测到A型碳酸盐取代。B型碳酸盐取代导致了与原子无序有关的v(1)P-O伸缩模式的展宽，并使原子的局域对称性从C-6h(2)降低到C-3h。CFAP脱碳后，v(3c)PO4伸缩红外吸收模移近15 cm(-1)。晶格动力学计算证实了这种位移，指出当碳酸盐离开磷灰石结构时，镜面上的P-O键长增加。这一结果支持在相同样品的中子粉末衍射研究基础上提出的取代机理，即碳酸盐取代磷酸盐四面体的镜面。在不同碳酸盐含量的样品中，v(2)IR CO3和v(1)PO4谱带的强度比提供了盖子碳化程度的衡量标准。(C)2007爱思唯尔有限公司。保留所有权利。
B-type synthetic carbonate hydroxyapatite (CHAp), natural carbonate fluorapatite (CFAp) and silicon-substituted hydroxyapatite (SiHAp) have been studied by using micro-Raman and infrared (IR) spectroscopy. It was found that while B-type carbonate substitution predominates in carbonate apatites (CAps), A-type is also detected. B-type carbonate substitution causes a broadening of the v(1) P-O stretching mode that is associated with the atomic disorder and lowering of the local symmetry in CAps from C-6h(2) to C-3h. An similar to 15 cm(-1) shift of the v(3c) PO4 stretching IR mode was observed upon decarbonation of the CFAp. Such shift which was confirmed by lattice dynamics calculations points out that the P-O bond lengths on the,mirror plane increase when carbonate leaves the apatite structure. The present results support the substitution mechanism proposed on the basis of neutron powder diffraction studies of the same samples whereby carbonate substitutes on the mirror plane of the phosphate tetrahedron. The intensity ratios of the v(2) IR CO3 and v(1) PO4 bands in samples of various carbonate contents provide a measure of the degree of carbonation for CAps. (C) 2007 Elsevier Ltd. All rights reserved.