Department of Physics, Faculty of Science, Ryerson University , 350 Victoria Street, Toronto, Ontario M5B 2K3, Canada.
Anal Chem. 2013 Oct 1;85(19):9189-95. doi: 10.1021/ac401877d. Epub 2013 Sep 16.
Plaster of Paris [poP, CaSO4·(1)/(2) H2O] is the standard phantom material used for the calibration of in vivo X-ray fluorescence (IVXRF)-based systems of bone metal quantification (i.e bone strontium and lead). Calibration of IVXRF systems of bone metal quantification employs the use of a coherent normalization procedure which requires the application of a coherent correction factor (CCF) to the data, calculated as the ratio of the relativistic form factors of the phantom material and bone mineral. Various issues have been raised as to the suitability of poP for the calibration of IVXRF systems of bone metal quantification which include its chemical purity and its chemical difference from bone mineral (a calcium phosphate). This work describes the preparation of a chemically pure hydroxyapatite phantom material, of known composition and stoichiometry, proposed for the purpose of calibrating IVXRF systems of bone strontium and lead quantification as a replacement for poP. The issue with contamination by the analyte was resolved by preparing pure Ca(OH)2 by hydroxide precipitation, which was found to bring strontium and lead levels to <0.7 and <0.3 μg/g Ca, respectively. HAp phantoms were prepared from known quantities of chemically pure Ca(OH)2, CaHPO4·2H2O prepared from pure Ca(OH)2, the analyte, and a HPO4(2-) containing setting solution. The final crystal structure of the material was found to be similar to that of the bone mineral component of NIST SRM 1486 (bone meal), as determined by powder X-ray diffraction spectrometry.
熟石膏[poP，CaSO4·(1)/(2)H2O]是用于体内 X 射线荧光（IVXRF）骨金属定量系统校准的标准体模材料（即骨锶和铅）。骨金属定量 IVXRF 系统的校准采用相干归一化程序，该程序需要将相干校正因子（CCF）应用于数据，该因子计算为体模材料和骨矿物质的相对论形函数的比值。已经提出了关于 poP 适用于骨金属定量 IVXRF 系统校准的各种问题，包括其化学纯度及其与骨矿物质（磷酸钙）的化学差异。这项工作描述了一种化学纯羟基磷灰石体模材料的制备，该材料具有已知的组成和化学计量比，旨在替代 poP 用于校准 IVXRF 骨锶和铅定量系统。通过氢氧化物沉淀制备纯 Ca(OH)2 解决了分析物污染的问题，发现这将使锶和铅的水平分别降至<0.7 和<0.3μg/g Ca。通过已知量的化学纯 Ca(OH)2、从纯 Ca(OH)2 制备的 CaHPO4·2H2O、分析物和含有 HPO4(2-)的凝固溶液制备 HAp 体模。通过粉末 X 射线衍射光谱法确定，该材料的最终晶体结构与 NIST SRM 1486（骨粉）的骨矿物质成分相似。
