Ca/P-1.67

Ca-1 ratio

PO-.67 ratio

There are, at least, several dozens preparation techniques of HAP from various precursors and all of them have been described in literature very many times. Ca(NO3)2 and (NH4)3PO4 are the most common starting chemicals. Just Google for the information. However, all of these techniques require mixing Ca-containing and PO4-containing compounds in amounts to get Ca/P atomic ratio 1.67. The proper weights of the Ca- and PO4-precursors depend on their chemical composition and are calculated based on their molecular weights. How to do perform calculations is studied at secondary school and a person holding a Ph.D. degree must be able to do this.

You should calculate in accordance with Ca/P ratio from your chemicals. It depends on what you use as a reactant. The precipitated HA always has carbonate groups in it. But if your point is really produce carbonated HA you should change your reactant  which should contains carbonate. Another way, you can use carbon dioxide gas and relase it to precipitation beaker slowly.

I think you will need sintering to produce scaffold. It is known that carbonate group leads to decomposition of HA  at lower temperature. You should check the thermal stabilty and decide the sintering temperature as well.

Best regards.

There is alot of literature present in which different reagents have been used for the synthesis of Hydroxyapatite. Calculate the Molar Mass in accordance with the reagent you are choosing in according with the calcium:Phosphate ratio of 1.67

hey dhivya 

Please read the data given below in this they have prepared a chemical media by creating a suitable precursor I hope this might help. Good Luck !!

1H NMR at 400MHz in toluene-d8 of evaporated mixtures of lithium ethoxide and titanium (IV) isopropoxide in ethanol, used to prepare the spinel Li4Ti5O12 by the sol-gel method, may help to understand why the atomic ratio 5Li:5Ti and no 4Li:5Ti is the right choice to obtain the pure phase when performing hydrolysis at room temperature. The mixtures xLiOEt/yTi(OPri)4 in ethanol undergo alcohol exchange at room temperature and the evaporated residues contain the double lithium-titanium ethoxide [LiTi3(OEt)13] rather than simple mixtures of single metal alkoxides and this is of great relevance to the real understanding of the chemistry and structural changes in the sol-gel process. Detailed inspection of the 1H and 13C VT NMR spectra of the mixtures at different Li/Ti atomic ratios unequivocally show the formation of [LiTi3(OEt)13] in solution at low temperature. The methylene signals of free lithium ethoxide and Li[Ti3(OEt)13] coalesce at 20°C when the atomic ratio is 5:5 but the same coalescence is only observed above 60°C when the atomic ratio is 4:5. We suggest that the highest chemical equivalence observed in the 1H NMR and achieved through chemical exchange of ethoxide groups involves the highest microscopic structural homogeneity of the sol precursor and will lead to the best gel after hydrolysis. Variable temperature 1H NMR at 400 MHz of variable molar ratios of LiOEt/Ti(OPri)4 are discussed to understand the structural features of the sol precursor. While the precursor with atomic ratio 5Li:5Ti shows no signal of free LiOEt at 20°C, both 4Li:5Ti and 7Li:5Ti show free LiOEt at 20°C in their 1H NMR spectra indicating that the molar ratio 5Li:5Ti gives the maximum rate of chemical exchange. DFT calculations have been performed to support the structure of the anion [Ti3(OEt)13]- at room temperature

Use 0.5M calcium hydroxide and 0.3M orthophosphoric acid and titrate till proper stoichiometry is achieved. This gives pure hap devoid of other prwcursor residues.

If you want to prepare carbonate apatite, I would suggest to take 0.5M CaCO3 as Ca-precursor and 0.3M H3PO4 as PO4-precursor, maintain pH around 10-11.