I have prepared Hydroxyapatite pellets and immersed it in SBF solution for 28 days. The xrd analysis of post SBF Hydroxyapatite shows decrease in the intensity of peak and merging of some peaks compared to XRD spectra of pure Hydroxyapatite. I would like to know the reason behind these decrease in the intensity and merging of peaks. Thanks in advance.
Dear Sumit Das Sala,
you may a) explain what 'SBF solution' is and b) you may show your XRD pattern.
I guess there is a lot of water in the solution so that in your 'post SFB Hydroxyapatite' there is still Hydroxyapatite present, but the peaks are superimposed by the broad amorphous peak caused by water. The Hydroxyapatite peaks are smaller now due to smaller amount of material in the x-ray beam (partly replaced by water).
But let us have a look at the XRD pattern....
After soaking the hydroxyapatite pellets in SBF, a surface layer can grow, perhaps containing poorly crystallised hydroxyapatite, and/or other poorly crystallised phosphates, such as octacalciumphosphate, and/or amorphous tricalcium phosphate. Eventually, the XRD pattern also responds to that layer, and not just to the pellets core.
FTIR absorption bands may possibly help to identify such surface contribution(s), as shown at the signalled papet for a layer deposited over phosphosilicate glasses after immersion in SBF:Article Network connectivity and bio-mineralization of 0.45SiO2-(0....
Thank you for your answer Gerhard Martens . SBF is simulated body fluid.
Pleasefind herewith XRD pattern of pure HA, post SBF HA after 7 days and 28 days.
Kindly specify the reason of decreasing intensity and merging of peaks in XRD pattern post SBF treatment.
Thank you very much for your answer Carlos Araújo Queiroz . Please specify is the formation of octacalciumphosphate, and/or amorphous tricalcium phosphate decreases the intensity of XRD peaks?? Moreover also clearify the reason behind merging of peaks. Thanks in advance
Thanks for sharing the pattern.
Your SBF treated sample look quite similar with respect to the upcoming (relative) peak position.
But in addition to intensity reduction, peak resolution is getting worse and significant overall peak shifts (to higher 2theta) show up in your pattern of SBF treated sample.
I fear that there is an experimental issue with alignment anyhow; e.g. sample alignment (e.g. mismatch in sample height position).
Is there a chance to repeate the measurements, e.g. with a reference simultaneously put into the x-ray beam?
By the way;
a) does your reference sample (pre SBF) also consist of pellets or is is a homogenous layer of powder? and
b) do you have milled your SBF treated samples to powder?
c) if not; what is the approximate pellet size?
Sumit Das Lala
What is surface morphology of Hydroxyapatite pellets ?
A simulated body fluid (SBF) is a solution with an ion concentration close to that of human blood plasma.
Hydroxyapatite pellets adsorbed different ions present in SBF,.
You can make different concentration of SBF and then immerse Hydroxyapatite pellets and see the effect by measuring XRD analysis.
Due to surface adsorbed SBF ions, the XRD peak intensity of Hydroxyapatite pellets is decreased.
Thank you sir Muhammad Asim Khan. Could you also let me know the reason for merging of peaks??
Dear Sumit Das Sala,
I would expect changes in lattice parameters of HA by soaking in SBF, that you could quantify by using Pawley fits.
I actually tried to fit your "pure" HA and but there seems to be already an impurity in your starting material. You can see the marked peaks that are not explained by the hexagonal unit cell of HA
There are actually 3 impurity phase in you starting material. One which is identifiable is Buchwaldite (Sodium Calcium Phosphate) and this one is present at about 20weight% (relative). But there are still two major un-explained peaks in the attached Rietveld refinement.
Thank you Nevin Koshy sir for your answer. Kindly attach one or two papeers relevance to this so that we can site the same in our papers. Thank you in advance.
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