Considerations and Influencing Parameters in EDS Microanalysis of Biogenic Hydroxyapatite

Abstract

Calcium phosphates (CPs) used as biomaterials have been intensively studied in recent years. In most studies, the determination of the chemical composition is mandatory. Due to the versatility and possibilities of performing qualitative and quantitative compositional analyses, energy dispersive spectrometry (EDS) is a widely used technique in this regard. The range of calcium phosphates is very diverse, the first method of approximating the type of compound being EDS microanalysis, by assessing the atomic Ca/P ratio. The value of this ratio can be influenced by several factors correlated with instrumental parameters and analysed samples. This article highlights the influence of the electron beam acceleration voltage (1 kV–30 kV) and of the particle size of calcium phosphate powders on the EDS analysis results. The characterised powders were obtained from bovine bones heat-treated at 1200 °C for 2 h, which have been ground and granulometrically sorted by mechanical vibration. The granulometric sorting generated three types of samples, with particle sizes < 20 μm, < 40 μm and < 100 μm, respectively. These were morphologically and dimensionally analysed by scanning electron microscopy (SEM) and compositionally by EDS, after the spectrometer was calibrated with a standard reference material (SRM) from NIST (National Institute of Standards and Technology). The results showed that the adjusting of acceleration voltage and of the powder particle size significantly influences the spectrum profile and the results of EDS analyses, which can lead to an erroneous primary identification of the analysed calcium phosphate type.

Influence of Ceramic Particles Size and Ratio on Surface—Volume Features of the Naturally Derived HA-Reinforced Filaments for Biomedical Applications

“…Regarding the calcium, phosphor, and magnesium elements, their variable concentrations spiked in an upward trendline with the incremented addition of HA. These minor differences can be assigned to the varying surface roughness, particles sizes, or the overall method inaccuracies [ 42 , 43 , 44 ].…”

Synthesis of a graphene oxide/agarose/hydroxyapatite biomaterial with the evaluation of antibacterial activity and initial cell attachment

“…The particle size affects both qualitatively and quantitatively the ratio of Ca and P. As the accelerating voltage increases, the signal strength increases corresponding to the Ca and P elements (up to 15 kV) regardless of the particle size of the Ca/P. In the 15–30 kV range, shape variation is observed for particle sizes with minimum and maximum dimensions, and is uniform in the median case 49 .…”

Genes encoding putative bicarbonate transporters as a missing molecular link between molt and mineralization in crustaceans

“…For SEM images, polished gastroliths and manually fractured cuticles were gold coated for 6 s and viewed under an electron microscope at the IKI. For EDXS and determination of carbonate and phosphate contents, gastroliths from the first silencing experiment were either gently polished in dry conditions in order to avoid differential dissolution effects and viewed at the IKI under an electron microscope with an EDXS detector (Kevex; Thermo Scientific, Scotts Valley, CA; the acceleration voltage was set at 10 kV 53 , 54 ) or ground to a powder and viewed under an electron microscope at the Center for Nanoscience and Nanotechnology (acceleration voltage set at 20 kV).…”