Elemental Impurities in Pharmaceutical Products – Analysis using an Energy-Dispersive X-ray Fluorescence Spectrometer
The analysis processes that are recommended in many pharmacopoeias for the determination of impurities can require complex sample preparation. They sometimes do not show very good reproducibility and have to be matched to the sample matrix. Energy-dispersive XRF conforms to the analysis processes described without the requirement of extensive sample preparation. Using optimized excitation and evaluation parameters, the technology provides detection limits that are sufficient for the analysis of most of the relevant elements.
The production of pharmaceutical products requires the analysis of a series of essential trace elements such as Fe, Cu, Zn, Se, Ca,Mg,Co, Si, and Mn as well as elements that are toxic in larger concentrations such as Cd, Pb, As, Hg, Cr, Mo, Ni, V, and Cu. In addition elements from the use of catalysts like Ir, Os, Pd, Pt, Rh, and Ru have to be monitored.
Aspects such as the bio-availability, toxicity, and quantity of the elements must be considered. The sources of such impurities can be production-related contamination from sieving and grinding processes, treatment with catalysts, and transportation in piping. Additional impurities may result from packing material and preservatives. It is also possible that the raw material, e.g. from plants, is already contaminated.