The main components (Ti, V, Cr, Co, Ni, and Mo) of metallic alloys currently used in hip and knee articular prostheses have been simultaneously determined in human whole blood and urine of implanted people by a (HR)-ICP-MS method previously developed in our laboratory. The determination of those elements has been carried out in patients with knee and hip prosthesis and in a group of pre-operation patients without any metallic device in their bodies, used as controls, demonstrating the usefulness of this technique to perform multielement analysis at ppt levels in complex matrices. The concentrations of V, Cr, Co, Ni, and Mo in urine and blood of implanted people turned out to be very similar to those obtained in control patients. However, raised Ti levels could be found both in urine and blood of patients with articular prostheses made or coated with a titanium alloy (Ti(6)Al(4)V).

Titanium (Ti) has long been regarded as an inert and biocompatible metal, ideal for biomedical applications such as dental implants or joint replacements. However, concerns about the biocompatibility of Ti have lately arisen. Unfortunately, information on reliable Ti baseline physiological levels in blood and organ tissues is still pending and the real effects of physiological corrosion as opposed to wear processes of Ti or Ti alloys implants is controversial so far. In this work a previously developed and validated methodology, based on using double-focusing inductively coupled plasma mass spectrometry (DF-ICP-MS) has been used to establish Ti basal levels in blood and organs (heart, liver, spleen, kidneys, and lungs) of Wistar rats. These data were compared with the levels found in three Wistar rats implanted with a Ti wire embedded in their femur for 18 months, in order to assign possible Ti released purely due to non-wear physiological mechanisms. Results showed that Ti content in all the selected organ tissues and blood was higher than previously determined Ti basal levels, clearly showing both corrosion of the Ti implant and systemic Ti accumulation in target tissues. These results indicate that Ti metal corrosion occurs. This seems to be the only mechanism responsible in the long term for the observed passive dissolution of Ti of the implant in the absence of wear. A comparative study of the systemic distribution of the soluble and particulate Ti potentially released from Ti implants was also carried out by intraperitoneally injection of soluble Ti(citrate)(3) and insoluble TiO(2) particles, respectively. Different systemic Ti storage was observed. Whereas soluble Ti was rapidly transported to all distal organs under study, TiO(2) particles were only accumulated in lung tissue.

A sector field high-resolution (HR)-ICP-MS and an octapole reaction system (ORS)-ICP-MS have been compared for the simultaneous determination of traces of metals (Ti, V, Cr, Co, Ni, and Mo) released from dental implants and articular prostheses in human biological fluids. Optimum sample treatments were evaluated to minimize matrix effects in urine and whole blood. Urine samples were diluted tenfold with ultrapure water, whereas whole blood samples were digested with high-purity nitric acid and hydrogen peroxide and finally diluted tenfold with ultrapure water. In both matrices, internal standardization (Ga and Y) was employed to avoid potential matrix interferences and ICP-MS signal drift. Spectral interferences arising from the plasma gases or the major components of urine and whole blood were identified by (HR)-ICP-MS at 3,000 resolving power. The capabilities of (HR)-ICP-MS and (ORS)-ICP-MS for the removal of such spectral interferences were evaluated and compared. Results indicate that polyatomic interferences, which hamper the determination of such metallic elements in these biological samples, could be overcome by using a resolving power of 3,000. Using (ORS)-ICP-MS, all those elements could be quantified except Ti and V (due to the polyatomic ions 31P16O and 35Cl16O, respectively). The accuracy of the proposed methodologies by (HR)- and (ORS)-ICP-MS was checked against two reference materials. Good agreement between the given values and the concentrations obtained for all the analytes under scrutiny was found except for Ti and V when analyzed by (ORS)-ICP-MS.

Little is known about the effects of titanium found in patients wearing prostheses or about the biochemical pathways of this metal when used as an anticancer drug (e.g., titanocene dichloride). In this work, transferrin has been confirmed as the only carrier protein binding Ti in human blood serum samples by making use of different HPLC protein separations followed by element-specific Ti detection by ICPMS. Besides, isotope dilution analysis has been applied to the quantitative speciation of Ti-Tf in standards and human blood serum samples. Species-unspecific and species-specific isotope dilution modes have been explored. In the first case, very low Ti-Tf results were obtained even using two different chromatographic mechanisms, anion exchange (20-24%) and size exclusion (33-36%). Surprisingly, no major Ti species except Ti-Tf were observed in the chromatograms, suggesting that Ti(IV) hydrolysis and precipitation as inactive titanium oxide species could take place inside the chromatographic columns. These results demonstrate that chemical degradation of metalloproteins during analytical separations could ruin the sought speciation quantitative results. The isotope dilution species-specific mode, much more accurate in such cases, has been instrumental in demonstrating the possibility of gross errors in final metalloprotein quantification. For this purpose, an isotopically enriched standard of (49)Ti-Tf was synthesized and applied to the quantitative speciation of Ti-Tf again. Using this species-specific spike, Ti-Tf dissociation inside the chromatographic columns used could be corrected, and thus, quantitative Ti-Tf binding in serum (92-102%) was observed. In other words, the usefulness and potential of a species-specific isotope dilution analysis approach to investigate quantitatively metal-protein associations, which can be dissociated at certain experimental conditions, is demonstrated here for the first time.