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In the present work we evaluate the potential as chemotherapeutic agents of two groups of new Ru(II) complexes containing water soluble phosphane ligands and either a tris(pyrazol-1-yl)borate (Tp) or a pyridine bis(oxazoline) (pybox) ligand and their interactions with DNA. Since the interaction of these drugs can be diverse (from binding to DNA nucleobases to intercalation within the DNA strands), different approaches need to be taken for addressing such possibilities. In this regard, mass spectrometry, MS (elemental and molecular), has been exploited in this study to unequivocally elucidate the structures of the interaction products (molecular MS) and their quantity (elemental MS). First, a systematic evaluation of the interaction of the four Ru-Tp complexes with the individual DNA nucleotides revealed the formation of the Ru-Tp complex containing the phosphane 1-CH3-PTA and chloride as ligands (Asr3), which is the most reactive species providing positive interactions with 2'-deoxyguanosine-5'-monophosphate (dGMP) in a 1:1 stoichiometry confirmed by electrospray MS (ESI-MS). The further coupling of liquid chromatography to inductively coupled plasma mass spectrometric (ICP-MS) detection permitted Ru-specific detection to obtain quantitative data on the interaction showing reaction yields >75%. This interaction was also confirmed, when dGMP was present in an oligonucleotide structure, by both MS techniques and also in the case of DNA. On the other hand, if the Ru-complex interaction with DNA occurs through the intercalation between the DNA strands without specific binding, alternative analytical techniques need to be applied. Here, we illustrate the use of column-gel electrophoresis (GE) on-line coupled to ICP-MS which is a suitable technique to address conformational changes in plasmid DNA induced by interaction with the two assayed Ru-pybox complexes. [ABSTRACT FROM AUTHOR]

Increased concentrations of circulating metal-degradation products derived from the use of Ti orthopaedic implants may have deleterious biological effects over the long term. Therefore, there is an increasing need to establish the basal level of Ti in the serum of the population (exposed and non-exposed) with appropriate highly sensitive techniques and strategies. With this aim, we have developed a quantitative strategy for the determination of total Ti concentration in human serum samples by isotope dilution analysis using a double-focussing inductively coupled plasma mass spectrometer. Minimizing sample handling and therefore contamination issues, we obtained detection limits of about 0.05 μg L Ti working at medium resolution (m/Δm 4000). Such extremely good sensitivity permitted us to establish the range of Ti concentration in serum of 40 control individuals (mean 0.26 μg L) and also to compare it with the level in exposed patients with different Ti metal implants. On the other hand, Ti transport 'in vivo' studies have been enabled by online coupling of liquid chromatography (anion-exchange) separation and double-focussing inductively coupled plasma mass spectrometry for sensitive detection of Ti. The development of a postcolumn isotope dilution strategy permitted quantitative characterization of the Ti-transporting biomolecules in human serum. The results for unspiked serum revealed that 99.8% of the Ti present in this fluid is bound to the protein transferrin, with column recoveries greater than 95%. [Figure not available: see fulltext.] [ABSTRACT FROM AUTHOR]