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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]

Detection of specific DNA sequences is nowadays an important tool in many scientific areas such as forensic science or clinical diagnosis. Although numerous approaches have been suggested for this challenging analysis, certain limitations still remain. In order to overcome these disadvantages, novel and alternative methodologies are required. In this work, we present a strategy based on elemental (lanthanide) labelling of DNA probes followed by size-exclusion chromatography (SEC) coupled with inductively coupled plasma-mass spectrometry (ICP-MS) for monitoring and determining complementary oligonucleotide sequences (oligonucleotide targets) and for visualising the corresponding hybridisation processes. The synthesis and characterisation of the DNA probes are described in detail. SEC was found to be suitable to discriminate between the DNA probe and the hybridised product. Using labelling of different probes with different lanthanides, multiplexed detection of the sought DNA sequences was possible as demonstrated here on three DNA probes (derivatised with Eu, Tb, and Ho, respectively). The achievable detection limits were in the range between 5 and 11 fmol absolute.

Fast protein liquid chromatography (FPLC) was used with electrothermal atomic absorption spectrometric (ETAAS) detection for quantitative studies of aluminium binding species in unspiked human uremic serum. A rapid and reproducible separation of human serum proteins and other aluminium binders (citrate and desferroxiamine) was achieved on a Mono Q (HR 5/5) anion-exchange column using a sodium chloride gradient (0-0.25 mol l-1) at the physiological human serum pH of 7.4 (0.05 mol l-1 buffer TRIS-HCl). The aluminium distribution in the column fractions was determined by ETAAS. Aluminium contamination was avoided by using an inert chromatographic system equipped with an on-line aluminium-chelating scavenger column (Kelex 100-impregnated silica C18). The sensitivity of the proposed method (detection limit for Al in serum = 5 micrograms l-1) allowed aluminium speciation studies at clinically relevant concentrations (unspiked serum from dialysis patients). The results obtained confirmed that transferrin is the only serum protein binding aluminium and it contains about 90% of total serum aluminium (post-elution aluminium recovery = 105 +/- 5%). It was also confirmed that in the presence of the chelating drug desferrioxamine (DFO) most of the serum aluminium (80%) is bound to DFO.