Double-focusing Inductively Coupled Plasma Mass Spectrometry Research Articles

Titanium levels in the organs and blood of rats with a titanium implant, in the absence of wear, as determined by double-focusing ICP-MS

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.

An attempt for determining 235U/238U ratio for a trace amount of uranium: Search for an extinct radionuclide 247Cm in the early solar system

In order to search for isotopic anomalies of U caused by the disintegration of 247Cm in meteorite samples, an analytical scheme for determining 235U/238U ratio for a small amount of uranium (less than 1 ng U) was established. The isotopic ratio of U was determined by double-focusing inductively coupled plasma mass spectrometry (DF-ICP-MS). With a great improvement of chemical procedure for purifying the uranium fraction separated from meteorite samples, a variation in 235U/238U ratios was resolved at an order of ±4‰ for 100 ppt or 200 pg U in solution. For applying the procedure in searching an evidence of 247Cm as an extinct radionuclide in the early solar system, a selective chemical dissolution of constituent minerals of meteorites using EDTA and HCl was introduced and a chemical purification scheme of uranium for ICP-MS was established.

Influence of different bentonites on the rare earth element concentrations of clarified Romanian wines

The rare earth element (REE) concentrations of 19 Romanian young wine samples originating from the Dealurile Moldovei viticulture area were determined by double focusing inductively coupled plasma mass spectrometry (DF-ICP-MS) after microwave-assisted digestion with nitric acid. The determination of Eu was hampered by the BaO molecular interference. Generally, the red wine samples were more concentrated for REEs than the white wine samples studied. The REE concentrations of the four bentonites (Gelbenton, Evergel, BW200, Tükrös) determined after their fusion were higher by three orders of magnitude than those of the wine samples. After a simulated wine purification process performed with these bentonite samples and a red and white pool samples, the REE concentrations of the clarified wine samples increased by 1.2–1.5 times for red, and 1.3–3 times for white wines in case of the fibrous bentonite sample (Gelbenton), by about 2–5 times in case of the bentonite containing ovalbumin, caseine and gelatine (Evergel), meanwhile this factor was about 20–25 for Na bentonite powder samples (BW200, Tükrös). On basis of the chemometric evaluation using the REE concentrations as input data, the majority of the Feteasca wines belonged to the same cluster as well as the two Cabernet Sauvignon to another subcluster. The adequate choice of the bentonite may allow the use of REEs as fingerprints for determining the wine provenance.

HPLC-ICP-MS and ESI-Q-TOF analysis of biomolecules induced in Brassica juncea during arsenic accumulation

Arsenic (As) bioaccumulation by plants can be used as a strategy to detoxify arsenic polluted sites. Genetic engineering may provide a means of optimizing this natural process to increase its efficiency. However, this approach requires a thorough understanding of As metabolism and detoxification in plants. Identifying As-containing metabolites in plants is an important first step in elucidating As metabolism. Brassica juncea (Indian mustard) is studied here as a model for As accumulation in terms of total metalloid accumulation and its elemental speciation. A study on extraction conditions using 25 mM ammonium acetate buffer at increasing pH of 4.4, 5.6 and 7.8 has been performed. Those extracting solutions were also employed as mobile phases for the separation of the As species formed by size exclusion chromatography with inductively coupled plasma mass spectrometry (ICP-MS) as a selective As detector. Two main As containing species have been found in Brassica tissues (one of them at about 2 kDa and the other below 1.2 kDa). The first As species was found to be associated to thiol groups (monitoring 32S with double focusing ICP-MS). This can be ascribed to the presence of As-phytochelatin complexes. Electrospray-quadrupole-time of flight (ESI-Q-TOF) results indicated the presence of phytochelatins (apo-forms), the main metal bioligands in plants, which have also been shown to be induced by As. Oligomers of two, three and four sub-units, respectively (PC2, PC3 and PC4), with internal oxidation of the SH groups, have been extracted from Brassica leaves as well as a potential As–PC4 complex. These species have been further identified by collisional induced dissociation (CID).

Determination of uranium isotopic composition and 236U content of soil samples and hot particles using inductively coupled plasma mass spectrometry

As a result of the accident at the Chernobyl nuclear power plant (NPP) the environment was contaminated with spent nuclear fuel. The 236U isotope was used in this study to monitor the spent uranium from nuclear fallout in soil samples collected in the vicinity of the Chernobyl NPP. Nuclear track radiography was applied for the identification and extraction of hot radioactive particles from soil samples. A rapid and sensitive analytical procedure was developed for uranium isotopic ratio measurement in environmental samples based on double-focusing inductively coupled plasma mass spectrometry (DF-ICP-MS) with a MicroMist nebulizer and a direct injection high-efficiency nebulizer (DIHEN). The performance of the DF-ICP-MS with a quartz DIHEN and plasma shielded torch was studied. Overall detection efficiencies of 4 x 10(-4) and 10(-3) counts per atom were achieved for 238U in DF-ICP-QMS with the MicroMist nebulizer and DIHEN, respectively. The rate of formation of uranium hydride ions UH+/U+ was 1.2 x 10(-4) and 1.4 x 10(-4), respectively. The precision of short-term measurements of uranium isotopic ratios (n = 5) in 1 microg L(-1) NBS U-020 standard solution was 0.11% (238U/235U) and 1.4% (236U/238U) using a MicroMist nebulizer and 0.25% (235U/238U) and 1.9% (236U/P38U) using a DIHEN. The isotopic composition of all investigated Chernobyl soil samples differed from those of natural uranium; i.e. in these samples the 236U/238U ratio ranged from 10(-5) to 10(-3). Results obtained with ICP-MS, alpha- and gamma-spectrometry showed differences in the migration properties of spent uranium, plutonium, and americium. The isotopic ratio of uranium was also measured in hot particles extracted from soil samples.

Speciation of metallothionein-like proteins of the mussel Mytilus edulis at basal levels by chromatographic separations coupled to quadrupole and double-focusing magnetic sector ICPMS.

Characterization and partial purification of metallothionein-like proteins (MLPs) of the mussel Mytilus edulis from natural populations of three coastal regions in Spain were performed. Size exclusion chromatography (SEC) with quadrupole (Q-ICPMS) or double-focusing inductively coupled plasma mass spectrometry (DF-ICPMS) detection was used first for speciation of cadmium in such natural samples and those of mussels exposed to 500 mg x L(-1) Cd in an aquarium tank. SEC results showed always a single Cd-MLP peak (MLP fraction). The contents in Cd, Cu, and Zn of this MLP fraction, of the high molecular weight protein pool (HMW), and of the whole cytosol were then measured by DF-ICPMS. Then, a given aliquot (50 microL) of MLPs with the highest values for UV molecular absorption at 254 nm (also the maximum sulfur and Cd, Cu, or Zn contents) was used to further fractionation. Fast protein liquid chromatography "on line" with Q-ICPMS was used for the purpose. Two Cd-MLP isoforms (MLP-1, MLP-2), with retention times (tR) of 15.7 and 16.0 min, were then detected in cytosols of the mussel samples of aquarium tank and also of the industrial area and Galicia coast. Conversely, wild coast mussels did not show any Cd-MLP signals at all. Analysis of essential elements copper and zinc in such cytosols by FPLC-Q-ICPMS revealed that these two metals were associated just to MLP-1. These results tend to indicate a different role for the two MLP isoforms detected in mussels (i.e., essential metals' homeostasis role seems to be tied to the MLP-1 isoform only). They illustrate the fact that trace metal speciation of unknown species in biological materials is becoming a challenge and points to the use of several complementary analytical techniques to obtain the required speciation information.

Metal distribution patterns in the mussel Mytilus edulis cytosols using size-exclusion chromatography and double focusing ICP-MS detection

In order to estimate metal distribution patterns in biomolecules of different sizes and their possible relationship with environmental heavy metal contamination, multi-elemental distributions in different fractions of the cytosols of mussels were studied. To do so, samples were collected from natural populations of two coastal regions in Spain: a wild (uncontaminated) coast and an industrialised (contaminated) area in Asturias. Moreover, some commercial mussels from the Galicia coast were also investigated for comparison. Aliquots of the mussel cytosol extracts from each sample were applied to a calibrated Sephadex G-75 column (100 x 1 cm) and forty 3 ml fractions were obtained. After suitable dilution, 18 trace metals were determined by double focusing inductively coupled plasma mass spectrometry (DF-ICP-MS). The use of DF-ICP-MS detection allowed the resolution of several spectral interferences that cannot be resolved by quadrupole ICP-MS. Accurate results for ultratrace elements at basal levels are possible even after sample dilution to prevent matrix effects. After biomolecule-metal association pattern has been established, quantitative analysis of mussel cytosols from the three coastal areas was carried out, using external aqueous calibration plus standard additions to correct for possible matrix effects. Results showed that total metal contents increased following the expected order: wild coast < Galicia coast < industrial area coast. Speciation of Cu, Zn, Ca, U, Ni, Mo, Mn, Cr, V, Cd, Al and Sb showed a similar distribution pattern among cytosolic ligands for all the studied samples. Conversely, Fe, Pb, Sn, Co, Hg and Ag were found to exhibit different speciation patterns when samples from industrialised (contaminated) and non-industrialised areas were compared.

Multielemental trace analysis of biological materials using double focusing inductively coupled plasma mass spectrometry detection

The analytical potential of double focusing-inductively coupled plasma-mass spectrometry (DF-ICP-MS) for total elemental analysis in clinical samples (serum, blood, urine and other biological fluids), tissues and food products is illustrated by reviewing typical applications recently published. Also, the use of DF-ICP-MS as specific detector for trace element speciation in biological samples is discussed. After adequate separation of interferences in the chromatographic column, low resolution measurements ( R = 300) can be used to provide enhanced sensitivities of more than 100 times compared with quadrupole-inductively coupled plasma-mass spectrometry (Q-ICP-MS). This capability is extremely valuable in speciation studies. Also, the use of DF-ICP-MS at low resolution could provide very precise isotope ratio measurements for isotope dilution analysis due to the ‘flat topped’ peaks obtained at this resolution. Unfortunately, the literature on these last two issues is rather scarce so far, in spite of their extremely high analytical possibilities for biological research. Moreover, the bright future of DF-ICP-MS as a most powerful multielemental detector for trace element applications in biological systems will be highlighted. Apart from applications detailed above other important application fields can be envisaged. In particular, we will speculate on its possible use to confirm/establish ‘reference values’ of trace element content in ‘normal’ populations and so to help to diagnose health and disease status, related with trace element total content or their speciation in clinical specimens.