Estudo comparativo de métodos de preparo de amostras de tinta para a determinação de metais e metalóides por técnicas de espectrometria atômica

This work deals with paint decomposition methods for major, minor and trace elements determination. Three methods were investigated: (1) decomposition in closed quartz vessel and heating in microwave oven; (2) decomposition in open vessel using HNO3 and ashing, following the ASTM D 3335-85a method; and (3) decomposition in open vessel using HNO3 + HF and ashing. Paints of different types and colours were analyzed, in which several elements were determined using inductively coupled plasma mass spectrometry (ICP-MS) and inductively coupled plasma optical emission spectrometry (ICP OES). It was observed that method (1) is appropriate for trace, minor and major elements determination, while method (3) is appropriate for Ti.

Uso da técnica HRICP-MS na avaliação dos isótopos de boro em eucalipto

The 10B isotope tracer technique is essential to study the B mobility in plants. Factors that can influence the quality of measured B isotope ratios were optimized experimentally using High Resolution Inductively Coupled Plasma Mass Spectrometry (HRICP-MS). An isotopically certified standard (NIST SRM-951) was used. The best combination was obtained using a resolution of 400, a RF power of 1250 W, followed by 15 measurements over a 10-s integration period each (15*10). Utilizing this approach it was possible to obtain a precision of 0.3 % in standard material and 2z % in the experimental samples. The results show the importance of establishing optimized work conditions before carrying out the analytical series.

Determinação de bromo e iodo em alga marinha comestível por ICP-MS após decomposição por combustão iniciada por micro-ondas

A method based on microwave-induced combustion (MIC) was applied for the decomposition of different types of edible seaweed (Nori, Hijiki and Wakame) for subsequent determination of bromine and iodine by inductively coupled plasma mass spectrometry (ICP-MS). Decomposition of 500 mg of each sample was achieved in less than 30 min. A single and diluted solution (150 mmol L-1 (NH4)2CO3) was used for the absorption of both analytes and a reflux step of 5 min was applied to improve analyte recoveries. Accuracy was evaluated using certified reference materials and agreement was between 103 and 108% for both elements.

Ion selective electrodes for determination of low and ultra low concentrations of lead (II) in natural waters

Att övervaka förekomsten av giftiga komponenter i naturliga vattendrag är nödvändigt för människans välmående. Eftersom halten av föroreningar i naturens ekosystem bör hållas möjligast låg, pågår en ständig jakt efter kemiska analysmetoder med allt lägre detektionsgränser. I dagens läge görs miljöanalyser med dyr och sofistikerad instrumentering som kräver mycket underhåll. Jonselektiva elektroder har flera goda egenskaper som t.ex. bärbarhet, låg energiförbrukning, och dessutom är de relativt kostnadseffektiva. Att använda jonselektiva elektroder vid miljöanalyser är möjligt om deras känslighetsområde kan utvidgas genom att sänka deras detektionsgränser. För att sänka detektionsgränsen för Pb(II)-selektiva elektroder undersöktes olika typer av jonselektiva membran som baserades på polyakrylat-kopolymerer, PVC och PbS/Ag2S. Fast-fas elektroder med membran av PbS/Ag2S är i allmänhet enklare och mer robusta än konventionella elektroder vid spårämnesanalys av joniska föroreningar. Fast-fas elektrodernas detektionsgräns sänktes i detta arbete med en nyutvecklad galvanostatisk polariseringsmetod och de kunde sedan framgångsrikt användas för kvantitativa bestämningar av bly(II)-halter i miljöprov som hade samlats in i den finska skärgården nära tidigare industriområden. Analysresultaten som erhölls med jonselektiva elektroder bekräftades med andra analytiska metoder. Att sänka detektionsgränsen m.hj.a. den nyutvecklade polariseringsmetoden möjliggör bestämning av låga och ultra-låga blyhalter som inte kunde nås med klassisk potentiometri. Den verkliga fördelen med att använda dessa blyselektiva elektroder är möjligheten att utföra mätningar i obehandlade miljöprov trots närvaron av fasta partiklar vilket inte är möjligt att göra med andra analysmetoder. Jag väntar mig att den nyutvecklade polariseringsmetoden kommer att sätta en trend i spårämnesanalys med jonselektiva elektroder.

Surface studies of limestones and dolostones : characterisation using various techniques and batch dissolution experiments with hydrochloric acid solutions

In this thesis, stepwise titration with hydrochloric acid was used to obtain chemical reactivities and dissolution rates of ground limestones and dolostones of varying geological backgrounds (sedimentary, metamorphic or magmatic). Two different ways of conducting the calculations were used: 1) a first order mathematical model was used to calculate extrapolated initial reactivities (and dissolution rates) at pH 4, and 2) a second order mathematical model was used to acquire integrated mean specific chemical reaction constants (and dissolution rates) at pH 5. The calculations of the reactivities and dissolution rates were based on rate of change of pH and particle size distributions of the sample powders obtained by laser diffraction. The initial dissolution rates at pH 4 were repeatedly higher than previously reported literature values, whereas the dissolution rates at pH 5 were consistent with former observations. Reactivities and dissolution rates varied substantially for dolostones, whereas for limestones and calcareous rocks, the variation can be primarily explained by relatively large sample standard deviations. A list of the dolostone samples in a decreasing order of initial reactivity at pH 4 is: 1) metamorphic dolostones with calcite/dolomite ratio higher than about 6% 2) sedimentary dolostones without calcite 3) metamorphic dolostones with calcite/dolomite ratio lower than about 6% The reactivities and dissolution rates were accompanied by a wide range of experimental techniques to characterise the samples, to reveal how different rocks changed during the dissolution process, and to find out which factors had an influence on their chemical reactivities. An emphasis was put on chemical and morphological changes taking place at the surfaces of the particles via X-ray Photoelectron Spectroscopy (XPS) and Scanning Electron Microscopy (SEM). Supporting chemical information was obtained with X-Ray Fluorescence (XRF) measurements of the samples, and Inductively Coupled Plasma-Mass Spectrometry (ICP-MS) and Inductively Coupled Plasma-Optical Emission Spectrometry (ICP-OES) measurements of the solutions used in the reactivity experiments. Information on mineral (modal) compositions and their occurrence was provided by X-Ray Diffraction (XRD), Energy Dispersive X-ray analysis (EDX) and studying thin sections with a petrographic microscope. BET (Brunauer, Emmet, Teller) surface areas were determined from nitrogen physisorption data. Factors increasing chemical reactivity of dolostones and calcareous rocks were found to be sedimentary origin, higher calcite concentration and smaller quartz concentration. Also, it is assumed that finer grain size and larger BET surface areas increase the reactivity although no certain correlation was found in this thesis. Atomic concentrations did not correlate with the reactivities. Sedimentary dolostones, unlike metamorphic ones, were found to have porous surface structures after dissolution. In addition, conventional (XPS) and synchrotron based (HRXPS) X-ray Photoelectron Spectroscopy were used to study bonding environments on calcite and dolomite surfaces. Both samples are insulators, which is why neutralisation measures such as electron flood gun and a conductive mask were used. Surface core level shifts of 0.7 ± 0.1 eV for Ca 2p spectrum of calcite and 0.75 ± 0.05 eV for Mg 2p and Ca 3s spectra of dolomite were obtained. Some satellite features of Ca 2p, C 1s and O 1s spectra have been suggested to be bulk plasmons. The origin of carbide bonds was suggested to be beam assisted interaction with hydrocarbons found on the surface. The results presented in this thesis are of particular importance for choosing raw materials for wet Flue Gas Desulphurisation (FGD) and construction industry. Wet FGD benefits from high reactivity, whereas construction industry can take advantage of slow reactivity of carbonate rocks often used in the facades of fine buildings. Information on chemical bonding environments may help to create more accurate models for water-rock interactions of carbonates.

Yeast CUP1 protects HeLa cells against copper-induced stress

As an essential trace element, copper can be toxic in mammalian cells when present in excess. Metallothioneins (MTs) are small, cysteine-rich proteins that avidly bind copper and thus play an important role in detoxification. YeastCUP1 is a member of the MT gene family. The aim of this study was to determine whether yeast CUP1 could bind copper effectively and protect cells against copper stress. In this study,CUP1 expression was determined by quantitative real-time PCR, and copper content was detected by inductively coupled plasma mass spectrometry. Production of intracellular reactive oxygen species (ROS) was evaluated using the 2',7'-dichlorofluorescein-diacetate (DCFH-DA) assay. Cellular viability was detected using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay, and the cell cycle distribution of CUP1 was analyzed by fluorescence-activated cell sorting. The data indicated that overexpression of yeast CUP1 in HeLa cells played a protective role against copper-induced stress, leading to increased cellular viability (P<0.05) and decreased ROS production (P<0.05). It was also observed that overexpression of yeast CUP1 reduced the percentage of G1 cells and increased the percentage of S cells, which suggested that it contributed to cell viability. We found that overexpression of yeast CUP1 protected HeLa cells against copper stress. These results offer useful data to elucidate the mechanism of the MT gene on copper metabolism in mammalian cells.

Effet du calcium, plomb et cuivre sur la bioaccumulation du cadmium et la production des phytochélatines par Chlamydomonas reinhardtii

Dans les milieux contaminés par les métaux, les organismes vivants sont exposés à plusieurs d’entre eux en même temps. Les modèles courants de prédiction des effets biologiques des métaux sur les organismes (p. ex., modèle du ligand biotique, BLM ; modèle de l’ion libre, FIAM), sont des modèles d’équilibre chimique qui prévoient, en présence d'un deuxième métal, une diminution de la bioaccumulation du métal d’intérêt et par la suite une atténuation de ses effets. Les biomarqueurs de toxicité, tels que les phytochélatines (PCs), ont été utilisés comme étant un moyen alternatif pour l’évaluation des effets biologiques. Les phytochélatines sont des polypeptides riches en cystéine dont la structure générale est (γ-glu-cys)n-Gly où n varie de 2 à 11. Leur synthèse semble dépendante de la concentration des ions métalliques ainsi que de la durée de l’ exposition de l’organisme, aux métaux. L'objectif de cette étude était donc de déterminer, dans les mélanges binaires de métaux, la possibilité de prédiction de la synthèse des phytochélatines par les modèles d’équilibres chimiques, tel que le BLM. Pour cela, la quantité de phytochélatines produites en réponse d’une exposition aux mélanges binaires : Cd-Ca, Cd-Cu et Cd-Pb a été mesurée tout en surveillant l’effet direct de la compétition par le biais des concentrations de métaux internalisés. En effet, après six heures d’exposition, la bioaccumulation de Cd diminue en présence du Ca et de très fortes concentrations de Pb et de Cu (de l’ordre de 5×10-6 M). Par contre, avec des concentrations modérées de ces deux métaux, le Cd augmente en présence de Cu et ne semble pas affecté par la présence de Pb. Dans le cas de la compétition Cd-Cu, une bonne corrélation a été observée entre la production de PC2, PC3 et PC4 et la quantité des métaux bioaccumulés. Pour la synthèse des phytochélatines et la bioaccumulation, les effets étaient considérés comme synergiques. Dans le cas du Cd-Ca, les quantités de PC3 et PC4 ont diminué avec le métal internalisé (effet antagoniste), mais ce qui était remarquable était la grande quantité de cystéine (GSH) et PC2 qui ont été produites à de fortes concentrations du Ca. Le Pb seul n’a pas induit les PCs. Par conséquent, il n’y avait pas de variation de la quantité de PCs avec la concentration de Pb à laquelle les algues ont été exposées. La détection et la quantification des PCs ont été faites par chromatographie à haute performance couplée d’un détecteur de fluorescence (HPLC-FL). Tandis que les concentrations métalliques intracellulaires ont été analysées par spectroscopie d’absorption atomique (AAS) ou par spectrométrie de masse à source plasma à couplage inductif (ICP-MS).

Les effets de revêtements de surface sur la dissolution et la bioaccumulation de nanoparticules d'oxyde de zinc par l'algue unicellulaire, C. reinhardtii

Au cours de la dernière décennie, les nanoparticules ont connu un essor sans précédent dans plusieurs domaines. On peut retrouver ces nanoparticules dans des secteurs aussi variés tels que la médecine, l’électronique, les écrans solaires, les cosmétiques et les plastiques, pour ne nommer que ceux-là. Cette utilisation massive a eu un effet pervers sur l’environnement, sachant qu’une grande partie de ces produits se sont retrouvés inévitablement dans les milieux naturels. Plusieurs études révèlent qu’autant la présence des nanoparticules que leurs produits de dissolution sont à prendre en considération lorsque des travaux toxicologiques ou le devenir de ces matériaux sont étudiés. Il est désormais clair que les propriétés de surface de ces nanoparticules jouent un rôle central sur leur comportement dans les solutions aqueuses; que ce soit les interactions avec des organismes ou entre les particules elles-mêmes. Afin d’évaluer le devenir de nZnO, une étude sur la dissolution ainsi que la bioaccumulation a été réalisée avec l’algue modèle Chlamydomonas reinhardtii en présence de nanoparticules ayant différents enrobages. Les nanoparticules d’oxyde de zinc suivantes ont été étudiées : (i) nZnO sans enrobage (nZnO); (ii) nZnO avec enrobage d’acide polyacrylique (nZnO-PAA) et (iii) nZnO avec enrobage d’hexamétaphosphate de sodium (nZnO-HMP). La dissolution était mesurée à l’aide de trois techniques : ultrafiltration par centrifugation (CU); technique potentiométrique (scanned stripping chronopotentiometry, SSCP) et spectrométrie de masse – plasma à couplage inductif couplé à une résine échangeuse d’ions (resin-based inductively coupled plasma-mass spectrometry, resin-based ICP-MS). Les résultats obtenus démontrent une grande tendance à la dissolution pour le nZnO (presque totale) tandis que pour le nZnO-PAA et le nZnO-HMP, la dissolution est dépendante de la nature de l’enrobage le composant. Pour la bioaccumulation sur l’algue testée, les données montrent une grande dépendance au zinc libre issu de la dissolution pour nZnO et nZnO-PAA. À l’inverse, le nZnO-HMP démontre une bioaccumulation plus élevée par comparaison aux mêmes concentrations d’expositions du zinc libre, expliquée par la stimulation de l’internalisation du zinc provoqué par la présence de phosphate constituant l’enrobage de nZnO-HMP.

Séparation, détection et caractérisation de nanoparticules manufacturées dans des eaux naturelles et usées avec la chromatographie hydrodynamique et de multiples détecteurs

L’utilisation accrue des nanomatériaux manufacturés (NM) fait en sorte que les différents acteurs de réglementation se questionnent de plus en plus par rapport à leur destin et leurs impacts sur les écosystèmes et la santé humaine suite à leur rejet dans l’environnement. Le développement de techniques analytiques permettant de détecter et de caractériser les NM en matrice environnementale est impératif étant donné la nécessité d’évaluer le risque relié à ces polluants émergents. Une des approches de plus en plus favorisée est d’utiliser une technique chromatographique et un ou plusieurs détecteurs sensibles dans les buts de réduire les effets de matrice, d’identifier des nanoparticules (NP) selon leurs temps de rétention et de les quantifier à des concentrations représentatives de la réalité environnementale. Une technique analytique utilisant la chromatographie hydrodynamique (HDC) et des détecteurs en ligne ou hors ligne (détecteurs de diffusion statique ou dynamique de la lumière, spectromètre de masse par torche à plasma en mode particule unique (SP-ICPMS), l’ultracentrifugation analytique) a donc été développée. Le couplage de la colonne HDC avec ces détecteurs a permis de caractériser des NP standards et l’optimisation des conditions de séparation de ces nanoparticules de polystyrène, d’or et d’argent a permis de confirmer que les NP y sont bel et bien séparées seulement selon leur taille, tel que la théorie le prédit. De plus, l’utilisation de la colonne HDC couplée au SP-ICPMS a permis de séparer un mélange de nanoparticules d’argent (nAg) et de les détecter à des concentrations représentatives de celles rencontrées dans l’environnement, soit de l’ordre du μg L-1 au ng L-1. Par exemple, dans un échantillon d’eau usée (effluent), un mélange de nAg de 80 et de 40 nm a été séparé et les nAg ont été détectées à l’aide du SP-ICPMS connecté à la colonne HDC (temps de rétention de 25.2 et 25.6 minutes et diamètres déterminés de 71.4 nm et 52.0 nm). Finalement, pour plusieurs échantillons environnementaux auxquels aucun ajout de nanoparticules n’a été fait, les analyses HDC-SP-ICPMS effectuées ont permis de déterminer qu’ils ne contenaient initialement pas de nAg.

Elemental analysis of New Zealand Nephrite Jade (pounamu) for forensic purposes

Pounamu (NZ jade), or nephrite, is a protected mineral in its natural form following the transfer of ownership back to Ngai Tahu under the Ngai Tahu (Pounamu Vesting) Act 1997. Any theft of nephrite is prosecutable under the Crimes Act 1961. Scientific evidence is essential in cases where origin is disputed. A robust method for discrimination of this material through the use of elemental analysis and compositional data analysis is required. Initial studies have characterised the variability within a given nephrite source. This has included investigation of both in situ outcrops and alluvial material. Methods for the discrimination of two geographically close nephrite sources are being developed. Key Words: forensic, jade, nephrite, laser ablation, inductively coupled plasma mass spectrometry, multivariate analysis, elemental analysis, compositional data analysis

A dendrochemical study of Pinus sylvestris from Siljansfors Experimental Forest, central Sweden

Inductively coupled plasma mass spectrometry (ICP-MS) was used to investigate changes in trace element concentration in two high resolution sequences of tree rings from central Sweden. Individual annual growth increments from 18002002 to 1930-2002 were sampled from two Scots pine (Pinus sylvestris) trees from the Siljansfors Experimental Forest. The aims of the study were: to test the viability of conventional solution induction ICP-MS as a technique for investigating the multi-elemental chemistry of long tree ring sequences at annual resolution, and, to test this specifically with a view to detecting changes in elemental concentrations of Swedish tree rings contemporary with the major (and relatively proximal) Icelandic eruption of Askja (1875). It was found that despite a time consuming sample preparation process, it was possible to use conventional ICP-MS for multi-elemental analysis of a long sequence of tree rings at annual resolution. Although promising data were produced, no truly conclusive concentration anomaly could be detected in the sequence to indicate the impact of the Askja eruption on environmental chemistry. Overall findings underlined the complexity of the tree/environment interaction and the cautious approach to data interpretation essential for any dendrochemical study. (c) 2006 Elsevier Ltd. All rights reserved.

Record of natural and anthropogenic changes in reef environments (Barbados West Indies) using laser ablation ICP-MS and sclerochronology on coral cores

Coral growth rate can be affected by environmental parameters such as seawater temperature, depth, and light intensity. The natural reef environment is also disturbed by human influences such as anthropogenic pollutants, which in Barbados are released close to the reefs. Here we describe a relatively new method of assessing the history of pollution and explain how these effects have influenced the coral communities off the west coast of Barbados. We evaluate the relative impact of both anthropogenic pollutants and natural stresses. Sclerochronology documents framework and skeletal growth rate and records pollution history (recorded as reduced growth) for a suite of sampled Montastraea annularis coral cores. X-radiography shows annual growth band patterns of the corals extending back over several decades and indicates significantly lower growth rate in polluted sites. Results using laser-ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) on the whole sample (aragonite, organic matter, trapped particulate matter, etc.), have shown contrasting concentrations of the trace elements (Cu, Sn, Zn, and Pb) between corals at different locations and within a single coral. Deepwater corals 7 km apart, record different levels of Pb and Sn, suggesting that a current transported the metal pollution in the water. In addition, the 1995 hurricanes are associated with anomalous values for Sn and Cu from most sites. These are believed to result from dispersion of nearshore polluted water. We compared the concentrations of trace elements in the coral growth of particular years to those in the relevant contemporaneous seawater. Mean values for the concentration factor in the coral, relative to the water, ranged from 10 for Cu and Ni to 2.4 and 0.7 for Cd and Zn, respectively. Although the uncertainties are large (60-80%), the coral record enabled us to demonstrate the possibility of calculating a history of seawater pollution for these elements from the 1940s to 1997. Our values were much higher than those obtained from analysis of carefully cleaned coral aragonite; they demonstrate the incorporation of more contamination including that from particulate material as well as dissolved metals.

Distribution of calcium (Ca) and magnesium (Mg) in the leaves of Brassica rapa under varying exogenous Ca and Mg supply

Background and Aims Leafy vegetable Brassica crops are an important source of dietary calcium (Ca) and magnesium (Mg) and represent potential targets for increasing leaf Ca and Mg concentrations through agronomy or breeding. Although the internal distribution of Ca and Mg within leaves affects the accumulation of these elements, such data are not available for Brassica. The aim of this study was to characterize the internal distribution of Ca and Mg in the leaves of a vegetable Brassica and to determine the effects of altered exogenous Ca and Mg supply on this distribution. Methods Brassica rapa ssp. trilocularis ‘R-o-18’ was grown at four different Ca:Mg treatments for 21 d in a controlled environment. Concentrations of Ca and Mg were determined in fully expanded leaves using inductively coupled plasma-mass spectrometry (ICP-MS). Internal distributions of Ca and Mg were determined in transverse leaf sections at the base and apex of leaves using energy-dispersive X-ray spectroscopy (EDS) with cryo-scanning electron microscopy (cryo-SEM). Key Results Leaf Ca and Mg concentrations were greatest in palisade and spongy mesophyll cells, respectively, although this was dependent on exogenous supply. Calcium accumulation in palisade mesophyll cells was enhanced slightly under high Mg supply; in contrast, Mg accumulation in spongy mesophyll cells was not affected by Ca supply. Conclusions The results are consistent with Arabidopsis thaliana and other Brassicaceae, providing phenotypic evidence that conserved mechanisms regulate leaf Ca and Mg distribution at a cellular scale. The future study of Arabidopsis gene orthologues in mutants of this reference B. rapa genotype will improve our understanding of Ca and Mg homeostasis in plants and may provide a model-to-crop translation pathway for targeted breeding.

Chemical process to separate iron oxides particles in pottery sample for EPR dating

Ancient potteries usually are made of the local clay material, which contains relatively high concentration of iron. The powdered samples are usually quite black, due to magnetite, and, although they can be used for thermoluminescene (TL) dating, it is easiest to obtain better TL reading when clearest natural or pre-treated sample is used. For electron paramagnetic resonance (EPR) measurements, the huge signal due to iron spin-spin interaction, promotes an intense interference overlapping any other signal in this range. Sample dating is obtained by dividing the radiation dose, determined by the concentration of paramagnetic species generated by irradiation, by the natural dose so as a consequence, EPR dating cannot be used, since iron signal do not depend on radiation dose. In some cases, the density separation method using hydrated solution of sodium polytungstate [Na(G)(H(2)W(12)O(40))center dot H(2)O] becomes useful. However, the sodium polytungstate is very expensive in Brazil: hence an alternative method for eliminating this interference is proposed. A chemical process to eliminate about 90% of magnetite was developed. A sample of powdered ancient pottery was treated in a mixture (3:1:1) of HCI, HNO(3) and H(2)O(2) for 4 h. After that, it was washed several times in distilled water to remove all acid matrixes. The original black sample becomes somewhat clearer. The resulting material was analyzed by plasma mass spectrometry (ICP-MS), with the result that the iron content is reduced by a factor of about 9. In EPR measurements a non-treated natural ceramic sample shows a broad spin-spin interaction signal, the chemically treated sample presents a narrow signal in g= 2.00 region, possibly due to a radical of (SiO(3))(3-), mixed with signal of remaining iron [M. lkeya, New Applications of Electron Spin Resonance, World Scientific, Singapore, 1993, p. 285]. This signal increases in intensity under -gamma-irradiation. However, still due to iron influence, the additive method yielded too old age-value. Since annealing at 300 degrees C, Toyoda and Ikeya IS. Toyoda, M. Ikeya, Geochem. J. 25 (1991) 427-445] states that E `(1)-signal with maximum intensity is obtained, while annealing at 400 degrees C E`(1)-signal is completely eliminated, the subtraction of the second one from 300 degrees C heat-treated sample isolate E`(1)-like signal. Since this is radiation dose-dependent, we show that now EPR dating becomes possible. (C) 2008 Elsevier B.V. All rights reserved.

Major- and trace-element composition of REE-rich turkestanite from peralkaline granites of the Morro Redondo Complex, Graciosa Province, south Brazil

Turkestanite, a rare Th- and REE-bearing cyclosilicate in the ekanite-steacyite group was found in evolved peralkaline granites from the Morro Redondo Complex, south Brazil. It occurs with quartz, alkali feldspar and an unnamed Y-bearing silicate. Electron microprobe analysis indicates relatively homogeneous compositions with maximum ThO(2), Na(2)O and K(2)O contents of 22.4%, 2.93% and 3.15 wt.%, respectively, and significant REE(2)O(3) abundances (5.21 to 11.04 wt.%). The REE patterns show enrichment of LREE over HREE, a strong negative Eu anomaly and positive Ce anomaly, the latter in the most transformed crystals. Laser ablation inductively coupled plasma mass spectrometry trace element patterns display considerable depletions in Nb, Zr, Hf, Ti and Li relative to whole-rock sample compositions. Observed compositional variations suggest the influence of coupled substitution mechanisms involving steacyite, a Na-dominant analogue of turkestanite, iraqite, a REE-bearing end-member in the ekanite-steacyite group, ekanite and some theoretical end-members. Turkestanite crystals were interpreted as having precipitated during post-magmatic stages in the presence of residual HFSE-rich fluids carrying Ca, the circulation of which was enhanced by deformational events.