Retaining Geochemical Signatures During Aragonite-Calcite Transformation at Hydrothermal Conditions

Transformation of aragonite, a mineral phase metastable at Earth’s surface, to calcite widely occurs in both sedimentary and metamorphic systems with the presence of an aqueous phase. The transformation process can affect geochemical signatures of aragonite (a protolith). This study focused on quantification of the retention of Mg/Ca and Sr/Ca ratios, and d18O during the transformation process as well as evaluation of the transformation rate. To investigate the effect of transformation from aragonite to calcite on elemental and stable isotope ratios, we conducted a series of experiments in NaCl solutions at temperatures between 120 and 184 °C. Two additional experiments at 250 °C were conducted to estimate the transformation rate of aragonite to calcite. Protolith materials consist of (1) synthetic (Mg; Sr-bearing or non-Mg; Sr bearing) needle-shaped microcrystals of aragonite (<5 µm in size) and (2) larger chips (>100 µm in size) of natural aragonite. X-ray diffraction (XRD) showed that microcrystals successfully transformed to calcite within 30 h and scanning electron microscopy (SEM) yielded a change in the crystal size to >10 µm in rhombohedral shape. Electron backscatter diffraction (EBSD) of the larger aragonite chips showed that transformation to randomly oriented calcite occurred at the rims and along the cracks while the core retained an aragonite crystal structure. Isotope-ratio mass spectrometry (IRMS) analyses showed that calcite δ18O was controlled by temperature and δ18O of the solution. The obtained calibration curve of isotope fractionation factor versus temperature is consistent with other studies. Inductively coupled plasma optical emission spectroscopy (ICP-OES) analyses showed that calcite partially or completely retained Mg/Ca and Sr/Ca ratios through the transformation.

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Mechanochemical Synthesis of Nanocrystalline Hydroxyapatite Coating

Eurasian Chemico-Technological Journal ◽

10.18321/ectj30 ◽

2010 ◽

Vol 12 (2) ◽

pp. 79 ◽

Cited By ~ 2

Author(s):

Ahmed E. Hannora ◽

Alexander S. Mukasyan ◽

Zulkhair A. Mansurov

Keyword(s):

Heat Treatment ◽

Phase Transformation ◽

Inductively Coupled Plasma ◽

Optical Emission ◽

High Energy ◽

Transformation Process ◽

Paramagnetic Resonance ◽

Inductively Coupled ◽

Novel Approach ◽

Transmission Electron

A novel approach for depositing of hydroxyapatite (HA) films on titanium substrates by using high energy ball milling (HEBM) has been developed. It was demonstrated that a heat treatment of the mechanically coated HA at 800 °C for one hour leads to partial transformation of HA phase to -TCP. It appears that the grain boundary and interface defects formed during MCS reduce this characteristic transformation temperature. Also, it was shown that Ti incorporation into the HA structure causes the lattice shrinkage and reduction of its grain size as compared to pure HA, but also promote the phase transformation of HA to TCP at high temperature. It is important that doping HA by silicon, while also significantly decrease crystallinity of deposited HA layer, results in hindering of the phase transformation process. The Si-doped HA does not show phase transition or decomposition after heat treatment even at<br />900 °C. The samples were investigated by X-ray diffraction, scanning electron microscope, Energy dispersive spectroscopy, Atomic force microscopy, Transmission electron microscopy, inductively coupled plasma (ICP) optical emission spectrometer, Vickers microhardness, Electron paramagnetic resonance.

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Advances of Spectrometric Techniques in Food Analysis and Food Authentication Implemented with Chemometrics

Foods ◽

10.3390/foods9111550 ◽

2020 ◽

Vol 9 (11) ◽

pp. 1550

Author(s):

Ioannis K. Karabagias

Keyword(s):

Mass Spectrometry ◽

Natural Products ◽

Inductively Coupled Plasma ◽

Optical Emission ◽

Isotope Ratio Mass Spectrometry ◽

Food Composition ◽

Complete Characterization ◽

Emission Spectrometry ◽

Food Authentication ◽

Inductively Coupled

Given the continuous consumer demand for products of high quality and specific origin, there is a great tendency for the application of multiple instrumental techniques for the complete characterization of foodstuffs or related natural products. Spectrometric techniques usually offer a full and rapid screenshot of products’ composition and properties by the determination of specific bio-molecules such as sugars, minerals, polyphenols, volatile compounds, amino acids, organic acids, etc. The present special issue aimed firstly to enhance the advances of the application of spectrometric techniques such as gas chromatography coupled to mass spectrometry (GC-MS), inductively coupled plasma optical emission spectrometry (ICP-OES), isotope ratio mass spectrometry (IRMS), nuclear magnetic resonance (NMR), Raman spectroscopy, or any other spectrometric technique, in the analysis of foodstuffs such as meat, milk, cheese, potatoes, vegetables, fruits/fruit juices, honey, olive oil, chocolate, and other natural products. An additional goal was to fill the gap between food composition/food properties/natural products properties and food/natural products authenticity, using supervised and non-supervised chemometrics. Of the 18 submitted articles, nine were eventually published, providing new information to the field.

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Quantitative electron microprobe mapping of otoliths suggests elemental incorporation is affected by organic matrices: implications for the interpretation of otolith chemistry

Marine and Freshwater Research ◽

10.1071/mf15074 ◽

2016 ◽

Vol 67 (7) ◽

pp. 889 ◽

Cited By ~ 4

Author(s):

A. McFadden ◽

B. Wade ◽

C. Izzo ◽

B. M. Gillanders ◽

C. E. Lenehan ◽

...

Keyword(s):

Inductively Coupled Plasma ◽

Electron Backscatter Diffraction ◽

Growth Patterns ◽

Otolith Growth ◽

Inductively Coupled ◽

Icp Ms ◽

Organic Matrices ◽

Plasma Mass Spectrometry ◽

Minimal Damage ◽

Backscatter Diffraction

In an effort to understand the mechanism of otolith elemental incorporation, the distribution of strontium (Sr) and sulfur (S) in otoliths of Platycephalus bassensis was investigated in conjunction with otolith growth patterns. Optimisation of electron probe microanalysis (EPMA) quantitative mapping achieved both high spatial resolution (<3µm) and two-dimensional visualisation of the fine scale Sr and S distributions in otoliths of P. bassensis with minimal damage. Electron backscatter diffraction (EBSD) mapping confirmed that grain growth is aligned with the otolith c-axis, with grain orientation independent of both otolith elemental composition and growth patterns. Results showed a linear correlation between Sr and S distribution (R2=0.86), and a clear association with the otolith growth patterns determined by scanning electron microscopy. Further examination by laser ablation–inductively coupled plasma–mass spectrometry (LA-ICP-MS) showed that incorporation of Mg and Ba appeared independent of both S distribution and the growth patterns. The results suggest that element incorporation into the otolith is linked to the organic composition in the endolymph during mineralisation, and the organic matrices may assist, in part, the uptake of Sr. Thus, these findings may have significant implications for the interpretation of otolith Sr chemistry.

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Decoupling of Au and As during rapid pyrite crystallization

Geology ◽

10.1130/g48443.1 ◽

2021 ◽

Author(s):

Ya-Fei Wu ◽

Katy Evans ◽

Si-Yu Hu ◽

Denis Fougerouse ◽

Mei-Fu Zhou ◽

...

Keyword(s):

Mass Spectrometry ◽

Inductively Coupled Plasma ◽

Secondary Ion Mass Spectrometry ◽

Electron Backscatter Diffraction ◽

Local Variation ◽

Hydrothermal Systems ◽

Central China ◽

Inductively Coupled ◽

Plasma Mass Spectrometry ◽

Backscatter Diffraction

Gold (Au) is largely hosted by pyrite in a variety of hydrothermal systems, but the incorporation of Au into pyrite under disequilibrium conditions remains poorly understood. We integrate synchrotron X-ray fluorescence microscopy, electron backscatter diffraction, nanoscale secondary ion mass spectrometry, and laser ablation–multicollector–inductively coupled plasma–mass spectrometry to constrain the processes that sequester Au into zoned pyrite in the hydrothermal cement of breccia ores from the world-class Daqiao orogenic Au deposit, central China. Euhedral pyrite cores with oscillatory and sector zoning, variable δ34S values, and lower Au-As contents than the mantles are attributed to crystallization during oxidation of metal-depleted ore fluids with local variation in fluid conditions. The isotopically uniform colloform mantles are formed by pyrite crystallites separated by low-angle boundaries and are characterized by unusual decoupling of Au and As. Mantle formation is attributed to rapid disequilibrium precipitation from a metal-rich FeS2-supersaturated fluid. Incorporation of Au into the pyrite mantles was facilitated by abundant lattice defects produced by rapid nucleation. Gold-As–poor pyrite rims were deposited from an evolved ore fluid or other metal-depleted fluids. These results show that chemical variations recorded by fine layering within minerals can provide valuable insights into disequilibrium mass transfer and ore formation. The decoupling between Au and As in pyrite mantles indicates that As is not always a reliable proxy for Au enrichment in rapidly crystallized porous pyrite.

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Geographical Discrimination of Croatian Wines by Stable Isotope Ratios and Multielemental Composition Analysis

Frontiers in Nutrition ◽

10.3389/fnut.2021.625613 ◽

2021 ◽

Vol 8 ◽

Author(s):

Renata Leder ◽

Ivana Vladimira Petric ◽

Josipa Jusup ◽

Mara Banović

Keyword(s):

Inductively Coupled Plasma ◽

Cross Validation ◽

Optical Emission ◽

Isotope Ratio Mass Spectrometry ◽

Emission Spectrometry ◽

Composition Analysis ◽

Multivariate Statistical ◽

Inductively Coupled ◽

Geographical Discrimination ◽

The Cross

The δ18O and δ13C (analyzed by isotope ratio mass spectrometry, IRMS) and concentration of 22 selected elements (analyzed by inductively coupled plasma—optical emission spectrometry, ICP-OES) in 190 Croatian microvinified and commercial wine samples from continental and coastal winegrowing areas and from three viticultural zones (B, CI, and CII) were measured to investigate whether multivariate statistical methods could provide the fingerprint for geographical origin determination. The highest power for discrimination of wines produced in Croatian winegrowing areas was achieved by general discriminant analysis (GDA) showing correct classification of 97.9% of all investigated samples, 100.0% of microvinified samples and 84.8% of commercial samples in the cross-validation matrix. The most significant markers for discrimination of coastal and continental areas found by GDA were δ18O and Co, followed by K, Rb, Sn, Li, and δ13C in descending order. GDA showed higher levels of correctly classified samples from three viticultural zones in Croatia if only microvinified samples were employed in the analysis (94.9%) than for all samples together (86.3%) or for commercial samples (66.1%) in the cross-validation matrix. The discrimination of viticultural zones B, CI, and CII in Croatia was achieved by δ18O, Co, Rb, Li, K, and Sn. The results obtained showed that the relationships between the isotopic ratios and concentrations of different considered elements combined with appropriate statistical model represent a powerful tool in discrimination of wines produced in different Croatian winegrowing areas.

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