Molecules

Research

21 pages, 6952 KiB

Open AccessArticle

Determination of Background Concentrations of Ag, Pd, Pt and Au in Highly Mineralized Ground Waters at Sub-ng L^–1 Concentrations by Online Matrix Separation/Pre-Concentration Coupled to ICP-SFMS

by Lisa Fischer, Bernadette Moser and Stephan Hann

Molecules 2021, 26(23), 7253; https://doi.org/10.3390/molecules26237253 - 29 Nov 2021

Cited by 3 | Viewed by 2014

Abstract

Though not regulated in directives such as the Water Framework Directive of the European Union, the investigation of geogenic background concentrations of certain elements such as precious metals is of increasing interest, in particular for the early detection of a potential environmental pollution [...] Read more.

Though not regulated in directives such as the Water Framework Directive of the European Union, the investigation of geogenic background concentrations of certain elements such as precious metals is of increasing interest, in particular for the early detection of a potential environmental pollution due to the increased use in various industrial and technological applications and in medicine. However, the precise and accurate quantification of precious metals in natural waters is challenging due to the complex matrices and the ultra-low concentrations in the (sub-) ng L⁻¹ range. A methodological approach, based on matrix separation and pre-concentration on the strong anion exchange resin TEVA^® Resin in an online mode directly coupled to ICP-SFMS, has been developed for the determination of Ag, Pt, Pd and Au in ground water. Membrane desolvation sample introduction was used to reduce oxide-based spectral interferences, which complicate the quantification of these metals with high accuracy. To overcome errors arising from matrix effects—in particular, the highly varying major ion composition of the investigated ground water samples—an isotope dilution analysis and quantification based on standard additions, respectively, were performed. The method allowed to process four samples per hour in a fully automated mode. With a sample volume of only 8 mL, enrichment factors of 6–9 could be achieved, yielding detection limits <1 ng L⁻¹. Validation of the trueness was performed based on the reference samples. This method has been used for the analysis of the total concentrations of Ag, Pt, Pd and Au in highly mineralized ground waters collected from springs located in important geological fault zones of Austria’s territory. Concentrations ranges of 0.21–64.2 ng L⁻¹ for Ag, 0.65–6.26 ng L⁻¹ for Pd, 0.07–1.55 ng L⁻¹ for Pt and 0.26–1.95 ng L⁻¹ for Au were found. Full article

(This article belongs to the Special Issue Advances and Future Trends in Inductively Coupled Plasma – Mass Spectrometry)

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20 pages, 46020 KiB

Open AccessArticle

Semi-Automated Determination of Heavy Metals in Autopsy Tissue Using Robot-Assisted Sample Preparation and ICP-MS

by Heidi Fleischer, Christoph Lutter, Andreas Büttner, Wolfram Mittelmeier and Kerstin Thurow

Molecules 2021, 26(13), 3820; https://doi.org/10.3390/molecules26133820 - 23 Jun 2021

Cited by 10 | Viewed by 3277

Abstract

The endoprosthetic care of hip and knee joints introduces multiple materials into the human body. Metal containing implant surfaces release degradation products such as particulate wear and corrosion debris, metal-protein complexes, free metallic ions, inorganic metal salts or oxides. Depending on the material [...] Read more.

The endoprosthetic care of hip and knee joints introduces multiple materials into the human body. Metal containing implant surfaces release degradation products such as particulate wear and corrosion debris, metal-protein complexes, free metallic ions, inorganic metal salts or oxides. Depending on the material composition of the prostheses, a systemic exposure occurs and may result in increasing metal concentrations in body fluids and tissues especially in the case of malfunctions of the arthroplasty components. High concentrations of Cr, Co, Ni, Ti and Al affect multiple organs such as thyroid, heart, lung and cranial nerves and may lead to metallosis, intoxications, poly-neuropathy, retinopathy, cardiomyopathy and the formation of localized pseudo tumors. The determination of the concentration of metals in body fluids and tissues can be used for predicting failure of hip or knee replacements to prevent subsequent severe intoxications. A semi-automated robot-assisted measurement system is presented for the determination of heavy metals in human tissue samples using inductively coupled plasma mass spectrometry (ICP-MS). The manual and automated measurement processes were similarly validated using certified reference material and the results are compared and discussed. The automation system was successfully applied in the determination of heavy metals in human tissue; the first results are presented. Full article

(This article belongs to the Special Issue Advances and Future Trends in Inductively Coupled Plasma – Mass Spectrometry)

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8 pages, 677 KiB

Open AccessCommunication

Translating Analytical Techniques in Geochemistry to Environmental Health

by Cathleen L. Doherty and Brian T. Buckley

Molecules 2021, 26(9), 2821; https://doi.org/10.3390/molecules26092821 - 10 May 2021

Cited by 3 | Viewed by 2096

Abstract

From human health exposure related to environmental contamination to ancient deep-Earth processes related to differentiation of the Earth’s geochemical reservoirs, the adaptability of inductively coupled plasma mass spectrometry (ICP-MS) has proven to be an indispensable standard technique that transcends disciplines. Continued advancements in [...] Read more.

From human health exposure related to environmental contamination to ancient deep-Earth processes related to differentiation of the Earth’s geochemical reservoirs, the adaptability of inductively coupled plasma mass spectrometry (ICP-MS) has proven to be an indispensable standard technique that transcends disciplines. Continued advancements in ICP-MS, including improved auxiliary applications such as laser ablation (LA), ion/liquid chromatography (IC), automated pre-concentration systems (e.g., seaFAST), and improved desolvating nebulizer systems (e.g., Aridus and Apex) have revolutionized our ability to analyze almost any sample matrix with remarkable precision at exceedingly low elemental abundances. The versatility in ICP-MS applications allows for effective interdisciplinary crossover, opening a world of analytical possibilities. In this communication, we discuss the adaptability of geochemical techniques, including sample preparation and analysis, to environmental and biological systems, using Pb isotopes for source apportionment as a primary example. Full article

(This article belongs to the Special Issue Advances and Future Trends in Inductively Coupled Plasma – Mass Spectrometry)

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18 pages, 2227 KiB

Open AccessArticle

Combining Isotope Dilution and Standard Addition—Elemental Analysis in Complex Samples

by Christine Brauckmann, Axel Pramann, Olaf Rienitz, Alexander Schulze, Pranee Phukphatthanachai and Jochen Vogl

Molecules 2021, 26(9), 2649; https://doi.org/10.3390/molecules26092649 - 30 Apr 2021

Cited by 5 | Viewed by 2621

Abstract

A new method combining isotope dilution mass spectrometry (IDMS) and standard addition has been developed to determine the mass fractions w of different elements in complex matrices: (a) silicon in aqueous tetramethylammonium hydroxide (TMAH), (b) sulfur in biodiesel fuel, and (c) iron bound [...] Read more.

A new method combining isotope dilution mass spectrometry (IDMS) and standard addition has been developed to determine the mass fractions w of different elements in complex matrices: (a) silicon in aqueous tetramethylammonium hydroxide (TMAH), (b) sulfur in biodiesel fuel, and (c) iron bound to transferrin in human serum. All measurements were carried out using inductively coupled plasma mass spectrometry (ICP–MS). The method requires the gravimetric preparation of several blends (b_i)—each consisting of roughly the same masses (m_x,i) of the sample solution (x) and m_y,i of a spike solution (y) plus different masses (m_z,i) of a reference solution (z). Only these masses and the isotope ratios (R_b,i) in the blends and reference and spike solutions have to be measured. The derivation of the underlying equations based on linear regression is presented and compared to a related concept reported by Pagliano and Meija. The uncertainties achievable, e.g., in the case of the Si blank in extremely pure TMAH of u_rel (w(Si)) = 90% (linear regression method, this work) and u_rel (w(Si)) = 150% (the method reported by Pagliano and Meija) seem to suggest better applicability of the new method in practical use due to the higher robustness of regression analysis. Full article

(This article belongs to the Special Issue Advances and Future Trends in Inductively Coupled Plasma – Mass Spectrometry)

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10 pages, 1345 KiB

Open AccessArticle

Study of Long-Term Determination Accuracy for REEs in Geological Samples by Inductively Coupled Plasma Quadrupole Mass Spectrometry

by Xijuan Tan, Minwu Liu and Ke He

Molecules 2021, 26(2), 290; https://doi.org/10.3390/molecules26020290 - 8 Jan 2021

Cited by 5 | Viewed by 1900

Abstract

This work presents the long-term determination accuracy study of ICP-QMS for rare earth elements (REEs) in geological matrices. Following high-pressure closed acidic decomposition, REEs are measured repetitively across seven months by ICP-QMS. Under optimum experimental conditions (including spray chamber temperature, gas flow rate, [...] Read more.

This work presents the long-term determination accuracy study of ICP-QMS for rare earth elements (REEs) in geological matrices. Following high-pressure closed acidic decomposition, REEs are measured repetitively across seven months by ICP-QMS. Under optimum experimental conditions (including spray chamber temperature, gas flow rate, sampling depth, etc.), the REE contents in geological standard materials from basic (basalt BCR-2 and BE-N) to intermediate (andesite AGV-2) and up to acidic (granite GSR-1) show good agreement with the certified values, giving relative errors below 10%. Here, the influence of two storage materials (perfluoroalkoxy PFA and polypropylene PP) on the long-term determination accuracy of REEs has also been monitored. It is found that the relative errors of REEs using a PFA container range from −6.6 to 6.3% (RSDs < 6.0%), while that using a PP container are within −4.0 to 3.9% (RSDs < 4.6%). By using PP material as a solution storage container, the accuracy of REEs quantification in a series of real geological samples are checked, showing the RSDs of less than 5.0%. This work first clarifies the long-term stability of REEs quantification by ICP-QMS covering two types of storage materials, confirming the reasonability of PP material as a daily storage container in terms of higher data precision and lower cost. Full article

(This article belongs to the Special Issue Advances and Future Trends in Inductively Coupled Plasma – Mass Spectrometry)

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15 pages, 1506 KiB

Open AccessArticle

Measurement of CeO₂ Nanoparticles in Natural Waters Using a High Sensitivity, Single Particle ICP-MS

by Ibrahim Jreije, Agil Azimzada, Madjid Hadioui and Kevin J. Wilkinson

Molecules 2020, 25(23), 5516; https://doi.org/10.3390/molecules25235516 - 25 Nov 2020

Cited by 19 | Viewed by 3108

Abstract

As the production and use of cerium oxide nanoparticles (CeO₂ NPs) increases, so does the concern of the scientific community over their release into the environment. Single particle inductively coupled plasma mass spectrometry is emerging as one of the best techniques for [...] Read more.

As the production and use of cerium oxide nanoparticles (CeO₂ NPs) increases, so does the concern of the scientific community over their release into the environment. Single particle inductively coupled plasma mass spectrometry is emerging as one of the best techniques for NP detection and quantification; however, it is often limited by high size detection limits (SDL). To that end, a high sensitivity sector field ICP-MS (SF-ICP-MS) with microsecond dwell times (50 µs) was used to lower the SDL of CeO₂ NPs to below 4.0 nm. Ag and Au NPs were also analyzed for reference. SF-ICP-MS was then used to detect CeO₂ NPs in a Montreal rainwater at a concentration of (2.2 ± 0.1) × 10⁸ L⁻¹ with a mean diameter of 10.8 ± 0.2 nm; and in a St. Lawrence River water at a concentration of ((1.6 ± 0.3) × 10⁹ L⁻¹) with a higher mean diameter (21.9 ± 0.8 nm). SF-ICP-MS and single particle time of flight ICP-MS on Ce and La indicated that 36% of the Ce-containing NPs detected in Montreal rainwater were engineered Ce NPs. Full article

(This article belongs to the Special Issue Advances and Future Trends in Inductively Coupled Plasma – Mass Spectrometry)

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13 pages, 3131 KiB

Open AccessArticle

A Microwave Digestion Technique for the Analysis of Rare Earth Elements, Thorium and Uranium in Geochemical Certified Reference Materials and Soils by Inductively Coupled Plasma Mass Spectrometry

by Sharayu Kasar, Rajamanickam Murugan, Hideki Arae, Tatsuo Aono and Sarata Kumar Sahoo

Molecules 2020, 25(21), 5178; https://doi.org/10.3390/molecules25215178 - 6 Nov 2020

Cited by 23 | Viewed by 3694

Abstract

Two different digestion methods—microwave digestion (Mw) and Savillex digestion (Sx)—were used to evaluate the best quality control for analysis of the rare earth elements, Th and U in the geochemical certified reference material JSd-2, supplied by the Geological Survey of Japan (GSJ). The [...] Read more.

Two different digestion methods—microwave digestion (Mw) and Savillex digestion (Sx)—were used to evaluate the best quality control for analysis of the rare earth elements, Th and U in the geochemical certified reference material JSd-2, supplied by the Geological Survey of Japan (GSJ). The analysis of trace elements was carried out using inductively coupled plasma mass spectrometry (ICP-MS). The digestion recovery was > 90% for almost all elements by both methods. Mw-4 (four repeats of the microwave digestion) was found to be more effective and faster than Sx. In order to evaluate the efficiency of Mw-4, three other GSJ certified reference materials, JLk-1, JB-1 and JB-3, as well as five different soil samples from Belarus, Japan, Serbia and Ukraine were also analyzed. The Mw-4 method was seen to be promising for complete digestion and recovery of most of the elements. The U/Th ratio showed some heterogeneity for Ukraine and Serbia soils affected by Chernobyl nuclear power plant accident and depleted uranium contamination, respectively. This method can be successfully applied to any type of soils for elemental analyses. Full article

(This article belongs to the Special Issue Advances and Future Trends in Inductively Coupled Plasma – Mass Spectrometry)

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23 pages, 23715 KiB

Open AccessArticle

MH-ICP-MS Analysis of the Freshwater and Saltwater Environmental Resources of Upolu Island, Samoa

by Sasan Rabieh, Odmaa Bayaraa, Emarosa Romeo, Patila Amosa, Khemet Calnek, Youssef Idaghdour, Michael A. Ochsenkühn, Shady A. Amin, Gary Goldstein and Timothy G. Bromage

Molecules 2020, 25(21), 4871; https://doi.org/10.3390/molecules25214871 - 22 Oct 2020

Cited by 8 | Viewed by 3976

Abstract

The elemental composition of freshwater and saltwater samples around the South Pacific island of Upolu, Samoa has been investigated together with other indicators of water quality. Up to 69 elements from Li (3) to U (92) are measured in each sample, analyzed by [...] Read more.

The elemental composition of freshwater and saltwater samples around the South Pacific island of Upolu, Samoa has been investigated together with other indicators of water quality. Up to 69 elements from Li (3) to U (92) are measured in each sample, analyzed by Mattauch–Herzog-inductively coupled plasma-mass spectrometry (MH-ICP-MS). One hundred and seventy-six samples were collected from surface freshwater sources (24 rivers, two volcanic lakes, one dam) and from seawater sources from the surface to 30 m depth (45 inner reef, reef, and outer reef locations) around Upolu Island, including river mouths and estuaries. Principal component and hierarchical clustering correlation analyses were performed on quantile normalized log transformed elemental composition data to identify groups of samples with similar characteristics and to improve the visualization of the full spectrum of elements. Human activities, such as the use of herbicides and pesticides, may relate to observed elevated concentrations of some elements contained in chemicals known to have deleterious obesogenic effects on humans that may also cause coral reef decline. Furthermore, the salinity of some saltwater samples tested were very high, possibly due to climate variability, which may additionally harm the health and biodiversity of coral reefs. Full article

(This article belongs to the Special Issue Advances and Future Trends in Inductively Coupled Plasma – Mass Spectrometry)

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17 pages, 4199 KiB

Open AccessArticle

Chemical Separation of Uranium and Precise Measurement of ²³⁴U/²³⁸U and ²³⁵U/²³⁸U Ratios in Soil Samples Using Multi Collector Inductively Coupled Plasma Mass Spectrometry

by Nimelan Veerasamy, Asako Takamasa, Rajamanickam Murugan, Sharayu Kasar, Tatsuo Aono, Kazumasa Inoue, Masahiro Fukushi and Sarata Kumar Sahoo

Molecules 2020, 25(9), 2138; https://doi.org/10.3390/molecules25092138 - 3 May 2020

Cited by 19 | Viewed by 3979

Abstract

A new chemical separation has been developed to isolate uranium (U) using two UTEVA columns to minimize iron and thorium interferences from high background area soil samples containing minerals like monazites and ilmenite. The separation method was successfully verified in some certified reference [...] Read more.

A new chemical separation has been developed to isolate uranium (U) using two UTEVA columns to minimize iron and thorium interferences from high background area soil samples containing minerals like monazites and ilmenite. The separation method was successfully verified in some certified reference materials (CRMs), for example, JSd-2, JLk-1, JB-1 and JB-3. The same method was applied for purification of U in Fukushima soil samples affected by the Fukushima dai-ichi nuclear power station (FDNPS) accident. Precise and accurate measurement of ²³⁴U/²³⁸U and ²³⁵U/²³⁸U isotope ratios in chemically separated U were carried out using a multi-collector inductively coupled plasma mass spectrometer (MC-ICP-MS). In this mass spectrometric method, an array of two Faraday cups (10¹¹ Ω, 10¹² Ω resistor) and a Daly detector were simultaneously employed. The precision of U isotope ratios in an in-house standard was evaluated by replicate measurement. Relative standard deviation (RSD) of ²³⁴U/²³⁸U and ²³⁵U/²³⁸U were found to be 0.094% (2σ) and 0.590% (2σ), respectively. This method has been validated using a standard reference material SRM 4350B, sediment sample. The replicate measurements of ²³⁴U/²³⁸U in SRM shows 0.7% (RSD). This developed method is suitable for separation of U and its isotope ratio measurement in environmental samples. Full article

(This article belongs to the Special Issue Advances and Future Trends in Inductively Coupled Plasma – Mass Spectrometry)

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11 pages, 1578 KiB

Open AccessFeature PaperCommunication

Determination of Metals in Tree Rings by ICP-MS Using Ash from a Direct Mercury Analyzer

by Byunggwon Jeon and James V. Cizdziel

Molecules 2020, 25(9), 2126; https://doi.org/10.3390/molecules25092126 - 1 May 2020

Cited by 6 | Viewed by 3386

Abstract

Elemental profiles in cores of tree trunks (bole wood) have been used for environmental monitoring and reconstruction of metal pollution history. Mercury (Hg) is a global pollutant that can be accurately measured in tree rings in a simple and pragmatic fashion using a [...] Read more.

Elemental profiles in cores of tree trunks (bole wood) have been used for environmental monitoring and reconstruction of metal pollution history. Mercury (Hg) is a global pollutant that can be accurately measured in tree rings in a simple and pragmatic fashion using a direct mercury analyzer (DMA) that is based on thermal decomposition, amalgamation, and atomic absorption spectrophotometry. In this feasibility study, we demonstrate that the ash remaining after the DMA analyses can be used to quantify a wide range of other non-volatile elements (Ba, Be, Co, Cr, Cu, Fe, Ga, Mg, Mn, Ni, Pb, Sr, Th, and U) in that same sample of wood by inductively coupled plasma mass spectrometry (ICP-MS) after microwave-assisted acid digestion. Other elements (Ag, Cd, Cs, Rb, Tl, and V) exhibited poor recoveries, possibly due to losses during sample preparation. We assessed the accuracy with reference materials, spikes, and by comparison with EPA Method 3052 (Microwave Assisted Acid Digestion of Siliceous and Organically Based Matrices). For the first group of elements (deemed suitable for the method), recoveries ranged between 80% and 120% and the relative standard deviation was generally < 15%, indicating acceptable precision. We applied the method to five species of trees: eastern red cedar (Juniperus virginiana), loblolly pine (Pinus taeda), shortleaf pine (Pinus echinata), white oak (Quercus alba), and tulip poplar (Liriodendron tulipifera) from Holly Springs National Forest in north Mississippi, USA. Mercury concentrations (ng/g ± SE) were highest in the cedar (1.8 ± 0.3; n = 5), followed by loblolly pine (1.6 ± 0.3, n = 3), shortleaf pine (1.2 ± 0.2; n = 3), oak (1.1 ± 0.2; n = 5), and poplar (0.5 ± 0.1; n = 5). Concentrations of other elements were generally Fe > Mg > Ba ≈ Sr ≈ Mn > Cr ≈ Cu > Ni ≈ Rb > Co > Ga ≈ Ag, with the other elements generally below the method detection limit (MDL). Overall, we showed that the DMA can be used to not only determine total Hg in segments of tree core, but can serve as the ashing step in the preparation of wood for ICP-MS analysis, thus allowing the determination of non-volatile elements along with Hg in the very same sample. Full article

(This article belongs to the Special Issue Advances and Future Trends in Inductively Coupled Plasma – Mass Spectrometry)

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14 pages, 2824 KiB

Open AccessArticle

Precise Measurement of Tellurium Isotope Ratios in Terrestrial Standards Using a Multiple Collector Inductively Coupled Plasma Mass Spectrometry

by Rajamanickam Murugan, Tatsuo Aono and Sarata Kumar Sahoo

Molecules 2020, 25(8), 1956; https://doi.org/10.3390/molecules25081956 - 23 Apr 2020

Cited by 4 | Viewed by 2900

Abstract

Precise tellurium (Te) isotope ratio measurement using mass spectrometry is a challenging task for many decades. In this paper, Te isotope ratio measurements using multi-collector inductively coupled plasma mass spectrometry (MC–ICP–MS) in terrestrial Te standards have been reported. Newly developed Faraday cup with [...] Read more.

Precise tellurium (Te) isotope ratio measurement using mass spectrometry is a challenging task for many decades. In this paper, Te isotope ratio measurements using multi-collector inductively coupled plasma mass spectrometry (MC–ICP–MS) in terrestrial Te standards have been reported. Newly developed Faraday cup with 10¹² Ω resistor is used to measure low abundance ¹²⁰Te, whereas the 10¹¹ Ω resistor is used to measure other Te isotopes. The relative standard deviation obtained for Te isotope ratio measurement by Faraday cups of ¹²⁰Te/¹²⁸Te [0.002907(05)], ¹²²Te/¹²⁸Te [0.079646(10)], ¹²³Te/¹²⁸Te [0.027850(07)], ¹²⁵Te/¹²⁸Te [0.221988(09)], ¹²⁶Te/¹²⁸Te [0.592202(20)], and ¹³⁰Te/¹²⁸Te [1.076277(30)] were 0.140%, 0.014%, 0.026%, 0.005%, 0.004%, and 0.004%, respectively. The measured isotope ratio results are compared with previous results obtained by thermal ionization mass spectrometry (TIMS), negative thermal ionization mass spectrometry (N–TIMS), and MC–ICP–MS, showing an improvement in the precision about one order of magnitude for ¹²⁰Te/¹²⁸Te ratio. The present study shows better precision for Te isotope ratios compared to earlier studies. Full article

(This article belongs to the Special Issue Advances and Future Trends in Inductively Coupled Plasma – Mass Spectrometry)

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12 pages, 794 KiB

Open AccessArticle

Magnesium–Isotope Fractionation in Chlorophyll-a Extracted from Two Plants with Different Pathways of Carbon Fixation (C3, C4)

by Katarzyna Wrobel, Jakub Karasiński, Andrii Tupys, Missael Antonio Arroyo Negrete, Ludwik Halicz, Kazimierz Wrobel and Ewa Bulska

Molecules 2020, 25(7), 1644; https://doi.org/10.3390/molecules25071644 - 3 Apr 2020

Cited by 13 | Viewed by 3842

Abstract

Relatively few studies have been focused so far on magnesium–isotope fractionation during plant growth, element uptake from soil, root-to-leaves transport and during chlorophylls biosynthesis. In this work, maize and garden cress were hydroponically grown in identical conditions in order to examine if the [...] Read more.

Relatively few studies have been focused so far on magnesium–isotope fractionation during plant growth, element uptake from soil, root-to-leaves transport and during chlorophylls biosynthesis. In this work, maize and garden cress were hydroponically grown in identical conditions in order to examine if the carbon fixation pathway (C4, C3, respectively) might have impact on Mg-isotope fractionation in chlorophyll-a. The pigment was purified from plants extracts by preparative reversed phase chromatography, and its identity was confirmed by high-resolution mass spectrometry. The green parts of plants and chlorophyll-a fractions were acid-digested and submitted to ion chromatography coupled through desolvation system to multiple collector inductively coupled plasma-mass spectrometry. Clear preference for heavy Mg-isotopes was found in maize green parts (∆²⁶Mg_{plant-nutrient} 0.65, 0.74 for two biological replicates, respectively) and in chlorophyll-a (∆²⁶Mg_{chlorophyll-plant} 1.51, 2.19). In garden cress, heavy isotopes were depleted in green parts (∆²⁶Mg_{plant-nutrient} (−0.87)–(−0.92)) and the preference for heavy isotopes in chlorophyll-a was less marked relative to maize (∆²⁶Mg_{chlorophyll-plant} 0.55–0.52). The observed effect might be ascribed to overall higher production of energy in form of adenosine triphosphate (ATP), required for carbon fixation in C4 compared to C3, which could reduce kinetic barrier and make equilibrium fractionation prevailing during magnesium incorporation to protoporphyrin ring. Full article

(This article belongs to the Special Issue Advances and Future Trends in Inductively Coupled Plasma – Mass Spectrometry)

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20 pages, 1134 KiB

Open AccessReview

Moving toward a Handheld “Plasma” Spectrometer for Elemental Analysis, Putting the Power of the Atom (Ion) in the Palm of Your Hand

by Brian T. Buckley, Rachel Buckley and Cathleen L. Doherty

Molecules 2021, 26(16), 4761; https://doi.org/10.3390/molecules26164761 - 6 Aug 2021

Cited by 4 | Viewed by 2870

Abstract

Many of the current innovations in instrument design have been focused on making them smaller, more rugged, and eventually field transportable. The ultimate application is obvious, carrying the instrument to the field for real time sample analysis without the need for a support [...] Read more.

Many of the current innovations in instrument design have been focused on making them smaller, more rugged, and eventually field transportable. The ultimate application is obvious, carrying the instrument to the field for real time sample analysis without the need for a support laboratory. Real time data are priceless when screening either biological or environmental samples, as mitigation strategies can be initiated immediately upon the discovery that contaminant metals are present in a location they were not intended to be. Additionally, smaller “handheld” instruments generally require less sample for analysis, possibly increasing sensitivity, another advantage to instrument miniaturization. While many other instruments can be made smaller just by using available micro-technologies (e.g., eNose), shrinking an ICP-MS or AES to something someone might carry in a backpack or pocket is now closer to reality than in the past, and can be traced to its origins based on a component-by-component evaluation. While the optical and mass spectrometers continue to shrink in size, the ion/excitation source remains a challenge as a tradeoff exists between excitation capabilities and the power requirements for the plasma’s generation. Other supporting elements have only recently become small enough for transport. A systematic review of both where the plasma spectrometer started and the evolution of technologies currently available may provide the roadmap necessary to miniaturize the spectrometer. We identify criteria on a component-by-component basis that need to be addressed in designing a miniaturized device and recognize components (e.g., source) that probably require further optimization. For example, the excitation/ionization source must be energetic enough to take a metal from a solid state to its ionic state. Previously, a plasma required a radio frequency generator or high-power DC source, but excitation can now be accomplished with non-thermal (cold) plasma sources. Sample introduction, for solids, liquids, and gasses, presents challenges for all sources in a field instrument. Next, the interface between source and a mass detector usually requires pressure reduction techniques to get an ion from plasma to the spectrometer. Currently, plasma mass spectrometers are field ready but not necessarily handheld. Optical emission spectrometers are already capable of getting photons to the detector but could eventually be connected to your phone. Inert plasma gas generation is close to field ready if nitrogen generators can be miniaturized. Many of these components are already commercially available or at least have been reported in the literature. Comparisons to other “handheld” elemental analysis devices that employ XRF, LIBS, and electrochemical methods (and their limitations) demonstrate that a “cold” plasma-based spectrometer can be more than competitive. Migrating the cold plasma from an emission only source to a mass spectrometer source, would allow both analyte identification and potentially source apportionment through isotopic fingerprinting, and may be the last major hurdle to overcome. Finally, we offer a possible design to aid in making the cold plasma source more applicable to a field deployment. Full article

(This article belongs to the Special Issue Advances and Future Trends in Inductively Coupled Plasma – Mass Spectrometry)

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Other

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15 pages, 2327 KiB

Open AccessPerspective

Nanoplastic Labelling with Metal Probes: Analytical Strategies for Their Sensitive Detection and Quantification by ICP Mass Spectrometry

by Lucile Marigliano, Bruno Grassl, Joanna Szpunar, Stéphanie Reynaud and Javier Jiménez-Lamana

Molecules 2021, 26(23), 7093; https://doi.org/10.3390/molecules26237093 - 24 Nov 2021

Cited by 18 | Viewed by 3298

Abstract

The detection and quantification of nanoplastics in aquatic environments is one of the major challenges in environmental and analytical research nowadays. The use of common analytical techniques for this purpose is not only hampered by the size of nanoplastics, but also because they [...] Read more.

The detection and quantification of nanoplastics in aquatic environments is one of the major challenges in environmental and analytical research nowadays. The use of common analytical techniques for this purpose is not only hampered by the size of nanoplastics, but also because they are mainly made of carbon. In addition, the expected concentrations in environmental samples are below the detection limit of the majority of analytical techniques. In this context, the great detection capabilities of Inductively Coupled Plasma Mass Spectrometry (ICP-MS) in its Single Particle mode (SP-ICP-MS) have made of this technique a good candidate for the analysis of nanoplastics. Since the monitoring of carbon by ICP-MS faces several difficulties, the use of metal tags, taking advantage of the great potential of nanoplastics to adsorb chemical compounds, has been proposed as an alternative. In this perspectives paper, three different strategies for the analysis of polystyrene (PS) nanoplastics by SP-ICP-MS based on the use of metals species (ions, hydrophobic organometallic compound, and nanoparticles) as tags are presented and discussed. Advantages and disadvantages of each strategy, which rely on the labelling process, are highlighted. The metal nanoparticles labelling strategy is shown as a promising tool for the detection and quantification of nanoplastics in aqueous matrices by SP-ICP-MS. Full article

(This article belongs to the Special Issue Advances and Future Trends in Inductively Coupled Plasma – Mass Spectrometry)

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