In this work a high throughput, robust and sensitive method for the precise isotopic analysis of 87 Sr/ 86 Sr by coupling Ion Chromatography (IC) and Multicollector Inductively Coupled Plasma Mass Spectrometry (MC-ICPMS) is presented. The effective separation of Sr from a sample matrix by IC enables on-line isotopic determination of the 87 Sr/ 86 Sr ratio in transient signals by MC-ICPMS, without laborious off-line and time consuming sample preparation step and the need for clean room facilities. Mass discrimination and instrument drift were corrected by using the natural constant 86 Sr/ 88 Sr ratio as an internal standard. A precision (2s) of the 87 Sr/ 86 Sr ratio of 0.003% was achieved in natural fresh water and high salinity samples, e.g. Dead Sea water, as well as carbonate and silicate rocks. Robustness, relatively high precision and accuracy, as well as minimum possibility of sample contamination of the developed analytical method have been demonstrated in complex natural samples of water and rocks as well. This method for the first time reports a possibility of isotopic analysis of cations by on-line IC separation with precision close to that obtained by an off-line technique.

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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 (∆26Mgplant-nutrient 0.65, 0.74 for two biological replicates, respectively) and in chlorophyll-a (∆26Mgchlorophyll-plant 1.51, 2.19). In garden cress, heavy isotopes were depleted in green parts (∆26Mgplant-nutrient (−0.87)–(−0.92)) and the preference for heavy isotopes in chlorophyll-a was less marked relative to maize (∆26Mgchlorophyll-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.

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In this work, a method for the accurate and precise determination of 82 Se/ 78 Se isotope ratio in natural samples of environmental and biological origin, using multicollector inductively coupled plasma mass spectrometry in a wet plasma mode without using neither hydride generation nor separation of Se, was developed. It was based on the optimized regression model with standard–sample bracketing (ORM–SSB) to efficiently correct instrumental isotopic fractionation/mass bias and matrix effects. In addition, three mass bias correction models of SSB alone, SSB combined with internal standard (IS–SSB), and ORM–SSB were compared for the Se isotope ratio measurements. NIST SRM 987 Sr was used as an internal standard, and the reproducibility of the results obtained with the proposed method was verified by measuring NIST SRM 3149 standard over different days (nine independent measurement sessions). Delta values of the 82 Se/ 78 Se isotope ratio were measured in selenium-enriched yeast-certified reference material SELM-1, natural selenomethionine samples, and model solutions of artificial seawater. Solutions obtained after thiol resin treatment were measured to demonstrate the applicability of the proposed method in eliminating matrix effects due to residual of thiol resin in the sample solutions. Among three mass bias correction models, ORM–SSB correction model proved to be the best to eliminate the matrix effects and instrumental drift. IS–SSB model offered also a good precision but was slightly less accurate. Both models showed good robustness against effects of different sample matrices. Finally, the SSB alone could not be recommended for Se isotope analysis as it produces inaccurate and imprecise results.

In this study, we examine the possibility of detecting PTFE microparticles by ICP-qMS equipped with O2 dynamic reaction cell (DRC) and operated in single-particle mode.

The present study evaluated the level of heavy metal (HM) pollution in Vistula river sediments in a highly urbanized Warsaw agglomeration (Poland). Magnetometry was used to assess the pollution level by measuring the fine fractions (0.071 mm and < 0.071 mm) of sediments collected from the surface layer of the riverbank. The magnetic methods (e.g., mass magnetic susceptibility χ, temperature-dependence magnetic susceptibility, and hysteresis loop parameters) were supplemented by microscopy observations and chemical element analyses. The results showed the local impact of Warsaw's activity on the level of HM pollution, indicated by the maximum concentrations of magnetic particles and HM in the city center. The sediment fraction < 0.071 mm was dominated by magnetite and by a large amount of spherical-shaped anthropogenic magnetic particles. The pollution from the center of Warsaw was transported down-river over a relatively short distance of approximately 11 km. There was a gradual decrease in the concentrations of magnetic particles and HM in areas located to the north of the city center (down-river); furthermore, χ and concentrations of HM did not decrease to the values observed for the area to the south of Warsaw (up-river). The study showed two possible sources of sediment pollution: traffic-related and heat and power plant emissions. The influence of an additional source of pollution cannot be excluded as the amount of spherules in the sediments at the center was extremely high. The present study demonstrates that magnetometry has a practical application in detecting and mapping HM pollution in river systems.

Liquid chromatography-high-resolution mass spectrometry was used for the first time to investigate the impact of Se(IV) (10 mgSe L as sodium selenite) on Allium cepa L. root proteome. Using MaxQuant platform, more than 600 proteins were found; 42 were identified based on at least 2 razor + unique peptides, score > 25, and were found to be differentially expressed in the exposed versus control roots with t-test difference > ±0.70 (p < 0.05, Perseus). Se(IV) caused growth inhibition and the decrease of total RNA in roots. Different abundances of proteins involved in transcriptional regulation, protein folding/assembly, cell cycle, energy/carbohydrate metabolism, stress response, and antioxidant defense were found in the exposed vs nonexposed roots. New evidence was obtained on the alteration of sulfur metabolism due to S-Se competition in A. cepa L. which, together with the original analytical approach, is the main scientific contribution of this study. Specifically, proteins participating in assimilation and transformation of both elements were affected; formation of volatile Se compounds seemed to be favored. Changes observed in methionine cycle suggested that Se(IV) stress might repress methylation capability in A. cepa L., potentially limiting accumulation of Se in the form of nonprotein methylated species and affecting adversely transmethylation-dependent signaling pathways.