Determination of Se at low concentration in coal by collision/reaction cell technology inductively coupled plasma mass spectrometry

The authors are grateful to Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq, Grant 309297/2016-8), Instituto Nacional de Ciência e Tecnologia de Bioanalítica – INCTBio (CNPq Grant Nr. 573672/2008-3) and Fundação de Amparo à Pesquisa do Estado do Rio Grande do Sul (FAPERGS, Grants16/2551-0000 (182-0) and 16/2551-0000516-8) for supporting this study. Funding for the sample collection provided by NERC Security of Supply programme UK (grant NE/L001764/1).Peer reviewedPostprin

Ultrasonics and sonochemistry: Editors’ perspective

Ultrasonic waves can induce physical and chemical changes in liquid media via acoustic cavitation. Various applications have benefitted from utilizing these effects, including but not limited to the synthesis of functional materials, emulsification, cleaning, and processing. Several books and review articles in the public domain cover both fundamental and applied aspects of ultrasonics and sonochemistry. The Editors of the Ultrasonics Sonochemistry journal possess diverse expertise in this field, from theoretical and experimental aspects of acoustic cavitation to materials synthesis, environmental remediation, and sonoprocessing. This article provides Editors' perspectives on various aspects of ultrasonics and sonochemistry that may benefit students and early career researchers

Selenium and tellurium concentrations of British coals

Standard mode and collision/reaction cell mass spectroscopy methods have been utilised in order to overcome spectral interferences and provide ultra-low quantification of selenium (Se) and tellurium (Te) in British coals for the first time. The accurate detection of Se and Te in coals is becoming increasingly important, as coals and pyrite have been identified as potentially significant trace element sources. The mean Se concentration of British coals bear comparison to that of world coals, with anomalous Se content (concentrations above 4 mg/kg) across westerly exposures, often coinciding with high sulphur (S) content and visible pyrite. New Te data for British coals gives a mean concentration of 0.02 mg/kg, with anomalous Te in Ayrshire. There is a positive correlation in the Te/Se ratio across the sample set. The close relationship between Se and Te, as well as Se-Te with both early syngenetic and later cleat filling pyrite, confirms an important role for sulphides in Se and Te sequestration in British coals. The high Se-Bowland Shale and/or Ordovician volcanics may have provided the trace element source British coals of similar or younger age. Regional intrusive activity (shallow Se and Te concentrations of British coals LB draft manuscript tabular intrusions or more extensive plutons) and episodes of intense deformation can alter the thermal maturity of coals, and may have driven the movement of trace element-rich fluids through strata, locally enriching coals in Se and Te

Anesthetic activity and bio-guided fractionation of the essential oil of Aloysia gratissima (Gillies & Hook.) Tronc. in silver catfish Rhamdia quelen

This work aimed to determine the efficacy of the essential oil of A. gratissima as anesthetic for silver catfish, and to perform the bio-guided fractionation of essential oil aiming to isolate compounds responsible for the noted effects. Fish were submitted to anesthesia bath with essential oil, its fractions and isolated compounds to determine time of anesthetic induction and recovery. Eugenol (50 mg L-1) was used as positive control. Essential oil of A. gratissima was effective as an anesthetic at concentrations of 300 to 900 mg L-1. Fish presented involuntary muscle contractions during induction and recovery. The bio-guided fractionation of essential oil furnishedE-(-)-pinocamphone, (-)-caryophyllene oxide, (-)-guaiol and (+)-spathulenol. E-(-)-pinocamphone caused the same side effects observed for essential oil. (-)-Caryophyllene oxide, (-)-guaiol and (+)-spathulenol showed only sedative effects at proportional concentrations to those of the constituents in essential oil. (+)-Spathulenol (51.2 mg L-1) promoted deep anesthesia without side effects. A higher concentration of (+)-spathulenol, and lower or absent amounts ofE-(-)-pinocamphone could contribute to increase the activity and safety of the essential oil of A. gratissima. (+)-Spathulenol showed potent sedative and anesthetic activities in silver catfish, and could be considered as a viable compound for the development of a new anesthetic

Determination of Se and Te in coal at ultra-trace levels by ICP-MS after microwave-induced combustion

A method for ultra-trace determination of Se and Te in coal by inductively coupled plasma mass spectrometry (ICP-MS) was developed. Samples (up to 500 mg) were prepared by microwave-induced combustion (MIC) in a closed system pressurized with 20 bar of oxygen. Inorganic acids or their mixtures were evaluated as absorbing solution. Using HNO3 + HCl (1 + 1), results obtained for Se and Te after sample preparation by MIC agreed with those obtained by reference methods, microwave-assisted wet digestion (MAWD) using concentrated HNO3 and HF, and solid sampling electrothermal vaporization inductively coupled plasma mass spectrometry (SS-ETV-ICP-MS), and also with a certified reference material of coal (NIST 1632c) for Se. Very low limits of quantification (LOQ) were obtained: 0.002 and 0.007 mg kg1 for Se and Te, respectively. Major elements were determined in final solutions obtained by MAWD and MIC, and their concentration in solutions of MIC was negligible (<10 mg L1), minimizing the risk of interference in ICP-MS analysis. The proposed method was applied to samples of coal from the United Kingdom, with a wide range of inorganic composition (from 3 to 41% ash content), showing its robustness and feasibility for routine analysis. Se concentration ranged from 0.291 to 11.5 mg kg1, and Te was mainly found at ultra-trace levels (<0.007 to 0.11 mg kg1). The proposed method presents several advantages over the reference methods, such as the use of a higher sample mass, low LOQs and, an important aspect, no need of using HF