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Abstract: Synthetic zeolite ZSM5 and its copper forms containing N,N-dimethylethylenediamine (dmen) have been investigated by CHN, energy dispersive spectroscopy (EDS) analysis, X-ray powder diffractometry, X-ray photoelectron spectroscopy and continuous waves hydrogen nuclear magnetic resonance (CW 1H NMR) spectroscopy. Thermal properties have been studied by methods of thermal analysis—TG, DTA and DTG in the temperature range 20–1000°C in air atmosphere. Mass spectroscopy method was used for the study of the released gas products of thermal decomposition. The results of thermal analyses of two zeolitic samples Cu-ZSM5 and Cu(dmen) x ZSM5 (x depends on the mode of preparation) demonstrated their different thermal properties. The main part of the decomposition process of the samples Cu(dmen) x ZSM5 occurs at considerably higher temperatures than the boiling point of dimethylethylenediamine, proving strong bond and irreversibility of dmen–zeolite interaction. According to the results of mass spectroscopy the decomposition process in inert atmosphere is characterized by the development of a large spectrum of products with atomic mass from 18 to 447 atomic mass units as a consequence of the catalytic effect of the silicate surface. [Copyright &y& Elsevier]

A method was developed for determination of fipronil (FIP) pesticide and its three major degradates (fipronil desulfinyl, fipronil sulfide, fipronil sulfone) in water at the levels required by the EU Commission in the Decision 2022/1307. The method combines solvent-free stir bar sorptive extraction (SBSE) with thermal desorption-gas chromatography-tandem mass spectrometry (TD-GC-MS/MS). Simple sample processing involves 16 h of stirring a 100 mL water sample with a polydimethylsiloxane-coated sorptive stir bar, followed by TD of the trapped analytes into the GC. The greenness assessment by analytical Eco-Scale approach resulted in classification of the entire analytical method as "an excellent green analysis". The obtained limits of quantification for all FIPs determined in tap, lake, MilliQ water and artificial seawater were in the range of 0.12-0.30 ng L -1 . The recoveries ranged between 81.7 and 109% with relative standard deviations from 2.8 to 14%. The results show that the method is suitable for screening and monitoring the studied analytes in selected matrices., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023. Published by Elsevier B.V.)

An environmentally friendly method was developed to determine tributyltin (TBT) in water at the levels required by the European Union Water Framework Directive (EU WFD) using stir bar sorptive extraction (SBSE) in combination with thermal desorption‒gas chromatography‒triple quadrupole tandem mass spectrometry. The main focus of the method development was on addressing some aspects of reducing blank values (minimizing the use of chemicals, glassware cleaning, pretreatment of sorptive stir bars) and optimizing the SBSE procedure variables (sample volume, polarity of sample solution, extraction time). The performance of the method was studied in terms of linearity, matrix effect, method limits and accuracy (precision and trueness) using MilliQ, tap and surface water. TBT quantification limit for the studied matrices ranged from 0.049 to 0.055 ng L ‒1 and repeatability (RSD%, n = 10) and recovery at the environmental quality standard (EQS) concentration of 0.2 ng L ‒1 were in the range of 6‒18% and 88‒107%, respectively, indicating good performance of the method. The matrix effect of river water (‒78%) and artificial seawater (‒83%) compared to MilliQ water showed the necessity to use a matrix-matched calibration when analysing TBT in surface water samples. The developed sample preparation was further evaluated for greenness using the recently introduced AGREEprep assessment, which revealed a much greener performance of the proposed method over the compared CEN/TS 16692 method. The method meets the requirements of the EU WFD and is suitable for monitoring, evaluation and classification of the chemical status of surface waters., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2022 Elsevier B.V. All rights reserved.)

The study presents the development and validation of a method for the determination of seven priority polycyclic aromatic hydrocarbons (PAHs, including fluoranthene and benzo[a]pyrene, for which the EU has set environmental quality standards, EQS, for biota) in gammarid samples combining focused ultrasound solid-liquid extraction and dispersive solid-phase extraction clean-up in one step followed by gas chromatography-triple quadrupole tandem mass spectrometry (GC-QqQ-MS/MS). The method is designed to analyse small about 100 mg dry weight (dw) samples obtained after lyophilisation of 500 mg wet weight (ww) samples. The sample preparation procedure is simple, environment friendly (method was classified as "an excellent green analysis" according to the analytical Eco-Scale assessment), non-laborious and low-cost and, apart from the sample extract concentration step, is quick. Thorough disintegration of the gammarids is achieved by a combination of sonication and the addition of granular anhydrous Na 2 SO 4 to the gammarid suspension, thus avoiding the need to grind the sample prior to analysis. The QqQ-MS/MS detector, thanks to its excellent selectivity and sensitivity, allows to meet the EQS requirements for PAHs in biota with a good margin (limits of quantification in the range of 0.12 and 0.56 ng g ‒1 ww). The method has been successfully validated (in terms of linearity, method limits, precision, trueness, robustness, measurement uncertainty and comparative analysis of real samples), and has been shown to be suitable for monitoring and evaluating the PAHs contamination in surface water biota., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2022 Elsevier B.V. All rights reserved.)

A rapid method is proposed for the determination of selected H₂SO₄ stable organic compounds-eight organochlorines (OCs; hexachloro-1,3-butadiene, pentachlorobenzene, hexachlorobenzene, hexachlorocyclohexane-HCH-isomers, heptachlor) and six polybrominated diphenyl ethers (PBDEs; BDE-28, 47, 99, 100, 153, 154)-in fish samples. In the method, a modified QuEChERS (quick, easy, cheap, effective, rugged and safe) sample preparation using pH-tuned dispersive liquid⁻liquid microextraction (DLLME) and H₂SO₄ digestion fish extract clean-up is followed by gas chromatography⁻triple quadrupole tandem mass spectrometry (GC⁻QqQ-MS/MS) analysis. The method was validated in terms of linearity, limits of the method, recovery, accuracy, analysis of standard reference material (NIST SRM 1946), and estimation of combined uncertainty of the measurement (top-down approach). For validation, chub composite samples were used, and subsequently, the method was successfully applied to analysis of real samples of eight fish species. Finally, the method passed the analytical Eco-Scale evaluation as "an acceptable green analysis method", and showed its advantages (simplicity, rapidity, low cost, high extract clean-up efficiency, good sensitivity) when compared to other reported QuEChERS based methods., Competing Interests: The authors declare no conflict of interest.

As future scientists, university students need to learn how to avoid making errors in their own manuscripts, as well as how to identify flaws in papers published by their peers. Here we describe a novel approach on how to promote students' ability to critically evaluate scientific articles. The exercise is based on instructing teams of students to write intentionally flawed manuscripts describing the results of simple experiments. The teams are supervised by instructors advising the students during manuscript writing, choosing the 'appropriate' errors, monitoring the identification of errors made by the other team and evaluating the strength of their arguments in support of the identified errors. We have compared the effectiveness of the method with a journal club-type seminar. Based on the results of our assessment we propose that the described seminar may effectively complement the existing approaches to teach critical scientific thinking. © 2017 by The International Union of Biochemistry and Molecular Biology, 46(1):22-30, 2018., (© 2017 The International Union of Biochemistry and Molecular Biology.)

Zeoadsorbents on the basis of copper forms of synthetic zeolite ZSM5 and natural zeolite of the clinoptilolite type (CT) have been studied taking into account their environmental application in removing harmful pyridine (py) from liquid and gas phase. Sorption of pyridine by copper forms of zeolites (Cu-ZSM5 and Cu-CT) has been studied by CHN, X-ray photoelectron spectroscopy, X-ray powder diffractometry, FTIR spectroscopy, thermal analysis (TG, DTA and DTG) and analysis of the surface areas and the pore volumes by low-temperature adsorption of nitrogen. The results of thermal analyses of Cu-ZSM5, Cu-(py)(x)ZSM5, Cu-CT and Cu-(py)(x)CT zeolitic products with different composition (x depends on the experimental conditions of sorption of pyridine) clearly confirmed their different thermal properties as well as the sorption of pyridine. In the zeolitic pyridine containing samples the main part of the pyridine release process occurs at considerably higher temperatures than is the boiling point of pyridine, which proves strong bond and irreversibility of py-zeolite interaction. FTIR spectra of Cu-(py)(x)zeolite samples showed well resolved bands of pyridine. The results of thermal analysis and FTIR spectroscopy are in a good agreement with the results of other used methods., (Copyright © 2010 Elsevier B.V. All rights reserved.)