Hasil untuk "Analytical chemistry"

A. Gałuszka, Z. Migaszewski, J. Namieśnik

Ana B Silva, Ana Bastos, C. Justino et al.

Microplastics can be present in the environment as manufactured microplastics (known as primary microplastics) or resulting from the continuous weathering of plastic litter, which yields progressively smaller plastic fragments (known as secondary microplastics). Herein, we discuss the numerous issues associated with the analysis of microplastics, and to a less extent of nanoplastics, in environmental samples (water, sediments, and biological tissues), from their sampling and sample handling to their identification and quantification. The analytical quality control and quality assurance associated with the validation of analytical methods and use of reference materials for the quantification of microplastics are also discussed, as well as the current challenges within this field of research and possible routes to overcome such limitations.

J. Miller, J. Miller

Taichi Inagaki, Miho Hatanaka

The hydration of magnesium oxide (MgO) to magnesium hydroxide (Mg(OH)$_2$) is a fundamental solid-surface chemical reaction with significant implications for materials science. Yet its molecular-level mechanism from water adsorption to Mg(OH)$_2$ nucleation and growth remains elusive due to its complex and multi-step nature. Here, we elucidate the molecular process of MgO hydration based on structures of the MgO/water interface obtained by a combined computational chemistry approach of potential-scaling molecular dynamics simulations and first-principles calculations without any a priori assumptions about reaction pathways. The result shows that the Mg$^{2+}$ dissolution follows the dissociative water adsorption. We find that this initial dissolution can proceed exothermically even from the defect-free surface with an average activation barrier of $\sim$12 kcal/mol. This exothermicity depends crucially on the stabilization of the resulting surface vacancy, achieved by proton adsorption onto neighboring surface oxygen atoms. Further Mg$^{2+}$ dissolution then occurs in correlation with proton penetration into the solid. Moreover, we find that the Mg(OH)$_2$ nucleation and growth proceeds according to the dissolution-precipitation mechanism, rather than a solid-state reaction mechanism involving a direct topotactic transformation. In this process, Mg$^{2+}$ ions migrate away from the surface and form amorphous Mg-OH chains as precursors for Mg(OH)$_2$ nucleation. We also demonstrate that sufficient water facilitates the formation of more ordered crystalline nuclei. This computational study provides a comprehensive molecular-level understanding of MgO hydration, representing a foundational step toward elucidating the mechanisms of this class of complex and multi-step solid-surface chemical reactions.

M. Mayer, A. Baeumner

The Internet of Things (IoT) is a megatrend that cuts across all scientific and engineering disciplines and establishes an integrating technical evolution to improve production efficiencies and daily human life. Linked machines and sensors use decision-making routines to work toward a common product or solution. Expanding this technical revolution into the value chain of complex areas such as agriculture, food production, and healthcare requires the implementation and connection of sophisticated (bio)analytical methods. Today, wearable sensors, monitors, and point-of-care diagnostic tests are part of our daily lives and improve patients' medical progression or athletes' monitoring capabilities that are already beyond imagination. Also, early contributions toward sensor networks and finally the IT revolution with wireless data collection and transmission via Bluetooth or smartphones have set the foundation to connect remote sensors and distributed analytical chemical services with centralized laboratories, cloud storage, and cloud computing. Here, we critically review those biosensor and chemosensor technologies and concepts used in an IoT setting or considered IoT-ready that were published in the period 2013-2018, while also pointing to those foundational concepts and ideas that arose over the last two decades. We focus on these sensors due to their unique ability to be remotely stationed and that easily function in networks and have made the greatest progress toward IoT integration. Finally, we highlight requirements and existing and future challenges and provide possible solutions important toward the vision of a seamless integration into a global analytical concept, which includes many more analytical techniques than sensors and includes foremost next-generation sequencing and separation principles coupled with MS detection.

S. Armenta, S. Garrigues, F. Esteve-Turrillas et al.

Abstract Green analytical chemistry concept, involving the development of analytical methodologies with an environmental concern, encourages the use of direct analysis to avoid any sample treatment that involves energy and reagent consumption and generation of wastes. However, the determination of target analytes at trace concentration levels or in complex matrices frequently requires previous extraction, pre-concentration, or clean-up steps offering thus, additional possibilities for greening classical methods. So, a green evaluation of alternative extraction techniques to currently used ones for the extraction of solid, liquid, and gaseous samples has been carried out in this study. Moreover, the incidence of the continuous increase of laboratory plastic ware consumption, employed for sample treatment, has been highlighted and discussed as a new challenge to enhance the sustainability of analytical methods.

M. Rezazadeh, Shahram Seidi, Marthe Lid et al.

Abstract Nowadays, in situ analysis attracts the interests and becomes one of the main purposes in analytical chemistry. Design of portable analysis devices facilitates reaching this goal. An ideal analysis system contains different parts enabling extraction, detection and quantification of target analytes. Preparation of a portable quantification approach is a bottle neck in such system creation. Common lab analysis instruments do not have the transportation ability and using these facilities limits the complete in situ analysis. Smartphones are the modern life phenomena and their usage becomes more widespread, every day. Their abilities and features are also swiftly developed. There are several strategies making the smartphone a suitable quantifier. This paper provides an overview of the currently applications of smartphones in analytical chemistry. Different applications of smartphones including optical detection (colorimetric, fluorescence, chemiluminescence, bioluminescence, and photoluminescence detections, pixelation as well as label-free detection), electrochemical detection, barcode reading, chemometric applications and smartphone imaging with fluorescence microscopy were classified and advantages and disadvantages of each approach were investigated. This modern common item could be a new part of analytical chemistry.

Agata Kryczyk-Poprawa, Wojciech Baran, Katarzyna Sułkowska-Ziaja et al.

Oxybenzone, a common sunscreen ingredient, has been widely detected in various environmental matrices, posing significant ecological and health risks. The present study demonstrates, for the first time, the capacity of <i>Pleurotus djamor</i> to degrade oxybenzone in in vitro cultures. After 14 days of mycelial incubation, oxybenzone concentrations in the medium decreased from 25 mg to 1.5394 ± 0.095 mg. The final amount of oxybenzone in the mycelium after lyophilization was 6.2067 ± 0.2459 mg. Furthermore, oxybenzone addition significantly reduced biomass growth from 2.510 ± 0.6230 g to 1.4697 ± 0.0465 g. The transformation products in the dry mycelium and medium were assessed and identified using UPLC-Q-tof based on monoisotopic molecular mass and fragmentation spectra. In processes initiated by <i>P. djamor</i>, mainly acylated derivatives of oxybenzone were formed. Additionally, compounds with thiol and amino groups were identified. Alterations in antioxidant profiles (L-tryptophan, 6-methyl-D,L-tryptophan, p-hydroxybenzoic acid, ergosterol, lovastatin, L-phenylalanine, and ergothioneine) in response to oxybenzone exposure were observed. Our findings reveal significant changes in the antioxidant levels and biomass growth inhibition, underscoring the potential toxicological risks associated with oxybenzone. The observed reduction in oxybenzone concentration highlights the potential of <i>P. djamor</i> as an effective and environmentally friendly strategy for mitigating this pollutant.

Camille R. Reaux, Shelby A. Meche, Jordan M. Grider et al.

Given the exponential growth of biochemical data and deep effect of computational methods on life sciences, there is a need to rethink undergraduate curricula. A project-oriented learning approach based on the Triangular Spatial Relationship (TSR) algorithm has been developed. The TSR-based method was designed for protein 3D structural comparison, motif discovery and probing molecular interactions. The uniqueness of the method benefits students’ learning of big data and computational methods. Specifically, students learn (i) how to search proteins of interest from the PDB archive, (ii) basic supercomputer skills, (iii) how to prepare datasets, (iv) how to perform protein structure and sequence analyses, (v) how to interpret the results, visualize protein structures and make graphs. Five specific strategies have been developed to achieve students’ highest potentials. (i) This lab exercise is designed as a project-oriented learning approach. (ii) The skills-first and concept-second approach is used. (iii) Students choose the proteins based on their interests. (iv) Students are encouraged to learn from each other to promote student–student interactions. (v) Students are required to write a report and/or present their studies. To assess students’ performance, we have developed an assessment rubric that includes (i) demonstration of supercomputer skills in job script preparation, submission and monitoring, (ii) skills in preparation of datasets, (iii) data analytical skills, (iv) project report, (v) presentation, and (vi) integration of the TSR-based method with other computational methods (e.g., molecular 3D structural visualization and protein sequence analysis). This project has been introduced in undergraduate biochemistry research and teaching labs for 4 years. Most students have learned the basic supercomputer skills as well as structure data analysis skills. Students’ feedback is positive and encouraging. It can be further developed as a module for an integrated computational chemistry lecture course.

A. E. Sitnitsky

A solution of the two-dimensional Schrödinger equation with Pauli-Fierz Hamiltonian and trigonometric double-well potential is obtained within the framework of the first-order of adiabatic approximation. The case of vibrational strong coupling is considered which is pertinent for polariton chemistry and (presumably) for enzymatic hydrogen transfer. We exemplify the application of the solution by calculating the proton transfer rate constant in the hydrogen bond of the Zundel ion ${\rm{H_5O_2^{+}}}$ (oxonium hydrate) within the framework of the Weiner's theory. An analytic formula is derived which provides the calculation of the proton transfer rate with the help of elements implemented in {\sl {Mathematica}}. The parameters of the model for the Zundel ion are extracted from the literature data on IR spectroscopy and quantum chemical calculations. The approach yields a vivid manifestation of the phenomenon of vibrationally enhanced tunneling, i.e., a sharp bell-shaped peak of the rate enhancement by the external vibration at its symmetric coupling to the proton coordinate. The results obtained testify that the effect of resonant activation in our model is robust and stable to variations in the types of the quadratically coupled mode (vibrational strong coupling or symmetric one).

Dennis Lima, Saif Al-Kuwari, Ivan Gladich

Stratospheric aerosol injection (SAI) has been proposed as a geoengineering strategy to mitigate global warming by increasing Earth's albedo. Silica-based materials, such as diamond-doped silica aerogels, have shown promising optical properties, but their impact on stratospheric chemistry, ozone one in particular, remains largely unknown. Here, we present first-principles molecular dynamics (MD) simulations of the heterogeneous reaction between hydrogen chloride ($\mathrm{HCl}$) and chlorine nitrate ($\mathrm{ClONO_2}$), two main reservoirs of stratospheric chlorine and nitrogen species, on a dry, hydroxylated $α$-quartz silica interface. Our results reveal a barrierless reaction pathway toward the formation of chlorine gas ($\mathrm{Cl}_2$), a major contributor to stratospheric ozone loss. We design a heterogeneous kinetic model informed by our MD simulation and available experimental data: despite the barrierless formation of $\mathrm{Cl_2}$, the higher surface affinities and partial pressures of $\mathrm{HNO_3}$ and $\mathrm{HCl}$ compared to those of $\mathrm{ClONO_2}$ result in a negligible reaction probability, $γ_\mathrm{ClONO_2}$, upon chlorine nitrate collision with the silica surface. Since $γ_\mathrm{ClONO_2}$ enters as a proportionality constant in the definition of the heterogeneous reaction rate, our kinetic model indicates that the injection of silica-based aerosols may have only a limited impact on stratospheric ozone depletion driven by $\mathrm{HCl}$ and $\mathrm{ClONO_2}$ chemistry. At the same time, our findings also underscore the scarcity of experimental data, the need of better theoretical frameworks for the inclusion of MD results into kinetic models, and the urgency for further experimental validations of silica-based SAI technologies before their deployment in climate intervention strategies.

Idaira Pacheco-Fernández, V. Pino

Current trends in incorporating the principles of green chemistry in analytical methods have led to the design and usage of new solvents to replace conventional organic solvents, which characterize by their high volatility, flammability, and toxicity. Among the alternatives that have emerged, amphiphilic solvents, ionic liquids, and deep eutectic solvents are the most explored candidates in this research field. Taking advantage of the solvation properties of these new solvents, together with the synthetic versatility in the case of ionic liquids and deep eutectic solvents, a wide variety of applications of these solvents within green analytical chemistry appear in the recent literature. The aim of this article is to provide a quick summary of the state of the art on the usage of these new green solvents in analytical chemistry, particularly in liquid-phase microextraction methods (within sample preparation) and as additives or pseudostationary phases in liquid chromatography (within analytical separation methods).

Pattipong Wisanpitayakorn, Narumol Jariyasopit, Kassaporn Duangkumpha et al.

Fahad Alfhaid, Mansour Khater Alzahrani, Mohammed Zaid Aljulifi et al.

Objective: This study was carried out to assess the prevalence and perception of human papilloma virus (HPV) vaccination in health science students in Majmaah University, Saudi Arabia. Methodology: A descriptive cross-sectional study was conducted at different health science colleges of Majmaah University on female students. The knowledge of the participants regarding HPV was assessed using a pre-tested questionnaire. The history of vaccination of these female participants was also enquired. Results: More than three-fifth of the participants had heard about HPV. Of these, 83 participants, 59 (71.1%), were aware that it is a disease of women and how to diagnose it. Most participants (86.7%) knew that it can cause cervical cancer, while only 57.8% knew it could be asymptomatic. There were 18% of such participants who thought that HPV and human immunodeficiency virus are the same and that there is no vaccine for the prevention of HPV. Only 14.5% (n = 12) were vaccinated against HPV. Conclusion: A clear gap between knowledge and practice of HPV vaccination was observed, and health education should be planned to educate health professionals to avoid misconceptions.

Rajeev K Jaiswal, Deepti Chandra, Md Arif Khan et al.

Aim: To evaluate “coronally advanced flap” with or without “a platelet-rich fibrin membrane for the root coverage.” Materials and Methods: All the clinical parameters were assessed at different time intervals (at baseline, 1, 3, and 6 months) in both experimental and control group. Following “clinical parameters” were recorded using “UNC-15” “Probe-Plaque Index (PI)” (Silness and Loe, 1964), “Gingival Index” (GI) (Loe and Silness, 1963), “Recession depth (RD),” “Recession width (RW),” “Clinical attachment level (CAL),” and “Width of keratinized gingiva (WKG)”. Results: At final evaluation (i.e., mean change from baseline to 6 months), “the decrease in Plaque Index was 2.5% higher in Group B (66.0%) as compared to Group A (63.5%). The decrease in Gingival Index was 6.1% higher in Group B (91.4%) as compared to Group A (85.3%), and the decrease in recession width was 4.0% higher in Group B (75.2%) as compared to Group A (71.2%). The decrease in clinical attachment level was 4.4% higher in Group B (53.2%) as compared to Group A (48.4%). The increase in width of keratinized gingiva was 1.9% higher in Group A (28.8%) as compared to Group B (26.9%).” Conclusion: The controlled, randomized, split mouth design showed that CAF surgery, either by alone or in combination with PRF, is an efficient treatment method for covering denuded roots. “This design was used to treat bilateral isolated Miller's class I and II recessions in gingival part. When compared to the CAF approach, the results from a combination of CAF and PRF after a 6-month period showed additional advantages in addition to mean root coverage in the treatment of Miller's classes I and II recessions in gingival part.”

Dagmara Słota, Josef Jampilek, Agnieszka Sobczak-Kupiec

Coating materials offers an intriguing solution for imparting inert implants with additional bioactive characteristics without changing underlying parameters such as mechanical strength. Metallic implants like endoprostheses or polymeric implants can be coated with a thin layer of bioactive film capable of stimulating bone-forming cells to proliferate or release a drug. However, irrespective of the final implantation site of such a coating biomaterial, it is necessary to conduct detailed mechanical and physicochemical in vitro analyses to determine its likely behavior under biological conditions. In this study, polymeric and composite coatings with hydroxyapatite obtained under UV light underwent incubation tests in four different artificial biological fluids: simulated body fluid (SBF), artificial saliva, Ringer’s fluid, and water (as the reference fluid). The potentiometric and conductometric properties, sorption capacity, and degradation rate of the coatings were examined. Furthermore, their hardness, modulus of elasticity, and deformation were determined. It was demonstrated that the coatings remained stable in SBF liquid at a pH value of around 7.4. In artificial saliva, the greatest degradation of the polymer matrix (ranging between 36.19% and 39.79%) and chipping of hydroxyapatite in the composite coatings were observed. Additionally, the effect of ceramics on sorption capacity was determined, with lower capacity noted with higher HA additions. Moreover, the evaluation of surface morphology supported by elemental microanalysis confirmed the appearance of new apatite layers on the surface as a result of incubation in SBF. Ceramics also influenced mechanical aspects, increasing hardness and modulus of elasticity. For the polymer coatings, the value was 11.48 ± 0.61, while for the composite coating with 15% ceramics, it increased more than eightfold to a value of 93.31 ± 11.18 N/mm². Based on the conducted studies, the effect of ceramics on the physicochemical as well as mechanical properties of the materials was determined, and their behavior in various biological fluids was evaluated. However, further studies, especially cytotoxicity analyses, are required to determine the potential use of the coatings as biomaterials.

M. Bezerra, S. Ferreira, C. Novaes et al.

This manuscript covers the application of the main techniques for simultaneous optimization of multiple responses generated by the application of multivariate designs (two-factor factorial, Central Composite, Doehlert, etc.) or by chromatographic runs in the development of analytical methods. Special attention will be given to the graphical method, desirability function, multiple response function and chromatographic response functions, since they are more frequently used in the analytical area. The advantages, disadvantages, limitations, and potentialities of these methods will also be addressed, as well as some of their applications, commenting on real examples from the literature. Some less usual methods in multiple response optimization in Analytical Chemistry will also be commented.

S. Restaino, I. White

For decades surface enhanced Raman spectroscopy (SERS) has been intensely investigated as a possible solution for performing analytical chemistry at the point of sample origin. Unfortunately, due to cost and usability constraints, conventional rigid SERS sensors and microfluidic SERS sensors have yet to make a significant impact outside of the realm of academics. However, the recently introduced flexible and porous paper-based SERS sensors are proving to be widely adaptable to realistic usage cases in the field. In contrast to rigid and microfluidic SERS sensors, paper SERS sensors feature (i) the potential for roll-to-roll manufacturing methods that enable low sensor cost, (ii) simple sample collection directly onto the sensor via swabbing or dipping, and (iii) equipment-free separations for sample cleanup. In this review we argue that movement to paper-based SERS sensors will finally enable point-of-sample analytical chemistry applications. In addition, we present and compare the numerous fabrication techniques for paper SERS sensors and we describe various sample collection and sample clean-up capabilities of paper SERS sensors, with a focus on how these features enable practical applications in the field. Finally, we present our expectations for the future, including emerging ideas inspired by paper SERS.

František Foret, Doo Soo Chung, Jana Lavická et al.

In a demonstration of modern analytical chemistry at its best, the International Interdisciplinary Conference of Chemical Analysis, APCE-CECE-ITP-IUPAC 2022 was held after two years of COVID-19-related delays in Siem Reap, Cambodia. The quadruple meeting included: 18th Asia Pacific International Symposium on Microscale Separations and Analyses, 17th International Interdisciplinary Meeting on Bioanalysis, 28th International Symposium on Electro- and Liquid Phase-Separation Techniques, and IUPAC Special Symposia by Division of Chemistry and the Environment. While, under normal circumstances, these conferences would take place in different countries, we have decided to bring together analytical chemists from all over the world for a conference covering all aspects of modern analytical chemistry. Our goal remained the same: “bring together scientists from different disciplines who may not meet at other meetings”. With plenary and invited lectures delivered by distinguished scientists, this in-person meeting allowed to broaden our knowledge, meet new friends, and start new collaborations. The organizers want to thank all speakers, sponsors, and participants for their support. Please, check the conference web for more information about the history, programs, photos, and videos.

Azra Đulović, Franko Burčul, Vedrana Čikeš Čulić et al.

Glucosinolates (GSLs) in <i>Brassica oleracea</i> L. convar. <i>acephala</i> var. <i>viridis</i> (collard) flower, leaf, stem, and root were analyzed qualitatively and quantitatively via their desulfo-counterparts using UHPLC-DAD-MS/MS. Twelve GSLs were identified, including Met-derived GSLs (sinigrin, glucoibervirin, glucoerucin, glucoiberin, glucoraphanin, progoitrin), Trp-derived GSLs (4-hydroxyglucobrassicin, glucobrassicin, 4-methoxyglucobrassicin, and neoglucobrassicin), and Phe-derived GSLs (glucotropaeolin and gluconasturtiin). Total GSL content was highest in the root, having 63.40 μmol/g dried weight (DW), with gluconasturtiin (34.02 μmol/g DW) as the major GSL, followed by sinigrin and glucoibervirin (12.43 and 7.65 μmol/g DW, respectively). Total GSL contents in the flower, leaf, and stem were lower than in root, having 6.27, 2.64, and 1.84 μmol/g DW, respectively, with Trp and/or Met-derived GSLs as the predominant ones. GSL breakdown products were obtained via microwave hydrodiffusion and gravity (MHG) and volatile breakdown products were analyzed using GC-MS techniques. Volatile isolates were tested for their cytotoxic activity using MTT assay. MHG volatile extract from the root demonstrated the best cytotoxic activity against human bladder cancer cell line T24 and breast cancer cell line MDA-MB-231 during an incubation time of 72 h (IC₅₀ 21.58, and 11.62 μg/mL, respectively). The activity of the root extract can be attributed to its major volatile, 2-phenylethyl isothiocyanate (gluconasturtiin breakdown product).