2024 - Repozytorium publikacji - Politechnika Gdańska

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A Computational Analysis of the Proton Affinity and the Hydration of TEMPO and Its Piperidine Analogs
- Abolfazl Shiroudi
- Maciej Śmiechowski
- Jacek Czub
- Mohamed A. Abdel-Rahman
2024 CHEMPHYSCHEM
The study investigated the impact of protonation and hydration on the geometry of nitroxide radicals using B3LYP and M06-2X methods. Results indicated that TEMPO exhibited the highest proton affinity in comparison to TEMPOL and TEMPONE. Two pathways contribute to hydrated protonated molecules. TEMPO shows lower first enthalpies of hydration (ΔH1-M), indicating stronger H-bonding interactions, while TEMPONE shows higher values, indicating weaker interactions with H2O. Solvent effects affect charge distribution by decreasing their atomic charge. Spin density (SD) is primarily concentrated in the NO segment, with minimal water molecule contamination. Protonation increases SD on N-atom, while hydration causes a more pronounced redistribution for water molecules. The stability of the dipolar structure (>N•+-O-) is evident in SD redistributions. The frontier molecular orbital (FMO) analysis of TEMPONE reveals a minimum EHOMO-LUMO gap (EH-L), enhancing the piperidine ring's reactivity. TEMPO is the most nucleophilic species, while TEMPONE exhibits strong electrophilicity. Transitioning from NO radicals to protonated forms increases the EH-L gap, indicating protonation stabilizes FMOs. Increased water molecules make the molecule less reactive, while increasing hydration decreases this energy gap, making the molecule more reactive. A smaller EH-L gap indicates the compound becomes softer and more prone to electron density and reactivity changes.
A Concept of Thermal Effort for Heat-Induced Metal Plasticity
- Waldemar Dudda
- Piotr Józef Ziółkowski
- Paweł Ziółkowski
- Mateusz Bryk
- Janusz Badur
2024 Materials
This paper proposes a new concept of material effort that considers heat-induced plasticity for heat-resistant steels. These steels indicate a strength differential effect, a stress shearness effect, pressure sensitivity, and other features. Therefore, a three-parameter, temperature-dependent yield function was presented and, next, analytically and geometrically researched. To validate the accuracy of the formulated yield function, experiments were conducted with the designed specimens to characterize the heat-resistant steels St12T and 26H2MF, which underwent simple shear, uniaxial strain tension, and compression tests. The yield function was calibrated by using a simple analysis. Next, the calibrated constitutive equations were used to numerically determine the load–stroke responses of different tests. The numerical analysis showed that the proposed yield function based on three parameters could accurately describe the thermal effort in various loading conditions from the onset of yielding to the ultimate rupture. Accordingly, the proposed yield function is recommended to model material strength under various thermal loading conditions.
A Data-Driven Comparative Analysis of Machine-Learning Models for Familial Hypercholesterolemia Detection
- Tomasz Kocejko
2024 Applied Sciences-Basel
This study presents an assessment of familial hypercholesterolemia (FH) probability using different algorithms (CatBoost, XGBoost, Random Forest, SVM) and its ensembles, leveraging electronic health record data. The primary objective is to explore an enhanced method for estimating FH probability, surpassing the currently recommended Dutch Lipid Clinic Network (DLCN) Score. The models were trained using the largest Polish cohort of patients enrolled in an FH clinic, all of whom underwent genetic testing for FH-associated mutations. The initial dataset comprised over 100 parameters per patient, which was reduced to 48 clinically accessible features to ensure applicability in routine outpatient settings. To preserve balance, the data were stratified according to DLCN score ranges (<0–2>, <3–5>, <6–8>, and ≥9), representing varying levels of FH likelihood. The dataset was then split into training and test sets with an 80/20 ratio. Machine-learning models were trained, with hyperparameters optimized via grid search. The accuracy of the DLCN score in predicting FH was first evaluated by examining the proportion of patients with positive DNA tests relative to those with a DLCN score of 6 and above, the threshold for genetic testing. The DLCN score demonstrated an accuracy of approximately 40%. In contrast, the CatBoost model and its ensembles achieved over 80% accuracy. While the DLCN score remains a clinically valuable tool, its diagnostic accuracy is limited. The findings indicate that the ML models offer a substantial improvement in the precision of FH diagnosis, demonstrating its potential to enhance clinical decision making in identifying patients with FH.
A Deformation Sweep Testing Procedure to Evaluate Damage in Cold Recycled Material Mixtures
- Andrea Graziani
- Vittoria Grilli
- Amedeo Virgili
- Mariusz Jaczewski
2024
This chapter describes a new testing procedure to assess damage in cold recycled material mixtures. Specifically, stiffness modulus tests were performed at increasing deformation levels, with the objective of creating a gradual increase in damage. The succession of tests with increasing deformation was interspersed with tests at small deformation, with the objective of evaluating the damage gradually inflicted on the specimen. In the present research, the resilient stiffness modulus test was carried out in indirect tensile configuration at peak horizontal deformations from 2 μm to 15 μm. Cement–bitumen-treated materials specimens (80% of RAP, 4.0% of bitumen emulsion and 2% of cement) with three level of voids (12%, 14%, and 16%) were tested. The results showed that even small deformation levels lead to a significant reduction in stiffness, which can be interpreted as damage accumulation. Moreover, the dissipated energy approach shows that the damage is probably due to the failure of cementitious bonds.
A dissimilar welded joint of grade 92 steel and AISI 304L steel obtained using IN82 buttering and IN617 fller: relationship of microstructure and mechanical properties
- Hardik Sanjay Surkar
- Amit Kumar
- Sachin Sirohi
- Shailesh M. Pandey
- Aleksandra Świerczyńska
- Dariusz Fydrych
- Chandan Pandey
2024 Archives of Civil and Mechanical Engineering
Unfavourable operating conditions of equipment in the energy industry resulting from high-temperature loads determine the need to use special materials and technological solutions, including welding procedures. In this article, buttering using IN82 (ERNiCr-3) consumables was proposed as a method to improve the weldability of grade 92 steel joined by the gas tungsten arc welding (GTAW) process with AISI 304L (IN617 fller). The microstructural characterization of samples was carried out using an optical microscope, scanning electron microscope (SEM) and energy-dispersive X-ray spectroscopy. The welded joint was further characterized by hardness, tensile (room temperature and at 620 °C temperature) and impact tests. Additionally, the fracture surfaces of tensile and impact tests were studied by SEM. Despite the confrmation of the difusion of alloying elements and signifcant changes in their concentration, which indicates the formation of Ti and Nb-rich phases, no welding imperfections were detected and favourable joint structures and acceptable properties were obtained. In particular, this concerns the limitation of the formation of brittle structures and the elimination of the untempered martensitic layer. At the same time, there was a signifcant decrease in the maximum hardness of heat-afected zone (HAZ) on the grade 92 steel side to a relatively low value of 310 HV, and a minimum tensile strength criterion of 600 MPa was achieved with a simultaneous increase in ductility (35% elongation) of the joint. Comparatively, when compared to a non-buttered welded joint, the joint produced with a buttering layer exhibited an increase in the elongation and impact toughness of the welded joint without any compromise in ultimate tensile strength (Sut). The fracture surface of tensile and impact-tested specimens was also characterized using SEM/EDS. Summarizing all the results, it can be concluded that the proposed GTAW procedure of grade 92 and 304L steels can be used in extreme working conditions, in ultra-supercritical power units or the petrochemical and chemical industries.
A Finite Element Approach for Wave Propagation in Elastic Solids
- Arkadiusz Żak
2024
This book focuses on wave propagation phenomena in elastic solids modelled by the use of the finite element method. Although the latter is a well-established and popular numerical tool used by engineers and researchers all around the word the process of modelling of wave propagation can still be a challenge. The book introduces a reader to the problem by presenting a historical background and offering a broad perspective on the development of modern science and numerical methods. The principles of wave phenomena are clearly presented to the reader as well as the necessary background for understanding the finite element method, which is the following chapter of the book is viewed from the modeller point-of-view. Apart from the principles the book also addresses more advanced topics and problems including the use of the spectral-finite element method, the spline-based finite element method as well as the problems of undesired and hidden properties of discrete numerical models.
A framework for risk matrix design: A case of MASS navigation risk
- Cunlong Fan
- Jakub Montewka
- Di Zhang
- Zhepeng Han
2024 ACCIDENT ANALYSIS AND PREVENTION
Risk matrix, a tool for visualizing risk assessment results, is essential to facilitate the risk communication and risk management in risk-based decision-making processes related to new and unexplored socio-technical systems. The use of an appropriate risk matrix is discussed in the literature, but it is overlooked for emerging technologies such as Maritime Autonomous Surface Ships (MASS). In this study, a comprehensive framework for developing a risk matrix based on fuzzy Analytic Hierarchy Process (AHP) is proposed. In this framework, a linear function is defined where the risk index is treated as a response variable, while the probability and consequence indices are explanatory variables, with weights of these two indices representing their importance on given risk level. This significance is assessed by experts and quantified using AHP in interval type 2 fuzzy environment. A continuous risk diagram is then created and converted into a risk matrix that can be improved. To verify the feasibility of the proposed framework, a risk matrix is designed in the context of MASS grounding. The results show that the proposed approach is feasible. Our discussion results can provide new insights for the design of risk matrices and promote the management of MASS navigational risks.
A framework to analyse the probability of accidental hull girder failure considering advanced corrosion degradation for risk-based ship design
- Krzysztof Wołoszyk
- Floris Goerlandt
- Jakub Montewka
2024 RELIABILITY ENGINEERING & SYSTEM SAFETY
Ship’s hull girder failure could result from maritime accident that can cause human life loss, environmental disaster, and major economic impacts. In risk-based ship design paradigm, accounting for rare phenomena (e.g. ship-ship collision or grounding) is important to provide safe and durable structure. In-service corrosion-induced hull degradation should be considered at the design stage, as it can significantly affect structural strength. The current study presents a novel framework to estimate the probability of ship hull girder failure, accounting for novel corrosion modelling techniques and accidental damage. The associated uncertainties are considered using statistical sampling from evidence-based distributions. A state-of-the-art deterministic model for ultimate strength calculation is applied using Monte Carlo simulation approach, resulting in the probability of hull failure through a reliability assessment. Wave and still-water bending moments are considered random variables. Two case studies of tanker ships with varying sizes are executed to show the applicability of the proposed framework. The results indicate that proper consideration of corrosion is of high importance, as ageing can significantly increase the probability of failure if accidental damage happens. Therefore, whereas future research and model refinement are discussed, the presented framework can serve for risk-based ship design tool and assess existing structures’ safety.
A gap waveguide-based mechanically reconfigurable phase shifter for high-power Ku-band applications
- Ali Farahbakhsh
- Davood Zarifi
- Michał Mrozowski
2024 Scientific Reports
This paper presents a novel design of a low-loss, reconfgurable broadband phase shifter based on groove gap waveguide (GGW) technology. The proposed phase shifter consists of a folded GGW and three bends with a few pins forming the GGW and one bend attached to a movable plate. This movable plate allows for adjustments to the folded waveguide length, consequently altering the phase of electromagnetic waves. The advantage of GGW technology is that it does not require electrical contact between diferent parts of a structure. Therefore, it enables the moving parts to slide freely without electromagnetic energy leakage, resulting in improved insertion loss in high-power applications. In addition, in the proposed design, the position of the input and output waveguide ports of the phase shifter remains fxed, which is advantageous from a practical point of view. As shown by measurement and simulation results, there is nearly 37% impedance bandwidth with the highest insertion loss of 0.6 dB, and the developed device has a maximum phase shift of 770° at the center frequency of 13GHz. The phase shifter can be used for various radar and satellite applications that require phase control, such as beamforming networks and phased array antennas.
A green route for high-performance bio-based polyurethanes synthesized from modified bio-based isocyanates
- Joanna Brzoska
- Joanna Smorawska
- Ewa Głowińska
- Janusz Datta
2024 INDUSTRIAL CROPS AND PRODUCTS
The need for sustainability and a circular economy leads to the development of innovative greener materials and technologies. This paper is focused on a novel class of bio-based polyurethanes (PUs) synthesized with the use of bio-monomers including bio-based isocyanates. The novelty of this work is related to the usage of bio-based modified isocyanate via a two-step solvent-free synthesis of novel cast bio-based poly(ester-urethanes) and poly(ether-urethanes). The designed and prepared bio-based PUs were analysed in terms of their chemical structure, thermal stability, mechanical and thermomechanical properties. Fourier transform infrared spectroscopy confirmed the formation of urethane groups and allowed the calculation of the carbonyl index and the degree of phase separation. Differential scanning calorimetry and X-ray diffraction indicated the amorphous behavior of the obtained bio-based materials. It was established that not only the thermal stability but also the degradation steps depended on the structure of the hard segments and the phase separation between hard and soft segments. The modification of hard segments was also revealed in the results of thermomechanical and mechanical behavior of bio-PU which indicated a mixed phase structure.
A hierarchical observer for a non-linear uncertain CSTR model of biochemical processes
- Mateusz Czyżniewski
- Rafał Łangowski
2024 Pełny tekst International Journal of Applied Mathematics and Computer Science
The problem of estimation of unmeasured state variables and unknown reaction kinetic functions for selected biochemical processes modelled as a continuous stirred tank reactor is addressed in this paper. In particular, a new hierarchical (sequential) state observer is derived to generate stable and robust estimates of the state variables and kinetic functions. The developed hierarchical observer uses an adjusted asymptotic observer and an adopted super-twisting sliding mode observer. The stability of the proposed hierarchical observer is investigated under uncertainty in the system dynamics. The stability analysis of the estimation error dynamics is carried out based on the methodology associated with linear parameter-varying systems and sliding mode regimes. The developed hierarchical observer is implemented in the Matlab/Simulink environment and its performance is validated via simulation. The obtained satisfactory estimation results demonstrate high effectiveness of the devised hierarchical observer.
A high-gain gap waveguide-based 16 × 16 slot antenna array with low sidelobe level for mmwave applications
- Davood Zarifi
- Ali Sabbaghi Saber
- Ashraf Uz Zaman
2024 Scientific Reports
This study presents the design of a high-gain 16 × 16-slot antenna array with a low sidelobe level (SLL) using a tapered ridge gap waveguide feeding network for Ka-band applications. The proposed antenna element includes four cavity-backed slot antennas. A tapered feeding network is designed and utilized for unequal feeding of the radiating elements. Ridge gap waveguide technology is used to reduce the feeding network loss and achieve a low-loss array antenna. The feed layer of the proposed antenna is coupled to a standard rectangular waveguide (WR-28) using a proper transition. The measured results show an impedance bandwidth of more than 17% over the frequency range of 27.5–32.6 GHz covering one of the standard vehicle-to-satellite band (29.4–31.0 GHz) and 5G mmWave N261 band (27.5– 28.35 GHz), a maximum gain of 28.9 dBi, and SLL lower than − 20 dB. Thanks to its high performance and desirable features, the proposed antenna shows potential for use in vehicular radar systems and high data rate mmWave communications.
A Highly Compact Split Ring Resonator Based Rectangular Dielectric Resonator Antenna with Multiband Characterization
- Shahid Khan
- Owais Khan
- Kiran Raheel
- Syed Ahson Ali Shah
- Bilal Malik
- Salahuddin Khan
- Neelam Gohar
- Sławomir Kozieł
2024 Pełny tekst IEEE Access
This work encompasses a novel highly compact Split Ring Resonator (SRR) based quad-band Dielectric Resonator Antenna (DRA) for 4G and 5G applications. The proposed antenna comprises of an extended rectangular feedline and a rectangular DR in combination with two SRRs. The DRA uses the extended rectangular microstrip feedline for providing better impedance matching and enhanced performance. Remarkably, the introduction of SRRs on either side of the feedline enables the DRA to resonate at four distinct frequency bands, i.e., 1.62 GHz, 3.03 GHz and 4.7 GHz and 6.56 GHz respectively. The two lower operating bands with narrow band response are due to SRRs while two upper bands with wide band characteristics are due to rectangular DR. The simulated performance of the rectangular DRA is validated through measurements, performed on a fabricated prototype. At the corresponding resonance frequencies, the suggested design exhibits -10 dB impedance bandwidths of 9.2%, 5%, 8.3%, and 5.6%. With a notable peak gain of 2.3 dBi and an efficiency of 93%, the suggested design has excellent radiation pattern stability. To the best of authors knowledge, this is the first design where SRRs are incorporated with rectangular DR to achieve multiband operations. The simulated and measured findings show a strong agreement, highlighting the SRR-based DRA appropriateness for multiband wireless applications (such as satellite television, radio astronomy, Bluetooth, WiFi, and 6G), while demonstrating its significant contribution to the field.
A learning community model: the Center for Innovative Education supporting academic didactics at Gdańsk University of Technology, Poland
- Joanna Mytnik
- Barbara Wikieł
- Mariusz Kaczmarek
2024 Global Journal of Engineering Education
The current digital transformation requires academics to apply their pedagogical and technological skills to their teaching and professional development to address the newly emerging needs of the digital era. This study aims to analyse the operating model of the Center for Innovative Education (CIE) at Gdańsk University of Technology (Gdańsk Tech), Poland, as an incubator for professional development of academic staff at Gdańsk Tech, and outline the programmes carried out at the CIE. The focus is on systemic actions capable to elicit innovation at an organisational and personal level, including community building, higher education trend analyses, evidence-based professional training, designing new methods and tools for innovative teaching and appreciation programmes. The CIE’s offer extends to well-being support and providing measures against professional burnout. The establishment of the CIE enabled academic teachers at Gdańsk Tech to improve their professional competence and build a strong peer-learning community.
A Low-Profile 3-D Printable Metastructure for Performance Improvement of Aperture Antennas
- Md Yeakub Ali
- Ali Lalbakhsh
- Sławomir Kozieł
- Łukasz Gołuński
- Foez Ahmed
- Mohsen Asadnia
2024 Pełny tekst Scientific Reports
In order to increase the radiation performance of aperture-type antennas, this paper demonstrates a low-profile, planar, single-layer, three-dimensional (3-D) printable metastructure. The proposed hybridized metastructure is highly transparent as it is made out of novel hybrid meta-atoms having transmission coefficient magnitudes greater than -0.72 dB and fully complies with the near-field phase transformation principle. The hybridized design approach makes the metastructure planar, low-profile, light in weight, and compatible with additive printing technology. For the proof-of-concept, such metastructure is developed and numerically verified to enhance the radiation performance of a resonant cavity antenna (RCA). With the proposed metastructure, the peak directivity of the RCA is improved by 8.6 dBi (from 11.4 dBi to 20 dBi) at the operating frequency of 12.4 GHz. The aperture efficiency and 3-dB directivity bandwidth of the RCA with the metastructure are 41.46% and 16.5%, respectively. Using readily accessible thermoplastics or polymers and copper with cost-effective fused deposition modeling (FDM) 3-D printing technology, the proposed planar hybridized metastructure can be prototyped commercially.
A Low-Profile Metal-backed Dipole Loaded with Closely Coupled Arc-shaped Open Stubs for On-metal Tag Design with Wide Frequency Tuning Capability
- Fuad Erman
- Sławomir Kozieł
- Eng-Hock Lim
- Leifur Leifsson
- Effariza Hanafi
- Muthukannan Murugesh
2024 IEEE TRANSACTIONS ON ANTENNAS AND PROPAGATION
This research has presented a single-layer metal-backed dipole antenna, which consists of a feedline loaded with two pairs of closely-coupled arc-shaped open stubs, for designing a metal-mountable tag that features tuning capability over a wide range of frequency. Here, the stubs can generate sufficient inductive reactance for bringing down the tag resonant frequency tunable in both the regulated UHF RFID passbands (North American (NA) and Lower European (LEu) standards). Adjusting the stubs’ length can be utilized as a simple and effective tuning mechanism, enabling broadband frequency adjustment in between the two major spectra in a straightforward manner, while maintaining a maximum power transmission coefficient (τ=1). In addition, the proposed antenna structure is easy to construct. The tuning mechanism has enabled the antenna to match well with any commercial RFID chips, and it does not require the use of any external lumped components or shorting elements (vias or stubs). The proposed tag can be easily fabricated using an inexpensive flexible polytetrafluoroethylene (PTFE) substrate, which is broadly adopted by the RFID industry. Stable read performance is achievable, providing freedom of frequency tuning without the need to modify the radiator structure. The volume of the tag is reasonably small:   (28)2  1.5 mm3. It has a measured detection distance is 9.75 m (4 W EIRP) on metal surface in the NA RFID passband while 8.41 m (3.24 W EIRP) in the LEu passband.
A Machine Learning Approach for Estimating Overtime Allocation in Software Development Projects
- Hammed Mojeed
- Rafał Szłapczyński
2024 Pełny tekst
Overtime planning in software projects has traditionally been approached with search-based multi-objective optimization algorithms. However, the explicit solutions produced by these algorithms often lack applicability and acceptance in the software industry due to their disregard for project managers' intuitive knowledge. This study presents a machine learning model that learns the preferred overtime allocation patterns from solutions annotated by project managers and applied to four publicly available software development projects. The model was trained using 1092 instances of annotated solutions gathered from software houses, and the Random Forest Regression (RFR) algorithm was used to estimate the PMs' preference. The evaluation results using MAE, RMSE, and R2 revealed that RFR exhibits excellent predictive power in this domain with minimal error. RFR also outperformed the baseline regression models in all the performance measures. The proposed machine learning approach provides a reliable and effective tool for estimating project managers' preferences for overtime plans.
A machine learning approach to classifying New York Heart Association (NYHA) heart failure
- Krystian Jandy
- Paweł Weichbroth
2024 Pełny tekst Scientific Reports
According to the European Society of Cardiology, globally the number of patients with heart failure nearly doubled from 33.5 million in 1990 to 64.3 million in 2017, and is further projected to increase dramatically in this decade, still remaining a leading cause of morbidity and mortality. One of the most frequently applied heart failure classification systems that physicians use is the New York Heart Association (NYHA) Functional Classification. Each NYHA class describes a patient’s symptoms while performing physical activities, delivering a strong indicator of the heart performance. In each case, a NYHA class is individually determined routinely based on the subjective assessment of the treating physician. However, such diagnosis can suffer from bias, eventually affecting a valid assessment. To tackle this issue, we take advantage of the machine learning approach to develop a decision-tree, along with a set of decision rules, which can serve as additional blinded investigator tool to make unbiased assessment. On a dataset containing 434 observations, the supervised learning approach was initially employed to train a Decision Tree model. In the subsequent phase, ensemble learning techniques were utilized to develop both the Voting Classifier and the Random Forest model. The performance of all models was assessed using 10-fold cross-validation with stratification.The Decision Tree, Random Forest, and Voting Classifier models reported accuracies of 76.28%, 96.77%, and 99.54% respectively. The Voting Classifier led in classifying NYHA I and III with 98.7% and 100% accuracy. Both Random Forest and Voting Classifier flawlessly classified NYHA II at 100%. However, for NYHA IV, Random Forest achieved a perfect score, while the Voting Classifier reported 90%. The Decision Tree showed the least effectiveness among all the models tested. In our opinion, the results seem satisfactory in terms of their supporting role in clinical practice. In particular, the use of a machine learning tool could reduce or even eliminate the bias in the physician’s assessment. In addition, future research should consider testing other variables in different datasets to gain a better understanding of the significant factors affecting heart failure.
A magnetic imprinted polymer nano-adsorbent with embedded quantum dots and mesoporous carbon for the microextraction of triazine herbicides
- Nurhasima Phirisi
- Justyna Płotka-Wasylka
- Opas Bunkoed
2024 JOURNAL OF CHROMATOGRAPHY A
A magnetic molecularly imprinted polymer (MMIP) adsorbent incorporating amino-functionalized magnetite nanoparticles, nitrogen-doped graphene quantum dots and mesoporous carbon (MIP@MPC@NGQDs@ Fe3O4–NH2) was fabricated to extract triazine herbicides from fruit juice. The embedded magnetite nanoparticles simplified the isolation of the adsorbent from the sample solution. The N-GQDs and MPC enhanced adsorption by affinity binding with triazines. The MIP layer provided highly specific recognition sites for the selective adsorption of three target triazines. The extracted triazines were determined by high-performance liquid chromatography (HPLC) coupled with diode-array detection (DAD). The developed method exhibited linearity from 1.5 to 100.0 μg L 1 with a detection limit of 0.5 μg L 1. Recoveries from spiked fruit juice samples were in the range of 80.1– 108.4 %, with a relative standard deviation of less than 6.0 %. The developed MMIP adsorbent demonstrated good selectivity, high extraction efficiency, ease of fabrication and use, and good stability.
A magnetic stir bar sorbent of metal organic frameworks, carbon foam decorated zinc oxide and cryogel to enrich and extract parabens and bisphenols from food samples
- Sirintorn Jullakan
- Natnaree Rattanakunsong
- Justyna Płotka-Wasylka
- Opas Bunkoed
2024 JOURNAL OF CHROMATOGRAPHY B-ANALYTICAL TECHNOLOGIES IN THE BIOMEDICAL AND LIFE SCIENCES
A porous composite magnetic stir bar adsorbent was fabricated for the extraction and enrichment of parabens and bisphenols from selected beverage samples. The adsorbent comprised a metal organic framework, carbon foam decorated zinc oxide and magnetic nanoparticles embedded in polyvinyl alcohol cryogel. The porous composite stir bar adsorbent could adsorb parabens and bisphenols via hydrogen bonding, π-π and hydrophobic interactions. In the best conditions, linearity was good from 5.0 to 200.0 µg/L for methyl paraben, ethyl paraben and bisphenol A and from 10.0 to 200.0 µg/L for bisphenol B and butyl paraben. Limits of detection ranged from 1.5 to 3.0 µg/L. The developed composite stir bar was successfully applied to extract and determine parabens and bisphenols in fruit juice, beer and milk. Recoveries ranged from 89.5 to 99.5 % with RSDs lower than 6 %. The developed sorbent and new methodology were evaluated in terms of its green character with satisfactory results.