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Gdańsk University of Technology

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Publications from the year 2023

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  • Design and Evaluation of the Compact and Autonomous Energy Subsystem of a Wave Energy Converter
    • Marcin Drzewiecki
    • Jarosław Guziński
    2023 Full text ENERGIES

    This paper presents the results of the design process focused on the development of the energy subsystem (ES) of a wave energy converter (WEC). The ES is an important electrical part that significantly affects the energy reliability and energy efficiency of the entire WEC device. The designed ES was intended for compact WECs powering IoT network devices working in the distributed grid. The developed ES is an electronic circuit consisting of three cooperating subsystems used for energy conversion, energy storage, and energy management. The energy conversion subsystem was implemented as a set of single-phase bridge rectifiers. The energy storage subsystem was a battery-less implementation based on the capacitors. The energy management subsystem was implemented as a supervisory circuit and boost converter assembly. The designed ES was verified using the physical experiment method. The model experiment reflected the operation of the designed ES with a piezoelectric PZT-based WEC. The experimental results showed a 41.5% surplus of the energy supplied by ES over the energy demanded by the considered load at a duty cycle of ca. 6 min—37.2 mJ over 26.3 mJ, respectively. The obtained results have been evaluated and discussed. The results confirmed the designed ES as a convenient solution, which makes a significant contribution to the compact WECs that can be applied among others to a distributed grid of autonomous IoT network devices powered by free and renewable energy of sea waves. Finally, it will also enable sustainable development of mobile and wireless communication in those maritime areas where other forms of renewable energy may not be available.

  • Design and Optimization of a Compact Super-Wideband MIMO Antenna with High Isolation and Gain for 5G Applications
    • Bashar Esmail
    • Sławomir Kozieł
    • Anna Pietrenko-Dąbrowska
    2023 Full text Electronics

    This paper presents a super-wideband multiple-input multiple-output (SWB MIMO) antenna with low profile, low mutual coupling, high gain and compact size for microwave and millimeter wave (mm-wave) fifth-generation (5G) applications. A single antenna is a simple elliptical-square shape with a small physical size of 20 × 20 × 0.787 mm3. The combination of both square and elliptical shapes results in an exceptionally broad impedance bandwidth spanning from 3.4 to 70 GHz. An-tenna dimensions are optimized using the trust-region algorithm to enhance its impedance band-width, and maintain the gain within a predefined limit across the entire band. For that purpose, regularized merit function is defined, which permits to control both the single antenna reflection response and gain. Subsequently, the SWB MIMO system is constructed with four radiators ar-ranged orthogonally. This arrangement results in high isolation, better than 20 dB, over a fre-quency band from 3.4 to 70 GHz band. Further, the system achieves an average gain of approxi-mately 7 dB below 45 GHz and a maximum gain equal to 12 dB for 70 GHz. The system exhibits excellent diversity performance throughout the entire bandwidth, as evidenced by the low enve-lope correlation coefficient (ECC) (<3∙10−3), total active reflection coefficient (TARC) (≤−10 dB), and channel capacity loss (CCL) (<0.3 bit/s/Hz) metrics, as well as high diversity gain (DG) of approxi-mately 10 dB. Experimental validation of the developed SWB MIMO demonstrates a good match-ing between the measurements and simulations.

  • Design and Optimization of Metamaterial-Based 5G Millimeter Wave Antenna for Gain Enhancement
    • Bashar Esmail
    • Sławomir Kozieł
    2023 IEEE TRANSACTIONS ON CIRCUITS AND SYSTEMS II-EXPRESS BRIEFS

    In this brief, a low profile, broadband, high-gain antenna array based on optimized metamaterials (MMs) with dual-beam radiation is reported for 5G millimeters wave (mm-wave) applications. The design is a simple bow tie operating at a 5G band of 28 GHz. It consists of two bow ties with substrate integrated waveguide (SIW)-based power splitter. A broad impedance bandwidth of 26.3−29.8 GHz is obtained by appropriately combining the resonances of the bow ties and the SIW. Further, the antenna exhibits symmetrical dual-beam radiation at ±25˚ over a broad bandwidth in the end-fire direction due to the arrangement of the two radiators. A MM array has been etched in the same substrate shared with the antenna to improve the gain performance while preserving compact size. The trust-region (TR) gradient-based algorithm is used to optimize the structure dimensions and to achieve a maximum gain of 12.2 dB at 29 GHz. The developed MM-based antenna is validated experimentally with a good matching between the simulated and measured data. The system features a small size, low profile, high gain, broad bandwidth, and dual-beam in the E-plane, demonstrating its suitability for 5G mm-wave indoor scenarios.

  • Design and Preparation of Magnetically-Oriented Poly(styr-co-MMA)-3MPS Capped Fe(ZnO) Hybrid Microspheres for Ion Exchange Removal of Toxic Pollutants from Wastewater
    • Sahar Fatima
    • Muhammad Imran
    • Farah Kanwal
    • Ayesha Javaid
    • Shoomaila Latif
    • Grzegorz Boczkaj
    2023 Full text Water

    In this work, polymeric microspheres derived from polystyrene-co-methyl methacrylate embedded with magnetic ZnO nanoparticles (poly(styrene-co-MMA)-3MPS-Fe (ZnO)) were synthesized using the suspension polymerization method. The surfaces of polymeric Fe(ZnO) microspheres were improved by functionalization with amino and sulphonate groups. The physicochemical analysis indicated a large number of positively charged (anion exchange) groups (91 mmol/g) on the amine-modified polymeric microsphere (MFZPI) and a large number of negatively charged (cation exchange) groups (90 mmol/g) on the sulphonate-modified polymeric microsphere (SMFZPI)—revealing ambivalent character of obtained sorbent. The characterization of the synthesized compounds using various analytical techniques such as TGA, FTIR, XRD, SEM/EDX, UV-VIS and VSM indicated that synthesized microspheres were thermally stable, semi-crystalline in structure with hollow irregular morphology, optically active in UV region and slightly magnetic in nature. Due to the introduction of groups having ion exchange properties, these modified poly(styrene-co-MMA)-3MPS-Fe(ZnO) microspheres were used for the ion exchange sorptive removal of Cr(III) and fluorescein from aqueous matrix. The equilibrium sorption capacity of Cr(III) was 16.79 mg/g whereas of fluorescein was 12.03 mg/g under optimized conditions. Therefore, SMFZPI was found to be a promising sorbent for both cationic heavy metals and anionic dyes due to the presence of both acidic and basic groups. The mathematical modelling revealed that the sorption phenomenon followed pseudo-second-order kinetics with Freundlich equilibrium isotherm, indicating multilayer chemisorption of the pollutants on the synthesized ion exchange sorbents. This work establishes the utilization of polymeric magnetic ZnO-based ion exchange sorbents to effectively remove harmful toxins from wastewater.

  • Design and Synthesis of NTU-9/C3N4 Photocatalysts: Effects of NTU-9 Content and Composite Preparation Method
    • Damian Makowski
    • Wojciech Lisowski
    • Mateusz Baluk
    • Tomasz Klimczuk
    • Beata Bajorowicz
    • Mateusz Adam Baluk
    2023 Full text Materials

    Hybrid materials based on graphitic carbon nitride (g-C3N4) and NTU-9 metal–organic frameworks (MOF) were designed and prepared via solvothermal synthesis and calcination in air. The as-prepared photocatalysts were subsequently characterized using Brunauer–Emmett–Teller (BET) analysis, UV-Vis diffuse reflectance spectroscopy (DRS), photoluminescence (PL) emission spectroscopy, X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and scanning electron microscopy (SEM). The obtained NTU-9/C3N4 composites showed a greatly improved photocatalytic performance for the degradation of toluene in the gas phase under LED visible-light irradiation (max = 415 nm). The physicochemical properties and photocatalytic activities of the obtained NTU- 9/C3N4 materials were tuned by varying the NTU-9 content (5–15 wt%) and preparation method of the composite materials. For composites prepared by calcination, the photocatalytic activity increased with decreasing NTU-9 content as a result of the formation of TiO2 from the MOFs. The best photocatalytic performance (65% of toluene was photodegraded after 60 min) was achieved by the NTU-9/C3N4 sample prepared via the solvothermal method and containing 15 wt% MOF, which can be attributed to the appropriate amount and stable combination of composite components, efficient charge separation, and enhanced visible-light absorption ability. The photocatalytic mechanisms of the prepared hybrid materials depending on the preparation method are also discussed.

  • Design and synthesis of TiO2/Ti3C2 composites for highly efficient photocatalytic removal of acetaminophen: The relationships between synthesis parameters, physicochemical properties, and photocatalytic activity
    • Anna Grzegórska
    • Agnieszka Gajewicz-Skrętna
    • Grzegorz Trykowski
    • Karol Sikora
    • Anna Zielińska-Jurek
    2023 Full text CATALYSIS TODAY

    In this study, we report the potential of TiO2/Ti3C2 composite fabricated by oxidation of MXene for degradation of persistent organic pollutants. The effect of the synthesis conditions (time, temperature, and reaction environment) on the morphology, physicochemical properties, and photocatalytic activity was investigated. It was found that acetaminophen degradation was positively correlated with TiO2 content in the composite structure. Furthermore, the findings confirmed that the synthesis reaction environment strongly influenced the obtained materials photocatalytic activity. The TiO2/Ti3C2 composite obtained by solvothermal route in the presence of hydrochloric acid and ammonium fluoride exhibited the highest efficiency towards acetaminophen degradation than other composite materials, for which ACT removal reached 92 % within 60 min of irradiation under simulated solar light. The improved photocatalytic performance can be attributed to the presence of anataserutile polymorphs exposing highly active { 0 0 1} and { 1 0 1} facets coupled with MXene. Superoxide anion radicals and hydroxyl radicals played a major role in ACT degradation. Moreover, 3-hydroxyacetaminophen was detected as the first intermediate of ACT degradation, leading quickly to aromatic ring opening and production of aliphatic acids. Overall, this work provides an effective strategy for designing novel and efficient MXene-based photocatalysts for the degradation of emerging contaminants in water systems.

  • Design of an Autonomous IoT Node Powered by a Perovskite-Based Wave Energy Converter
    • Marcin Drzewiecki
    • Jarosław Guziński
    2023 Full text Polish Maritime Research

    This paper presents the results of experimental research focused on wave energy harvesting and its conversion to power Internet of Things (IoT) devices. The harvesting and conversion process was performed using a wave energy converter (WEC) consisting of a lead zirconate titanate piezoelectric ceramic perovskite material and a prototype power electronic circuit. The designed WEC was considered as a power supply for an end node device (END) of an IoT network. The END consisted of a long-range radio module and an electronic paper display. A set of physical experiments were carried out, and the results confirmed that an energy surplus was supplied by WEC compared to the energy consumed by the END. Hence, the proposed scheme was experimentally validated as a convenient solution that could enable the autonomous operation of an IoT device. The use case presented here for the proposed WEC was analysed for selected sea areas on the basis of wave statistics. The novelty of this paper arises from an investigation that confirms that WECs can significantly contribute to the development of wireless and mobile IoT communication powered by freely available sea wave energy.

  • Design of compact self-quintuplexing antenna with high-isolation for penta-band applications
    • Rusan Kumar Barik
    • Sławomir Kozieł
    2023 Full text IEEE Access

    This article presents a novel compact self-quintuplexing antenna architecture based on a substrate-integrated rectangular cavity (SIRC) for pentaband applications. The proposed self-quintuplexing antenna is constructed by employing an SIRC, one Pi-shaped slot (PSS), one T-shaped slot (TSS), and five 50Ω microstrip feedlines. The PSS and TSS are engraved on the top of the SIRC to create five radiating patches, which are excited by five 50Ω feedlines to achieve pentaband operation with self-quintuplexing characteristics. The resonating frequencies can be tuned independently based on the dimension of the radiator without disturbing other bands. A detailed parametric analysis is carried out to provide a suitable frequency tunable range and high isolation. In addition, an equivalent lumped circuit is developed to analyze the proposed self-quintuplexing antenna. To validate the proposed antenna architecture, an SIRC-based self-quintuplexing antenna operating at 2.29, 2.98, 3.65, 4.37, and 5.08 GHz is fabricated and demonstrated. The fabricated antenna offers competitive performance with a compact size of 0.173λ2, pentaband operation, high isolation of 29.31 dB, and a wide frequency tunability range from 2.29 GHz to 6.03 GHz. Furthermore, the fabricated self-quintuplexing antenna exhibits the measured realized gain of 3.59, 4.55, 3.91, 5.70, and 4.92dBi at 2.29, 2.98, 3.64, 4.37, and 5.08 GHz, respectively.

  • Design of Frequency-Reconfigurable Branch-Line Crossover Using Rectangular Dielectric Channels
    • Rusan Kumar Barik
    • Sławomir Kozieł
    • Eirikur Bernhardsson
    2023 Full text IEEE Access

    This paper presents an efficient yet straightforward passive reconfiguration technique to tune the operating frequency of a branch-line crossover (BLCO). The underlying principle is to fill rectangular dielectric channels (RDCs) prepared beforehand with either air or materials of different relative permittivity. Two configurations (one RDC and three RDCs in each arm) of the branch-line crossover are employed to estimate the tunability range of the operating frequency. The introduction of RDCs packed with different materials in the branch lines modifies the effective permittivity of the dielectric medium, resulting in an alteration of the operating frequency. The size and the positions of the RDCs are optimized using full-wave electromagnetic simulations to achieve maximum tunability range while ensuring reasonable bandwidth. A lumped circuit model (LCM) is developed to analyze the working principle of the proposed technique. To validate computational models, two prototypes of the branch-line crossover are realized, fabricated, and experimentally demonstrated. The first BLCO packed with seven RDCs exhibits a frequency tuning range of 15.8%, whereas the second prototype filled with twenty-one RDCs features a tuning range of 36.9%.

  • Design of metamaterials: Preface
    • Anil Misra
    • François Hild
    • Victor Eremeev
    2023 Full text MECHANICS RESEARCH COMMUNICATIONS

    This special issue “Design of metamaterials” collects several papers that have presented theoretical, numerical, and experimental studies of metamaterials.

  • Design of novel highly sensitive sensors for crack detection in metal surfaces: theoretical foundation and experimental validation
    • Zahra Shaterian
    • Ali Karami Horestani
    • Ferran Martin
    • Michał Mrozowski
    2023 Full text Scientific Reports

    The application of different types of microwave resonators for sensing cracks in metallic structures has been subject of many studies. While most studies have been focused on improving the sensitivity of planar crack sensors, the theoretical foundation of the topic has not been treated in much detail. The major objective of this study is to perform an exhaustive study of the principles and theoretical foundations for crack sensing based on planar microwave resonators, especially defective ground structures (DGS) including complementary split ring resonators (CSRRs). The analysis is carried out from the equivalent circuit model as well as the electromagnetic (EM) field perspectives, and guidelines for the design of crack sensors with high sensitivity are developed. Numerical and experimental validation of the provided theoretical analysis is another aim of this article. With this aim, the developed guidelines are used to design a crack sensor based on a single-ring CSRR. It is shown that the sensitivity of the proposed sensor is almost three times higher than the sensitivity of a conventional double-ring CSRR. Moreover, it is demonstrated that folded dumbbell-shape DGS resonators can be used to achieve even higher sensitivities. The CSRR-based crack sensors presented in this study and other studies available in the literature are only sensitive to cracks with a specific orientation. To address this limitation, a modified version of the DGS is proposed to sense cracks with arbitrary orientations at the cost of lower sensitivity. The performance of all the presented sensors is validated through EM simulation, equivalent circuit model extraction, and measurement of the fabricated prototypes.

  • Designing efficient A-D-A1-D-A type fullerene free acceptor molecules with enhanced power conversion efficiency for solar cell applications
    • Malik Muhammad Iqbal Asif
    • Muhammad Arshad
    • Muhammad Yasir Mehboob
    • Muhammad Khan
    • Sanwal Piracha
    2023 SPECTROCHIMICA ACTA PART A-MOLECULAR AND BIOMOLECULAR SPECTROSCOPY

    The achievement of highly efficient power conversion efficiency (PCE) is a big concern for non-fullerene organic solar cells (NF-OSCs) because PCE can depend on numerous variables. Here, new five novel acceptor molecules without fullerenes were developed and investigated using DFT (density functional theory) and TD-DFT (time dependent-density functional theory). Compared to the recently synthesized molecule (PZ-dIDTC6), the developed molecules display a narrow optical band gap, exhibiting a red shift in the absorption spectrum. The developed molecules (YM1-YM5) express high mobility of electrons and holes in the active layer of OSCs (organic solar cells). In addition, high open-circuit voltage (Voc) values with maximum charge density shifting are noted in designed molecules. YM1-YM5 is also associated with low binding energy and excitation energy. This work proves that noncovalent conformational locking is favourable for improving PCE devices.

  • Detecting Lombard Speech Using Deep Learning Approach
    • Krzysztof Kąkol
    • Grazina Korvel
    • Gintautas Tamulevicius
    • Bożena Kostek
    2023 Full text SENSORS

    Robust Lombard speech-in-noise detecting is challenging. This study proposes a strategy to detect Lombard speech using a machine learning approach for applications such as public address systems that work in near real time. The paper starts with the background concerning the Lombard effect. Then, assumptions of the work performed for Lombard speech detection are outlined. The framework proposed combines convolutional neural networks (CNNs) and various two-dimensional (2D) speech signal representations. To reduce the computational cost and not resign from the 2D representation-based approach, a strategy for threshold-based averaging of the Lombard effect detection results is introduced. The pseudocode of the averaging process is also included. A series of experiments are performed to determine the most effective network structure and the 2D speech signal representation. Investigations are carried out on German and Polish recordings containing Lombard speech. All 2D signal speech representations are tested with and without augmentation. Augmentation means using the alpha channel to store additional data: gender of the speaker, F0 frequency, and first two MFCCs. The experimental results show that Lombard and neutral speech recordings can clearly be discerned, which is done with high detection accuracy. It is also demonstrated that the proposed speech detection process is capable of working in near real-time. These are the key contributions of this work.

  • Detecting type of hearing loss with different AI classification methods: a performance review
    • Michał Kassjański
    • Marcin Kulawiak
    • Tomasz Przewoźny
    • Dmitry Tretiakow
    • Jagoda Kuryłowicz
    • Andrzej Molisz
    • Krzysztof Koźmiński
    • Aleksandra Kwaśniewska
    • Paulina Mierzwińska-Dolny
    • Miłosz Grono
    2023

    Hearing is one of the most crucial senses for all humans. It allows people to hear and connect with the environment, the people they can meet and the knowledge they need to live their lives to the fullest. Hearing loss can have a detrimental impact on a person's quality of life in a variety of ways, ranging from fewer educational and job opportunities due to impaired communication to social withdrawal in severe situations. Early diagnosis and treatment can prevent most hearing loss. Pure tone audiometry, which measures air and bone conduction hearing thresholds at various frequencies, is widely used to assess hearing loss. A shortage of audiologists might delay diagnosis since they must analyze an audiogram, a graphic representation of pure tone audiometry test results, to determine hearing loss type and treatment. In the presented work, several AI-based models were used to classify audiograms into three types of hearing loss: mixed, conductive, and sensorineural. These models included Logistic Regression, Support Vector Machines, Stochastic Gradient Descent, Decision Trees, RandomForest, Feedforward Neural Network (FNN), Convolutional Neural Network (CNN), Graph Neural Network (GNN), and Recurrent Neural Network (RNN). The models were trained using 4007 audiograms classified by experienced audiologists. The RNN architecture achieved the best classification performance, with an out-of-training accuracy of 94.46\%. Further research will focus on increasing the dataset and enhancing the accuracy of RNN models.

  • Detection of Toxoplasma gondii Infection in Small Ruminants: Old Problems, and Current Solutions
    • Lucyna Holec-Gąsior
    • Karolina Sołowińska
    2023 Full text Animals

    Toxoplasmosis is a parasitic zoonosis of veterinary importance, with implications for public health. Toxoplasma gondii infection causes abortion or congenital disease in small ruminants. Moreover, the consumption of infected meat, cured meat products, or unpasteurized milk and dairy products can facilitate zoonotic transmission. Serological studies conducted in various European countries have shown the high seroprevalence of specific anti-T. gondii antibodies in sheep and goats related to the presence of oocysts in the environment, as well as climatic conditions. This article presents the current status of the detection possibilities for T. gondii infection in small ruminants and their milk. Serological testing is considered the most practical method for diagnosing toxoplasmosis; therefore, many studies have shown that recombinant antigens as single proteins, mixtures of various antigens, or chimeric proteins can be successfully used as an alternative to Toxoplasma lysate antigens (TLA). Several assays based on DNA amplification have been developed as alternative diagnostic methods, which are especially useful when serodiagnosis is not possible, e.g., the detection of intrauterine T. gondii infection when the fetus is not immunocompetent. These techniques employ multicopy sequences highly conserved among different strains of T. gondii in conventional, nested, competitive, and quantitative reverse transcriptase-PCR.

  • Detection of Water on Road Surface with Acoustic Vector Sensor
    • Józef Kotus
    • Grzegorz Szwoch
    2023 Full text SENSORS

    This paper presents a new approach to detecting the presence of water on a road surface, employing an acoustic vector sensor. The proposed method is based on sound intensity analysis in the frequency domain. Acoustic events, representing road vehicles, are detected in the sound intensity signals. The direction of the incoming sound is calculated for the individual spectral components of the intensity signal, and the components not originating from the observed road section are discarded. Next, an estimate of the road surface state is calculated from the sound intensity spectrum, and the wet surface detection is performed by comparing the estimate with a threshold. The proposed method was evaluated using sound recordings made in a real-world scenario, and the algorithm results were compared with data from a reference device. The proposed algorithm achieved 89% precision, recall and F1 score, and it outperforms the traditional approach based on sound pressure analysis. The test results confirm that the proposed method may be used for the detection of water on the road surface with acoustic sensors as an element of a smart city monitoring system.

  • Determinants of the incidence of non-academic staff in European and US HEIs
    • Alessandro Avenali
    • Cinzia Daraio
    • Joanna Wolszczak-Derlacz
    2023 Full text HIGHER EDUCATION

    In this article, we contribute to the scant literature covering quantitative studies on the determinants of the non-academic staff incidence in higher education institutions by analysing how the proportion of non-academic staff is related to key features such as size, prestige, year of foundation and financial structure of universities. We apply nonlinear regression analysis to compare HEIs across Europe and the USA, taking into account time and cross-country heterogeneity of the two balanced panel datasets concerning European and American universities over a period of 6 years (2011–2016 for Europe and 2012–2017 for the USA). Evidence suggests that in both Europe and the USA, public and larger (if sufficiently large) as well as more research-oriented units are characterised by a higher proportion of non-academic staff. In Europe, we observe an inverted U-shaped effect of the share of non-personnel expenditure and the foundation year on the proportion of nonacademic staff, while the proportion of non-academic staff decreases with the share of core and third-party funding. For the USA, we obtain similar findings except that the share of core funding and third-party funding is characterised by a U-shaped effect, and the impact of the share of non-personnel expenditure has no empirical effect on the proportion of nonacademic staff. Additionally, we discover that some factors that contribute to the proportion of non-academic staff may constitute indicators of performance, suggesting the need for further research to extend our knowledge on the complex issue of the role played by non-academic staff in university performance.

  • Determinanty stabilności fiskalnej jednostki samorządu terytorialnego
    • Maria Jastrzębska
    2023

    Celem rozdziału jest omówienie istoty i znaczenia stabilności fiskalnej JST oraz dokonanie klasyfikacji jej determinant w podziale na instytucjonalno- -prawne, ekonomiczno-finansowe, społeczne i naturalne, polityczne i organizacyjne, a także zwrócenie uwagi na te z nich, które szczególnie negatywnie oddziałują na stabilność fiskalną JST (w podziale na niezależne i zależne od JST).

  • Determinanty stabilności fiskalnej jednostki samorządu terytorialnego
    • Maria Jastrzębska
    2023 Full text FINANSE Czasopismo Komitetu Nauk o Finansach PAN

    . Celem rozdziału jest omówienie istoty i znaczenia stabilności fiskalnej JST oraz dokonanie klasyfikacji jej determinant w podziale na instytucjonalno- -prawne, ekonomiczno-finansowe, społeczne i naturalne, polityczne i organizacyjne, a także zwrócenie uwagi na te z nich, które szczególnie negatywnie oddziałują na stabilność fiskalną JST (w podziale na niezależne i zależne od JST)

  • Determination of benzodiazepines and Z-hypnotic drugs in whole blood samples by GC–MS/MS: Method development, validation and application
    • Laura Banaszkiewicz
    • Mateusz Kacper Woźniak
    • Michal Kaliszan
    • Agata Kot-Wasik
    2023 MICROCHEMICAL JOURNAL

    Benzodiazepines (BZDs) and Z-drugs are widely used as anxiolytics, sedative hypnotics, anticonvulsants and muscle relaxants. “Designer benzodiazepines” (DBZDs) are a new psychoactive substance class consisting of benzodiazepine derivatives that are not allowed for medical use and are known for being used recreationally. From a toxicologist standpoint, the huge number of such substances implicate a necessity for developing fast and reliable methods to identify and quantify these substances in biological matrices, especially in blood. In this study, a method based on gas chromatography–tandem mass spectrometry (GC–MS/MS) was developed and validated for the determination of 28 benzodiazepine derivatives and 3 Z- drugs. Liquid–liquid extraction requiring the use of a 0.5 mL sample of whole blood and 1 mL of ethyl acetate was applied. No derivatization was necessary to obtain sensitivity and selectivity. All validation data met the established acceptance criteria in accordance with international forensic toxicology guidelines. The method was linear within the tested range of 1–100 ng/mL, 1–200 ng/mL, 1–250 ng/mL, 5–200 ng/mL and 10–250 ng/mL depending on the analyte. The LOD was in the range of 0.09 to 0.66 ng/mL, while the LOQ was between 1 and 10 ng/mL. The calculated mean accuracy ranged between 85.1% and 114.4% for intraday replicates and between 85.2% and 111.2% for interday replicates. Intraday precision (as CVs) ranged from 0.2% to 12.5%, while interday precision ranged from 2.0% to 14.5%. Recovery was between 83.8% and 111.2%. This study was the first attempt to apply GC–MS/MS for the multianalyte determination of benzodiazepines and Z-drugs without analyte derivatization. The developed method proved to be sensitive, specific, simple and fast. The analysis in MRM mode gives high sensitivity and selectivity. Thus, the presented method can be successfully utilized for clinical and forensic toxicology analysis, for interpretation of results and for the preparation of forensic toxicological opinions for courts of law.