1. A review of analytical techniques for the analysis of oral smokeless products and heated tobacco productsMatjaž Rantaša, David Majer, Matjaž Finšgar, 2025, review article Abstract: The increasing popularity in recent years of oral smokeless products (OSPs) and heated tobacco products (HTPs) has raised significant public health and regulatory concerns. Although these products are often marketed as less harmful alternatives to traditional cigarettes, they differ considerably in both design and, more importantly, in their chemical composition. Notably, they contain potentially dangerous compounds such as tobacco-specific nitrosamines, flavorings, heavy metals, and nicotine, which can be addictive and harmful to human health at certain concentrations. This work provides an overview of the analytical techniques and methods used to analyze OSPs and HTPs, including the determination of moisture content and pH, the extraction of various compounds, the generation of HTP aerosol, and non-targeted analysis, as well as the quantification of extracted compounds using gas chromatography, liquid chromatography, and spectroscopy. Identifying and quantifying the chemical composition of OSPs and HTPs is essential for assessing their health impact and developing proper regulatory standards regarding these products.
Keywords: gas chromatography, heated tobacco products, liquid chromatography, nicotine, oral smokeless products
Published in DKUM: 13.11.2025; Views: 0; Downloads: 0
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2. Surface analysis of sodium metamizolate as an active pharmaceutical ingredient in solid formMatjaž Finšgar, Katja Andrina Varda, 2026, original scientific article Abstract: This study focuses on the surface and subsurface characterization of a pharmaceutical tablet containing sodium metamizolate (NaMET), with an emphasis on mass spectrometry using time-of-flight secondary ion mass spectrometry (ToF-SIMS). ToF-SIMS enabled the identification of NaMET-specific fragment ions, which served as signals for the determination of the spatial distribution of this active pharmaceutical ingredient (API) within the tablet matrix. A ToF-SIMS fragmentation mechanism for NaMET was proposed based on the ToF-SIMS spectra analysis measured on a NaMET reference standard. 3D ToF-SIMS imaging showed heterogeneous localization of the API across a 5 μm depth. Complementary techniques, including 3D profilometry and atomic force microscopy (AFM), provided surface roughness and morphological data, while X-ray photoelectron spectroscopy (XPS) confirmed the elemental composition and chemical states. Depth profiling by XPS further supported the non-uniform distribution of NaMET.
Keywords: matamizole, sodium metamizolate, ToF-SIMS, XPS, surface analysis, API
Published in DKUM: 10.11.2025; Views: 0; Downloads: 5
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4. Uporaba sistema dissowash&dose v farmacevtski analitiki : magistrsko deloLana Embreuš, 2025, master's thesis Abstract: Magistrsko delo prikazuje uporabo sistema dissoWASH&DOSE za izvajanje ciklov čiščenja med izvajanjem testov raztapljanja in določanje prenosa analita (angl. carry over, CO). Teste raztapljanja smo izvedli s tremi aktivnimi farmacevtskimi učinkovinami (API) – kofeinom (KOF), paracetamolom (PA) in natrijevim naproksenatom (NN). Najprej smo izvedli delno validacijo spektrofotometričnih metod za vsak analit. Linearno koncentracijsko območje smo za KOF določili od 1,00 mg/L do 30,00 mg/L, za PA in NN pa od 1,00 mg/L do 19,00 mg/L. Linearnost smo ovrednotili z izračunom kvadrata korelacijskega koeficienta, ki je bil za vse API ≥0,9990 in izračunom koeficienta kvalitete, katerega vrednosti so bile ≤5,00 %. Točnost smo ovrednotili z izračunom povprečnih izkoristkov, ki so bili na treh testiranih koncentracijskih nivojih znotraj zastavljenega kriterija 95,00–105,00 %. Natančnost smo ovrednotili z relativnim standardnim odmikom, ki je bil za vse API <10,00 %. Meja zaznavnosti je bila za vse API <0,01 mg/L. Z določanjem volumnov (V) odmerjanja medija za raztapljanje in medija za čiščenje pri ciklu čiščenja reakcijskih posod in pri ciklu čiščenja pokrova, temperaturnih senzorjev, vzorčevalnih kanul in mešal, smo preverili točnost in natančnost odmerjanja sistema dissoWASH&DOSE. Zastavljena hipoteza je bila, da bo sistem dissoWASH&DOSE uspešno izvedel cikel čiščenja s CO nižjim od 0,50 %. Izvedli smo preizkuse nižanja V čistilnega medija za čiščenje reakcijskih posod ter čiščenje pokrova, temperaturnih senzorjev, vzorčevalnih kanul in mešal, da bi preverili, kako skupni V čistilnega medija obeh ciklov čiščenja vpliva na CO. CO je bil <0,50 % za vse API pri vseh testiranih V čistilnega medija obeh ciklov čiščenja, tj. pri skupnih V obeh ciklov čiščenja 430 mL, 330 mL, 230 mL, 130 mL in 40 mL. Posledično lahko s sistemom dissoWASH&DOSE zadovoljivo očistimo reakcijske posode, pokrove, temperaturne senzorje, vzorčevalne kanule in mešala tudi pri nižjih V čistilnega medija ter je zato primeren za zaporedno izvajanje testov raztapljanja za KOF, NN in PA v farmacevtski analitiki.
Keywords: testi raztapljanja, UV-VIS spektrofotometrija, prenos analita, KOF, paracetamol, natrijev naproksenat
Published in DKUM: 02.07.2025; Views: 0; Downloads: 48
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5. 3D-printed cellulose aerogels minimally cross-linked with polyurea : a robust strategy for tissue engineeringAna Iglesias-Mejuto, Grigorios Raptopoulos, Nanthilde Malandain, Mariana Neves Amaral, Inés Ardao Palacios, Matjaž Finšgar, Anna Laromaine, Anna Roig, Catarina Pinto Reis, Carlos A. García-González, Patrina Paraskevopoulou, 2025, original scientific article Abstract: Cellulose and its derivatives are increasingly explored in biomedical applications due to their biocompatibility,biodegradability, and mechanical performance. In regenerative medicine, aerogel scaffolds with tunable morphology and compositionare highly valued for their ability to support tissue regeneration. Three-dimensional (3D) printing offers an effective method tofabricate aerogels with hierarchical pore structures, comprising interconnected macropores and mesopores, that are crucial for tissueengineering. For clinical use, 3D printing should ensure the structural integrity of printed structures and achieve a printing resolutionthat allows for customization. In this work, the X-aerogel technology, implemented via polyurea cross-linking, was applied to 3D-printed cellulose structures, thereby expanding the potential applications of both technologies. Specifically, 3D-printedmethylcellulose (MC) and MC doped with bacterial cellulose nanofiber (MCBCf) gels were cross-linked with an aliphaticpolyurea, yielding, after supercritical drying, the corresponding (X-MC and X-MCBCf) aerogels. Elaborate characterization withATR-FTIR, XPS, ToF-SIMS, N2 porosimetry, He pycnometry, and SEM confirmed the formation of polyurea on the biopolymerframework, reinforcing the structure and improving the mechanical properties without altering the morphology or texturalcharacteristics of the materials. A significant outcome of cross-linking with polyurea is the long-term stability of X-MC and X-MCBCf aerogels in water, in contrast to their native counterparts, and their capacity to absorb water up to 1800% w/w within only 2h. Preliminary biological evaluation of the materials, including in vitro (cell compatibility, hemolytic activity), in ovo (HET-CAM),and in vivo (A. salina model) tests, showed good cell viability, blood compatibility, and safety for living organisms. From afundamental materials perspective, the most important finding of this work is the disproportionally high stability of X-MC and X-MCBCf in physiological environments, achieved with only a minimal (almost undetectable) amount of cross-linking polyurea. Froman application standpoint, the findings of this study, collectively, position these aerogels as sustainable and promising candidates fortissue engineering scaffolds.
Keywords: 3D printing, aerogels, cellulose, methylcellulose, polyurea, tissue engineering, X-aerogels
Published in DKUM: 30.05.2025; Views: 0; Downloads: 6
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6. Surface and subsurface mass spectrometric analysis of dexamethasone in solid pharmaceutical dosage formsMatjaž Finšgar, 2025, original scientific article Abstract: This study presents an in-depth mass spectrometric investigation of dexamethasone (DEX) distribution within pharmaceutical tablets using time-of-flight secondary ion mass spectrometry (ToF-SIMS) combined with gas cluster ion beam (GCIB) sputtering. Fragmentation mechanism of DEX was identified, which enabled the determination of three-dimensional chemical imaging of the active ingredient in both surface and subsurface regions. The data reveal that a 4-mg DEX formulation exhibits a continuous and extended distribution of the drug into the tablet matrix, while a 0.5-mg formulation shows DEX localized in distinct, isolated domains. Topographical features and the overall composition of the surface were confirmed by complementary analyses employing atomic force microscopy (AFM) and x-ray photoelectron spectroscopy (XPS). These results demonstrate how molecule distribution patterns can be linked to formulation heterogeneity using advanced mass spectrometric techniques, opening new possibilities for pharmaceutical manufacturing quality control and optimization.
Keywords: mass spectrometry, dexamethasone, pharmaceutical tablets, DEX, ToF-SIMS
Published in DKUM: 30.05.2025; Views: 0; Downloads: 5
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7. Macroscale superlubricity with a high load-carrying capacity enabled by nitrogen-doped graphene quantum dots in lubricated silicon-doped amorphous carbon filmsIrfan Nadeem, Matjaž Finšgar, Goran Dražić, Bojan Ambrožič, Matjaž Malok, Albano Cavaleiro, Mitjan Kalin, 2025, original scientific article Abstract: Achieving macroscale superlubricity with engineering materials is highly desirable for energy conservation, environmental benefits, and longevity of mechanical components. However, attaining superlubricity in aqueous-lubricated systems with enhanced load-bearing capacity remains challenging in metallic materials. Herein, nitrogen-doped graphene quantum dots (NGQDs) as a nano-additive in aqueous glycerol facilitate macroscale superlubricity between friction pairs of steel and silicon-doped hydrogenated amorphous carbon (a-C:H:Si). Superlubricity is observed in boundary-lubrication regime with a friction coefficient of 0.0055–0.0097 under various sliding conditions. Notably, the wear of the steel counterface (k = 8.51 × 10−9 mm3/Nm) decreased by 47.8%, resulting in a final contact pressure of 206.7 MPa, which exceeds values reported for aqueous-lubricated systems during superlubricity. The lubrication mechanism reveals that NGQDs' adsorption on the steel-worn surface, coupled with the tribocatalytic generation of FeNxCy moieties on a-C:H:Si surface, is crucial for reducing friction. These FeNxCy moieties, with a multitude of active sites, facilitate the subsequent anionic adsorption of pyrrolic-rich NGQDs. Simultaneously, the formation of amorphous graphitic film, driven by continuous shearing and exfoliation of graphene sheets within the adsorbed NGQDs, contributes to the stability of superlubricity. These findings provide insights into the functional characteristics of NGQDs for achieving superlubricity in aqueous-lubricated systems, paving the way for future energy-saving applications.
Keywords: macroscale superlubricity, metallic materials, streel
Published in DKUM: 29.05.2025; Views: 0; Downloads: 100
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8. Artificial biomimetic electrochemical assembliesTanja Zidarič, Matjaž Finšgar, Uroš Maver, Tina Maver, 2022, review article Abstract: Rapid, selective, and cost-effective detection and determination of clinically relevant
biomolecule analytes for a better understanding of biological and physiological functions are becoming increasingly prominent. In this regard, biosensors represent a powerful tool to meet these
requirements. Recent decades have seen biosensors gaining popularity due to their ability to design
sensor platforms that are selective to determine target analytes. Naturally generated receptor units
have a high affinity for their targets, which provides the selectivity of a device. However, such
receptors are subject to instability under harsh environmental conditions and have consequently low
durability. By applying principles of supramolecular chemistry, molecularly imprinted polymers
(MIPs) can successfully replace natural receptors to circumvent these shortcomings. This review summarizes the recent achievements and analytical applications of electrosynthesized MIPs, in particular,
for the detection of protein-based biomarkers. The scope of this review also includes the background
behind electrochemical readouts and the origin of the gate effect in MIP-based biosensors.
Keywords: MIP-based biosensors, MIP, biosensors, molecularly imprinted polymer, biomolecules, electroanalysis
Published in DKUM: 15.05.2025; Views: 0; Downloads: 6
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9. Recent progress in non-enzymatic electroanalytical detection of pesticides based on the use of functional nanomaterials as electrode modifiersTanja Vrabelj, Matjaž Finšgar, 2022, review article Abstract: This review presents recent advances in the non-enzymatic electrochemical detection and
quantification of pesticides, focusing on the use of nanomaterial-based electrode modifiers and their
corresponding analytical response. The use of bare glassy carbon electrodes, carbon paste electrodes,
screen-printed electrodes, and other electrodes in this research area is presented. The sensors were
modified with single nanomaterials, a binary composite, or triple and multiple nanocomposites
applied to the electrodes’ surfaces using various application techniques. Regardless of the type
of electrode used and the class of pesticides analysed, carbon-based nanomaterials, metal, and
metal oxide nanoparticles are investigated mainly for electrochemical analysis because they have
a high surface-to-volume ratio and, thus, a large effective area, high conductivity, and (electro)-
chemical stability. This work demonstrates the progress made in recent years in the non-enzymatic
electrochemical analysis of pesticides. The need for simultaneous detection of multiple pesticides
with high sensitivity, low limit of detection, high precision, and high accuracy remains a challenge in
analytical chemistry.
Keywords: electroanalysis, non-enzymatic sensors, nanomaterials, pesticides
Published in DKUM: 15.05.2025; Views: 0; Downloads: 7
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10. The effect of preconditioning strategies on the adsorption of model proteins onto screen-printed carbon electrodesTea Romih, Ivan Konjević, Lea Žibret, Ika Fazarinc, Ajda Beltram, David Majer, Matjaž Finšgar, Samo B. Hočevar, 2022, original scientific article Abstract: The preconditioning and modification of the supporting electrode surface is an essential
step in every biosensor architecture. In particular, when using screen-printed carbon electrodes (SPEs)
as inexpensive and convenient disposable sensor substrates, their somewhat lower electrochemical
(surface) reproducibility might represent a complex hurdle. Herein, we investigated the effect of
selected preconditioning strategies, such as cyclic voltammetric pretreatment, in H2SO4 and H2O2
and plasma pretreatment with a positive and negative glow discharge, which all improved the electrochemical stability of the unmodified SPEs. Furthermore, we studied the influence of preconditioning
strategies on the adsorption kinetics of the two most commonly used building blocks for biosensor
preparation, i.e., bovine serum albumin (BSA) and protein A. We observed an advantageous effect
of all the examined preconditioning strategies for the modification of SPEs with protein A, being
the most effective the negative glow discharge. On the other hand, BSA exhibited a more complex
adsorption behavior, with the negative glow discharge as the only generally beneficial preconditioning strategy providing the highest electrochemical stability. Protein A revealed a more substantial
impact on the electrochemical signal attenuation than BSA considering their same concentrations in
the modification solutions. For both BSA and protein A, we showed that the concentrations of 5 and
10 µg mL−1 already suffice for an electrochemically satisfactorily stable electrode surface after 60 min
of incubation time, except for BSA at the positive-plasma-treated electrode.
Keywords: screen-printed carbon electrode, SPE, electrochemical biosensor, adsorption, bovine serum albumin, protein A, glow discharge
Published in DKUM: 15.05.2025; Views: 0; Downloads: 2
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