Analytical science advances最新文献

Synthetic opioids are lab-synthesized substances that target the brain's opioid receptors, offering analgesic and sedative effects. Amongst them, fentanyl is one of the most widely used to intervene in chronic pain in moderate to severe cancer situations. Butyryl fentanyl (BF) is a novel synthetic opioid whose use is growing. Its potency is seven times that of morphine and, unlike fentanyl, BF can only be obtained through illegal sources. Fentanyl and its analogues are related to harmful intoxications and an increase in opioid-related mortality in many countries, such as in the United States and Europe in recent years. This work developed and validated an effective and sensitive method based on solid-phase extraction followed by gas chromatography-mass spectrometry (GC-MS) for the determination of fentanyl and BF in oral fluid samples. To the best of our knowledge, it is the first successful attempt to quantify these analytes using GC-MS with a limit of quantification (LOQ) of 1 ng/mL in OF. Intra-day and inter-day percentage coefficient of variation were found within 1%–3% and 1%–14%, respectively, while accuracy ranged from 92% to 102% at four concentration levels (lower LOQ [LLOQ], 3, 20, 40 ng/mL) in accordance with the established criteria. The absolute recovery values were in the range of 80.0%–100.0%. The method was linear for all analytes, with quadratic regression of calibration curves always higher than 0.99. The validated method demonstrated its great potential to detect and quantify fentanyl and its analogue in OF and it can be useful not only in forensic investigations of addiction histories but also in epidemiological studies on the spread of fentanyl and BF among workers and/or drivers.

Cell signalling is a vital process in cell physiology, which is driven by protein phosphorylation. Global phosphoproteome analysis by liquid chromatography-tandem mass spectrometry (LC-MS/MS) has thus gained importance in cell signalling research. However, phosphoprotein identification by LC-MS/MS in whole cell lysates, which are complex protein mixtures, is hindered by their poor ionization coupled with suppression of peaks due to low abundance. Enrichment by immobilized metal ion- and metal oxide-affinity chromatography (IMAC and MOAC), which preferentially enrich multi- and mono-phosphorylated proteins, respectively, have improved their detection by MS. However, preferential enrichment limits phosphoproteome coverage in global analyses of cell lysates which contain mono- and multi-phosphorylated proteins. Improvement in their coverage by sequential elution approach that exploits the complementary chemistries of these matrices has been reported. In this study, we observed that the number of phosphoproteins detected using the sequential elution approach was lower (∼250–400) as compared to the theoretically predicted number (>500) based on their reported 30% abundance in the cell proteome (1700–2200 proteins detected by MS in our cell lines). Acknowledging the merit of using multiple matrices, we used IMAC and MOAC individually and pooled the data. We observed a remarkable increase (>30%) in phosphoproteome coverage. Further, though 98% of phosphoproteins were enriched by IMAC, among the remaining 2%, those detected exclusively by MOAC were biologically important. This justified the use of multiple matrices. Thus, an incremental modification of using multiple matrices individually rather than sequentially and pooling the data markedly improved the phosphoproteome coverage, which can positively impact cell signalling research.

Cannabis inflorescences represent an important source of many high-value bioactive specialized metabolites, among which the family of terpenes or terpenoids that are the largest classes of natural products known. Besides their biological activities either alone or synergistic with other terpenoids and/or cannabinoids, they are responsible for their distinctive flavour. In this study, we exploited the separation power and identification capabilities of comprehensive two-dimensional gas chromatography coupled to mass spectrometry (GC×GC-MS) for the profiling of terpenes and terpenoids in cannabis inflorescences. The dynamic headspace (DHS) used herein for the extraction was chosen for its sensitivity, portability, suitability, as well as its versatility of sampling various natural products, including plant raw materials and different plant parts. The enrichment method and the following desorption into the GC were developed and optimized on both standards and real samples considering different sorbent traps (i.e. Tenax-TA, Carbotrap T420, Carbotrap 202), and evaluating key performance values. Analyte coverage, recovery and response reproducibility were used for the evaluation of the best performing thermal desorption tube. Considering terpenoids profiling on cannabis inflorescences, satisfactory extraction performance was observed with both Tenax-TA and Carbotrap T420. However, Tenax-TA provided a wider analyte coverage beyond the class of terpenoids, thus can be better suited for non-targeted analysis. On the other hand, peak width, peak height, peak quality and resolution were considered for the optimization of the chromatographic process, and more specifically the injection process, demonstrating the benefit of a secondary trapping/desorption stage with a cryotrap. Finally, considering the final DHSE-TD-GC×GC-MS conditions, terpenes and terpenoids were profiled in real-world cannabis inflorescences, highlighting the differences among the chemovars.

Thermogravimetry coupled with simultaneous evolved gas analysis by mass spectrometry was used for discerning organic compounds released during the thermal degradation of paint whose chemical compositions are not readily accessible. Thermogravimetric analyses up to 600°C revealed distinct degradation patterns under inert and oxidative conditions. Significant degradation of paint initiates at around 360°C and concludes at 500°C in a nitrogen atmosphere. However, under oxidative conditions, degradation began at 100°C, with notable mass loss extending from 300 to 600°C, with a distinct event at 500°C. Moreover, the overall mass loss in air has been observed to be 3% higher than that in nitrogen. The rapid characterization of the volatiles was made possible by model-free target factor analyses of evolved gas mass spectra. The temperature-correlated mass analyses revealed potential volatile sources, including structural breakdown and oxidative conversion. Comparative analyses revealed predominantly oxidative conversion of organics to CO₂ during degradation in air. The evolution of several classes of organics during the thermal degradation of paint is a matter of great concern for postulated accident scenarios in nuclear power plants. The low molecular weight organic volatiles may be taken up by iodine aerosols released into the containment during an accident, potentially forming organic iodides, which are biological hazards. Thus, identifying these volatile organics is crucial for accurately estimating the source term of volatile organic iodine.

Surface water from springs, rivers, and dams is often used as an unconventional drinking water source in rural areas where potable water is often unavailable. However, this practice carries significant health risks due to potential contaminants. In this study, the concentrations of arsenic (As) and chromium (Cr) were assessed seasonally using graphite furnace atomic absorption spectrometry (GFAAS). Highly dispersed Fe₃O₄ nanoparticles were synthesized, characterized, and utilized as adsorbents to remove As and Cr ions from various water matrices. The removal process was optimized by adjusting the mass of the nanoparticles, pH levels, and sonication time. To further understand the adsorption process, adsorption isotherms and kinetics were conducted. Physicochemical properties such as pH, electrical conductivity, and total dissolved solids were seasonally evaluated. The average As concentrations were in the range of 13.3–46.8 µg/L, while Cr was in the range of 1.02–5.04 µg/L. Expectedly, higher concentrations of As and Cr were observed in summer when there was intense precipitation, and the lowest concentrations were observed in winter, with little to no precipitation. The calibrated GFAAS displayed an excellent limit of detection, limit of quantification, and linearity of 0.092–0.13, 0.27–0.34, and 0.27–70 µg/L for As, while 0.031–0.07, 0.16–0.21, and 0.16–70 µg/L were attained for Cr, respectively. Arsenic levels exceeded 10 µg/L in all seasons, indicating that these concentrations were above the maximum permitted levels set by the World Health Organization and the South African National Standards. According to the health risk assessment, high As concentrations were alarming, as they were seasonally increasing, with the chronic daily intake exceeding the oral reference dose, whilst the incremental lifetime cancer risk was significantly high.

Dengue (DENV) and Zika virus (ZIKV), transmitted by Aedes mosquitoes, pose significant public health challenges. Effective treatments for these viruses remain elusive, highlighting the urgent need for new efficient antiviral therapies. This study explores prodigiosin, a microbial tripyrrole pigment, as an antiviral agent against both DENV and ZIKV employing advanced analytical approaches which integrate molecular docking, CASTp 3.0 validation and molecular dynamics (MD) simulations providing insights into molecular interactions at an atomic level. Prodigiosin exhibited favourable drug-likeness properties, meeting Lipinski's rule of five and demonstrating optimal physicochemical and pharmacokinetic characteristics according to Ghose's, Veber's, Egan's and Muegge's filters, essential for oral bioavailability. Absorption, Distribution, Metabolism, Excretion, and Toxicity profiling indicated high intestinal absorption, minimal risk for drug-drug interactions and a low toxicity profile, with no AMES toxicity, hepatotoxicity, or skin sensitization. Molecular docking revealed prodigiosin's strong binding affinities to NS5 methyltransferases of both DENV (−7.6 kcal/mol) and ZIKV (−7.7 kcal/mol) viruses, suggesting potential disruption of viral replication. Notably, prodigiosin's binding affinities were comparable to ribavirin-5'-triphosphate and chloroquine, known inhibitors of DENV and ZIKV, respectively. MD simulations confirmed stable and specific interactions with prodigiosin with low root-mean-square deviation values. Additional analyses, including root-mean-square fluctuation, radius of gyration and solvent-accessible surface area, indicated compact and stable complexes. These multi-parametric in-silico analytical strategies provide a novel perspective of prodigiosin as an antiviral agent, demonstrating its drug interactions at the molecular level. These promising results suggest that prodigiosin could serve as a broad-spectrum antiviral agent against both DENV and ZIKV, warranting further experimental validation for therapeutic development against flaviviral infections.

The performance of many known fluorescent sensors for Ca²⁺ is pH-dependent. We set out to address this by preparing a novel calcium sensor based on diacylated 1,10-diaza-18-crown-6 and containing no basic centres. The sensor is sensitive to sub-millimolar levels of Ca²⁺ and partially tolerant of an aqueous environment. However, it suffers from a lack of selectivity over some other divalent cations, and retained pH sensitivity in the acidic range. The relations between these properties and the sensor's structure are discussed.

Testosterone is a critical hormone involved in regulating various physiological processes in both men and women. Accurate testosterone measurement is essential for diagnosing endocrine disorders such as hypogonadism and polycystic ovary syndrome and for routine testing. Traditionally, testosterone levels are measured using serum or plasma samples, which present challenges in sample collection, storage, and transport, particularly in resource-limited settings. Dried blood spot (DBS) sampling has emerged as an effective alternative for hormone analysis, offering significant advantages in terms of sample stability, ease of collection, and simplified logistics. This study aimed to validate a DBS-based testosterone assay using liquid chromatography-tandem mass spectrometry (LC-MS/MS) to ensure accuracy and precision comparable to conventional serum-based methods. Drops of whole blood samples were collected from adult volunteers using a single-use safety lancet for finger pricks, with blood applied onto DBS cards (PerkinElmer 226 Spot Saver RUO card) for further analysis. The testosterone was extracted from DBS using a liquid-liquid method and analyzed with LC-MS/MS. The assay demonstrated excellent linearity across a wide concentration range (0.1–100 ng/mL) with a correlation coefficient (r²) of 0.999 and achieved a lower limit of detection of 0.058 ng/mL and a lower limit of quantification of 0.086 ng/mL. The method showed high precision, with intra- and inter-day coefficients of variation below 10%, and satisfactory recovery rates. Hematocrit correction and matrix effect evaluations confirmed the robustness of the assay for clinical and research applications. Additionally, the assay displayed a strong clinical correlation between testosterone levels in DBS and venous serum samples, supporting its reliability for testosterone monitoring. This validation study supports that the DBS-based LC-MS/MS testosterone assay is a reliable tool for testosterone quantification for routine testing.

Through a collection of editorials titled “Emerging Scientists in Analytical Sciences,” we aim to spotlight promising individuals who are actively engaged in the realm of analytical sciences. For this editorial, we invited Zhuoheng Zhou who recently submitted his PhD thesis at the Vrije Universiteit Brussel.

During my junior high school years, I was very grateful to have attended a scientific event named “knowing about colours”, where teachers demonstrated the light dispersion through a prism and the separation of chlorophyll green and carotenoid yellow by a piece of filter paper (until many years later that I realized it was the “Eureka moment” of chromatography). I was fascinated by the hidden complexity of mother nature, as much as the fact that it tends to leave us a backdoor to have a glimpse of the core. There was no such thing as attractive to a teenager as solving riddles with obscure hints scattered here and there. I later read about the biography of Antoine Lavoisier and his illumination on the essence of combustion [1]. The profound impact of his quantitative and analytical thinking on modern chemistry research made me realize that analytical science is de facto pro-science, the philosophies, methodologies and techniques it comprises are primers for any scientific research activities. To understand something, you have to “see” or “feel” it first.

I also owe my special thanks to Professor Bo Zhang at Xiamen University for hosting me as a research trainee during the summer of my second bachelor's year. This was the first time I had a chance to step on the floor of a research lab and to have a flavour of modern analytical instruments (mainly chromatographs, electrophoresis apparatus and spectrometers). Despite my “greenness”, I was still assigned to a small project on developing a fast reverse-phase chromatographic method as the second-separation dimension in a two-dimensional liquid chromatography (2D-LC) set-up, following a first-dimension strong cation-exchange separation, for intact protein profiling in velvet antler (a constituent of traditional Chinese medicines). The trainee program had a very generous deadline which permitted me to start with extensive exploratory scouting runs (a nicer way to say “trial-and-error”) and to get myself familiarized with various column chemistries and separation conditions (although in a rather primitive and intuitive way). I remember vividly the goose bumps that I had when I saw my first chromatogram on the screen with five distinctive peaks, only five minutes after I manually injected some sort of colourless, transparent, and homogeneous liquid that a senior prepared for me. The joy of knowing the supposedly unknown (more like finishing the last chapter of a detective fiction book) sparked my deep interest in the world of analytical science and particularly separation science up to this day.

My PhD thesis comprised of two major parts. The first