MS Measurements Research Articles

Structures of dibenzo-24-crown-8 complex with an NH4+ ion studied by cryogenic ion mobility-mass spectrometry

Cryogenic drift-tube ion mobility–mass spectrometry (IM–MS) was applied to study structures of conformers of dibenzo-24-crown-8 complex with NH4+ ion. Two types of conformers which have different distances between two benzene rings of the crown ether, closed and open conformers, were separately observed in the IM–MS measurement at 86 K. The two types of conformers differed not only in the distance between the two benzene rings, but also in the depth at which the NH4+ was wrapped. The collision cross sections of M+(dibenzo-24-crown-8) (M = Na, K, and NH4) complexes depend on the ionic radii of guest ions.

Brown carbon from biomass burning imposes strong circum-Arctic warming

Brown carbon from biomass burning imposes strong circum-Arctic warming

Low Power Respiration Monitoring Using Wearable 3D Knitted Helical Coils

We demonstrate a novel low power inductive wearable plethysmography system. This consists of ultra-sensitive 3D knitted helical coils integrated in a garment and an oscillator circuit with high quality factor. The low power oscillator is built using two cross coupled FET pairs with low capacitance drawing only 95 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\mu \text{A}$ </tex-math></inline-formula> during operation and with a response time smaller than 10 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\mu \text{s}$ </tex-math></inline-formula> . The sensor system is linear, with negligible hysteresis. The best compromise in sensitivity and power consumption is obtained with a 3D knitted helical coil using jersey knit with elastic yarn, a lower knitting needle size than recommended for the yarn and minimizing both the number of stitches per winding as well as the stitches containing metal. A sensitivity of 2.7 kHz per mm change in circumference with a power consumption of 6.85 mW per 30 ms measurement time is reported. This system can be used for long term breathing monitoring using a garment indistinguishable from everyday clothing.

Efficient fluorescent recognition of ATP/GTP by a water-soluble bisquinolinium pyridine-2,6-dicarboxamide compound. Crystal structures, spectroscopic studies and interaction mode with DNA.

The new dicationic pyridine-2,6-dicarboxamide-based compound 1 bearing two N-alkylquinolinium units was synthesized, structurally determined by single-crystal X-ray diffraction, and studied in-depth as a fluorescent receptor for nucleotides and inorganic phosphorylated anions in pure water. The addition of nucleotides to 1 at pH = 7.0 quenches its blue emission with a selective affinity towards adenosine 5'-triphosphate (ATP) and guanosine 5'-tripohosphate (GTP) over other nucleotides such CTP, UTP, ADP, AMP, dicarboxylates and inorganic anions. On the basis of the spectroscopic tools (1H, 31P NMR, UV-vis, fluorescence), MS measurements and DFT calculations, receptor 1 binds ATP with high affinity (log K = 5.04) through the simultaneous formation of strong hydrogen bonds and π-π interactions between the adenosine fragment and quinolinium ring with binding energy calculated in 8.7 kcal mol-1. High affinity for ATP/GTP is attributed to the high acidity of amides and preorganized rigid structure of 1. Receptor 1 is an order of magnitude more selective for ATP than GTP. An efficient photoinduced electron transfer quenching mechanism with simultaneous receptor-ATP complexation in both the excited and ground states is proposed. Additionally, multiple spectroscopic studies and molecular dynamics simulations showed that 1 can intercalate into DNA base pairs.

Elimination of Spectral Interference of 87Rb (an Isobar of 87Sr) with 87Sr in ICP–MS Measurement Using Chromatographic Technique

Elimination of Spectral Interference of 87Rb (an Isobar of 87Sr) with 87Sr in ICP–MS Measurement Using Chromatographic Technique

Mössbauer study of some novel iron-bis-glyoxime and iron-tris-glyoxime complexes

Dioximes as ligands are used as analytical reagents and serve as models for biological systems as well as catalysts in chemical processes. A number of novel mixed complexes of the type [Fe(DioxH)2(amine)2] have been prepared and characterised by FTIR, 57Fe Mössbauer and mass spectroscopy by us. We have found strong Fe–N donor acceptor interactions and iron occurred in low-spin FeII state in all complexes. Later, we have also found that the incorporation of branching alkyl chains (isopropyl) in the complexes alters the Fe–N bond length and results in high-spin iron(II) state [1, 2]. The question arises: can the spin state of iron be manipulated generally by replacing the short alkyl chains with high volume demand ones in Fe-azomethine-amine complexes? To answer the question we have synthetized novel iron-bis-glioxime and iron-tris-gloxime complexes when long chain alkyl or aromatic ligands replaced the short alkyl ones and studied by 57Fe Mössbauer spectroscopy, MS, FTIR, UV-VIS, TG-DTA-DTG and XRD methods. Novel iron-bis-glyoxime and iron-tris-glyoxime type complexes, [Fe(Diethyl-Diox)3(BOH)2], [Fe(Diethyl-Diox)3(BOEt)2] and [Fe(phenyl-Me-Diox)3(BOEt)2], were synthesized similarly as described in [2]. The FTIR, UV-VIS, TG-DTA-DTG and MS measurements indicated that the expected novel complexes could be successfully synthesized.

Phlegmatization of TATP and HMTD with Activated Charcoal as Training Aid for Explosive Detection Dogs

AbstractBoth TATP and HMTD could be phlegmatized by coprecipitation with active charcoal resulting in mixtures with a nominal content of 40 wt‐% (d40‐TATP) and 10 wt‐% (d10‐HMTD), respectively. In terms of impact and friction sensitivity for both peroxides a content of 40 wt‐% resulted in &gt;30 Nm impact sensitivity and &gt;360 N friction sensitivity. Both phlegmatized peroxides passed the Koenen Tube and Thermal Stability Test according to the UN recommendation on the transport of dangerous goods test manual. Investigations with a process mass spectrometer indicate that d40‐TATP can produce a saturated TATP headspace at least in the same time as the same amount of pure TATP. Measurements with the transpiration method demonstrated that the vapor pressure at 298.15 K of d40‐TATP (2.3 Pa) and d32.7‐TATP (0.9 Pa) is lower than that of pure TATP (6.7 Pa). Headspace SPME‐GC/MS measurements revealed that the active charcoal does not contribute to the vapor profile of the training aid. Both d40‐TATP and d10‐HMTD were tested as training aids for explosive detection dog teams (EDD). In both differentiation track and realistic environment scenarios a detection rate of 100 % could be achieved by German Federal Police EDD with a false positive rate of solely 3 %.

Impact of instrumental settings in electrospray ionization ion trap mass spectrometry on the analysis of multi-CH3-/CD3-isotopologs in cellulose ether analysis: a quantitative evaluation

Exact quantification of the molar ratios of isotopologous mixed O-methyl-O-methyl-d3-cellooligosaccharides (COS) comprising all combinations from fully methylated to fully deuteromethylated constituents within an individual degree of polymerization (DP) is the key step in the analysis of the substituent distribution over the polymer chains in methyl celluloses (MC). Deuteromethylation of MC is performed to level chemical differences, but due to a m/z range of 3 DP·ΔMe/Me-d3, bias during MS measurement cannot certainly be excluded. Therefore, ionization, ion transportation, and ion storage were studied with an electrospray ionization ion trap mass spectrometer (ESI-IT-MS) using binary equimolar mixtures of per-O-Me- and per-O-Me-d3-COS, defining the border cases of a particular Me/Me-d3-profile. Reference data of their molar ratio were determined after reductive amination with m-amino benzoic acid by HPLC-UV. COS of DP2–6 were measured as their sodium adducts at c = 10−6 M by syringe pump infusion. The impact of the RF voltage of the ion trap (TD), the octopole RF and DC voltages, and the Cap Exit potential on absolute and relative ion intensities were studied. Adapting the Cap Exit voltage was essential for correct quantification of DP2, while all COS of higher DP behaved insensitive with respect to bias. To check whether any bias occurs in the electrospray ionization process of the isotopologs, concentration-dependent measurements were performed with optimized instrumental settings for each DP. Intensity ratios IR = I (Me-d3)/I (Me) did not show any concentration-dependent trend and no selective ion suppression. Its decrease with DP observed under usually applied standard conditions (smart mode) is a consequence of discrimination according to m/z and can be overcome by appropriate instrumental settings of Oct 2 DC and TD. IR between 0.971 ± 0.008 and 1.040 ± 0.009 with no trend for DP (2-6) were obtained by averaging all measurements in the range 2 · 10−7 to 2 · 10−5 M total concentration. The DP-related optimized settings were applied to two MCs and compared with the results obtained under so far applied standard conditions.Graphical abstract

Automated 3D Sampling and Imaging of Uneven Sample Surfaces with LA-REIMS.

The analysis of samples with large height variations remains a challenge for mass spectrometry imaging (MSI), despite many technological advantages. Ambient sampling and ionization MS techniques allow for the molecular analysis of sample surfaces with height variations, but most techniques lack MSI capabilities. We developed a 3D MS scanner for the automated sampling and imaging of a 3D surface with laser-assisted rapid evaporative ionization mass spectrometry (LA-REIMS). The sample is moved automatically with a constant distance between the laser probe and sample surface in the 3D MS Scanner. The topography of the surface was scanned with a laser point distance sensor to define the MS measurement points. MS acquisition was performed with LA-REIMS using a surgical CO2 laser coupled to a qTOF instrument. The topographical scan and MS acquisition can be completed within 1 h using the 3D MS scanner for 300 measurement points on uneven samples with a spatial resolution of 2 mm in the top view, corresponding to 22.04 cm2. Comparison between the automated acquisition with the 3D MS scanner and manual acquisition by hand showed that the automation resulted in increased reproducibility between the measurement points. 3D visualizations of molecular distributions related to structural differences were shown for an apple, a marrowbone, and a human femoral head to demonstrate the imaging feasibility of the system. The developed 3D MS scanner allows for the automated sampling of surfaces with uneven topographies with LA-REIMS, which can be used for the 3D visualization of molecular distributions of these surfaces.

Signatures of Transient Overvoltages in Low Voltage Power Systems in Tea Factories and Their Implications on Insulation Deterioration and Allied Power Quality Issues

Electrical equipment and supply cables demand a better quality of supply, with the recent advancements in integrated sensitive solid-state controls. Divergently, proliferated heavy inductive motors and some performance additions based on power electronics have introduced power quality issues to the network. Thus, this study mainly investigates the impact of switching transients generated by electromechanical machines in industrial power systems on insulation deterioration while taking transient overvoltages due to capacitor bank switching also to support. Transients with a high rate of rise are likely to catalyze the degradation of the insulation quality and break down the insulating material through ionization. These steeply passing overvoltage stresses let partial discharges ensue, which can attack the insulation over long service. To unveil this danger, 314 common-mode transient waveforms were measured in the electrical machines of five tea factories in Sri Lanka, in a 50 ms measurement window, taken in 55 measuring attempts. Most of the transients observed are in the form of a damped oscillatory waveform tailed by fast exponential collapse. That correlates to insulation degradation having a very steep rise as 30.04 V/ns, the highest at the withering section. When machines are heavily loaded, situations tend to generate transients with high amplitudes. There were transient bursts that spread as 426.3 ms, while 14 ns fast rise times were recorded from withering motors. Unlike electrical resonance and power-frequency overvoltages, electromagnetic switching transients last even less than 100 ms. To underline this, an analysis of the frequency domain of transients was also presented, which proves high density of high-frequency components reaching 107 kHz range. Accepting the fact that frequency and amplitude are always under the influences of innumerable dynamics, the observational evidence of the study endorses that electrical stress built by the transient nature of the factories reduces the life expectancy of electrical insulation.

Volatility Factors of Returns and Risk Analysis Using Quantile Risk Measures in the Gold and Silver Market

The aim of the paper is to identify unobservable factors that may significantly determine the level of gold and silver returns and to assess the risk of investment in these metals. To measure risk, the value at risk and other, less popular measures are used: the ES, MS, Rachev ratio and GlueVaR risk measure. Normal and Student’s t‑distributions are used as theoretical distributions. The results of the study show that we can identify latent factors based on observable variables that have a significant impact on the level of gold and silver returns. In addition, it was observed that the risk measures would vary depending on the period of research. It was shown that the estimates of the risk measures using Student’s t‑distribution have a lower estimation error than those based on the normal distribution.

Urinary excretion of amino acids and their advanced glycation end-products (AGEs) in adult kidney transplant recipients with emphasis on lysine: furosine excretion is associated with cardiovascular and all-cause mortality

Arginine (Arg) and lysine (Lys) moieties of proteins undergo various post-translational modifications (PTM) including enzymatic NG- and Nε-methylation and non-enzymatic NG- and Nε-glycation. In a large cohort of stable kidney transplant recipients (KTR, n = 686), high plasma and low urinary concentrations of asymmetric dimethylarginine (ADMA), an abundant PTM metabolite of Arg, were associated with cardiovascular and all-cause mortality. Thus, the prediction of the same biomarker regarding mortality may depend on the biological sample. In another large cohort of stable KTR (n = 555), higher plasma concentrations of Nε-carboxymethyl-lysine (CML) and Nε-carboxyethyl-lysine (CEL), two advanced glycation end-products (AGEs) of Lys, were associated with higher cardiovascular mortality. Yet, the associations of urinary AGEs with mortality are unknown. In the present study, we measured 24 h urinary excretion of Lys, CML, and furosine in 630 KTR and 41 healthy kidney donors before and after donation. Our result indicate that lower urinary CML and lower furosine excretion rates are associated with higher mortality in KTR, thus resembling the associations of ADMA. Lower furosine excretion rates were also associated with higher cardiovascular mortality. The 24 h urinary excretion rate of amino acids and their metabolites decreased post-donation (varying as little as − 24% for CEL, and as much as − 62% for ADMA). For most amino acids, the excretion rate was lower in KTR than in donors pre-donation [except for S-(1-carboxyethyl)-l-cysteine (CEC) and NG-carboxyethylarginine (CEA)]. Simultaneous GC–MS measurement of free amino acids, their PTM metabolites and AGEs in urine is a non-invasive approach in kidney transplantation.

Thermodynamic study of pH and sodium chloride impact on gemcitabine binding to cucurbit[7]uril in aqueous solutions

In solutions of pH < 5, cucurbit[7]uril (Q[7]) spontaneously includes a molecule of the anticancer drug gemcitabine within its cavity, forming a supramolecular complex. The results of ITC calorimetric studies of the gemcitabine cation (Gem) complexation with the Q[7] macrocycle in 20 mM aqueous HCOOH–HCOONa buffer mixtures with pH ranging from 5 to 2, indicate that the acidification of the solution facilitates binding of the drug by cucurbit[7]uril. In mixtures with a fixed pH = 4 and an increasing concentration of sodium chloride (10–4000 mM), the binding constant of Gem by Q[7] decreases rapidly, as is the absolute value of the binding enthalpy. This phenomenon illustrates the hindering effect of the association of sodium cations with Q[7] portals on gemcitabine binding, which is confirmed by ESI MS measurements. However, gemcitabine is still efficiently bound by cucurbit[7]uril (logK≥3) in aqueous 10 – 250 mM sodium chloride solutions. The Q[7] macrocycle may therefore be used as a stabilizing agent for this drug in pharmaceutical formulations.

Radio frequency He4 and sonoluminescence photons are combined

Two systems are presented in this paper: 1) describes the Radio Frequency, RF, reactor that produces alphas and 2) the polycarbonate reactor that produced sonoluminescence, SL or gammas several years earlier. During experiments, dV/dt rapid changes were noted in volumes of proton and deuteron capturing an electron as the initial temperature cools. This is a very basic event at the atomic level. The D+ + e−D* will produce a shockwave that is only compressive for the elemental hydrogen isotopes. The shock wave that destroys the MC cluster of deuterons in a squeezing process, ends with an explosion that excites the MC debris. An excited state occurs where a free MC deuteron combines with the D*forming an alpha as part of the debris system for that cycle. He4 was collected in the Ar gas phase for a mass spectroscopy analysis, MS. Only the 3 hydrogen isotopes have the potential of the large dV/dt compression. Old measurements of the sonoluminescence (SL) photons emitted during DOD cavitation fits RF experiments, and it was never thought He4 might be associated with SL. But a closer look makes a case that SL and gamma photons were the same. The RF system during DOD cavitation could be associated with the improbable equation 2D He4 + g. The measured SL fits the RF He4 MS measurements. The advantage of the RF amplifier driven system was its freedom of a locked frequency of the oscillator driven systems and can be frequency tuned while running. The system could be tuned off for 5 s temperature measurement in the 30 s run mode, thus avoiding the high RF field interference to thermocouple measurements. This SW system was impressed with Lawandy’s like charge attractive forces system that was compatible with MC SW system making the experiments that yield other He4 paths. These were single events of a few atoms, with high activity electrons for a short time, during a 2-MHz cycle.

Novel Cofacial Porphyrin-Based Homo- and Heterotrimetallic Complexes of Transition Metals.

We present a straightforward and generally applicable synthesis route for cofacially linked homo‐ and heterotrimetallic trisporphyin complexes. The protocol encompasses synthesising the first aryl‐based, trans‐o‐phenylene trisporphyrin starting from pyrrole and benzaldehyde with an overall yield of 3.6 %. It also allows investigating the respective cis‐isomer as the first conformationally restricted planar‐chiral trisporphyrin. The free‐base ligand was used in subsequent metalation reactions to afford the corresponding homotrimetallic Mn(III)‐, Fe(III)‐, Ni(II)‐, Cu(II)‐, Zn(II)‐ and Pd(II) complexes – additionally, a small adaptation of the protocol resulted in the defined Ni(II)Fe(III)Ni(II) complex in a total yield of 2.3 %. By monitoring Ni(II) insertion into the empty trimeric ligands, we affirmed that the outer porphyrin rings are filled before the internal ring. The molecular species were characterised by 1H NMR, UV‐Vis, photoluminescence, IR, MS, CID, and high‐resolution IMS measurements.

Tautomeric equilibrium, proton affinity and mass spectrometry fragmentation of flexible hydrogen-bonded precursors and rigid hbox {N}longrightarrow hbox {BF}_2 fluorescent dyes

The stability of two groups of conformationally locked molecules, similar in topology, but differing only by the type of the bridge rigidifying their structure, is studied. The series of the less-rigid 2-phenacylheterocyclic compounds and their stiff difluoroboranyl derivatives are investigated for the determination of the effect of hbox {NCH}_3/S/O replacement in a five-membered heterocyclic ring and the presence of a strong electron-donating group on the tautomeric equilibrium, protonation affinity, and fragmentation pattern observed in the structural elucidation by means of mass spectrometry technique. The results of the omega B97X-D/6-311++G(d,p) calculations, the topological analysis of electron density as well as the experimental MS measurements show the importance of the number of heteroatoms, their properties, and location in the molecule for the rational design of the systems of desired stable tautomers or the favorable protonation sites. The obtained data allow for the understanding of the fundamentals of the novel highly fluorescent difluoroborates fragmentation behavior, vital for their structural elucidation with the application of high-resolution tandem mass spectrometry methods.

Synthesis of novel seco-acyclo-N-diazolyl-thione nucleosides analogous derived from acetic acid: characterization, complex formation with ions Pb(II), Hg(II) and antibacterial activity

Three diazoles namely 5-methyl-1,3,4-oxadiazole -2(3H)-thione, 5-methyl-1,3,4-thiadiazol-2(3H)-thione and 4-amino-5-methyl-2H-1,2,4-triazole-3-thiol were synthesized from acetic acid or ethyl acetate. Seco-acyclo-N-nucleoside analogous was synthesized by condensation of 1,3-benzylidine-glyceryl-2-tosylate with the three diazoles. Structural proof was based upon IR, 1H-NMR, 13C-NMR spectroscopy and MS measurements. The tendency to form complex between 1,3,4-oxadiazole and 1,3,4-thiadiazoles and Pb(II) and Hg(II) ions was achieved, and their structures were assigned by observing some changes in physical properties such as, MP, coloration, Rf (TLC), IR and UV spectroscopy. Most compounds were tested in vitro against Gram-positive and Gram-negative bacteria and showed variable activity. Hg2+ complexes of oxadiazole and thiadiazole derivatives exhibited appreciable antibacterial effect at lower MIC, compatible to the reference vancomycin. Similarly, oxadiazole-nucleoside exhibited high effect on Gram-positive bacteria.Graphic abstract Supplementary InformationThe online version contains supplementary material available at 10.1007/s13738-021-02358-x.

The Role of Cerebral Metabolism in Improving Time Pressured Decisions.

Speed-accuracy tradeoff (SAT) theory dictates that decisions can be made more quickly by sacrificing accuracy. Here we investigate whether the human brain can operate in a brief metabolic overdrive to overcome SAT and successfully make decisions requiring both high levels of speed and accuracy. In the context of BOLD fMRI we expect “a brief metabolic overdrive” to involve an increase in cerebral oxygen metabolism prior to increased cerebral blood flow–a phenomenon known as the “initial dip” which results from a sudden drop in oxyhemoglobin in perfusing blood. Human subjects performed a motion discrimination task consisting of different difficulties while emphasizing either accuracy (i.e., without time pressure) or both speed and accuracy (i.e., with time pressure). Using simultaneous multi-slice fMRI, for very fast (333 ms) measurement of whole brain BOLD activity, revealed two modes of physiological overdrive responses when subjects emphasized both speed and accuracy. The majority of subjects exhibited the hypothesized enhancement of initial dip amplitude in posterior visual cortex (PVC) with the size of the enhancement significantly correlated with improvement in behavioral performance. For these subjects, the traditionally analyzed post-stimulus overshoot was not affected by task emphasis. These results demonstrate the complexity and variability of the BOLD hemodynamic response. The discovered relationships between BOLD response and behavior were only observed when subjects emphasized both speed and accuracy in more difficult trials suggesting that the brain can perform in a state of metabolic overdrive with enhanced neural processing of sensory information specifically in challenging situations.

Low noise frequency upconversion imaging based on Hadamard coding and time-gate detection

The nonlinear frequency upconversion with the tight focused pump beam based on photon counting and Hadamard coding is presented to acquire low noise converted images. The pump beam is optimized by tight focusing to enhance its power density in nonlinear crystal. In order to reduce the distortion caused by the point spread function effect, the object is encoded by measurement matrices and the converted photons corresponding to each pattern is measured. Thus the converted image with sharp edges can be reconstructed by the measurements and the measurement matrices. The time-gated detection is applied to increase the signal-to-noise ratio(SNR) of the measurements. The experimental results show the peak of the dark noise is less than 0.34 photons/spatial/s element for an image with 64 × 64 pixels by taking into account 10 ms measurement time for each pattern. Compared with the converted image reconstructed by the measurements of the photomultiplier tube(PMT) directly, the peak signal to noise ratio (PSNR) of photon counting image increases about 30.91%.

Chemical and Biological Profiles of Dendrobium in Two Different Species, Their Hybrid, and Gamma-Irradiated Mutant Lines of the Hybrid Based on LC-QToF MS and Cytotoxicity Analysis.

The Dendrobium species (Orchidaceae) has been cultivated as an ornamental plant as well as used in traditional medicines. In this study, the chemical profiles of Dendrobii Herba, used as herbal medicine, Dendrobium in two different species, their hybrid, and the gamma-irradiated mutant lines of the hybrid, were systematically investigated via ultra-performance liquid chromatography coupled with quadrupole time-of-flight mass spectrometry (UPLC-QToF MS). Among the numerous peaks detected, 17 peaks were unambiguously identified. Gigantol (1), (1R,2R)-1,7-hydroxy-2,8-methoxy-2,3-dihydrophenanthrene-4(1H)-one (2), tristin (3), (−)-syringaresinol (4), lusianthridin (5), 2,7-dihydroxy-phenanthrene-1,4-dione (6), densiflorol B (7), denthyrsinin (8), moscatilin (9), lusianthridin dimer (10), batatasin III (11), ephemeranthol A (12), thunalbene (13), dehydroorchinol (14), dendrobine (15), shihunine (16), and 1,5,7-trimethoxy-2-phenanthrenol (17), were detected in Dendrobii Herba, while 1, 2, and 16 were detected in D. candidum, 1, 11, and 16 in D. nobile, and 1, 2, and 16 in the hybrid, D. nobile × candidum. The methanol extract taken of them was also examined for cytotoxicity against FaDu human hypopharynx squamous carcinoma cells, where Dendrobii Herba showed the greatest cytotoxicity. In the untargeted metabolite analysis of 436 mutant lines of the hybrid, using UPLC-QToF MS and cytotoxicity measurements combined with multivariate analysis, two tentative flavonoids (M1 and M2) were evaluated as key markers among the analyzed metabolites, contributing to the distinction between active and inactive mutant lines.