Search Results (108)

Background/Objectives: Mass spectrometry-based newborn screening for small-molecule biomarkers typically employs a rapid first-tier screen that omits chromatographic separations before mass spectrometric analysis, followed, only for a subset of samples and disorders, by a longer, more specific second-tier assay that includes liquid chromatographic separation prior to mass spectrometry. The second-tier screen is used when the primary biomarker lacks sufficient specificity and may result in higher false-positive rates. The throughput and specificity of first-tier newborn screening assays have been relatively stagnant over the past two decades despite significant improvements in mass spectrometry instrumentation. With the continuous expansion of disorders added to the Recommended Uniform Screening Panel in the United States, newborn screening laboratories have a need for higher-throughput assays and improved specificity. Methods: We developed and evaluated two first-tier tandem mass spectrometry approaches using a modern dual-needle, dual-loop LC-MS/MS platform: (1) a 30-s flow injection analysis tandem mass spectrometry (FIA-MS/MS) assay and (2) a rapid first-tier liquid chromatography tandem mass spectrometry (LC-MS/MS) assay using a hydrophilic interaction chromatography (HILIC) guard column (1TH). Analytical performance was assessed using dried blood spot quality control and linearity materials, including evaluations of recovery, precision, linearity, and matrix effects. Results: The 30-s FIA-MS/MS assay quadrupled the throughput of current 2-min FIA-MS/MS assays used routinely in newborn screening laboratories. The throughput improvement was achievable due to increased scan speeds of the mass spectrometer as well as the dual needle/loop design of the autosampler. In addition, these instrumentation improvements made it possible to employ liquid chromatographic separations prior to MS/MS analysis without sacrificing the approximately 2-min sample-to-sample throughput of conventional FIA-MS/MS workflows. The 1TH LC-MS/MS method separated critical isobaric and isomeric biomarkers, reduced matrix effects, improved specificity and quantification accuracy, and demonstrated acceptable recovery, precision, and linearity for newborn screening applications. Conclusions: Recent advances in LC-MS/MS instrumentation can be leveraged to either substantially increase first-tier newborn screening throughput or improve analytical specificity while maintaining current workflow timelines. First-tier LC-MS/MS using a HILIC guard column provides improved specificity that can reduce the need for second-tier testing, thereby improving overall throughput and turnaround time of the newborn screening workflow. These approaches provide flexible solutions for newborn screening laboratories seeking to accommodate expanding screening panels without compromising analytical quality or efficiency. Full article

Train-induced ground vibrations can propagate into pile foundations, potentially causing undesirable vibration in nearby buildings, laboratories housing vibration-sensitive equipment, and manufacturing facilities for high-precision processes. This paper presents an innovative method for predicting building vibration from free-field ground vibration measurements at locations away from the tracks during train pass-bys. The proposed method accounts for site-specific soil profiles and train-soil-pile-structure interactions and is implemented in four steps. In Step 1, train-induced vibration transmission into the ground is estimated using an axisymmetric finite element model that simulates wave propagation through layered soils from the tracks to free-field ground locations. Step 2 estimates free pile head vibration using a three-dimensional finite-element model that captures the ground-borne transmission of track inputs through soil layers to the pile. Step 3 estimates vibration at the junction of the pile head and depot column base using a finite-element model to estimate the pile head impedance and an analytical impedance model for the depot structures supported by the pile. In Step 4, estimates of column-base vibration that transmits into over-track buildings are compared to measured column-base vibration levels obtained during train pass-bys. The method was applied at a metro depot in China, where tracks were in close proximity to columns supporting over-track buildings. Ground and column base vibration levels were measured during multiple train pass-bys. The estimated vibration levels at the base of depot columns closely agreed with the measured vibration levels at the columns during six-car train pass-bys. It demonstrated the potential effectiveness of this hybrid method for assessing vibration transmission into structures atop existing railway tracks. By integrating field measurements, finite element simulations, and analytical impedance models, the proposed hybrid method provides a framework for evaluating the transmission of the train-induced vibration to nearby building structures. Full article

Ethylene oxide (EtO) has been banned in the European Union since 1991 as a fumigant for food commodities. Nevertheless, recurrent contamination incidents, especially since 2020, involving imports from India, have raised significant food safety concerns. Despite regulatory measures, EtO and its metabolite, 2-chloroethanol (2-CE), continue to be detected in a variety of food products, including dried foods, dietary supplements, and food additives. This study presents a QuEChERS-based method involving the conversion of EtO into 2-CE, which is subsequently quantified by isotope dilution gas chromatography–tandem mass spectrometry (GC-MS/MS). In contrast to previously published methods, this protocol utilises an Agilent HP-5ms Ultra Inert column (30 m × 250 μm × 0.25 mm), routinely employed in our laboratory for multi-residue pesticide analysis. The proposed approach is therefore readily adaptable to laboratories already performing multi-residue analyses, as it does not require modifications to existing instrumental configurations. The method was validated in accordance with SANTE/11312/2021 guidelines. A total of 84 samples, primarily imported from India, as well as from Brazil, Argentina, and the United Kingdom, were analysed. 2-CE was detected in four samples, and in two cases, the sum of EtO and 2-CE, expressed as EtO, exceeded the European Union (EU) maximum residue limit (MRL). Full article

This article considers the causes of inter-column pressures (ICP) in wells and their impact on operational reliability. The analysis of Karachaganak field well stock for the period from 2001 to 2024 demonstrates that inter-column pressures manifest in a time frame of five to six years following drilling. These pressures are characterized by a spontaneous emergence and subsequent dissipation. This study proposes a mechanism where the formation of ICP is influenced by multiple factors, including cementing defects, as well as physical and chemical processes. Additionally, the geological heterogeneity of the section has been identified as a contributing factor. The results of studies employing a mobile laboratory and pumping unit are presented. The mobile laboratory unit (MLU) operates with pressure sensors in the range of 0–100 MPa (accuracy ±0.5%), a pump rate of 0.5–20 L/min, and an injection pressure up to 70 MPa; fluid sampling is performed by a discrete sampler with a volume of 500 mL. These allow the identification of sources and channels of fluid migration into the inter-column space, as well as the carrying out of technological operations to reduce and eliminate ICP. This paper sets out a risk-oriented method of inter-column pressure assessment. The proposed risk-based method classifies wells into three risk levels (low, medium, high) based on a composite index R = (P/Pmax) + (V/Vmax) + (C/Cmax) where P is annulus pressure, V is escaped fluid volume per day, C is concentration of H₂S, CO₂, or mercaptan, respectively, and threshold values are Pmax = 35 MPa (API RP 90), Vmax = 50 m³/day, and Cmax = 10 ppm for H₂S. This method takes into account not only the pressure value, but also the volume of escaping fluid and the concentration of aggressive components. It is concluded that an integrated approach to diagnostics and management of inter-column pressures is necessary. This approach should be supported by technological solutions that ensure increased reliability and environmental safety of well operation. Full article

Elemental sulfur frequently coexists with organic polysulfides in environmental samples and laboratory sulfurization experiments, complicating the accurate analysis of sulfur speciation. Reliable methods for selective sulfur removal are therefore required to avoid analytical artifacts. In this study, we systematically evaluated commonly used chemical sulfur removal approaches, including treatment with metallic copper and silver and reaction with tetrabutylammonium sulfite, and compared them with a chromatographic separation method based on C18 reversed-phase silica gel column chromatography. Model organic polysulfides, dimethyl polysulfides, diallyl polysulfides, dibenzyl disulfide, and cyclic polysulfide lenthionine were used to assess method performance under controlled conditions. The results demonstrate that chemical treatments are non-selective and lead to substantial decomposition of organic polysulfides, particularly for longer-chain compounds. In contrast, C18 reversed-phase silica gel column chromatography enables efficient and selective removal of elemental sulfur while preserving the original composition of organic polysulfides, with recoveries in the range of ~90–107%. These findings indicate that commonly applied sulfur removal procedures may introduce significant biases in sulfur speciation analyses. The chromatographic approach presented here provides a reproducible and non-destructive alternative for sample preparation, improving the reliability of studying sulfur speciation and transformation in natural and laboratory systems. Full article

Cracks in concrete structures significantly affect structural safety, durability, and serviceability. To address key limitations of conventional concrete defect detection techniques, this study proposes a new crack localization method based on the AE signal attenuation characteristics. In a laboratory environment, multiple sets of concrete columns are prepared, and a controlled excitation method is used to generate vibration sources. A series of AE sensors are arranged to monitor and analyze the propagation and attenuation characteristics of vibration signals in the concrete medium in real time. The research results indicate that by analyzing the maximum amplitude attenuation characteristics of signals collected by four sensors, this method can effectively determine the approximate location of cracks on the concrete surface, providing a reliable basis for the preliminary identification of cracks. This method differs from the conventional detection concept centered on “wave velocity changes” and does not require large detection equipment. It is suitable for rapid non-destructive testing of concrete beams and columns on site. This technical approach has not yet been widely reported in existing research. This provides a new technical reference for the detection of cracks in concrete structures and adds promising solutions to the field of non-destructive test. Full article

Aim: The aim of this study was to develop and validate a reliable HS-GC-FID/FID method for the determination of ethanol and other low-molecular-weight volatile compounds in biological fluids for forensic applications. Method: The method is based on headspace gas chromatography with dual-column and dual flame ionization detection (HS-GC-FID/FID), using Zebron ZB-BAC1 and ZB-BAC2 columns. The procedure was validated in terms of linearity, limits of detection and quantification, precision, and accuracy, as well as carryover. Results: The method demonstrated linearity over the concentration range of 0.05–5.0‰, with R² values of 0.997–0.999. The limit of quantification (LOQ) was 0.05‰, and the limit of detection (LOD) was 0.025‰. Precision and accuracy were both below 5%. Retention times (min) on the two columns were as follows: methanol (1.70/1.81), ethanol (2.06/2.29), acetone (2.60/2.59), isopropanol (2.45/2.73), n-propanol (3.24/3.98), and n-butanol (6.35/8.45). The developed method was successfully evaluated through international proficiency testing and is routinely applied in our laboratory for forensic casework. Conclusions: The developed HS-GC-FID/FID method provides accurate and reliable determination of ethanol and other relevant volatile compounds in biological fluids (i.a., blood) and meets the requirements for forensic toxicology. Additionally, the literature review conducted in this study highlights that globally unified principles for forensic alcohol analysis are still lacking, and that certain inappropriate methodological approaches remain in use. The present paper also provides recommendations defining essential methodological requirements to ensure the evidential reliability of ethanol analysis in forensic toxicology. Full article

In this study, the applicability of achiral column chromatography—including both medium-pressure liquid chromatography (MPLC) and classical gravity-driven techniques—was evaluated as a laboratory method for enantiomeric enrichment of scalemic (non-racemic) samples of axially chiral compounds. As model substrates, 3-(ortho-substituted-phenyl)quinazolin-4-one derivatives were employed. The results confirmed that self-disproportionation of enantiomers (SDE), occurring during column chromatography (SDEvCC), enabled the efficient isolation of enantiomerically pure fractions, with MPLC demonstrating particularly high effectiveness. Additionally, the parameters governing gravity-driven column chromatography were systematically optimized, with particular attention to variables such as eluent type and concentration, stationary phase composition, sample preparation protocol, and solvent purity. Furthermore, leveraging known crystallographic data and quantum chemical calculations based on Density Functional Theory (DFT), a molecular association mechanism was proposed to elucidate the physicochemical basis of the SDE phenomenon. Full article

Background/Objectives: Mass spectrometry-based multi-attribute methods (MAM) have the potential to transform therapeutic protein analysis by enabling comprehensive monitoring of multiple quality attributes in a single assay. However, the widespread adoption of MAM is hindered by significant challenges, most notably artificial oxidation during sample preparation and analysis. This report summarizes long-term operational observations and several case studies that substantiate this concern. Methods: A tryptic digest, high-resolution LC-MS MAM workflow was applied to an Fc-fusion protein and multiple antibody-based therapeutics, with a frozen reference standard analyzed in each run for system suitability and longitudinal trending. Oxidation excursions were investigated by comparing laboratories, consumables, LC-MS configurations, and other method parameters. Results: In a seven-year trending record, apparent total methionine oxidation in the Fc-fusion protein reference standard showed an abrupt, sustained increase (up to ~5-fold); the shift was traced to a specific bag of microcentrifuge-tubes used during buffer exchange and resolved after those tubes were discontinued. In an antibody–drug conjugate, observed methionine oxidation was strongly influenced by the sample preparation procedure. In other antibodies, variability of observed methionine oxidation was attributed to on-column oxidation, which produced a broad and noisy peak that interferes with automated peak integration. EDTA flushing reduced this feature, implicating exposure to metal ions. Conclusions: While advances continue to address many MAM challenges, artificial oxidation remains unpredictable and constitutes a major obstacle to robust implementation in regulated QC environments. Enhanced control strategies and further research are urgently needed to ensure reliable therapeutic protein analysis. Such control strategies include consumable qualification and change control, system suitability/trending using a reference standard, metal management across LC flow path/column lifecycle, reduction of trifluoracetic acid (TFA) exposure, data analysis to safeguard excessive on-column oxidation, etc. Full article

Background: low-quantity or degraded samples are often studied in forensic genetics. Therefore, it is important to efficiently obtain all the available DNA from the biological sample analyzed to provide the most reliable results. This is particularly challenging in bone marrow processing due to its hydrophobic molecular structure, as for other lipid-rich tissues, especially if rancid. In fact, during adipose tissue decomposition, the putrefaction of fatty acids can in some instances give a compact cerous consistency to the lipidic tissue, hardly susceptible to the nucleic acid extraction mechanisms. According to environmental circumstances, this condition is notably observable in submerged bodies or in putrefied bone marrow. Thus, this study is focused on developing an optimized nucleic acids extraction protocol for putrefied bone marrow. Methods: genetic analyses were performed on putrefied yellow bone marrow collected from 20 human femora recovered from bodies in different decomposition stages. The optimized method was developed by integrating additional steps, reagents and time intervals on a silica-based column commercial kit. This strategy was compared in DNA yield to a standard extraction protocol, represented by the same commercial kit, but following the manufacturer’s directions. Both these strategies were tested in nucleic acid isolation efficiency by performing DNA typing, including real-time PCR quantification, Short Tandem Repeats (STR) amplification and fragments analysis steps. The analytical parameters evaluated were allele count, DNA concentration (ng/µL) and Degradation Index (DI). Results: for allele count and DNA concentration parameters, the optimized protocol showed clear and significant qualitative and quantitative improvements compared with the standard protocol, supporting its potential applicability in forensic casework and laying the foundation for future studies. Conclusions: prior to appropriate laboratory internal validation, the optimized protocol can be used for tough lipid-rich tissues processing without the need to purchase a dedicated system and using a same commercial kit routinely adopted for other forensic genetics matrices. Full article

Monitoring peptide and protein self-association is essential for understanding biological function, formulation stability, and aggregation mechanisms. While size-exclusion chromatography (SEC) is routinely used to quantify protein-size variants under native conditions, its hyphenation to high-resolution mass spectrometry (HRMS) for simultaneous structural characterization remains limited. Here, we report the development and validation of a robust SEC-UV/HRMS method optimized for native-like analysis of bovine serum albumin (BSA) monomers and higher-order oligomers using standard-flow electrospray ionization. Systematic evaluation of source parameters, mobile-phase composition, and chromatographic conditions enabled retention of native BSA structure, minimized in-source unfolding, and enhanced MS sensitivity, allowing detection of oligomers up to the heptamer. A short, narrow-bore 200 Å UHPLC SEC separation column was used. Low-flow separations (~0.05 mL/min) enabled efficient ionization and 10 min run times. An accelerated 60 °C stress-testing protocol demonstrated that SEC-MS can semi-quantitatively monitor oligomerization dynamics, complementing UV-based quantification and revealing transient species not resolved by UV alone. The method showed acceptable linearity, precision, and sample stability, and comparison with SEC-RALS/LALS confirmed molecular-weight trends across aggregation states. Overall, the developed SEC-UV/HRMS workflow provides a rapid, sensitive, and widely accessible approach for UV-based quantification of monomer- and HRMS-based characterizing protein aggregation in research and quality control in pharmaceutical laboratories. Full article

This study describes a single-laboratory validation of an ultra-high-performance liquid chromatographic (UHPLC) method for the determination of key compounds like hericenones, hericenes, erinacines, and ergosterol in Hericium erinaceus (H. erinaceus, Lion’s Mane) raw materials and finished products. The expanding market for Hericium erinaceus (Lion’s Mane) has increased the need for practical, routine-ready analytical methods that can quantify characteristic marker compounds and strengthen quality control across both raw materials and finished products. In this study, an ultra-high-performance liquid chromatographic (UHPLC) separation method was developed for the determination of hericenones, hericenes, erinacines, and ergosterol in Hericium erinaceus raw materials and finished products. Under the optimized conditions, the major target analytes—hericenones, hericenes, erinacine A, and ergosterol—were fully resolved (R_s > 1.5) within 38 min using an HSS T3 column at 30 °C. All the peaks in the LC chromatogram of Hericium erinaceus samples and standard solutions were structurally confirmed by LC–UV-MS/MS based on the possible mass spectra. The quantitative calibration curves were linear, covering a range of 10–300 μg/mL for hericenone C, D and E, and hericene A, D and C; 3–100 μg/mL for deacylhericenone and deacylhericene; 1–50 μg/mL for erinacine A, and 5–200 μg/mL for ergosterol. Limits of quantification (LOQs) for hericenone C, D, and E and for hericene A, D, and C were approximately 9.263, 4.545, 4.650, 1.854, 10.72, and 11.18 µg/mL, respectively, while LOQs for deacylhericenone and deacylhericene were 1.083 and 2.109 µg/mL. Erinacine A and ergosterol showed LOQs of 0.642 and 8.352 µg/mL, respectively. The recovery of ergosterol was evaluated for the method at two different levels: 91.6~93.9% for 0.2% spiking and 93.0~102.6% for 0.08% spiking. The method was successfully validated, demonstrating inter-day Relative Standard Deviation (RSD) values between 1.1% and 5.7% for detected analytes across diverse matrices. This validated method provides a consistent quantification of hericenones, hericenes, erinacine A, and ergosterol across a range of commercial products and raw Hericium erinaceus materials, providing a sensitive and reliable tool for product characterization and quality control. This method provides QC laboratories with a robust, UV-based tool for standardized product characterization without requiring mass spectrometry. Full article

Background/Objectives: MDMA and MDA are among the stimulant drugs most frequently encountered in forensic casework, and oral fluid represents a practical biological matrix for their detection. However, liquid oral fluid requires refrigeration, is susceptible to degradation, and can be logistically demanding for routine laboratories. Dried Oral Fluid Spots (DOFS) offer a low-cost and stable alternative. This study aimed to develop and validate a DOFS-based analytical workflow for quantifying MDMA and MDA using liquid chromatography and a diode-array detector. Methods: Watercolor paper was selected as the substrate and pretreated with diluted nitric acid to improve analyte desorption. DOFS were prepared using 150 µL of pooled oral fluid, dried for 4 h, and extracted with methanol. Chromatographic separation was performed on a phenyl column using aqueous TFA and acetonitrile mobile phase. Method validation followed the ICH M10 criteria. Results: The method showed linear responses between 12.5 and 5000 ng mL⁻¹, with LOD and LLOQ of 6 and 12 ng mL⁻¹ for both analytes, respectively. Precision and accuracy met acceptance criteria across all QC levels. Recoveries ranged from 84% to98%. DOFS samples demonstrated adequate stability under multiple storage and handling conditions. Conclusions: The optimized DOFS–LC–DAD workflow offers a robust, low-cost, and flexible approach for the analysis of MDMA and MDA in oral fluid for laboratory-based or semi-controlled collection environments. Its compatibility with both LC- and GC-based detectors enhances applicability in diverse forensic laboratory settings. Full article

A well construction plan includes a drilling program, drilling fluids, casing-setting-depth selection, casing-grade-combination design, bit selection, cementing, and a wellhead design. Casing-setting-depth selection techniques are an integral part of the construction of oil and gas wells, where setting-depth selection methods rely on both safety and economics. In this study, a new casing-setting-depth selection method is developed. This new method is based on the estimation of the fracturing pressure using the Mohr–Coulomb failure criterion. To validate this new casing-setting-depth selection method, ten core samples, representing ten underground formations in the Saudi lithological column, were tested for uniaxial compressive and tensile strengths. The results were utilized to establish rock failure criteria and estimate casing setting depth using a newly proposed casing-setting-depth selection method based on the Mohr–Coulomb failure criterion and compared to other traditional casing-setting-depth estimation methods. The results demonstrated that the Hubbert & Willis method provided a very narrow safe mud window compared to the other methods, while the leak-off, Eaton, Mathews & Kelly, and other methods provided more economical results. On the other hand, the Mohr–Coulomb method provided the widest and most economical safe mud window compared to all other traditional methods. One of the main requirements of the Mohr–Coulomb casing-setting-depth selection method is that it either requires appreciable core samples from various depths to be tested in the laboratory for their mechanical properties and failure criteria, or that core-calibrated well logs be used. Additionally, relying on Mohr–Coulomb casing-setting-depth selection methods requires the use of filtration loss control materials to seal any microcracks that may form. Economical comparisons in terms of casing string number and length yielded that Eaton, leak-off, and Mathews and Kelly methods reduced casing cost by 31% compared to Hubbert and Willis methods. On the other hand, the new casing-setting-depth selection method based on the Mohr–Coulomb method reduced casing costs by 41% compared with the Hubbert and Willis methods and by 10% compared with the leak-off and Mathews and Kelly methods. Therefore, this study provides a new proof of concept for developing an efficient method for selecting the casing setting depth for oil and gas wells. Full article

New-generation geostationary meteorological satellite radiometric imagers widely employ multi-column redundant long-linear-array detectors, for which the Best Detector Selection (BDS) strategy is crucial for enhancing the quality of remote sensing data. Addressing the limitation of current BDS methods that often rely on a single metric and thus fail to fully exploit the detector’s comprehensive performance, this paper proposes a detector evaluation method based on a modified Z-score. This method systematically categorizes detector metrics into three types: positive, negative, and uniformity. It introduces, for the first time, spectral response deviation (SRD) as an effective quantitative measure for the Spectral Response Function (SRF) and employs a robust normalization strategy using the Interquartile Range (IQR) instead of standard deviation, enabling multi-dimensional detector evaluation and selection. Validation using laboratory data from the FY-4C/AGRI long-wave infrared band demonstrates that, compared to traditional single-metric optimization strategies, the best detectors selected by our method show significant improvement across multiple performance indicators, markedly enhancing both data quality and overall system performance. The proposed method features low computational complexity and strong adaptability, supporting on-orbit real-time detector optimization and dynamic updates, thereby providing reliable technical support for high-quality processing of remote sensing data from geostationary meteorological satellites. Full article