Analysis Method Research Articles

Combined Quantification and Characterization of Dissolved Organic Matter by Liquid Chromatography-Mass Spectrometry Using Charged Aerosol Detection.

Dissolved organic matter (DOM) is a complex mixture of thousands of molecular formulas comprised of an unknown number of chemical compounds, the concentration and composition of which are critical to ecosystem function and biogeochemical cycling. Despite its importance, our understanding of the DOM composition is lacking. This is principally due to its molecular complexity, which means that no single method is capable of describing DOM in its entirety. Quantification is typically done by proxy (e.g., relative to carbon content) and does not necessarily match well to compositional data, due to incomplete analytical windows and selectivity of different analytical methods. We present an integrated liquid chromatography (LC)-diode array detector (DAD)-charged aerosol detector (CAD)-mass spectrometry (MS) pipeline designed to both characterize and quantify solid-phase extractable DOM (SPE-DOM) in a single analysis. We applied this method to a set of eight Swedish water bodies sampled in the summer and winter. Chromophoric SPE-DOM was proportionally higher in samples with higher SPE-DOM concentrations but remained relatively consistent between sampling occasions. Ionizable SPE-DOM was relatively consistent across sites but was proportionally higher in summer. Overall, the carbon content of DOM was very consistently ∼40% across sites in both summer and winter. These findings suggest that SPE-DOM concentration at these sites is driven by (presumably allochthonous) chromophoric inputs, with an increased relative contribution in summer of material that is more ionizable and less chromophoric and may be either autochthonous or selectively enriched from allochthonous sources. Thus, with minimal additional effort, this method provided further compositional insights not attained by any single analysis in isolation.

Fast determination of organophosphate esters and their metabolites in human matrices by a straightforward cold-induced strategy coupled with HPLC-MS/MS.

Organophosphate esters (OPEs) are commonly used chemicals and are also regarded as emerging environmental pollutants. Recently, it has been proved that metabolites of OPEs (mOPEs) could also cause health concerns. However, analytical methods for the concurrent measurement of OPEs and mOPEs in human matrices are still complicated. In this study, a convenient and efficient analytical method combining a cold-induced strategy and HPLC-MS/MS was developed to simultaneously determine 18 OPEs and 10 mOPEs in human serum, urine, and human milk. In brief, after the sample was extracted with acetonitrile, a "one-step" treatment combining purification and enrichment was accomplished by cold-induced liquid-liquid extraction (CI-LLE), and analytes were then quantified by HPLC-ESI-MS/MS. The ratio of acetonitrile/water, and the temperature and time set in the CI-LLE procedure were optimized for achieving the highest enrichment factors. Under thebest conditions, linearity, limits of detection (LODs), recovery, precision, and matrix effects of OPEs/mOPEs were verified. LODs of OPEs/mOPEs in serum, urine, and human milk were 0.1-113pg/mL, 0.1-22pg/mL, and 0.2-22pg/mL, respectively. Average recoveries ranged from 80 to 123%, with relative standard deviations lower than 15% for most analytes. The matrix effect test showed slight signal enhancement or inhibition, and the use of isotopically labeled internal standards (ISs) could compensate for the effects. In real sample analysis, both OPEs and mOPEs showed high detecting frequency, which indicated their ubiquity in humans.

Ring rolling with flat dies: An analytical method to optimize geometry, time or energy

Ring rolling with flat dies: An analytical method to optimize geometry, time or energy

Construction of dual-signal output sensing platform for different scene of rapid and sensitive ochratoxin A detection in corn

Photoelectrochemical (PEC) is a highly sensitive and fast analytical method that can be used at low concentrations, while photoelectrochromic is a simple and low-cost method primarily utilized for high concentration detection. Therefore, we have developed a dual-signal output sensing platform based on both PEC and photoelectrochromism for rapid and sensitive OTA detection. The sensing platform is divided into signal generation (SG) region and signal output (SO) region, which modified with WO3/BiVO4 photoactive nanocomposites and polyaniline (PANI), respectively. By irradiating the SG region, photogenerated electrons are generated and injected into the SO region through the conductive pathway, resulting in a decrease in surface blue polyaniline and a change to green. The smart device can accurately measure the RGB-Green values, enabling the construction of a photochromic visual sensing platform. After immobilizing the OTA aptamer in the SG region, a linear correlation was observed between the concentration of OTA and the RGB-Green value within the range of 20 ng/L ∼250 μg/L. The detection limit was determined to be 8.33 ng/L (S/N = 3). Furthermore, for a more sensitive OTA detection, a PEC sensing platform was developed utilizing the SG region as a photoanode, exhibiting a linear correlation in the range of 2 pg/L∼300 μg/L with a detection limit of 0.8 pg/L (S/N = 3). The detection of these two modes under the requirement of the international standard for the maximum limit realizes the sensitive OTA detection. The RGB-Green is verified to PEC signal, which improves the detection accuracy. The sensing platform has several advantages and is suitable for various application scenarios.

Monitoring the Biochemical Activity of Single Anammox Granules with Microbarometers.

Granule-based anaerobic ammonium oxidation (Anammox) is a promising biotechnology for wastewater treatments with extraordinary performance in nitrogen removal. However, traditional analytical methods often delivered an average activity of a bulk sample consisting of millions and even billions of Anammox granules with distinct sizes and components. Here, we developed a novel technique to monitor the biochemical activity of individual Anammox granules in real-time by recording the production rate of nitrogen gas with a microbarometer in a sealed chamber containing only one granule. It was found that the specific activity of a single Anammox granule not only varied by tens of folds among different individuals with similar sizes (activity heterogeneity) but also revealed significant breath-like dynamics over time (temporal fluctuation). Statistical analysis on tens of individuals further revealed two subpopulations with distinct color and specific activity, which were subsequently attributed to the different expression levels of heme c content and hydrazine dehydrogenase activity. This study not only provides a general methodology for various kinds of gas-producing microbial processes but also establishes a bottom-up strategy for exploring the structural-activity relationship at a single sludge granule level, with implications for developing a better Anammox process.

Deciphering electrocatalytic hydrogen production in water through a bioinspired water-stable copper(II) complex adorned with (N2S2)-donor sites.

Electrocatalytic hydrogen production stands as a pivotal cornerstone in ushering the revolutionary era of the hydrogen economy. With a keen focus on emulating the significance of hydrogenase-like active sites in sustainable H2 generation, a meticulously designed and water-stable copper(II) complex, [Cl-Cu-LN2S2]ClO4, featuring the N,S-type ligand, LN2S2 (2,2'-((butane-2,3-diylbis(sulfanediyl))bis(methylene))dipyridine), has been crafted and assessed for its prowess in electrocatalytic H2 production in water, leveraging acetic acid as a proton source. The molecular catalyst, adopting a square pyramidal coordination geometry, undergoes -Cl substitution by H2O during electrochemical conditions yielding [H2O-Cu-LN2S2]2+ as the true catalyst, showcases outstanding activity in electrochemical proton reduction in acidic water, achieving an impressive rate of 241.75 s-1 for hydrogen generation. Controlled potential electrolysis at -1.2 V vs. Ag/AgCl for 1.6 h reveals a high turnover number of 73.06 with a commendable Faradic efficiency of 94.2%. A comprehensive analysis encompassing electrochemical, spectroscopic, and analytical methods reveals an insignificant degradation of the molecular catalyst. However, the post-CPE electrocatalyst, present in the solution domain, signifies the coveted stability and effective activity under the specified electrochemical conditions. The synergy of electrochemical, spectroscopic, and computational studies endorses the proton-electron coupling mediated catalytic pathways, affirming the viability of sustainable hydrogen production.

Determining personal exposure to high production volume chemicals (HPVCs) and polycyclic aromatic hydrocarbons (PAHs) with silicone wristbands: A pilot study

High production volume chemicals (HPVCs) and polycyclic aromatic hydrocarbons (PAHs) are semi-volatile organic compounds (semi-VOCs) of great environmental concern because of their presence worldwide and health problems resulting from long-term exposure to some of them. It is essential to have robust analytical methods to monitor the concentrations of these compounds not only in environmental samples but also individual exposure. In this pilot study we develop and validate a multiresidue analytical method based on ultrasound-assisted extraction and gas-chromatography mass spectrometry for the simultaneous determination of 56 semi-VOCs using silicone wristbands (SWBs) as personal passive samplers. The developed method provided recoveries between 43% and 114% on sampled SWBs and method detection and quantification limits in the range of 0.1 - 35 ng/g and 0.3 - 119 ng/g, respectively. A preliminary study was performed with a small group of adults living in the industrial city of Tarragona (north-eastern Spain) to evaluate the applicability of SWBs for monitoring individual exposure to the studied HPVCs and PAHs. Benzothiazoles, benzenesulfonamides, UV stabilisers and phenolic antioxidants were determined for the first time in SWBs. Phthalates (PAEs), stood out above the rest, accounting for 52% of the total concentrations. Diethylhexyl phthalate was the compound found at the highest concentrations with values between 1.1 - 82 μg/g. Carcinogenic and non-carcinogenic dermal risk assessment was performed for adults and considering two scenarios (low and high). PAHs were the compounds with the highest carcinogenic and non-carcinogenic dermal risk regardless of the exposure scenario. The second family of compounds that contributed the most to the total risk were PAEs but high punctual concentrations of these compounds caused significant differences between exposure scenarios.

Evaluating the role of microbial degradation and analytical methods in monitoring imidacloprid persistence for white grub management in turfgrass

Evaluating the role of microbial degradation and analytical methods in monitoring imidacloprid persistence for white grub management in turfgrass

Estimating rate of lung function change using clinical spirometry data

RationaleIn chronic obstructive pulmonary disease (COPD), accurately estimating lung function from electronic health record (EHR) data would be beneficial but requires addressing complexities in clinically obtained testing. This study compared...

Manajemen Pembiayaan Pendidikan di Sekolah Dasar Islam Terpadu Al Fatih Depok

The operational structure and funding of education is an important component in educational administration management which has the capacity to have a significant impact on the quality of human resources. This study intends to ensure the following: (1) Plan the budget in order to improve educational standards; (2) allocate human resources for the purposes of managing education financing; (3) implementing education financing management; and (4) supervising the education financing system in order to improve standards at SDIT AL FATIH Depok. Qualitative, analytical and descriptive methods were used in this study. Documentation, interviews and observation are the techniques used to obtain data. Data collection, data reduction, data presentation, and drawing conclusions are the four components of Miles and Huberman's interactive analysis model used in the data analysis approach. Credibility, transferability, dependability and confirmability are used in the process of determining data validity.The findings show the following: 1) SDIT AL FATIH Depok prepares and describes education budget planning in the form of RAPBPT, which is implemented at the end of each year by identifying all appropriate programs and budgets. 1) The process of allocating funds for education starts from the source, where the head of the foundation decides on the choices that have been reached through meetings involving stakeholders from the school community and repeats the assessment. Putting human resources in charge of overseeing the money is secondary. The principal is responsible for the financial management of SDIT AL FATIH Depok, in accordance with the organizational structure; The foundation and education department oversee the management of SDIT AL FATIH Depok's education funds. 3. The budget implementation process is used to fund school programs, as well as spending on goods and services, development, and so on. 4. After that, the School Committee, the AL FATIH Depok Foundation, and the Education Office received the school's financial accountability report.

An impedimetric determination of zearalenone on MIP-modified carboceramic electrode

Zearalenone (ZEN) is a mycotoxin that poses significant risks to human and animal health due to its mutagenic, immunosuppressive, and carcinogenic properties. This study presents a novel analytical method for detecting ZEN using electrochemical impedance spectroscopy (EIS) combined with a molecularly imprinted polymer (MIP). ZEN, used as the template molecule, was incorporated into polypyrrole on screen-printed electrodes (SPE), and a ZEN-sensitive MIP sensor was created through template removal. The modified sensor surfaces were characterized by EIS and scanning electron microscopy (SEM). An impedimetric MIP sensor for ZEN was developed, offering a detection range from 1 pM to 500 pM. The method's limit of detection (LOD) was established at 1 pM (0.3 pg/mL) with a signal-to-noise ratio of 3 (S/N = 3). The method demonstrated high precision and accuracy, with a maximum relative standard deviation (RSD) of less than 4.4% at a 95% confidence level, and relative error (RE) values ranging from −0.8% to −2.7%. The selectivity of the developed MIP sensor was evaluated using ochratoxin A, ochratoxin B, and aflatoxin B1, with no significant interference observed. ZEN recovery from spiked samples was between 95% and 105%, indicating that the method was successfully applied to grain samples, including corn, rice, and wheat.

Evaluation of Numerical and Analytical Methods to Accurately Measure Elastic Modulus of the Cobalt Chromium Alloy Fabricated by Laser Direct Energy Deposition Process

Evaluation of Numerical and Analytical Methods to Accurately Measure Elastic Modulus of the Cobalt Chromium Alloy Fabricated by Laser Direct Energy Deposition Process

Chemical Characterization of Coal: Quality Control and Applications of Nuclear Analytical Methods Utilizing Neutrons (Thermal and Fast) and Low Energy Protons from Accelerators

Chemical Characterization of Coal: Quality Control and Applications of Nuclear Analytical Methods Utilizing Neutrons (Thermal and Fast) and Low Energy Protons from Accelerators

Accretion tori around rotating neutron stars I. Structure, shape, and size

We present a full general relativistic analytic solution for a radiation-pressure-supported equilibrium fluid torus orbiting a rotating neutron star (NS). We applied previously developed analytical methods that include the effects of both the NS's angular momentum and quadrupole moment in the Hartle-Thorne geometry. The structure, size, and shape of the torus are explored, with a particular focus on the critically thick solution -- the cusp tori. For the astrophysically relevant range of NS parameters, we examined how our findings differ from those obtained for the Schwarzschild space-time. The solutions for rotating stars display signatures of an interplay between relativistic and Newtonian effects where the impact of the NS angular momentum and quadrupole moment are almost counterbalanced at a given radius. Nevertheless, the space-time parameters still strongly influence the size of tori, which can be shown in a coordinate-independent way. Finally, we discuss the importance of the size of the central NS which determines whether or not a surrounding torus exists. We provide a set of tools in a Wolfram Mathematica code, which establishes a basis for further investigation of the impact of the NSs’ super-dense matter equation of state on the spectral and temporal behaviour of accretion tori.

Two-dimensional thermal and dynamical strain in landfast sea ice from InSAR: results from a new analytical inverse method and field observations

Abstract Observing continuous strain in sea ice at geophysical scales of tens of meters to kilometers requires displacement measurements made with millimeter-scale precision. Satellite-based interferometric synthetic aperture radar (InSAR) provides such precise measurements of relative surface displacement over broad spatial areas at regular intervals and, unlike point displacement measurements, it allows confident delineation of continuously deforming regions. However, InSAR only captures the 1-D component of surface displacement parallel to a radar's lines-of-sight. Additional analysis is required to translate between these 1-D observations and the horizontal or vertical displacements they arose from. Previous studies utilize an iterative inverse model to constrain estimates of horizontal surface displacement from InSAR. Here we build upon that work outlining a new analytical inverse modeling method for quantifying displacement and strain over continuous regions of sea ice and provide comparison between model results and independent displacement observations. We demonstrate the inverse method over both landfast and drifting ice along the Alaskan coastline. These intercomparisons highlight environments in which displacements inverted from interferograms may be used as an independent estimator of surface strain, as well as the potential for the outlined inverse methods to be used in conjunction with other observing methods.

B-056 Clinical and Analytical Performance Evaluation of Two Immunoassays for the Detection of Mite Specific Serum IgE for Allergy Diagnosis

Abstract Background IgE-mediated allergic diseases can be considered a modern epidemic, with exponential growth mainly in industrialized countries. Diagnosis is usually based on detailed medical history, physical examination, skin or challenge test and the determination of allergen-specific serum IgE - a laboratory test that has become a high-value tool in the allergy patient's journey over the last three decades. As the identification of specific immunoglobulin E (sIgE) for a given allergen is important to aid in the allergy diagnosis, several methods for detecting IgE in vitro are available worldwide and, in recent years, there have been several improvements in laboratory methodologies bringing greater advances in terms of clinical and analytical performance. The study aims to evaluate the clinical performance and correlation between two different sIgE assays (IMMULITE® 2000 3gAllergy™ and ImmunoCAP) and their concordance with Skin Prick Test (SPT) and clinical history. Methods This prospective study was conducted with approximately 130 consecutive patients who underwent evaluation of allergic diseases in different centers in Brazil. Clinical data, blood samples, and SPT results were collected. With the blood samples, the allergens D1, D2 and D201 were evaluated using both methods (IMMULITE® 2000 3gAllergy™ and ImmunoCAP) and the data were evaluated in a correlation study and clinical concordance analysis. Results Qualitatively evaluating the sIgE results between the two immunoassays, at the cutoff point considered clinically significant (≥ 0.35 KU/L), a total agreement of 95.2% (D1); 95.1% (D2), 91.7% (D201) and 96.8% (Derp2) was observed. Semi-quantitatively evaluating through reactive interpretation, an agreement of 89.5% (D1); 91.06% (D2); 87.60% (D201) and 93.33% (Derp2) was observed. Spearman's correlation between the analytical methods was 0.85 (D1), 0.93 (D2), 0.68 (D201) and 0.76 (Derp2). When compared with the SPT results, a total agreement of 78.7% and 80.1% was obtained for 3gAllergy and ImmunoCAP, respectively, with slightly higher positive agreement for both methods. Conclusions The two methods have good agreement with each other, with greater differences when evaluated quantitatively. However, when compared to clinical history and skin prick test results, both perform very similarly with a few differences that may be caused by the difference in the assay design.

B-166 Differentiation of Aziridine Functionality from Related Functional Groups in Protonated Analytes by Using Selective Ion-Molecule Reactions

Abstract Background The development of better methods for the rapid and reliable identification of unknown compounds in mixtures is urgently needed in drug development. Aziridines, in particular, are used for drug synthesis but are potentially mutagenic and carcinogenic compounds. However, the detection and identification of these compounds pose challenges for many analytical methods, such as Nuclear Magnetic Resonance (NMR) spectroscopy, Fourier-transform infrared spectroscopy (FT-IR), and X-ray crystallography. These techniques are time-consuming and often require large quantities of highly pure compounds. Methods Therefore, this study demonstrates that selective gas-phase ion-molecule reactions of protonated analytes with neutral tris(dimethylamino)borane (TDMAB), followed by diagnostic collision-activated dissociation (CAD), can be used to differentiate aziridines from structurally related compounds in a modified linear quadrupole ion trap (LQIT) mass spectrometer. The experiments were performed using an atmospheric pressure chemical ionization (APCI) source in positive ion detection mode. TDMAB was purchased from Sigma-Aldrich and used without purification. It was introduced into the ion trap (2 mtorr of helium buffer gas) via an external reagent mixing manifold through a syringe pump at a flow rate of 10 μL h-1 and diluted with helium before entering the ion trap through a variable leak valve. All analytes were prepared at a concentration of 1 mM in methanol. The protonated analytes were transferred into the ion trap, isolated, and allowed to react with TDMAB (MS2 experiments). Results Product ions formed upon reactions of the analyte ions with TDMAB were subjected to a collision-activated dissociation (CAD) experiment (MS3 experiments). CAD on product ions produced diagnostic fragment ions with 25- and 43 m/z-units lower m/z values than the adduct - DMA product ions. Quantum chemical calculations were employed using the Gaussian 16 program calculated at the M06-2X/6-311++G(d,p) level of theory to provide theoretical foundation and to explore the underlying mechanisms of the observed gas-phase reactions. None of the tested structurally related analytes produced a similar fragmentation pattern Conclusions The innovative approach presented in this study offers a promising avenue for enhancing efficiency and accuracy in drug development. The successful differentiation of aziridine is an alternative method in overcoming the limitation of traditional techniques. The findings from the research contributes to the advancement of analytical techniques, addressing critical issues in identifying impurities in drug products. The versatility of the methods extends beyond drug developments, making it applicable in various other fields such as in molecular diagnostics, metabolism and laboratory medicines.

NMR-Based Analysis of Cellular Central Energy Metabolism and Exchange Rates.

Cell cultures are widely used in studies to gain mechanistic insights of metabolic processes. The foundation of these studies lies on the quantification of intracellular and extracellular metabolites, and nuclear magnetic resonance (NMR) is one of the key analytical platforms used to this aim. Among the factors influencing the quality of the produced data are the sampling procedures as well as the acquisition and processing of spectroscopic data. Here we provide our workflow for obtaining quantitative metabolic data from adherent mammalian cells using NMR spectroscopy. The described protocol is compatible with other analytical methods like LC- or GC-MS-based lipidomics and untargeted metabolomics from the same sample. We also show how the collected extracellular data can be used to extract exchange flux rates, particularly useful for flux analysis studies and metabolic engineering of human-induced pluripotent stem cells.

A-331 Monitoring Operators Proficiency at Point of Care is Crucial for Reliable Patient Values. A Practical Example with Patient Blood Chloride, Potassium and Sodium Measurands Assayed with i-STAT®

Abstract Background While i-STAT® cartridges offer the Physician a spectrum of analytical methods at the point of care for prompt diagnosis and interventions, these methods have to be harmonized with the laboratory methods in order to reliably detect shifts and trends. With this practical example we illustrate the importance of a program of routine comparisons between the i-STAT® and laboratory methods to detect analytical differences exceeding the CLIA’s criterion and potentially having adverse clinical implications. Methods Patient blood chloride (Cl), potassium (K) and sodium (Na) values as obtained by nurses with i-STAT Chem 8 ™ cartridges (Abbott Laboratories) at the point of care, where daily compared with the values as obtained with the Laboratory method (two cobas 6000®, Roche Diagnostics) using green top BD® lithium heparin tubes (Becton Dickinson) collected within thirty minutes of the i-STAT assay. The data were electronically stored in RALS™ (RALS Informatics) and transferred to Minitab® (Version 21, Minitab Inc.) statistical software. The two analytical methods were compared using the orthogonal and the polynomial ordinary least squares (POLS) regression models and their graphic representations. The aptness of the methods was evaluated with the standardized residuals diagnostics for normality, independence, outliers (Standardized residual >|3|) and influential observations (Hi>0.5). For acceptance of the differences the CLIA’s total error criterion was employed. (CI: target value ± 5%; K: target value ± 0.5 mmol/L; Na: target value ± 4 mmol/L). Results In the first four months of the study the number of differences exceeding the CLIA’s criterion was not acceptable. [Cl: 10% (165/1564); K: 7% (109/1593); Na: 4% (66/1586)]. These differences were occurring throughout the analytical range (AMR). Consequently, the operator’s technique was suspected and the POCT senior technologists (CA, FA) adopted operator specific interventions. This strategy was effective in the following month and the improvements were maintained for seven consecutive months. Monthly differences exceeding the CLIA’s criterion decreased significantly [Cl:1.9% (52/2777): K:0.9% (25/2868): Na:0.5% (15/2896)]. This was clearly illustrated with the dot plot by date and the parallel box plots by month. Regression analysis showed that the orthogonal and the OLS models were equivalent. Cl: Orthogonal y=1.7+0.99x, OLS y=12+0.88x. K; Orthogonal y=0.2+1.2x, OLS y=0.1+0.96x. Na: orthogonal y=3+0.98x, OLS y=14+0.9x. Additionally, the POLS model showed a linear relationship within the AMR intervals with few outliers (Cl=11; K=7; Na=9), no influential observations (Hi<0.5) and equality of monthly regression lines (P>0.05). Conclusions The implementation of daily comparisons between patient values as obtained with the i-STAT method and those as obtained by the Laboratory method in the interval of thirty minutes, allowed the identification of individual operators requiring additional training. This strategy ensured reliable performance for eight consecutive months. This study clearly showed that the addition of continuous supervision and training of operators to quality control and quality assurance practices, ensured the interchangeability of patient values as obtained with i-STAT and those as obtained with the Laboratory method. Electronic collection of data and analysis with appropriate statistical software, such as Minitab, was crucial for the implementation of this program.

A-314 Influence of EDTA on TSH and 17-OHP in Newborn Screening: A Case Study

Abstract Background A 9-month-old infant presented with developmental motor delay. Comprehensive evaluation including microarray and brain MRI revealed no specific abnormalities except for hypotonicity. The patient's perinatal history, including newborn screening test (NST), showed no remarkable findings. Additionally, the infant exhibited facial dysmorphism and microcephaly, leading to another NST to explore potential metabolic diseases. Upon NST, Thyroid-Stimulating Hormone (TSH) levels were 1.86 and 1.27 mlU/L (duplicate testing results; reference value: <12 mlU/L), 17-Hydroxyprogesterone (17-OHP) levels were 0.55 and 0.48 ng/mL (duplicate testing results; reference value adjusted for body weight: <5.0 ng/mL), and total Galactose (Gal) and Galactose-1-Phosphate (Gal-1-P) levels were 1.68 mg/dL (reference value: <8 mg/dL). Methods Upon inspection of the dried blood spot (DBS) sample, the DBS used for the tests partially appeared to be inadequately collected on the absorbent filter paper, which could cause errors related to the disc and specimen itself. Consequently, re-sampling and re-testing were necessary to ensure accuracy. A second NST was performed with the new DBS samples. In the second NST results, most parameters were within the allowable ranges. However, the TSH levels were notably below the detectable limit (<0.7 mlU/L), and the 17-OHP levels were significantly elevated at 332ng/mL, diverging markedly from the initial NST results. To ensure reliability of the measured test results, TSH levels were analyzed using both the existing PerkinElmer equipment and compared with results from a Cobas 8000 system (Roche) and mass spectrometry. Similarly, 17-OHP levels were also compared using mass spectrometry. Results Upon comparing the TSH results, both analytical methods (PerkinElmer and Roche) yielded identical outcomes. However, significant discrepancy was observed when compared to mass spectrometry results. Review of the relevant testing batches showed no significant quality control issues with the NST, leading to clinical suspicion of ethylene-diamine-tetraacetic acid (EDTA)-induced interference. According to existing literature, when NST are conducted using the lanthanide fluorescence method, distortions can occur in DBS containing EDTA, depending on the concentration of EDTA present. In such cases, the EDTA-induced interference may result in false-negative TSH and false-positive 17-OHP results. These discrepancies can be differentiated using standard MS/MS testing. With regards to our case, upon enquiry, the second DBS sample was revealed to be collected from an existing EDTA sample rather than directly from the patient. Thus, adequate DBS discs from the initial sample were obtained and re-analyzed for NST using mass spectrometry, with final results reporting no specific abnormalities. Conclusions The discrepancies observed in TSH and 17-OHP levels between the first and second set of DBS samples were found to be unrelated to other laboratory factors, such as quality control issues. Instead, they were conclusively identified as false-negative and false-positive results associated with interference due to the use of EDTA-containing collection bottles. Mass spectrometry analysis was able to confirm the interference. Clinical awareness should be promoted in order to prevent EDTA-induced interference in NST.