Analysis Method Research Articles

Quantification of native lignin structural features with gel-phase 2D-HSQC0 reveals lignin structural changes during extraction.

Our ability to study and valorize the lignin fraction of biomass is hampered by the fundamental and still unmet challenge of precisely quantifying native lignin's structural features. Here, we developed a rapid elevated-temperature 1H-13C Heteronuclear Single-Quantum Coherence Zero (HSQC0) NMR method that enables this precise quantification of native lignin structural characteristics even with whole plant cell wall (WPCW) NMR spectroscopy, overcoming fast spin relaxation in the gel phase. We also formulated a Gaussian fitting algorithm to perform automatic and reliable spectral integration. By combining HSQC0 measurements with yield measurements following depolymerization, we can confirm the combinatorial nature of radical coupling reactions during biosynthesis leading to a random sequential organization of linkages within a largely linear lignin chain. Such analyses illustrate how this analytical method can greatly facilitate the study of native lignin structure, which can then be used for fundamental studies or to understand lignin depolymerization methods like reductive catalytic fractionation or aldehyde-assisted fractionation.

OILVEQ: an Italian external quality control scheme for cannabinoids analysis in galenic preparations of cannabis oil.

Italy legalized cannabis oil for specific medical conditions (neuropathic pain, refractory epilepsy and other established pathologies) in 2015, but mandates titration of principal cannabinoids before marketing each batch using iphenated techniques coupled with mass spectrometry. To assess reliability of laboratories from the Italian National Health Service in charge of titrating the batches, the Italian National Institute of Health set up an quality control program on determination of Δ9-tetrahydrocannabinol l (THC), cannabidiol (CBD), Δ9-tetrahydrocannabinolic acid A (THCA-A) and cannabidiolic acid (CBDA) in cannabis oil preparations. Two rounds of exercises have been carried out since 2019, involving sixteen Italian laboratories. Five different cannabis oil samples (19-1A and 19-1B for the first round and 22-1A, 22-1B and 22-1C for the second one were prepared and 1 mL amount of each sample was sent to the laboratories. The quantitative performance of each laboratory was assessed calculating the z-score value, a statistical measurement for value's relationship to the mean of a group of values. In the first round, eight out of fourteen laboratories employed an LC-MS while the remaining six used GC-MS. Differently, in the second round, six out of eleven laboratories employed a GC-MS while the remaining five used LC-MS. In the first round, only 28.6 % laboratories achieved an acceptable performance (z-score±2), and all of them used LC-MS as analytical method. In the second round, none of the laboratories achieved an acceptable performance. Satisfactory results, based on z-scores, were generally low (0.0-75.0 %), with only one exception of 100 % for THCA-A determination in sample 22-1B. In the second round, three false negatives (two THC and one CBD by GC-MS determination) were reported while no false positives were described in the blank sample. The two rounds yielded a mean ERR% of 42 % approximately and a mean CV% around 70 % in GC-MS determination. When applying LC-MS determination, the two rounds yielded a mean ERR% of 36 % approximately and a mean CV% around 33 %. The obtained results underline the need for a clear and consistent protocol to be adopted by all laboratories intending to include the titration of oily cannabis-based products into their routinely analytical techniques. This emphasis on methodology standardization and participation to quality control schemes is essential for ensuring reliable and accurate measurements, ultimately enhancing the overall effectiveness and reliability of medical cannabis treatments.

Restoring forest ecosystem services through trait-based ecology

Restoration is moving towards a more mechanistic approach that emphasizes restoration of ecosystem services. Trait-based approaches provide links between species identity and ecosystem functions and have been suggested as a promising way to formally integrate ecosystem services in the design of restoration programs. While practitioners have been routinely using informal knowledge on plant traits in their practices, these approaches are underutilized as operationalization remains challenging. The goal of this paper is to provide guidance for applied scientists and restoration practitioners looking to apply a trait-based approach to restore forest ecosystems. We present a five-step framework: 1) selection of services to be restored, 2) trait selection, 3) data acquisition, 4) analytical planning, and 5) empirical testing and monitoring. We use three Canadian case studies to illustrate the applicability of our framework and the variety of ways trait-based approaches can inform restoration practices: 1) restoration of urban woodlots after an insect outbreak, 2) restoration of a smelter damaged landscape surrounding an urban area, and 3) reclamation of remote upland forests after oil and gas related disturbances. We describe the major mechanisms and traits that determine vegetation effects on ecosystem services of importance in each case study. We then discuss data availability, methodological constraints, comparability issues, analytical methods, and the importance of empirical testing and monitoring to ensure realistic prediction of service restoration. By outlining issues and offering practical information, we aim to contribute to a more robust use of traits in ecological restoration.

Nutritional Characteristics and Sensory Properties of Maize-based Ogi Supplemented with Mushroom (Pleurotus ostreatus) Flour

The study evaluates the effect of supplementation of maize-based ogi with mushroom (Pleurotus ostreatus) flour on nutritional characteristics and sensory properties. Standard processing and analytical methods were used in raw material preparation and analyses. Ogi and mushroom flour were blended in ratio of 100:0, 90:10, 80:20, 70:30 and labeled A, B, C and D respectively. A commercial maize based complementary food was used as control. There was significant difference (p < 0.05) among all samples for all the Vitamin assayed with values ranging from 4.86 to 9.06 (µg/100g), 0.32 to 1.09 mg/100 g, 0.22 to 0.69 mg/100 g, 3.82 to 13.03 mg/100 g and 0.13 to 1.12 mg/100 g for vitamin A, B1, B2, B3 and C. The vitamin values compare favourably with that of control sample. Significant (P<0.05) difference exists across the samples for Zn, Mg, Fe, K and Ca with values ranging from 1.12 to 1.71 mg/100 g, 37.7 to 102 mg/100 g, 4.72 to 13.23 mg/100 g, 23.05 to 125.3 mg/100 g and 125.5 to 160.25 mg/100 g respectively with corresponding higher values for control sample. Result showed negligible amounts of anti-nutritional factors ranging from 0.29 to 0.36 mg/100 g, 0.02 to 0.03 mg/100 g, 0.03 to 0.06 mg/100 g and 0.56 to 0.83 mg/100 g for phytate, oxalate, trypsin inhibitor and tannin respectively. The functional properties of the flour blends values ranged from 0.58 to 0.72 g/mL, 0.99 to 2.2 g/g, 5.21 to 8.94 g/g, 1.75 to 3.72 mL/g and 5.5 to 9.0% for bulk density, water absorption capacity, water retention capacity, swelling capacity and least gelation concentration respectively. Sensory scores revealed substantial overall acceptability of the samples. The quality of ogi samples were greatly improved by mushroom supplementation and could be nutritional beneficial to children and adults.

Analysis of the Dynamical Properties of Discrete Predator-Prey Systems with Fear Effects and Refuges

This paper examines the dynamic behavior of a particular category of discrete predator-prey system that feature both fear effect and refuge, using both analytical and numerical methods. The critical coefficients and properties of bifurcating periodic solutions for Flip and Hopf bifurcations are computed using the center manifold theorem and bifurcation theory. Additionally, numerical simulations are employed to illustrate the bifurcation phenomenon and chaos characteristics. The results demonstrate that period-doubling and Hopf bifurcations are two typical routes to generate chaos, as evidenced by the calculation of the maximum Lyapunov exponents near the critical bifurcation points. Finally, a feedback control method is suggested, utilizing feedback of system states and perturbation of feedback parameters, to efficiently manage the bifurcations and chaotic attractors of the discrete predator-prey model.

Optimal integration and planning of PV and wind renewable energy sources into distribution networks using the hybrid model of analytical techniques and metaheuristic algorithms: A deep learning-based approach

The optimal integration of Renewable Energy Sources (RESs) into distribution networks is crucial for sustainable energy generation. However, existing approaches utilized for optimal RES integration, including metaheuristic and analytical methods, exhibit limitations. Analytical methods are simple to implement, computationally efficient, and able to model power system mechanisms, yet they face scalability issues, making them inefficient for large-scale distribution systems. On the other hand, metaheuristic approaches, while flexible for complex problems, suffer from premature convergence problems, limiting their application in real distribution networks. To address these issues, this paper introduces a novel hybrid model that combines the strengths of analytical and metaheuristic techniques. The proposed model employs a deep learning-based method called bi-directional long short-term memory (B-LSTM) network is utilized to handle the uncertainties associated with the Photovoltaic (PV) and Wind Turbine (WT) generation and load demand. Subsequently, a distinctive analytical multi-objective index-based procedure is developed to minimize the real and reactive energy loss and voltage deviation by analyzing the branch current change caused by the RES penetration in distribution networks. The optimization problem is then solved using the binary particle swarm optimization (BPSO) technique. Importantly, the presented method considers the long-term nature of optimal RES integration and reflects the seasonal impacts of the load and RES output powers. The proposed approach is applied to the IEEE 33-bus test system. The simulation results show that the introduced hybrid model, by addressing the limitations of existing approaches, offers a promising solution for efficient and effective RES integration in distribution systems while requiring low computational effort, thereby advancing the transition towards sustainable energy infrastructure.

A Systematic Review on Autism and Hyperserotonemia: State-of-the-Art, Limitations, and Future Directions

Hyperserotonemia is one of the most studied endophenotypes in autism spectrum disorder (ASD), but there are still no unequivocal results about its causes or biological and behavioral outcomes. This systematic review summarizes the studies investigating the relationship between blood serotonin (5-HT) levels and ASD, comparing diagnostic tools, analytical methods, and clinical outcomes. A literature search on peripheral 5-HT levels and ASD was conducted. In total, 1104 publications were screened, of which 113 entered the present systematic review. Of these, 59 articles reported hyperserotonemia in subjects with ASD, and 26 presented correlations between 5-HT levels and ASD-core clinical outcomes. The 5-HT levels are increased in about half, and correlations between hyperserotonemia and clinical outcomes are detected in a quarter of the studies. The present research highlights a large amount of heterogeneity in this field, ranging from the characterization of ASD and control groups to diagnostic and clinical assessments, from blood sampling procedures to analytical methods, allowing us to delineate critical topics for future studies.

Machine learning-based prediction models affecting the recovery of postoperative bowel function for patients undergoing colorectal surgeries

PurposeThe debate surrounding factors influencing postoperative flatus and defecation in patients undergoing colorectal resection prompted this study. Our objective was to identify independent risk factors and develop prediction models for postoperative bowel function in patients undergoing colorectal surgeries.MethodsA retrospective analysis of medical records was conducted for patients who undergoing colorectal surgeries at Peking University People’s Hospital from January 2015 to October 2021. Machine learning algorithms were employed to identify risk factors and construct prediction models for the time of the first postoperative flatus and defecation. The prediction models were evaluated using sensitivity, specificity, the Youden index, and the area under the receiver operating characteristic curve (AUC) through logistic regression, random forest, Naïve Bayes, and extreme gradient boosting algorithms.ResultsThe study included 1358 patients for postoperative flatus timing analysis and 1430 patients for postoperative defecation timing analysis between January 2015 and December 2020 as part of the training phase. Additionally, a validation set comprised 200 patients who undergoing colorectal surgeries from January to October 2021. The logistic regression prediction model exhibited the highest AUC (0.78) for predicting the timing of the first postoperative flatus. Identified independent risk factors influencing the time of first postoperative flatus were Age (p < 0.01), oral laxatives for bowel preparation (p = 0.01), probiotics (p = 0.02), oral antibiotics for bowel preparation (p = 0.02), duration of operation (p = 0.02), postoperative fortified antibiotics (p = 0.02), and time of first postoperative feeding (p < 0.01). Furthermore, logistic regression achieved an AUC of 0.72 for predicting the time of first postoperative defecation, with age (p < 0.01), oral antibiotics for bowel preparation (p = 0.01), probiotics (p = 0.01), and time of first postoperative feeding (p < 0.01) identified as independent risk factors.ConclusionsThe study suggests that he use of probiotics and early recovery of diet may enhance the recovery of bowel function in patients undergoing colorectal surgeries. Among the various analytical methods used, logistic regression emerged as the most effective approach for predicting the timing of the first postoperative flatus and defecation in this patient population.

Impact of Relational Coordination on Job Satisfaction and Willingness to Stay: A Cross-Sectional Survey of Healthcare Professionals in South Tyrol, Italy

Job satisfaction and willingness to stay are critical for workforce stability in a challenging healthcare environment. This study examined how relational coordination, a key factor in teamwork and communication, influences outcomes among healthcare professionals in a bilingual, culturally mixed region of Italy. This cross-sectional survey included general practitioners, hospital physicians, nurses, and administrators from the South Tyrol Health Service, using the ‘Relational Coordination Survey’ and additional measures of job satisfaction and willingness to stay. The analytical methods used included descriptive statistics, correlations, and regression analyses. This study applied path analysis, including mediation and moderation techniques, to investigate the roles of relational coordination and job satisfaction in influencing the willingness to stay. It employs Conditional Process Analysis with the PROCESS macro in SPSS, focusing on models for moderated mediation analysis. The results indicated a critical influence of relational coordination on both job satisfaction and willingness to stay among the 525 healthcare professionals. Job satisfaction varied by health district and years of service, with midcareer professionals being the least satisfied. The findings highlight the central role of relational coordination in job satisfaction and willingness to stay and confirm that low job satisfaction increases turnover intentions. Relational coordination directly enhanced job satisfaction and willingness to stay, while also serving as a mediating factor that amplifies the impact of job satisfaction on retention intentions. This study reinforces the need for strong teamwork and communication to stabilize the healthcare workforce. Targeted interventions aimed at improving relational coordination could significantly enhance job satisfaction and retention among healthcare professionals, particularly in culturally diverse settings such as South Tyrol.

An overview of power loss calculation methods for high-frequency litz wires

Accurate calculation of power losses has always been important for the design and optimization of magnetic components consisting of windings and magnetic cores, such as inductors and transformers. Focusing on windings, litz wire outperforms its counterparts in terms of eddy current losses, making it particularly suitable for high-frequency (HF) applications. The power loss calculation of litz wire is however challenging due to its complex structure of thin strands twisted in multiple levels. This article therefore aims to review various kinds of litz wire power loss calculation methods from analytical methods, numerical methods to coupling ones. In addition to, the principles and applications of each method, their inherent correlation and differences are also highlighted in this article. On this basis, a comprehensive review and comparison of different calculation methods of litz-wire power loss are provided. Finally, future challenges and directions are then summarized, whose ultimate goal is to calculate the power loss of litz wire accurately and efficiently.

Molecularly imprinted polymers using high-performance liquid chromatography to detect and determine ethion pesticide in apricot, grapes, strawberry and soil samples

ABSTRACT This paper demonstrates the synthesis of molecularly imprinted polymers-solid phase extraction-liquid chromatography method at room temperature using bulk polymerisation of ethion pesticide, by high sensitivity, low costs and high stability. By making MIP for ethion as ethion-MIP, which could be detected with a UV-Vis spectrophotometer at 276 nm, a functional monomer of acrylic acid with cross-linking ethylene glycol dimethyl acrylate. The high-performance liquid chromatography methods developed in this study are accurate, sensitive, and precise to apricot, grapes, strawberry and soil samples. The elution process to the template ethion from the ethion-MIP, caused by minimum volume using solution of 1.0 mL of methanol-acetic acid (9:1) was obtained. Different factors affecting the reaction were studied and optimised. The calibration plot is linear in the concentration range of (0.02 to 1.0 µg mL−1). The relative standard deviations of (±2.0%) and detection limit of the method are 0.02 µg mL−1, and the maximum imprinting factor of ethion-MIP was 6.8 mgg−1. The results obtained the evidence of efficiency and reliability of the method for the ethion pesticide analysis and estimation for the capacitance of molecular imprinted polymer, analytical technical method by molecularly imprinted polymer and high-performance liquid chromatography.

АНАЛИЗ КАЧЕСТВА ВЕДЕНИЯ МЕДИЦИНСКОЙ ДОКУМЕНТАЦИИ ПРИ ОЦЕНКЕ ДЕЯТЕЛЬНОСТИ СТОМАТОЛОГИЧЕСКОЙ КЛИНИКИ

One of the criteria for assessing the quality of medical care is the complete maintenance of medical records. Defects in the preparation of medical documents lead to serious errors, such as incorrect diagnosis, unreasonable choice of diagnostic methods and treatment. To clarify the causes of their occurrence and adverse consequences, the study and analysis of medical records in dental organizations is of no small importance. Properly completed medical documentation serves as the basis for conducting forensic investigations within the framework of a criminal case in case of defects in the provision of medical dental care. The outpatient card of a dental patient is the object of quality control of medical care in dental organizations in the event of conflict situations. Purpose of the study: To analyze the quality control and safety of medical activities and the examination of the quality of medical dental care carried out in the dental clinic of the Military Medical Academy named after. CM. Kirov. Material and methods. During the study, analytical and statistical methods were used. The collection of primary information was carried out on the basis of data from primary medical documentation - 1067 outpatient records of dental patients. Results and condemnation. A statistically significant influence of a doctor’s work experience on the completeness of providing information about patients’ complaints was revealed. Doctors with less experience provide more complete descriptions of patient complaints. Among all complaints, aesthetic ones were most often described; complaints of a morphological and functional nature were noted quite rarely. In the cards of form No. 043/u, in 46.67% there was no information about the bite, the hygiene index was not determined, treatment plans and visit diaries were not filled out correctly. Conclusions. Internal quality assessment helps to detect defects in filling out dental patient outpatient records. The importance of adequate medical record keeping is beyond doubt; the form of the medical record must meet the needs of dentists and contain information that complies with the legal and regulatory framework.

Cyclical issues of pricing of regulated services

The article reflects current issues of the formation and regulation of tariffs that have developed in the modern economy. A brief analysis of the historical development of tariff regulation with the assessment of the used methods and ways is conducted. The authors identified expediency of tariff formation and regulation by a single body determining functions and set tasks. The study uses descriptive, analytical, and comparative methods. The article describes a positive example of applying the practice of deregulation with subsequent possible extension to other areas. The reasons of inefficiency of using the marginal indices mechanism are determined and justified, which is directly related to underfunding of the industry and lack of investment components. The question is raised about the fulfillment of the development, or social function by tariff regulation. It is proved that the current tariff system is not able to change the situation of increasing the investment base necessary to stabilise the deterioration of infrastructure. The main components of the current tariff regulation system are identified, and the directions of a new development model are proposed with consideration to the problems found by the study. According to the research results, conclusions are given that reflect the essence of the designated topic for possible solutions to issues existing in the functioning development model.

Advancements in P3HT:PCBM solar cells through experimental and simulated techniques

Abstract Organic solar cells are a promising alternative in photovoltaics due to their low manufacturing cost and flexibility. In this study, we developed an organic solar cell of structure (ITO/PEDOT:PSS/P3HT:PCBM/Al) where the active layer is represented by P3HT:PCBM. Experimental studies revealed that this layer has an energy gap of 1.9 eV and a good absorption coefficient of 〖3×10〗^5 〖cm〗^(-1). Using analytical and experimental methods based on (J-V-T) curves, we extracted the key parameters of our device, including parasitic resistances (R_s and R_sh), ideality factor (n), and Schottky potential barrier (ϕ_B) at different temperatures. Also the charge transport mechanism in our junction is identified in this study. We then used simulation to evaluate the performance of our solar cell, obtaining an initial efficiency of 2.13%, in line with experimental results from other research. Our results confirm the feasibility of our theoretical approach, with performance consistent with previous work. However, by introducing an ETL layer (PFN-Br or PDINO), we were able to improve efficiency up to 4.25%. These results highlight the importance of optimising intermediate layers to maximise the efficiency of organic solar cells.

Design of Radial Distribution System to Study Load-Flow and Short Circuit Analysis Using ETAP Software

This work's analysis provides information on fault analysis and load flow studies, which help to understand how radial distribution networks operate both in normal and emergency circumstances. The research explores optimization methods, describing capacitor placement, transformer size, and feeder reconfiguration in order to lower losses and increase system efficacy. Moreover, the work looks at reliability-focused maintenance techniques, stressing the need of predictive maintenance and condition monitoring in raising the dependability of radial distribution networks. Modern electrical power networks depend heavily on their radial distribution system, which effectively and dependable distributes electricity to customers. Many radial distribution system-related topics are covered in detail on this website, including analytical methods, optimization processes, and dependability enhancement strategies. Power flow, voltage control, and losses in radial networks are investigated in this paper under a range of operational situations. The last and crucial stage of a power system, the electrical distribution system makes sure that customers have a steady supply of electricity. Regretfully, because it is often neglected and exposed to environmental risks, our distribution network has a number of problems. Our distribution feeder is rigorously analyzed for load flow and short-circuits in order to overcome these challenges and find and fix problems. The main topics of this study are the load flow and short-circuit analysis of a radial distribution feeder, which is mostly constructed with (ETAP). The final and crucial part of a power system, the electrical distribution system ensures that consumers receive an uninterrupted and steady supply of electricity. Our distribution feeder undergoes a rigorous and cautious process to address these issues front on because of the uncontrollable nature and susceptibility of our network to environmental hazards. This paper delves deeply into the issues of short-circuiting and load flow in radial distribution feeders. Both symmetrical and asymmetrical faults are thoroughly investigated by mathematical computations and ETAP simulations; the results of the software simulations are contrasted with those of the mathematical analysis. These discoveries will definitely influence the development and management of our system and point us in the direction of workable and practical solutions.

Selection of texture-associated biomarkers in chilled and iced grass carp (Ctenopharyngodon idella) fillets via DIA-based proteomics

Consumers care about the texture of fresh fish flesh, but a rapid quantitative analytical method for this has not been properly established. In this study, texture-associated biomarkers were selected by DIA-based proteomics for possible future application. Results indicated a significant decline in texture and moisture characteristics with extended storage under chilled and iced conditions, and flesh quality was categorized into three intervals. A total of 8 texture-associated biomarkers were identified in the chilled storage group, and 3 distinct ones in the iced storage group. Biomarkers were further refined based on their expression levels. Isobutyryl-CoA dehydrogenase, mitochondrial and [Phosphatase 2A protein]-leucine-carboxy methyltransferase were identified as effective texture-associated biomarkers for chilled fish, and Staphylococcal nuclease domain-containing protein 1 for iced fish. This study provided suitable proteins as indicators of fresh fish flesh texture, which could help establish a rapid and convenient texture testing method in future studies.

ИЗУЧЕНИЕ ВАЛИДАЦИОННЫХ ХАРАКТЕРИСТИК МЕТОДИК ИСПЫТАНИЯ НА ПОДЛИННОСТЬ И КОЛИЧЕСТВЕННОГО ОПРЕДЕЛЕНИЯ АЦИЗОЛА В СТОМАТОЛОГИЧЕСКОМ ГЕЛЕ

In the quality assurance system for medicinal products, an important role is played by the procedure for validation of analytical methods at the stages of development, testing, technology and serial production. The need for validation at the stage of drug development is due to the fact that it is possible to promptly identify the shortcomings of the method and significantly improve it. The purpose of this study is to validate methods for testing «The authenticity» and «Quantitative determination» of acyzole in dental gel. Materials and methods. To achieve this goal, an active pharmaceutical substance of pharmacopoeial quality was used. When developing methods for testing for “Authenticity,” a reaction with oxalic acid to the zinc cation determined in the composition of acyzole was used. For the quantitative determination of acyzole, the complexometric method was used. The objects of the study were three series of gel samples. Results and discussion. As a result of the research, a method for testing «Authenticity» was developed; it was found that the proposed method is characterized by a negative analytical signal on model mixtures free of the analyte component and placebo, and a positive analytical signal on model mixtures of various compositions containing the analyte component. The validation characteristics of methods for the quantitative determination of acyzole in the gel were studied. positive results were obtained. The proposed methods can be used for inclusion in the regulatory documentation for the developed gel. Conclusion. When assessing the validation characteristics of the proposed methods, it was established that the methods for testing the «Authenticity» and «Quantitative determination» of acyzole in the gel are specific, the methods of quantitative determination are characterized by accuracy and repeatability, a linear dependence in the analytical range of ±20% of the declared amount of acyzole, which allows them to be used for a reliable assessment quality of the developed dental gel.

Analysis of microcystins in alum water treatment sludges: holding times, temperatures, linearity of response, and sensitivity to pre-coagulation cell titers

ABSTRACT ELISA assays are a potential tool to screen for dissolved or cell bound microcystins in drinking water treatment sludges. In order to evaluate this potential more thoroughly, experiments were performed in alum sludges to: (1) evaluate the impacts of sample storage times, temperatures, and sludge composition on spiked microcystin-LR recovery by ELISA; (2) examine the linearity of ELISA responses to spiked microcystin-LR as a function of sludge composition; and (3) examine the sensitivity ELISA and LC/MS/MS to five different concentrations of microcystin-producing cyanobacteria entrained in sludges of two different compositions. During storage experiments, microcystin recovery efficiencies ranged from 85% to 125% across the range of 12 storage time and temperature combinations with recovery efficiencies in 7 of the 12 combinations falling into the 90% to 110% range. During the linearity experiments, linear models fit ELISA responses in all sludge compositions with R2 values ≥ 0.95. During the sensitivity studies, simple freeze/thaw/centrifugation processing combined with ELISA or LC/MS/MS analyses resulted in detection of microcystins in thickened sludges derived from pre-coagulation cell suspensions of 102–106 cells/mL. In addition, the relationships between toxin concentrations in sludges and the original cell titers were linear regardless of analytical method.

Development of a highly sensitive method based on QuEChERS and GC–MS/MS for the determination of polycyclic aromatic hydrocarbons in infant foods

Polycyclic aromatic hydrocarbons (PAHs) are environmental contaminants that can be found in various food products, including those intended for infants. Due to their potential health risks, it is crucial to develop sensitive analytical methods for the accurate determination of PAHs in infant foods. This study describes the development and validation of a highly sensitive method for the quantification of European PAH markers, namely benzo[a]pyrene, benzo[a]anthracene, chrysene, and benzo[b]fluoranthene, using gas chromatography–tandem mass spectrometry (GC–MS/MS), in baby food samples. The first step was the optimization of the sample preparation procedure, performed using different methods based on the QuEChERS approach, also testing different extraction solvents. Several factors such as extraction efficiency, selectivity, and recovery were evaluated to choose the most effective procedure for sample preparation. Furthermore, the GC–MS/MS method was optimized, evaluating parameters such as linearity, sensitivity, accuracy, and robustness using spiked infant food samples. The method demonstrated excellent linearities with a correlation coefficient higher than 0.999 over a wide concentration range, and limits of detection and limits of quantification in the range 0.019–0.036 μg/kg and 0.06–0.11 μg/kg, respectively. Extraction recoveries were between 73.1 and 110.7%, with relative standard deviations always lower than 8%. These findings are compliant with the indications of the European Commission (Reg. 836/2011). To assess the applicability of the method to official control activities, a survey was conducted on commercially available infant food products. Four markers were determined in commercial samples belonging to different food categories for infants and young children. The outcome of this monitoring showed that PAH contamination, in all samples, was below the quantification limits. In conclusion, the developed GC–MS/MS method provides a highly sensitive and reliable approach for the determination of PAHs in baby foods. The optimized sample preparation, instrumental parameters, and validation results ensure accurate quantification of 4 PAHs even at trace levels. This method could contribute to the assessment of PAH exposure in infants and it could support regulatory efforts to ensure the safety and quality of infant food products with regular monitoring.

Advancements in liquid chromatography‐mass spectrometry for amphetamine analysis in unconventional biological matrices: Focus on oral fluid and hair samples

AbstractAmphetamines (AMPHs) and their derivatives are potent central nervous system stimulants, in 2020 an astonishing 34 million regular users were reported worldwide. Consequently, there has been a critical need for the development of methods capable of detecting these compounds in alternative biological matrices. The review article discusses the analysis of amphetamines and their derivatives in alternative biological matrices, such as hair and oral fluid (OF), using liquid chromatography‐mass spectrometry. Compiles data from 28 articles published between 2012 and 2022, focusing on 13 articles on OFs and 15 on hair analysis. The article highlights the advantages of using these alternative matrices, including less invasive collection methods, greater sample stability, and simplified extraction processes. Additionally, prevalent analytical practices such as the use of C18 columns and the incorporation of formic acid and methanol into mobile phases are discussed. Furthermore, it demonstrates that the most used method for collecting OF is the Quantisal device, as well as solid phase extraction is also the most used for the same matrix. The review serves as a guide for researchers interested in analytical methods for identifying AMPHs, offering insights into advances, challenges, and the most used in the area.