Relative Standard Deviation Values Research Articles

Rapid and practical colorimetric biosensor for leishmaniasis diseases

In this article, a colorimetric biosensor for detection of Leishmania major surface protease (Gp63) antibody (anti-gp63) was developed by using gold nanoparticle (AuNP) as a color reagent. The dispersion or aggregation of AuNPs leads to a distinct and sensitive change in UV-vis spectra and solution color. For this purpose, kinetoplastid membrane protein-11 (KMP-11) was labeled with AuNPs surface directly. After that, Gp63 antibody was added in the KMP-11@AuNP solution and a color change from red/pink to purple/violet was observed. As a result, anti-gp63 solution diluted at a ratio of 1:640 can be detected with the developed colorimetric leishmania biosensor. The relative standard deviation value for 1:320 diluted anti-gp63 was calculated as 1.29 %. Furthermore, the linear range of the developed colorimetric biosensor was determined as 1:80 to 1:640. Moreover, developed Leishmania biosensor was applied for detection of leishmania parasite crude antigen and rabbit serum which were used as positive and negative samples respectively. As a result, the recovery values for the measurements of aforementioned samples were calculated as 95.3 % ± 0.02, 103.1 % ± 0.02, 96.2 % ± 0.01 and 95.5 % ± 0.03 for dilutions of 1:200, 1:160, 1:320 and 1:640 anti-gp63 solutions respectively.

Preparation and characterization of AChE immobilized magnetic bio-nanocomposites (Fe3O4@Cht/Au) for pesticide detection

Free enzymes cause difficulties in many applications due to their insufficient stability, loss of activity in a short time, and most importantly, although they are costly, they are used only once in reactions, lose their effect and cannot be recovered from the environment. Magnetic nanoparticles coated with biocompatible polymeric material are potential candidates for promising enzyme carriers due to their multifunctional pore surfaces, easy removal from the environment provided by the magnetization, ability to main stability under various harsh conditions. This study prepared a biosensor candidate based on the inhibiting acetylcholinesterase enzyme by organophosphate pesticides from chitosan-coated magnetic nanoparticles doped with gold. Transmission electron microscopy, scanning electron microscopy, X-ray diffraction diffractometry, and Fourier transform infrared spectroscopy analysis confirmed the structure of synthesized nanocomposites. Magnetic characteristics of the nanocomposites were assessed using VSM. Bio-nanocomposite (Fe3O4@Cht/Au/AChE) was used to determine environmental pollutants qualitatively. Remediation of organophosphate-containing wastewater is an essential issue for environmental sustainability. In this work, Dichlorvos and Chlorpyrifos were selected as organic pollutants to assess the enzymatic activity of immobilized Fe3O4@Cht/Au/AChE. Optimum conditions for AChE enzyme were immobilized nanostructures (Fe3O4@Cht/Au/AChE) were determined. The optimum pH for the immobilized enzyme was found to be 8, and the optimum temperature was found to be 60 °C. Retained immobilized enzyme activity is found to be around 50% for the 20th reuse. In the presence of 150 µL pesticide, retained immobilized enzyme activity is found to be around 25%. Method validation was performed for pesticides. When using immobilized AChE, the LOD (limit of detection)-LOQ (limit of quantitation) values for Dichlorovos and Chlorpyrifos was obtained in the range of 0.0087–0.029 nM and 0.0014–0.0046 nM, respectively. The relative standard deviation (RSD%) values, which are indicators of precision, were found to be below 2%.

A validated ultra-performance liquid chromatography with tandem mass spectrometry method for the quantification of Brazilian green propolis main compounds

Brazilian green propolis is used in folk medicine because of its various biological properties. The hydroalcoholic extract of Brazilian green propolis is characteristic for possessing several pharmacological properties. Phytochemical investigations have attributed some of these properties to the presence of compounds, which were chosen as analytical markers. This paper reports the development and analytical validation using UPLC-MS/MS in MRM mode. Veratraldehyde was used as an internal standard in qualitative and quantitative analyses of the extracts. Relative standard deviation values obtained for intra-day and inter-day precision were lower than 4%. Of the five parameters for robustness, wavelength detection and flow rate were the critical ones. Limits of detection and quantification ranged from 0.300 to 39.500 ng.mL−1 and from 1.400 to 85.00 ng.mL−1, respectively. The recoveries were between 94.00 and 119.00%, with relative standard deviation values around 5.0%. The developed method is precise, sensitive, and reliable for analysing Brazilian green propolis.

Synthesis of highly luminescent core-shell nanoprobes in a single pot for ofloxacin detection in blood serum and water.

Antibiotics are commonly used as antibacterial medications due to their extensive and potent therapeutic properties. However, the overconsumption of these chemicals leads to their accumulation in the human body via the food chain, amplifying drug resistance and compromising immunity, thus presenting a significant hazard to human health. Antibiotics are classified as organic pollutants. Therefore, it is crucial to conduct research on precise methodologies for detecting antibiotics in many substances, including food, pharmaceutical waste, and biological samples like serum and urine. The methodology described in this research paper introduces an innovative technique for producing nanoparticles using silica as the shell material, iron oxide as the core material, and carbon as the shell dopant. By integrating a carbon-doped silica shell, this substance acquires exceptional fluorescence characteristics and a substantial quantum yield value of 80%. By capitalising on this characteristic of the substance, we have effectively constructed a fluorescent sensor that enables accurate ofloxacin analysis, with a detection limit of 1.3 × 10-6 M and a linear range of concentrations from 0 to 120 × 10-6 M. We also evaluated the potential of CSIONPs for OLF detection in blood serum and tap water analysis. The obtained relative standard deviation values were below 3.5%. The percentage of ofloxacin recovery from blood serum ranged from 95.52% to 103.28%, and from 89.9% to 96.0% from tap water.

Development and validation of HPLC-ultraviolet method for quantitative determination of pritelivir in human placental perfusion medium.

A simple and reliable HPLC-ultraviolet (HPLC-UV) method was developed and validated for the quantification of pritelivir in the samples of medium from the experiments utilizing the ex vivo technique of dual perfusion of the human placental lobule. Phenacetin was used as an internal standard (IS) in our HPLC-UV method. Chromatographic separation of pritelivir and phenacetin was achieved on a Waters Symmetry C18 HPLC column (100 × 2.1 mm, 3.5 μm) at ambient temperature (22-25°C). The mobile phase was composed of 50% methanol in deionized water (v/v), the flow rate for isocratic elution was established at 0.25 mL/min, and the detection wavelength for pritelivir and IS was set at 254 nm. Pritelivir and IS were extracted with the protein precipitation method using methanol as a solvent. The calibration curve for pritelivir exhibited linearity (r2 > 0.99) within the concentration range from 0.155 to 6.62 μg/mL. Within- and between-day accuracy ranged from 97% to 110% with relative standard deviation (RSD) values not exceeding 10%. The extraction recovery of pritelivir and IS ranged from 89% to 91% with RSD not exceeding 7%. Pritelivir was stable under the storage and sample handling conditions. This validated HPLC-UV method was utilized to quantify pritelivir in the placental perfusion medium samples, and the resulting concentrations were authenticated with incurred sample reanalysis to confirm the reliability of the method.

Electrochemical Immunoassay Platform for Human Monkeypox Virus Detection.

In this study, we reported a selective impedimetric biosensor for the detection of A29 which is the target protein of the monkeypox virus (MPXV). The working principle of the biosensor relies on the interaction mechanism between A29, which is an internal membrane protein of MPXV, and the heparan sulfate receptor. For this purpose, after immobilizing heparan sulfate onto the gold screen-printed electrode surface, its interaction with A29 protein was monitored using electrochemical impedance spectroscopy. After the optimization of experimental parameters, the analytical characteristics of the developed MPVX immunosensor were examined. The developed immunosensor exhibited a linear detection range between 2.0 and 50 ng mL-1, with a detection limit of 2.08 ng mL-1 and a quantification limit of 6.28 ng mL-1. Furthermore, a relative standard deviation value of 2.82% was determined for 25 ng mL-1. Apart from that, sample application studies were also performed with the standard addition of A29 protein to 1:10 diluted real serum samples that were taken from healthy individuals, and very good recovery values were obtained.

DEVELOPMENT AND VALIDATION OF A SIMPLE AND COST-EFFECTIVE UV SPECTROPHOTOMETRIC METHOD FOR QUANTIFYING LINEZOLID

Objective: This study focuses on the development and validation of a sensitive, simple, accurate, precise and cost-effective Ultraviolet-Visible (UV) spectrophotometric method for the quantification of Linezolid, a widely used antibiotic in pharmaceutical formulations. Methods: The analysis utilized a solvent system comprising 80% water and 20% methanol (v/v). The absorbance of standard solutions was measured and a calibration curve was constructed. Various analytical performance parameters, including linearity, range, precision, accuracy, Limit of Detection (LOD), Limit of Quantification (LOQ) and ruggedness, were determined following the International Conference on Harmonization (ICH) Q2 (R1) guidelines. Results: The maximum absorption peak (λmax) of Linezolid was determined to be 251 nm in the selected medium. Beer-Lambert’s law was valid in the concentration range of 0.5–9 μg/ml, with a high correlation coefficient (R2) of 0.9955. The proposed method exhibited a recovery ranging from 99.08 to 100.37% with % Relative Standard Deviation (RSD) value consistently below 2%. Conclusion: The study findings confirm the accuracy, precision and reproducibility of the developed method. Additionally, it is characterized by its simplicity, affordability, and time efficiency. Thus, this method can be effectively employed for the quantification of Linezolid in lipid nanoparticles.

Graphene oxide-based stationary phase synthesis and separation of drug molecules for liquid chromatography (HPLC) analysis

A new graphene oxide-based liquid chromatography stationary phase was synthesized, characterized, and used for the first time in the separation of paracetamol and caffeine in pharmaceutical preparations under reversed phase conditions. For this purpose, graphene oxide was synthesized using the modified Hummers method, and Si-GO stationary phase was obtained by immobilizing graphene oxide on aminopropyl silica. The obtained graphene oxide, Si–GO and aminopropyl silica materials were characterized by XRD, SEM, TEM and FTIR analysis. Different mobile phases were used to separate drug molecules in order to determine the mechanism of interaction between drug molecules and the stationary phase. Once the appropriate solvent system was determined, optimum chromatographic parameters such as mobile phase composition (methanol percentage in water), flow rate and column temperature were determined. The linearity of the method was in the range of 0.989–0.997. The maximum relative standard deviation (% RSD) value was calculated as 0.54. Mean recoveries for paracetamol and caffeine were 98%–99%, respectively, and LOD and LOQ were 6 × 10−3 to 6.5 × 10−3 mg/L and 2 × 10−2 to 2.2 × 10−2 mg/L, respectively. The results showed that the new graphene oxide-based stationary phase could be used for the separation of paracetamol and caffeine in pharmaceutical preparations.

Development and validation of a UV spectrophotometric method for biowaiver studies in pyrazinamide tablets

Development and validation of a UV spectrophotometric method for biowaiver studies in pyrazinamide tablets

Consistency Analysis of the UF-1500 and UF-5000 Automated Urine Particle Analyzers.

The aim was to evaluate the consistency of the results between the UF-1500 and UF-5000, fully automated urine particle analyzers. A total of 554 randomly selected inpatient and outpatient urine samples were collected for analysis using the UF-1500, the UF-5000, and by manual microscopic examination. The coincidence rate, intraday repeatability, and interday reproducibility were evaluated on the UF-1500 and UF-5000. To analyze the review flags from the UF-1500, the UF-1500 results were compared to manual microscopy as the gold standard. The repeatability of red blood cells (RBCs), white blood cells (WBCs), epithelial cells (ECs), casts, and bacteria using the UF-1500 and UF-5000 is expressed as the relative standard deviations of the intraday and inter-day measurements. For the UF-1500, the relative standard deviation values ranged from 5.9% to 12.6% and 4.9% to 17.2% for the low and 1.6% to 9.3% and 2.3% to 16.9% for the high samples, respectively. The correlation co-efficient for RBCs, WBCs, ECs, SECs, casts, crystals, and bacteria for the UF-1500 were 0.981, 0.993, 0.968, 0.963, 0.821, 0.783, and 0.992, respectively. Review samples from the UF-1500 were confirmed by microscopic examination. Review flags for all 554 samples included 3 samples with "DEBRIS High" and 23 samples with "RBCs/YLC Abnormal classification". The identification of various urine components by both instruments meets laboratory requirements. These two instruments with different performances have specific characteristics and should be used based upon the needs of each laboratory.

Preconcentration of Cu2+, Cr3+, Co2+, and Ni2+ by Solid-Phase Extraction Using a Recently Developed Mixed-Mode Sorbent

The enrichment and simultaneous analysis of Cu2+, Cr3+, Co2+, and Ni2+ by solid-phase extraction method were performed using a stationary phase containing amide functional groups, an aromatic benzene ring, and aliphatic groups in a silica-based structure that we had synthesized for HPLC separations in our previous studies. Solid-phase extraction was performed using a column system and the results obtained were analysed by ICP-OES. Effects of pH, amount of sorbent, amount of eluting solvent, sample volume, flow rates of the eluent and the sample, and interfering ions were evaluated in recovery processes for the metals in the sample solutions. Linear range, detection limit, and relative standard deviation (% RSD) values were calculated for each metal. The linear range (ng/mL) was between 0.01 and 0.25 for all ions, while the limit of detection (ng/mL) was found to be 0.64, 1.7, 0.44, and 0.51 and % RSD was 2.8, 2.4, 2.6, and 2.9 for Cu2+, Cr3+, Co2+, ve Ni2+, respectively.

In situ fabrication of Ag nanoparticles modified vertically-grown ZnO nanorods on carbon fiber paper electrode for simultaneous detection of luteolin, daidzein and baicalein

In this paper, a facial strategy is employed to directly growing ZnO nanorods (ZnONR) on carbon fiber paper (CFP) and functionalizing with silver nanoparticles (AgNP), constructing a structural stable paper-based electrode (AgNP/ZnONR@CFP). This unique AgNP/ZnONR hierarchical nanoarchitecture provides large surface area and an easy substrate penetrable structure facilitating enhanced electrochemical features towards flavonoids oxidation. When the electrode is evaluated as a binder-free sensor for flavonoids detection, three distinct and separate differential pulse voltammetric peaks for luteolin, daidzein, and baicalein are observed, demonstrating the simultaneous and selective detection of these flavonoids possible. The AgNP/ZnONR@CFP sensor demonstrates a remarkable wide linear relationship with low detection limits for luteolin, daidzein, and baicalein detection in a mixed solution. When the sensor is employed to analyze luteolin, daidzein, or baicalein in real extracts from Japanese Honeysuckle, Soybean, and Chrysanthemum morifolium, satisfactory recovery rates (ranging from 96.3 % to 102.5 %) and low relative standard deviation (RSD) values (less than 5.0 %) are obtained. In addition, an assembled sensor device (two-electrode) based on this trimmable AgNP/ZnONR@CFP electrode exhibits remarkable quick response and excellent sensitivity for luteolin, daidzein, or baicalein detection, facilitating real-time and portable detection, highlighting its great potential in batch production of the sensor devices.

Phosphate and Nitrate Electrochemical Sensor Based on a Bifunctional Boron-Doped Diamond Electrode.

Phosphorus and nitrogen are important elements in both environmental cycles and biological growth, and their imbalance can lead to serious environmental and biological problems. It is important to be able to monitor the concentration of nitrate and phosphate in the water online. In this paper, a bifunctional boron-doped diamond (BDD) electrode with repeatable electrochemical renewal and modification ability has been developed and used as a shared working electrode for the determination of nitrate and phosphate. First, phosphate can be detected directly with a bare BDD electrode. After a thin copper (Cu) layer was electrodeposited on the BDD electrode, nitrate could be determined. The copper layer is then removed under a positive voltage, and the BDD electrode is renewed and can be used again for phosphate detection. This method enables the detection of both phosphate and nitrate while also improving the stability and repeatability through the renewal of the electrode surface. The segmented linear ranges for phosphate were 0.02-0.4 and 0.4-3 mg/L with a detection limit of 0.004 mg/L. The sensor detected nitrate in a wide concentration range, with segmented linear relationships in the ranges of 0.07-3 and 3-100 mg/L, with a detection limit of 0.065 mg/L. The electrochemical sensor based on the BDD electrode has a good reproducibility for phosphate and nitrate detection. The relative standard deviation (RSD) values of the current responses were 2.98, 2.79, 1.66, 1.81, and 1.23%, respectively, for 35 consecutive tests in 0.05, 0.2, 0.5, 1, and 1.5 mg/L phosphate solution. The RSD values of the current responses were 2.00, 0.97, and 1.03%, respectively, for 25 consecutive tests in 5, 7, and 10 mg/L nitrate solution.

Hierarchical PVDF/ZnO/Ag/ZIF-8 nanofiber membrane used in trace-level Raman detection of H2S

surface enhanced Raman scattering (SERS) detection of gases has always been difficult due to the low affinity and poor Raman cross section of the moving molecules. To mitigate the impact of these problems on detection of gases, a structure of zinc oxide/silver nanowires coated with zeolitic imidazolate framework-8 (ZnO NWs/Ag/ZIF-8) was constructed on polyvinylidene fluoride (PVDF) nanofiber membrane (PVDF/ZnO NWs/Ag/ZIF-8) and in detail researched in this work. Benefitting from the quadruple synergistic effect of efficient Knudsen diffusion of gas molecules inside ZIF-8, enrichment of ZIF-8 microsponges for gaseous molecules, regulation of ZIF-8 dielectric layer for light and reverse light scattering of ZnO NW/Ag tip, the structure was proven to have precise co-confinement on both hot spots and gaseous molecules. As a result, this PVDF/ZnO NWs/Ag/ZIF-8 achieved excellent detection for hydrogen sulfide (H2S), with a limit of detection of 1 × 10−10 v/v and the minimum relative standard deviation value of ca. 7.13 %. Furthermore, as a proof of concept, in practical application, we designed and assembled our substrate (3.5 cm × 3.5 cm) into a SERS face mask and realized efficient monitoring of H2S in human’s exhaled breath.

In-situ acetylation followed by liquid-liquid extraction and gas chromatography – mass spectrometry for the determination of bromophenols in urine

A novel and simple method combining in-situ acetylation, liquid-liquid extraction and gas chromatography-mass spectrometry (GC-MS) has been developed for the quantification of 10 bromophenols in urine, used as biomarkers of exposure to polybrominated diphenyl ethers. The analytical process involves an enzymatic hydrolysis of the bromophenol glucuronide fraction followed by an aqueous derivatization of the phenol group with acetic anhydride. A subsequent liquid-liquid extraction of the sample with hexane allows the injection of the organic layer, using a programmed temperature vaporizer, into a gas chromatograph coupled to a single quadrupole mass spectrometer. Quantification is performed by the standard addition method. Limits of detection are in the pg mL−1 range. Trueness, assessed in terms of percentages of recovery, varies between 100 % and 118 % in synthetic urine and between 79 % and 117 % in human urine. Precision, assessed at two different levels, 0.25 ng mL−1 and 2.5 ng mL−1, shows values of relative standard deviation below 14 % both in intra- and inter-day studies for both matrices. The method has been applied to the analysis of seven urine samples, measuring concentrations higher than the LOQ in three of them. These levels are in agreement with others found in literature, but they have been obtained by applying a much simpler and faster protocol. In addition, the replacement of silylating reagents by acetic anhydride, to derivatize the phenol moiety, provides a greener alternative to other GC-MS procedures published up to date.

Whole urine-based multiple cancer diagnosis and metabolite profiling using 3D evolutionary gold nanoarchitecture combined with machine learning-assisted SERS

To develop onsite applicable cancer diagnosis technologies, a noninvasive human biofluid detection method with high sensitivity and specificity is required, available for classifying cancer from the normal group. Herein, a three-dimensional evolutionary gold nanoarchitecture (3D-EGN) is developed by forming Au nanosponge (AuS) on a 96-well plate, followed by a decoration of Au nanoparticles (AuNPs) evolved with Au nanolamination (AuNL) for high-throughput urine sensing in liquid phase. The 3D-EGN exhibits not only strong electromagnetic field generated from numerous hotspot regions between AuNPs and further enhanced light scattering from multigrain boundaries after lamination process, but also highly volumetric field due to nanoporous structure of AuS, which is advantageous for sensitive liquid-phase SERS detection. SERS activity of the 3D-EGN platform is characterized using malachite green, showing a limit detection of 1.23 × 10−9 M in liquid phase, and excellent uniformities both within single well and well-to-well with relative standard deviation (RSD) values of about 10%. The 3D-EGN platform has been demonstrated for the detection of whole clinical human urine samples, proving effective molecular sensing in the presence of Brownian motion from liquid medium. Subsequently, cancer metabolite candidates are investigated to verify the metabolic alternations of multicancer, including pancreatic, prostate, lung, and colorectal cancers, simultaneously classifying them into five different groups, including normal with an accuracy of 95.6%, using machine-learning methods. The integration of nanomaterials with the conventional clinical platform provides rapid and high-throughput multicancer diagnostic system and opens a new era for noninvasive diseases diagnosis using clinical human biofluids.

Presence of hazardous chemical elements in low-cost children's toys: A risk to their development in early childhood

ObjectivesThe objectives of the current study was to study the presence of hazardous chemical elements (Ba138, Cd111, Cr52, Pb208, As75, Co59, Cu63, Mn55, Ni60, Se82, Sr88, Zn66 and Hg202) in low-cost children's toys, and the effect of color types on chemical element concentrations. MethodsChildren's toy samples were analyzed using microwave digestion and inductively coupled plasma/mass spectrometry (ICP/MS) method. Samples were prepared into small pieces, and 500 mg of homogenized sample was used for digestion by means of digesting regents HNO3 (65 %, 5 mL) and H2O2 (35 %, 1 mL). During the digestion process, the pressure was held constant at 90 bar and the temperature, hold time, and power were varied 150–170-40° C, 10–30-5 min, 70–90-0 %, respectively. The main operating conditions of ICP/MS were: spray chamber temperature (−20 °C), RF Power (1450 W), nebulizer gas flow (0.9 L/min), auxiliary gas flow (0.8 L/min) and plasma gas flow (14.85 L/min). Samples and blanks were analyzed for 30 s and system was operated in standard mode. ResultsThe excellent method performance was achieved in terms of limit of detection (LOD, 0.001–14.89 µg/L); limit of quantification (LOQ, 0.003–45.12 µg/L); correlation coefficient (R2, 0.975–0.999) with relative standard deviation values (RSD, 0.70–4.98 %). Chemical elements were found in all the toys (0.01–742.72 ng/g) except sample S2 where only Hg202 was found (0.01 ng/g). Outcomes revealed that the Hg202 was present at a very low level (0.01 ng/g) while Zn66 was present at very high level (742.72 ng/g). Furthermore, the toys contamination was also found to be color-specific, with significant amount of chemical elements was found in black type car sample (S5, 946.98 ng/g) whereas other color type samples constitute lower amounts (0.001–210.53 ng/g). Low-cost toys designed for children's use are found to contain chemical elements that should be addressed in the course of action. As a result of exposure to high amounts of chemical elements in toys, children have a high chance of developing cancer.

Applicability of QbD-assisted Analytical Method for Simultaneous Detection of Tetrahydrocurcumin and Folic Acid in Developed Nanostructured

Aims:: Applicability of QbD-assisted analytical method for simultaneous detection of tetrahydrocurcumin and folic acid in developed nanostructured. background: Background: Diabetic foot ulcer (DFU), a multifactorial disorder involves chronic inflammation, oxidative stress and neuropathy. Current treatment therapies, involving the use of growth factors and skin substitutes being costly, are out of reach for the majority of patients. The present research explored the usefulness of (5929IN008, application number 202211045937) a combination of tetrahydrocurcumin and folic acid loaded nanostructured lipidic carriers. Background:: Diabetic foot ulcer (DFU) is a multifactorial disorder that involves chronic inflammation, oxidative stress and neuropathy. Current treatment therapies involving the use of growth factors and skin substitutes being costly, are out of reach for the majority of patients. The present research explored the usefulness of (5929IN008, application number 202211045937), a combination of tetrahydrocurcumin and folic acid-loaded nanostructured lipidic carriers. Objectives:: To develop and validate a QbD-assisted method for simultaneous analysis of tetrahydrocurcumin (THC) and folic acid (FA). Applicability of the above method to determine total drug content (TDC) and entrapment efficiency (EE) of nanostructured lipid carriers (NLCs) loaded THC and FA. Methods:: A high-performance liquid chromatographic (HPLC) method was developed, optimized and validated using Box-Behnken design for improved method performance. Chromatographic separation was conducted on a Supelco 250 x 4.6 mm (5 μm) column with optimized mobile phase composition containing tetrahydrofuran: citric acid buffer pH 3.5 (50:50) at a flow rate of 0.4 mL.min-1 and diode array detection between 210 and 360 nm. Results:: The method developed in a concentration range of 1 to 100 μg.mL-1 was found to be linear (R2 0.999, p≤0.001), accurate (99.10-101.70%) and precise with high recovery values in intra and inter-day results. The system adaptability and robustness evaluation revealed that the percent recovery ranged from 96.90 to 102.80%, and the percent relative standard deviation (%RSD) values were less than 2%. Moreover, the method was further applied for the determination of TDC (86±6% and 96±8%) and drug EE (81±21% and 73±13%) for THC and FA, respectively. Conclusion:: The investigation indicated the applicability of the developed and validated method for the estimation of THC and FA in the developed nanostructured lipidic carriers.

Machine learning-enhanced drug testing for simultaneous morphine and methadone detection in urinary biofluids

The simultaneous identification of drugs has considerable difficulties due to the intricate interplay of analytes and the interference present in biological matrices. In this study, we introduce an innovative electrochemical sensor that overcomes these hurdles, enabling the precise and simultaneous determination of morphine (MOR), methadone (MET), and uric acid (UA) in urine samples. The sensor harnesses the strategically adapted carbon nanotubes (CNT) modified with graphitic carbon nitride (g-C3N4) nanosheets to ensure exceptional precision and sensitivity for the targeted analytes. Through systematic optimization of pivotal parameters, we attained accurate and quantitative measurements of the analytes within intricate matrices employing the fast Fourier transform (FFT) voltammetry technique. The sensor’s performance was validated using 17 training and 12 test solutions, employing the widely acclaimed machine learning method, partial least squares (PLS), for predictive modeling. The root mean square error of cross-validation (RMSECV) values for morphine, methadone, and uric acid were significantly low, measuring 0.1827 µM, 0.1951 µM, and 0.1584 µM, respectively, with corresponding root mean square error of prediction (RMSEP) values of 0.1925 µM, 0.2035 µM, and 0.1659 µM. These results showcased the robust resiliency and reliability of our predictive model. Our sensor’s efficacy in real urine samples was demonstrated by the narrow range of relative standard deviation (RSD) values, ranging from 3.71 to 5.26%, and recovery percentages from 96 to 106%. This performance underscores the potential of the sensor for practical and clinical applications, offering precise measurements even in complex and variable biological matrices. The successful integration of g-C3N4-CNT nanocomposites and the robust PLS method has driven the evolution of sophisticated electrochemical sensors, initiating a transformative era in drug analysis.

Multiple regional climate model projections to assess building thermal performance in Brazil: Understanding the uncertainty

Understanding the trends and uncertainties in Building Energy Simulation (BES) performance indicators under future climate conditions is crucial for mitigating issues such as overheating and power outages. To address this, we generated a set of weather files for all 27 state capitals in Brazil, considering six climate model projections (three General Circulation Models as driving models and two nested Regional Climate Models) and two distinct emission scenarios from the CORDEX project. We analyzed the variability in climatic variables and subsequently performed BES on a representative Brazilian social housing unit to evaluate its impact on the performance indicators outcomes. Consistent with previous studies, a substantial increase in cooling-related demands was observed in the more pessimistic scenario (RCP8.5) and mild increases in the more optimistic scenario (RCP2.6), with a trend toward stabilization after 2050. Regarding uncertainties, we found higher Relative Standard Deviation (RSD) values for the cooling degree hours indicator. The capitals in the Central-West, Southeast, and South regions exhibited greater uncertainty regarding temperature indicators, whereas the irradiation parameters displayed higher uncertainties in the Northeast region. For the BES outcomes, RSD values as high as 19.9% were found for cooling load values. It was also demonstrated that locations, periods, and scenarios exhibit different extreme climate model projections. Ideally, employing an ensemble of weather files developed from other models would help assess associated uncertainties in the building performance indicators.