Simple Analytical Method Research Articles

Plasmonic Cross-Linking Colorimetric PCR for Simple and Sensitive Nucleic Acid Detection.

Simple, low-cost, and accurate nucleic acid assay platforms hold great promise for point-of-care (POC) pathogen detection, disease surveillance, and control. Plasmonic photothermal polymerase chain reaction (PPT-PCR) is a powerful and efficient nucleic acid amplification technique, but it lacks a simple and convenient analysis method for POC applications. Herein, we propose a novel plasmonic cross-linking colorimetric PCR (PPT-ccPCR) assay by integrating plasmonic magnetic nanoparticle (PMN)-based PPT-PCR with gold nanoparticle (AuNP)-based cross-linking colorimetry. AuNPs form assembled structures with the PMNs in the presence of amplicons and collect in a magnetic field, resulting in color changes to the supernatant. Target DNA with concentrations as low as 5 copies/μL can be visually detected within 40 min. The achieved limit of detection was 1.8 copies/μL based on the absorption signals. This simple and sensitive strategy needs no expensive instrumentation and demonstrates high potential for POC detection while enabling further applications in clinical diagnostics.

Simple Method for the Determination of THC and THC-COOH in Human Postmortem Blood Samples by Gas Chromatography-Mass Spectrometry.

A simple and sensitive analytical method was developed for qualitative and quantitative analysis of Δ9-tetrahydrocannabinol (Δ9-THC) and its metabolite 11-nor-Δ9-tetrahydrocannabinol-carboxylic acid (Δ9-THC-COOH) in human postmortem blood using gas chromatography/mass spectrometry (GC-MS) in selected ion monitoring (SIM) mode. The method involved a liquid-liquid extraction in two steps, one for Δ9-THC and a second one for Δ9-THC-COOH. The first extract was analyzed using Δ9-THC-D3 as internal standard. The second extract was derivatized and analyzed using Δ9-THC-COOH-D3 as internal standard. The method was shown to be very simple, rapid, and sensitive. The method was validated for the two compounds, including linearity (range 0.05-1.5 µg/mL for Δ9-THC and 0.08-1.5 µg/mL for Δ9-THC-COOH), and the main precision parameters. It was linear for both analytes, with quadratic regression of calibration curves always higher than 0.99. The coefficients of variation were less than 15%. Extraction recoveries were superior to 80% for both compounds. The developed method was used to analyze 41 real plasma samples obtained from the Forensic Toxicology Service of the Institute of Forensic Sciences of Santiago de Compostela (Spain) from cases in which the use of cannabis was involved, demonstrating the usefulness of the proposed method.

Simplified Earned Value Analysis Method for Highway Construction Projects

Earned value (EV) methodology has been widely studied and implemented in academia and industry. Nonetheless, state departments of transportation (DOTs) are lagging in their acceptance and utilization of EV techniques to measure progress and assess performance for highway construction projects. Difficulty securing cost progress data and other information, such as a cost and resource-loaded schedule, necessary to generate EV metrics, is one of several reasons. This paper suggests DOTs adopt the simplified earned value analysis (SEVA) method, which uses project contract information and project progress payment data to calculate EV metrics. The SEVA method is proposed as an intermediate approach for DOTs to apply the EV concept without the burden of additional data collection. The study also addressed front-loading and auxiliary item costs and their impact on measuring project progress. By removing the costs of front-loading and auxiliary items, for example, mobilization and preparing right-of-way, from metrics calculations, the SEVA method provided a more accurate picture of project progress and performance. The SEVA method is also expected to help DOTs move toward wider earned value management implementation in highway construction. This study contributes to the academic body of knowledge by exploring little-studied challenges to EV application and their practical solutions in highway construction, and by introducing potential future research avenues in EV implementation in highway construction.

PENGARUH CITRA MEREK TERHADAP KEPUTUSAN PEMBELIAN PRODUK KECANTIKAN MS GLOW (STUDI KASUS PADA KONSUMEN WANITA DI DESA TEGALHARJO KABUPATEN BANYUWANGI)

This study aims to determine the significant influence of the brand image of MS Glow beauty products on purchasing decisions of female consumers in Tegalharjo Village, Banyuwangi Regency. This research was conducted by correlational quantitative method using simple linear analysis method. The data collection method used in this study is a closed questionnaire method with a Likert scale, interviews and literature study. The results showed significant results, namely the brand image variable can influence purchasing decisions by 70.6%, the remaining 29.4% is influenced by other variables not examined in this study.

Optimization of the QuEChERS extraction method to determine Polycyclic Aromatic Hydrocarbons (PAHs) in powder aerosol particles collected by cyclone

Conventional methods for collecting and extracting aerosol particles are challenging in accurately characterizing particle-bound polycyclic aromatic hydrocarbons (PAHs) contamination and conducting cellular exposure studies. Therefore, developing direct aerosol sample collection and simple pretreatment analytical methods is necessary. This study describes the optimization of the QuEChERS (quick, easy, cheap, effective, rugged, and safe) extraction method for the determination of PAHs in powder-form environmental standard materials (SRM1944) and proves it is also effective for analyzing PAHs in powder aerosol particle samples collected by cyclone. In this study, we used an I-optimal design response surface method combined with a desirability function to investigate the extraction effect of PAHs under different combinations of QuEChERS extraction factors, including extraction solvent, salt, and clean-up reagent. The optimized conditions of the method were determined using the 2-factor interaction (2FI) model combined with boundary conditions, resulting in acetonitrile/dichloromethane (7:1, v/v), Na2SO4/NaCl (1:1, w/w), and primary and secondary amine (PSA) as extraction solvents, extraction salts, and clean-up reagent, respectively. The optimized method showed good recoveries of PAHs reaching 76%–118% and 85%–121% for SRM1944 and standard solution. The results for cyclone-collected ambient powder aerosol particles extracted by the optimized QuEChERS illustrated that this improved procedure has good PAHs extraction efficiency as the traditional Soxhlet method, while reducing hazardous organic solvents usage, experimental cost (per mg sample) by 97% and sample pretreatment time. Overall, this combination of “powder aerosol particle collection and modified QuEChERS extraction” provides new insight on aerosol sample collection, extraction, and in vitro/in vivo exposure studies.

Simultaneous quantification of (E) and (Z) isomers of rilpivirine and four degradation products in bulk and tablets by reversed-phase ultra-high-performance liquid chromatography and confirmation of all by molecular weight.

The (E)-isomer of rilpivirine is an approved antiretroviral drug used to treat human immunodeficiency virus. A simple, fast, accurate, and precise analytical method is required to confirm the quality, purity, efficacy, and safety of drug substances and drug products containing rilpivirine. This research article offers a comprehensive ultra-high performance liquid chromatography method for the simultaneous separation and quantification of (E) and (Z) isomers of rilpivirine, including two amide impurities, one nitrile impurity, and one dimer impurity, in both bulk and tablet forms. After complete validation, the proposed reversed-phase ultra-high-performance liquid chromatography method has proven to be simple, fast, linear, accurate, and precise, with a lower limit of quantification and detection of 0.05 and 0.03μg/ml, respectively, for all six analytes. Separation was achieved on a Waters Acquity ethylene bridged hybrid Shield RP18 (150×2.1mm, 1.7μm) column maintained at 35.0°C using a gradient elution of acetonitrile and 0.05% formic acid in 10mM ammonium formate at a flow rate of 0.30ml/min. A systematic forced degradation study on the undissolved rilpivirine revealed the formation of acid-base hydrolyzed amide impurities (Impurity-A and Impurity-B), oxidative nitrile impurities (Impurity-C), and Z-isomer and dimer impurities of rilpivirine (Impurity-D and Impurity-E) due to alkaline hydrolysis and photodegradation. The proposed method is primarily appropriate for applications requiring the precise determination of desired and undesired isomers of rilpivirine and its degradation products, such as those involving the safety, efficacy, and quality roles of rilpivirine in bulk and tablet forms. Additionally, the proposed ultra-high-performance liquid chromatography method in combination with a mass spectrometer and photo-diode array detector is helpful for the confirmation and correct identification of all analytes.

Thymine-mediated electrochemical aptasensor for sensitive and simultaneous detection of Hg2+ and CH3Hg+ in fish samples

In this study, a thymine-mediated electrochemical aptasensor was constructed for instantaneous detection of Hg2+ and CH3Hg+ in fish muscle using ferrocene (Fc) and methylene blue (MB) as electrochemical tags. In the presence of Hg2+, a HP-Fc (ferrocene and thiol-labeled hairpin DNA) was opened and hybridized with a complementary S1 (single-stranded DNA) to form a stable thymine-Hg2+-thymine (T-Hg2+-T) structure. Then, the Fc tag got far away from the gold electrode surface, inducing a distinct decrease of its electrochemical signal. Meanwhile, SA−MB (methylene blue labeled single-stranded DNA) was designed to complement with S2 (thiol-labeled single-stranded DNA). When CH3Hg+ was present, the double-stranded DNA was dissociated, and a more stable CH3Hg+-T structure was generated by binding of screened S2 and CH3Hg+. Thus, the SA−MB was away from electrode surface and the significantly reduced current of MB was observed. As a result, Hg2+ and CH3Hg+ were differentiated through the thymine-mediating, realizing the simultaneous detection of Hg2+ and CH3Hg+ without extra separation procedure. Such a sensing strategy allowed sensitive and selective detection of Hg2+ and CH3Hg+ down to the picomolar level, with limits of detection (LOD, S/N = 3) of 0.06 pM and 0.13 pM, respectively. The sensor was finally successfully applied for the detection of Hg2+ and CH3Hg+ in fish samples, and the results were in good agreement with those obtained by liquid chromatography-inductively coupled plasma mass spectrometry (LC-ICP-MS). This technology provides a sensitive and simple method for speciation analysis and monitoring of Hg2+ as well as CH3Hg+ in biological samples.

High enhancement of macro and micronutrients quantification in Cajuína by ICP OES using ultrasound and multivariate analysis

A fast, safe, simple, and low-cost analytical method was developed for the determination of macro and microelements in Cajuína samples from Brazil combining UAE and ICP OES. A multiplexed approach using experimental designs was applied for method optimization. The optimal conditions were using 4 mL of 8 mol L−1 HNO3 and 1.5 mL H2O2 under 30 min of sonication. The detectability of the method has been improved. The precision was RSD < 5.5% while the accuracy of the method ranged from 87% to 108% as well as the results were in agreement with the reference method. The analysis of 38 samples of Cajuína juices presented a mean of Ca, Cu, Fe, K, Mg, Na, P, S and Zn of 8.70, 0.10, 0.97, 1223, 112, 60.1, 83.9, 65.1, and 0.99 mg L−1. So, the proposed analytical method demonstrated feasibility for the simultaneous determination of mineral nutrients in similar matrices as beverage.

Targeted HPLC-UV Polyphenolic Profiling to Detect and Quantify Adulterated Tea Samples by Chemometrics.

Tea can be found among the most widely consumed beverages, but it is also highly susceptible to fraudulent practices of adulteration with other plants such as chicory to obtain an illicit economic gain. Simple, feasible and cheap analytical methods to assess tea authentication are therefore required. In the present contribution, a targeted HPLC-UV method for polyphenolic profiling, monitoring 17 polyphenolic and phenolic acids typically described in tea, was proposed to classify and authenticate tea samples versus chicory. For that purpose, the obtained HPLC-UV polyphenolic profiles (based on the peak areas at three different acquisition wavelengths) were employed as sample chemical descriptors for principal component analysis (PCA) and partial least squares-discriminant analysis (PLS-DA) studies. Overall, PLS-DA demonstrated good sample grouping and discrimination of chicory against any tea variety, but also among the five different tea varieties under study, with classification errors below 8% and 10.5% for calibration and cross-validation, respectively. In addition, the potential use of polyphenolic profiles as chemical descriptors to detect and quantify frauds was evaluated by studying the adulteration of each tea variety with chicory, as well as the adulteration of red tea extracts with oolong tea extracts. Excellent results were obtained in all cases, with calibration, cross-validation, and prediction errors below 2.0%, 4.2%, and 3.9%, respectively, when using chicory as an adulterant, clearly improving on previously reported results when using non-targeted HPLC-UV fingerprinting methodologies.

Exploration of HPTLC Technology for Rapid Chemical Fingerprinting and Simultaneous Determination of Bioactive Constituents from Clitoria ternatea Linn.

AbstractThe analytical methods used for herbal analysis are need to be economic, fast and also produce minimum quantities of hazardous chemical waste. Presently analytical community put interest in the research area of non‐hazardous and eco‐friendly practices to develop various green chromatographic methods for routine quality analysis. High cost of phytochemical analysis and uses of hazardous chemicals with high‐end sophisticated instrument, the attempt made to develop a simple analytical method for multiple samples with short time and less uses of solvents. A HPTLC method was developed for simultaneous determination of biological important constituents like β‐sitosterol, taraxerol, clitorienolactone B and β‐sitosterol glycoside from Clitoria ternatea Linn. The proposed method was validated and satisfied the ICH guidelines to demonstrate that the method is adaptable for its intended purpose. The method is simple, sensitive and economic it therefore embraces potential for detection, monitoring, and simultaneous quantification of the four bioactive compounds for C. ternatea and could also be apply to other species.

Design of a printed electrochemical strip towards miRNA-21 detection in urine samples: optimization of the experimental procedures for real sample application

MicroRNAs (miRNAs) are clinical biomarkers for various human diseases, including cancer. They have been found in liquid biopsy samples, including various bodily fluids. They often play an important role in the early diagnosis and prognosis of cancer, and the development of simple and effective analytical methods would be of pivotal importance for the entire community. The determination of these targets may be affected by the different physicochemical parameters of the specimen of interest. In this work, an electrochemical detection platform for miRNA based on a screen-printed gold electrode was developed. In the present study, miRNA-21 was selected as a model sequence, due to its role in prostate, breast, colon, pancreatic, and liver cancers. A DNA sequence modified with methylene blue (MB) was covalently bound to the electrochemical strip and used to detect the selected target miRNA-21. After optimization of selected parameters in standard solutions, including the study of the effect of pH, the presence of interferent species, and NaCl salt concentration in the background, the application of square-wave voltammetry (SWV) technique allowed the detection of miRNA-21 down to a limit in the order of 2 nM. The developed device was then applied to several urine samples. In this case too, the device showed high selectivity in the presence of the complex matrix, satisfactory repeatability, and a limit of detection in the order of magnitude of nM, similarly as what observed in standard solutions.

Structural performance of orthotropic Steel-Concrete continuous composite decks with larger U-ribs and PBL shear connectors

This study investigates the structural performance of the OSCCCDs with larger U-ribs and PBL shear connectors. Four OSCCCDs with larger U-ribs and PBL shear connector specimens were fabricated and tested under a static load, in which the experimental parameters were the spacing of the PBL shear connector and the spacing of the holes of the PBL shear connectors. Parametric analysis via finite element models was also carried out to explore the effects of the reinforcement ratio, the thickness of the steel plate, the thickness of the U-ribs, the thickness of the concrete slab, and the hole diameter of the PBL shear connector on the structural performance. It can be concluded from the experimental and numerical results that the OSCCCDs exhibited higher bearing capacity and better ductility. The OSCCCDs exhibited flexure failure at the mid-span and diagonal tension failure at the intermediate supports. The thickness of the U-ribs and the thickness of the concrete slab showed the highest impact on the initial stiffness and ultimate load of the OSCCCDs, followed by the spacing of the PBL shear connectors and the spacing of holes in the PBL shear connectors. The reinforcement ratio, the thickness of the steel plate, and the hole diameter of the PBL shear connector had little influence on the initial stiffness and ultimate load of the OSCCCDs. Finally, a simplified flexural analysis method can be proposed to accurately predict the elastic deflection and ultimate bending moment of the OSCCCDs under the service loads, respectively. The maximum absolute discrepancies of the elastic deflection and ultimate bending moment of the theoretical results are 8.2% and 12.0% by validating against the experimental and numerical results within the investigated ranges of parameters, respectively.

Improving the Recognition Percentage of the Identity Check System by Applying the SVM Method on the Face Image Using Special Faces

Face recognition has attracted tremendous attention during the last three decades because it is considered a simple pattern recognition and image analysis method. Also, many facial recognition patterns have been introduced and used over the years. The SVM algorithm has been one of the successful models in this field. In this article, we have introduced the special faces first. In the following, we have fully explained the SVM method and its subsets, including linear and non-linear support vector machines. Suggestions for improving the recognition percentage of a person's identity check system by applying the SVM method on the face image using special faces are presented. For this test, 10 face images of 40 people (400 face images in total) have been selected from the ORL database. In this way, by choosing the optimal parameter C, determining the most suitable training samples, comparing more accurately with training images and using the distance with the closest training sample instead of the average distance, the proposed method has been implemented and tested on the famous ORL database. The obtained results are FAR=0.23% and FRR=0.48%, which shows the very high accuracy of the operation following the application of the above suggestions.

Curves Related to the Gergonne Point in an Isotropic Plane

The notion of the Gergonne point of a triangle in the Euclidean plane is very well known, and the study of them in the isotropic setting has already appeared earlier. In this paper, we give two generalizations of the Gergonne point of a triangle in the isotropic plane, and we study several curves related to them. The first generalization is based on the fact that for the triangle ABC and its contact triangle AiBiCi, there is a pencil of circles such that each circle km from the pencil the lines AAm, BBm, CCm is concurrent at a point Gm, where Am, Bm, Cm are points on km parallel to Ai,Bi,Ci, respectively. To introduce the second generalization of the Gergonne point, we prove that for the triangle ABC, point I and three lines q1,q2,q3 through I there are two points G1,2 such that for the points Q1,Q2,Q3 on q1,q2,q3 with d(I,Q1)=d(I,Q2)=d(I,Q3), the lines AQ1,BQ2 and CQ3 are concurrent at G1,2. We achieve these results by using the standardization of the triangle in the isotropic plane and simple analytical method.

A rapid and simple capillary electrophoresis procedure for quantification of vanillylmandelic acid in urine samples

Aim: To develop a one-step vortex-assisted liquid-liquid extraction (VALLE) method, without the need for evaporation and reconstitution steps, to establish a rapid and straightforward treatment procedure based on capillary electrophoresis-diode array detection (CE-DAD) for the determination of vanillylmandelic acid (VMA) in human urine. Methodology: Optimization of VALLE and CE-DAD procedures were studied in detail. The effects of various experimental parameters, such as the type of the extraction solvent, sample pH, salt addition, and extraction time were investigated. Also, CE separation conditions including background electrolyte type, concentration, and pH, injection time and separation voltage were optimized as well. Results: A successful separation of VMA was achieved in less than 6 min using a basic background electrolyte composed of 60 mmol·L-1 acetate/ACN (acetonitrile) 50% (v/v) (final apparent pH is 5.73). The linear response was obtained over the concentration range from 1.0 to 14 μg·mL-1. The limit of detection and quantification were 0.30 and 1.0 μg·mL-1, respectively. The intra- and inter-day precisions were found to be less than 4.3%. The extraction recoveries of VMA were between 95%-97%. Conclusion: The developed method is found to be a simple, rapid, and reliable method for quantitative analysis of urinary VMA.

A holistic framework for seismic analysis of extended pile-shaft-supported bridges against different extents of liquefaction and lateral spreading

This paper proposes a holistic framework for seismic analysis of extended pile-shaft-supported bridges experiencing different extents of liquefaction and lateral spreading. To this end, an excess-pore-pressure-ratio-based novel liquefaction severity index (LSIru) that explicitly accounts for liquefaction extents over the depth of soil profile is proposed to classify liquefiable ground into three levels, namely minor, moderate, and severe. For the ease of LSIru calculation, a regression function is developed to map LSIru with soil profile and seismic motion properties. Also, the popular Ishihara-inspired liquefaction potential index (LPIISH) is incorporated into the framework, as an alternative option, for the liquefaction level evaluation, where LPIISH thresholds for the three liquefaction levels are proposed in this study. To develop simplified analytical methods for different liquefaction levels, the separate effect of liquefaction and lateral spreading on multiple bridge demand parameters are quantified, including the maximum bearing displacement, column displacement, and pile curvature ductility. Results show that the effect of liquefaction on the examined demand parameters is generally slight regardless of liquefaction levels, whereas the effect of lateral spreading is significant on column displacement and pile curvature responses for the moderate and severe liquefaction levels, but negligible for the bearing displacement at any levels. The developed holistic framework and analytical methods provide an applied solution to seismic analyses of extended pile-shaft-supported bridges against liquefaction and lateral spreading, within the considered scenarios of soil-bridge systems.

The Influence Between Gender on Tax Compliance with Love of Money as a Moderation Variable

Indonesia has experienced a very rapid decline in the tax ratio due to economic pressures arising from the Covid-19 pandemic. With the achievement of a gross domestic product (GDP) of IDR 15,434.2 trillion in 2020, the tax ratio in a broad sense in 2020 was only 8.94% from the previous year of 10.74%. This study aims to find out whether gender has an effect on tax compliance, and whether the love of money can moderate the influence of gender on tax compliance. This study used primary data taken by distributing questionnaires to taxpayers, especially to MSME owners in Salatiga with a sample of 96 respondents. This research is descriptive and quantitative and uses a simple linear regression analysis method and also uses Moderated Regression Analysis (MRA). The results of this study prove that the influence between gender and tax compliance, as well as the love of money, can weaken the relationship between gender and tax compliance.

Simplified analytical solutions to the yaw dynamics of modular floating structures

Climate change has necessitated the development of modular floating structures (MFS) as a sustainable solution to enhance the resiliency of coastal cities against flooding and sea level rise. Hence, it is imperative that simplified methods of analysis are introduced to the design community. This technical note presents closed-form expressions parameterizing the response amplitude operators (RAO) of rectangular pontoons subject to yaw (rotation about the vertical z axis) to complement solutions derived by Wang (2022) for the five remaining degrees of freedom. Following validation, a parametric investigation was implemented to assess the influence of pontoon geometry on the yaw response of an idealized MFS exposed to realistic sea states. It was identified that pontoons exhibiting a characteristic width smaller than the wavelength are generally more resistant to yaw excitation as they become squarer in shape. Conversely, while larger pontoons are less sensitive to geometric effects, they exhibit heightened sensitivity to changes in wave conditions. The simplified analytical approach thus provides an accessible pathway towards the structural or architectural design of floating structures as a precursor to detailed computational modeling.

Simplified Method for Design and Analysis of Non-Cavitating Thrusters: Validation and Comparison

Simplified Method for Design and Analysis of Non-Cavitating Thrusters: Validation and Comparison

A Novel, Sustainable, and Eco-Friendly Spectrophotometric and Chemometric Approach for Determination of Severely Overlapped Spectrum via Unified Regression Equation: Greenness and Whiteness Assessment.

Nebivolol and valsartan (VAL) in combination with each other successfully control blood pressure and improve hypertension patient outcomes. To develop and validate innovative, simple, and sustainable spectrophotometric methods for the simultaneous analysis of nebivolol and valsartan. The new modified difference amplitude modulation (MD-AM) method uses only unified regression equation and does not require any resolution techniques. Other different approaches were also applied for the determination of the same mixture including univariate and multivariate spectrophotometric methods. The multivariate methods were PLS and PCR, whereas the univariate methods were derivative ratio (DD1), ratio difference (RD), constant center (CC), constant center spectrum subtraction (CC-SS), constant value coupled with amplitude difference (CV-AD), advanced concentration value (ACV), and amplitude difference (AD). The proposed methods use a green solvent; thus, the environmental impact of the presented procedures was evaluated qualitatively and quantitatively using six well-known evaluation tools. All methods were applied successfully for the analysis of the studied drugs in their bulk powder, pharmaceutical dosage form Byvalson®, and in vitro release at intestinal pH (7.4) using a USP dissolution tester. Results obtained were compared statistically with the reported method and with each other using a one-way ANOVA statistical test, and no significant differences were found. All green and white analytical chemistry evaluation tools results confirm the safety, sustainability, and cost-effectiveness of the approaches, indicating that the methods are regarded green and sustainable. Results were agreeable, encouraging their applicability in quality control laboratories for dosage form and making these methods an eco-friendly substitute for the analysis of this combined dosage form and for evaluating the dissolution profile. For the first time, a severely overlapped spectrum was determined using a unified regression equation without the need of extended part or zero contribution regions by the novel method MD-AM. The proposed methods are the first study of in vitro dissolution profiling of nebivolol hydrochloride (NEB) and VAL and the first sustainable and green methods applied without compromising the analytical criteria.