Rapid Method For Determination Research Articles

Novel Method for Rapid Determination of Octadecylamine Using UV Spectrophotometry

Novel Method for Rapid Determination of Octadecylamine Using UV Spectrophotometry

Simple andrapid detection ofthree amatoxins andthree phallotoxins inhuman body fluids by UPLC-MS-MS andits application in15 poisoning cases.

Amatoxins and phallotoxins are toxic cyclopeptides found in the genus Amanita and are among the predominant causes of foodborne sickness and poisoning-related fatalities in China. This study introduces and validates a simple, rapid and cost-effective ultra-performance liquid chromatography-mass spectrometry method for the simultaneous determination and quantification of α-amanitin, β-amanitin, γ-amanitin, phallisacin, phallacidin and phalloidin in human blood and urine. Quick therapeutic decision-making is supported by a 9 min chromatographic separation performed on a Waters Acquity UPLC HSS T3 column (100 mm × 2.1 mm, 1.8 µm) using a gradient of high-performance liquid chromatography (HPLC)-grade water and methanol:0.005% formic acid. The analyte limit of quantification was 1-3 ng/mL in blood and 0.5-2 ng/mL in urine. Calibrations curves, prepared by spiking drug-free blood and urine, demonstrated acceptable linearity with mean correlation coefficients (r) greater than 0.99 for all phallotoxins and amatoxins. Acceptable intraday and interday precision (relative standard deviation <15%) and accuracy (bias, -4.8% to 13.0% for blood and-9.0% to 14.7% for urine) were achieved. The validated method was successfully applied to analyze 9 blood samples and 2 urine samples testing positive for amatoxins and/or phallotoxins. Amatoxins and/or phallotoxins were identified in each whole blood sample at a range of 1.12-5.63 ng/mL and in two urine samples from 1.01-9.27 ng/mL. The method has the benefits of simple sample preparation (protein precipitation) and wide analyte coverage, making it suitable for emergency quantitative surveillance toxicological analysis in clinics and forensic poisoning practice.

A simple and rapid external standard calibration HPLC method for determination of lumefantrine in dried blood spot samples from malaria patients in Botswana.

A simple external calibration liquid chromatography-diode array detector method was developed, validated, and applied for the determination of lumefantrine (Lum) in dried blood spot (DBS) samples collected from malaria patients in Botswana. The samples were validated in accordance with the United States Food and Drug Administration guidelines for bioanalytical methods after sample preparation using solid-liquid extraction. Separation was achieved using an XTerra C18 column (50 × 4.6mm,5μm), and a binary solvent system of acetonitrile and water adjusted to pH2.3 was used as the mobile phase. The validated method was applied for the determination of Lum in DBS samples collected from malaria patients infected with Plasmodium falciparum in Botswana. The calibration curve was linear between 0.5 and 12 μg/mL with a coefficient of determination (R2 ) of 0.9996. The limit of detection and the lower limit of quantification were 0.5 and 1.4μg/mL, respectively. The efficiency of extraction measured as percentage recovery ranged between 84.2% and 107.8% at the three quality control (QC) levels, that is, low QC, mid QC, and high QC. In conclusion, data suggest that the method is suitable for the determination of trace Lum in biofluids and can also be used for therapeutic drug monitoring and pharmacokinetic profiling.

Carbon quantum dots as fluorescent probes in the measurement of the critical micelle concentration of surfactants

The critical micelle concentration (CMC) is one main parameter of surfactants, so an accurate, rapid, and convenient method for CMC determination is of great significance for surfactant applications. In this paper, three samples of carbon quantum dots (CQDs) with different fluorescence properties were developed as fluorescent probes for the CMC determination of CTAB, SDS, Triton X-100, perfluoro OBS and Pluronics® P-123. The fluorescence excitation and emission spectra of a constant amount of the CQDs in different concentrations of the surfactant solution were recorded, and then the CMC values of the surfactant were deduced from the fluorescence intensity change and the Stokes shift variation. The obtained CMC data using three samples of the CQDs agree well with those in the published literature. It is also demonstrated that in the micellization process the interaction between the CQDs and the surfactant molecules is complicated, because the fluorescence properties of the CQDs are found to be related to the characteristics of the CQDs, the head group type of ionic surfactants, the chemical structure between the hydrophobic and hydrophilic segment, and the chemical nature of the hydrophobic chains of the surfactants. So, the CQDs are demonstrated to be located at the palisade layer in the surfactant micelles due to the surface-attached polar groups on the CQDs although the CQDs are mainly hydrophobic as fluorescent probes. The fluorescent CQDs are considered to be new choices of the fluorescent probes in the facile CMC measurement of the surfactants.

Machine learning and DFT-based combined framework for predicting transmission spectra of quantum-confined bio-molecular nanotube.

The Adenine-based nanotube is theoretically designed, and its transmission spectra are investigated. The quantum-confined Adenine nanotube shows electronic transmission of the carrier at minimum stress. In this paper, the prediction of transmission spectra of the quantum-confined bio-molecular nanotube is investigated and deeply studied. Molecular level structure prediction and their electronic characterization can be possible with ab initio accuracy using a machine learning algorithmic approach. At the molecular level, it is difficult to predict quantum transmission spectra as these results are always hampered by the carrier backscattering effect. However, mostly these predictive models are available for intrinsic semi-conducting materials and other inorganic structures. Machine learning algorithms are designed to predict the electronic properties of the nano-scale structure. This task is even more difficult when quantum-confined molecular arrangements are considered, whose transmission spectra are sensitive to the confinements applied. This paper presents an effective machine learning algorithms framework for predicting transmission spectra of quantum-confined nanotubes from their geometries. In this paper, we consider regression machine learning algorithms to find maximum accuracy with varying configurations and geometries to excerpt their atoms' local environment information. The Hamiltonian components are then used to enable the utilization of the information to predict the electronic structure at any arbitrary sampling point or k-point. The theoretical basics introduced in this process help to capture and incorporate minor changes in quantum confinements into transmission spectra and provide the framework algorithm with more accuracy. This paper shows the ability to predict the accurate algorithmic models of the Adenine nanotube. In this framework, we have considered a tiny data set to achieve a rapid and reliable method for electronic structure determination and also propose the best algorithm for predictive model analysis.

Use of Satellite Data to Extract pH Values for Crop Planning and Management of Sorghum and Green Gram in Tharaka Nithi and Machakos Counties, Kenya

Soil pH is one of the most important soil properties influencing plant growth and productivity. The pH of the soil affects nutrient availability, microbial activity, and soil structure. As a result, accurate soil pH measurement is critical for effective soil management, plant growth, and sustainable agriculture practices. This study was conducted by analyzing the Landsat 8 satellite images, soil data of field surveys, laboratory analyses and statistical computations. The research combined and integrated the soil data from survey and laboratory with Landsat 8 satellite images to build two multiple regression equations model to enable the comparison of the two datasets i.e., field data and satellite data. The field and satellite data depicted the soil pH to range between 6.4 -7.8 for green gram while that of sorghum study area was 6.5 to 7.5. Field data showed a very strong relationship between field and satellite data with R2 for green gram soil pH being 0.91 while that for sorghum was 0.99. The positive relationship between field and satellite data is an indication that soil pH can be estimated from satellite thereby increasing the frequency of soil pH monitoring and as well as having a cost-effective and rapid method for soil pH determination.

Simple and rapid colorimetric method for determination of erythrocyte and plasma cholinesterase activities and comparison with the standard Ellman’s method

Simple and rapid colorimetric method for determination of erythrocyte and plasma cholinesterase activities and comparison with the standard Ellman’s method

An improved method for determining free amino acids by RP-HPLC/DAD with o-phthalaldehyde derivatization: Method evaluation in beers and wines

Rapid methods for amino acid determination are desired to reduce running times, and the main factors involved in the rapid separation of these compounds in HPLC are the columns, solvents, and gradient. The present study refers to a method optimization to rapidly analyze 19 amino acids in RP-HPLC/DAD with pre-column derivatization using o-phthalaldehyde. To evaluate the method's robustness, Indian Pale Ale-IPA beers and wines from the San Francisco Valley-SFV and Chapada Diamantina-CHD, Brazil, were analyzed. The method showed acceptable linearity (R2 > 0.992), precision (CV < 3.96%), recovery (74.2–113%), detection limits (<0.56 mg/L), and quantification limits (<3.62 mg/L) and separation gradient in 18.5 min. IPA beers were discriminated from wines by arginine, asparagine, tryptophan, alanine, phenylalanine, and tyrosine contents. Furthermore, CHD wines were discriminated from SFV wines by asparagine, glutamine, arginine, cystine, tyrosine, and leucine. In conclusion, a rapid method for amino acid determination was optimized and validated for wines and beers.

A rapid and sensitive method for determination of methylene-diphosphonate in rat bone using liquid chromatography-mass spectrometry

A liquid chromatography-tandem mass spectrometry (LC-MS/MS) method was developed and validated for the determination of methylene-diphosphonate (MDP) in rat bone. This method employed derivatization of MDP and allowed rapid and sensitive quantification of MDP in rat shin bone. The analyte was extracted from the bone tissues with phosphoric acid and derivatized to MDP tetramethyl phosphonate using trimethylsilyl diazomethane (TMS-DAM). MDP tetramethyl phosphonate was then quantified by liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS), with high selectivity, accuracy, and precision. The total run time was 6.5 min. The lower limit of quantification was 2.00 ng/mL. The intra- and inter-assay precision (in RSD) calculated from quality control samples was less than 15%, and the accuracy was between 98.1% and 100.2%. The analytical process for the determination of MDP in rat bone is fully described, which is a pivotal step for further biomedical research on MDP.

A study on the applicability of one-step vortex extraction and purification combined with gas chromatography-tandem mass spectrometry for analysis of four skin penetration enhancers in cosmetics

Based on one-step vortex extraction and purification combined with gas chromatography-tandem mass spectrometry (GC–MS/MS), we established a simple, rapid, and efficient method for the simultaneous determination of four skin penetration enhancers in cosmetics, including isosorbide dimethyl ether, isopropyl myristate, N-butylsaccharin and Azone. The extraction procedure was performed in a centrifuge tube, allowing extraction and purification in a single step. The cosmetic sample was extracted by n-hexane-ethyl acetate (1:1, V/V), purified by silica gel and anhydrous magnesium sulfate as the solid phase purification agent, separated on a TG-5 ms column (30.0 m × 0.25 mm × 0.25 μ m), confirmed and detected by GC–MS/MS in the selected reaction monitoring (SRM) mode, and quantified by the internal standard method with Di-n‑butyl phthalate-D4(DBP-D4) as the internal standard. The selections of a column, extraction solvent, and solid phase purification agent were optimized. Under the optimized conditions, the four skin penetration enhancers showed good linearities in the range of 0.02∼0.50 mg L − 1. The correlation coefficients (r) were 0.992 ∼ 0.997, exceeding the specifications requirements (r ≥ 0.990); The detection (LODs, S/N = 3) and quantification limits (LOQs, S/N = 10) of the method were 0.08 ∼ 0.12 mg kg−1 and 0.25 ∼ 0.40 mg kg−1, respectively. According to the cosmetic matrix in different formulation systems, the spiked recovery tests were carried out at three levels, i.e., low, medium, and high. The average recoveries of the analytes were 85.3% ∼ 95.6%, and the relative standard deviations (RSDs, n = 6) were 2.1% ∼ 7.8%. The established method was also employed to analyze cosmetics in the market. Azone, isosorbide dimethyl ether, and isopropyl myristate resulted as the most widely used skin penetration enhancers in cosmetics. The method established in this study has the advantages of operational simplicity, high sensitivity, good reproducibility, and low consumption of samples and solvents. Moreover, it can be used to determine skin penetration enhancers in cosmetics.

Determination of human monoclonal antibodies nivolumab and relatlimab in opdualag by using the RP-UPLC technique: method development and validation

A fixed combination of Nivolumab and Relatlimab (OPDUALAG) are human monoclonal antibodies (mAb) that are extensively used to treat skin cancer melanoma. The current investigation is to develop a robust, stability-indicating, and rapid method for the simultaneous determination of these two drugs by using the RP-UPLC technique. By utilizing this technique, the final chromatographic conditions were achieved with a Luna C18 column (50 x 2.1 mm, 1.6 μm), and a mobile phase made with acetonitrile and 0.1% formic acid, 6:4 ratio, respectively (Diluted 1.0 mL of Formic acid in 1000 mL of HPLC grade water) by adapting isocratic elution. Both Nivolumab and Relatlimab were detected at 229 nm, and a satisfactory separation was achieved in 3.0 minutes of run time with a flow rate of 0.2 mL/min. The method is linear from 15 - 90 μg/mL for Nivolumab (R2 = 0.9996) and 5 - 30 μg/mL for Relatlimab (R2 = 0.9997). Results of method repeatability for Nivolumab (% RSD=1.3 %) and Relatlimab (% RSD=0.48 %) and intermediate precision Nivolumab (% RSD=1.1 %) and Relatlimab (% RSD=0.48%) were found within acceptable limits. Also, the forced degradation study results show that it is discernible; the degradation products of both drugs were separated from the main peak, which demonstrates the efficiency of the stability-indicating method. So this method works well for routine analysis and stability studies.

BaTiO3 is a novel adsorbent for solid-phase extraction of copper at trace levels in food and water samples before HR-CS-FAAS detection

A simple, precise, and rapid method for preconcentration and determination of copper in food and water samples, based on sonication/vortex-free solid phase extraction with high resolution-continuum source flame atomic absorption spectrometry has been developed. In this study, BaTiO3 was synthesized using a single-step hydrothermal method and used as an adsorbent. BaTiO3 was characterized by FT-IR, SEM-EDX, STEM, XRD, and BET methods. The significant feature of the adsorbent is its high surface-to-volume ratio (177.4 m²/g). Important parameters (pH, adsorbent amount, eluent type and volume, adsorption and desorption time, model solution volume, and matrix effects) were optimized. The linear working range (5 – 250 µg L-1) and the detection limit (1.6 µg L-1) were calculated. The presented method was validated with certified reference material and the addition-recovery tests. The application of the method was evaluated for the extraction and determination of Cu(II) in selected food and water samples and quantitative data were obtained.

Rapid ultra-performance liquid chromatography-tandem mass spectrometry method for the simultaneous determination of three characteristic urinary saccharide metabolites in patients with glycogen storage diseases (type Ⅰb and Ⅱ)

Urinary 1,5-anhydroglucitol (1, 5-AG), 6-α-D-glucopyranosyl-maltotriose (Glc4) and maltotetraose (M4) are important biomarkers for glycogen storage disease (types Ib and Ⅱ). This study aimed to develop and validate an ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) to detect these three urinary saccharide metabolites. Urine samples were diluted and then analyzed. Chromatographic separation was performed on an Acquity™ UPLC Amide column (2.1 × 100 mm, 1.7 μm) with gradient elution. The quantitation of analytes was achieved on a 5500 Qtrap mass spectrometer using negative multiple reaction monitoring (MRM) mode. The calibration curves for all analytes were linear over the range of 0.500 to 100 μg/mL with a correlation coefficient, R2 ≥ 0.999. The percent relative standard deviations (RSD%) were ≤12.8%, and the percent relative errors (RE%) were in the range of −11.7%–11.0%. The relative matrix effects of all analytes were between 87.2% and 104% with RSD% < 3.10% across three concentrations. The developed analytical method was simple, accurate, and reliable for rapid and simultaneous analysis of these three urinary saccharide metabolites. It was applied to healthy volunteers and patients. To our knowledge, it was the first validated assay for urinary maltotetraose quantification. This work provides support for exploring the potential of maltotetraose as a biomarker for Pompe disease.

Construction of core–shell MOF@COF hybrid materials as highly efficient light-responsive oxidase-like nanozymes for colorimetric detection of glutathione

In this work, a novel and light-responsive nanozyme, with enzyme-like characteristics, was synthesized based on core–shell MOF@COF hybrid materials. The donor–acceptor type COF (as shell) synthesized by 1,3,6,8-tetrakis(4-aminophenyl)pyrene (Py, donor) and thieno[3,2-b]thiophene-2,5-dicarbaldehyde (Tt, acceptor) was wrapped on the NH2-Cu-MOF (robust catalyst, as core) through a sequential growth strategy. Surprisingly, with visible-light irradiation, the core–shell Cu-MOF@Py-Tt hybrid materials exhibited extremely high oxidase-like enzymatic catalytic activity attributing to the high separation efficiency of photogenerated carriers in core–shell hybrid materials and the shell with the characteristics of large π-conjugated and D-A electronic structure. With the light-control catalytic activity, Cu-MOF@Py-Tt can form the O2•- that can catalyze the TMB to blue color. Consequently, a light-control, sensitive and rapid colorimetric method for determination of glutathione (GSH) was designed based on light-responsive oxidase mimic of core–shell Cu-MOF@Py-Tt with the linear range of 0.2–70 μM and limit of detection of 0.17 μM. The proposed method demonstrated the future potential of core–shell MOF@COF hybrid materials to obtain excellent nanozyme activity.

Evaluation of Easy and Economic Protocols for High Quality Genomic DNA Extraction and Sex Determination in Papaya Using SCAR Markers

Rapid and precise identification of three sex types (male, hermaphrodite and female flowers) is the key in achieving good returns in papaya (Carica papaya L.) cultivation. This study presents a simple, reliable, fast and cost-efficient DNA isolation protocol and a rapid and precise method of sex determination in papaya. Three DNA isolation protocols viz., CTAB method, Modified Dellaporta method and BioBasic DNA isolation kit were comparatively evaluated for their simplicity, economic, DNA quantity and purity. Among them, CTAB method was regarded as relatively economic, with a cost of Rs. 11.80943 per sample with higher amount of DNA (4667.4 µg/ µl). However, it was noticed that DNA isolation with the BioBasic kit was fastest method, which took only 6 hours 7 minutes. On the other hand, relatively better DNA purity was noticed with the Modified Dellaporta method (average ratio of absorbance at 260 nm and 280 nm range between 1.8-2.0) and yielded clear, intact and distinct DNA bands. Hence, Modified Dellaporta method is suggested as an ideal DNA isolation protocol for papaya. Molecular markers (such as SCAR derived from RAPD T12, W11, NAPF-2 and PKBT-4) were employed in this study to identify the sex type and they have successfully distinguished between male and hermaphrodite plants in both dioecious and gynodioecious varieties; especially, NAPF-2 has successfully distinguished male in dioecious varieties. Evaluation of different kinds of molecular markers has shown that the SCAR marker T12 can be used as reliable marker for rapid and precise identification of papaya sex type.

Rapid chiral purity identification of mandelic acid by Raman spectra in the O–H stretching region

Chiral molecules play a very important role in biological systems, and more and more chiral drugs are used in the treatment of diseases. Mandelic acid (MA) is an important chiral starting substance or the key intermediate of some chiral drugs, and the rapid detection of its chiral purity is very important in the synthesis, separation and detection of drugs. In this study, we developed a method for rapid determination of chiral purity of MA by Raman spectroscopy, and measured a series of Raman spectra of different chiral MA. Through the analysis, it is found that the OH stretching vibration peak can be used to identify the components of chiral molecules, and the enantiomeric excess (ee value) obtained is in good agreement with the real value, and the error is about 5%. The experimental detection speed is fast and the efficiency is high. Our work firstly provides a new idea for the purity detection of chiral molecules by the original Raman spectrum.

Determination of the Carbamate Pesticides Fuberidazole and Pirimicarb in Crayfish (Procambarus Clarkii) Using Excitation-Emission Fluorescence Matrices with Self-Weighted Alternating Trilinear Decomposition (SWATLD)

Fuberidazole and pirimicarb are carbamate pesticides for insect control. There is pesticide accumulation through the food chain that may ultimately migrate into the human body through the crayfish. Here a rapid method for simultaneous determination of fuberidazole and pirimicarb in crayfish is reported. The excitation-emission fluorescence matrix was obtained by simple pretreatment of crayfish meat using acetonitrile, and qualitative and quantitative information was separated from overlapping spectra using the self-weighted alternating trilinear decomposition. The detection limits of the pesticides for fuberidazole and pirimicarb were 0.068 mg/kg and 0.160 mg/kg, respectively, and the limits of quantitation were 0.207 mg/kg and 0.485 mg/kg. The average recoveries were 90.79% and 98.77%. The results show that a combination of excitation-emission fluorescence matrix and alternating trilinear decomposition can be used for the determination of fuberidazole and pirimicarb in crayfish with simple pretreatment using acetonitrile.

An efficient and accurate droplet digital PCR method for rapid transgene copy number detection and homozygous identification in cotton (Gossypium hirsutum)

Transgene copy number characterization and homozygous identification are important steps for both the scientific research and transgenic breeding in plant. Traditionally, Southern blotting, quantitative PCR, genome sequencing and genetic analysis are the major methods to achieve these objectives. These methods are laborious, time-consuming and cost-expensive. Digital PCR is a breakthrough technology that is able to provide sensitive and absolute nucleic acid quantification. However, its application is rarely studied in transgene copy number detection and homozygous identification, especially in cotton, an important industrial crop worldwide. Here, we developed a droplet digital PCR (ddPCR) system to rapidly and efficiently detect the transgene copy number in cotton. The GhTPS, a single gene in per subgenome of Gossypium hirsutum, and NPT II, a marker gene in the transgenic T-DNA, were selected as the endogenous reference gene and exogenous insertion sequences, respectively. Results showed that probe concentration at 150 nM and DNA concentration at 5.0 ng/µL were the best conditions to perform ddPCR in tetraploid cotton. The detected T-DNA copy numbers obtained from the developed ddPCR system were in consistent with the results from Southern blotting analysis and genome resequencing results, respectively, demonstrating that the developed ddPCR system is accurate and efficient in identifying the T-DNA copy number. Moreover, the homozygous and heterozygous T1 offspring plants from a T0 plant were efficiently distinguished using this approach, greatly shortening the selection cycles of homozygous plants. The ddPCR system was further applied to detect the transgenic Bt copy numbers in commercialized cotton varieties, indicating the suitability and convenience in identifying transgenic cotton with different origins. This study provides a novel, rapid and efficient method for copy number and homozygous determination in transgenic cotton.

In vitro fitness of SARS-CoV-2 variants as assessed by competition experiments followed by ddRT-PCR and whole genome sequencing.

To develop a new method for reliable and rapid determination of the fitness of SARS-CoV-2 variants of concern. Competition experiments between two SARS-CoV-2 variants were performed in cells of the upper (nasal human airway epithelium) and lower (Calu-3 cells) respiratory tracts followed by quantification of variant ratios by droplet digital reverse transcription (ddRT)-PCR. In competition experiments, the delta variant outcompeted the alpha variant in both cells of the upper and lower respiratory tracts. A 50/50% mixture of delta and omicron variants indicated a predominance of omicron in the upper respiratory tract whereas delta predominated in the lower respiratory tract. There was no evidence of recombination events between variants in competition as assessed by whole gene sequencing. Differential replication kinetics were shown between variants of concern which may explain, at least partly, the emergence and disease severity associated with new SARS-CoV-2 variants.

Detection of Abnormal Wall Shear Stress and Oscillatory Shear Index via Ultrasound Vector Flow Imaging as Possible Indicators for Arteriovenous Fistula Stenosis in Hemodialysis.

The arteriovenous fistula (AVF) is an essential vascular access for hemodialysis patients. AVF stenosis may occur at sites with abnormal wall shear stress (WSS) and oscillatory shear index (OSI), which are caused by the complex flow in the AVF. At present, an effective method for rapid determination of the WSS and OSI of the AVF is lacking. The objective of this study was to apply an ultrasound-based method for determination of the WSS and OSI to explore the risk sites of the AVF. In this study, the ultrasound vector flow imaging technique V Flow was applied to measure the WSS and OSI at four different regions of the AVF to detect and analyze the risk sites: (i) anastomosis region, (ii) curved region, (iii) proximal vein and (iv) distal vein. Twenty-one patients were included in this study. The relative residence time was calculated based on the measured WSS and OSI. The curved region had the lowest WSS; the anastomosis region had a significantly higher OSI (p < 0.05) compared with the venous regions, and the curved region had a significantly higher RRT (p < 0.05) compared with the proximal vein region. V Flow is a feasible tool for studying WSS variations in AVF. The possible risk site in the AVF may be located in the anastomosis and curved regions, where the latter could present a higher risk for AVF stenosis.