Simple Method For Determination Research Articles

Simultaneous determination of amlodipine and lisinopril dihydrate using fourth derivative spectroscopy

A new fast and simple selective method for the simultaneous determination of lisinopril dihydrate and amlodipine in combined drugs was developed using the fourth derivative spectrum method, based on the zero-crossing-point technique for the determination of compounds in drugs. The wavelength values for lisinopril dihydrate and amlodipine in solvent medium were found to be (203, 207, and 231 nm) and (215, 254, and 277 nm), respectively, with the average obeying Beer’s law in the range of lisinopril dihydrate 2.0 to 45.0 µg/mL and amlodipine 2.0 to 35.0 µg/mL. Lisinopril dihydrate has molar absorptivity regions (9227.76-11700.28 L/mol.cm, 203 nm), (15320.74-20795.59 L/mol.cm, 207 nm), and (2207.60-3311.40 L/mol.cm, 231 nm), while amlodipine (5886.72-10914.96 L/mol.cm, 215 nm), (5518.8-6418.16 L/mol.cm, 254 nm) and (1676.08-1921.36 L/mol.cm, 277 nm). The recovery rate of lisinopril dihydrate in the pharmaceutical dosage forms range was 95.13 to 102.60% and amlodipine 95.14 to 102.80%. The results of the relative error showed that the interferences did not affect the method of estimating these compounds. The proposed method has been successfully applied to estimate pharmaceutical dosage forms.

Quality control of marketed herbal products of Asparagus racemosus Willd. through high performance thin layer chromatography (HPTLC) analysis

Asparagus racemosus Willd. is a valuable medicinal plant which is used all over the world. There are several marketed products of A. racemosus. The high demand for this herb has increased the risk of adulteration in its commercial products. The adulterated herbal products might pose serious ill effects on health. Therefore, it is necessary to check the quality of marketed products in terms of the presence of their major bioactive compounds. The present study aimed to carry out the qualitative and quantitative analysis of Shatavarin IV in marketed products of A. racemosus through a validated high performance thin layer chromatography (HPTLC) method. Ten marketed products were analysed and all of them had shown the presence of Shatavarin IV which was quantified. The identification and quantification were done by taking a standard Shatavarin IV as reference. The Shatavarin IV was detected at Rf 0.4±0.05 and showed maximum absorption at 425 nm. The Shatavarin IV was quantified using a 6-point calibration curve having a standard deviation of 3.89 % with an R2 value of 0.9968. The amount of Shatavarin IV varied between 1.47±0.25 to 2.69±0.51 mg/g on a dry weight basis which is a normal range in the raw plant materials. Thus, the present findings would be a simple, reliable and cost-effective method for the quality determination of herbal products of A. racemosus. The developed HPTLC chromatograms would serve as a reference for the quality assessment of commercial products of A. racemosus in future.

Experimental Study on Rapid Determination Method of Coal Seam Gas Content by Indirect Method

In view of the problems of heavy work, long cycle, high cost and low efficiency in the process of indirect determination of coal seam gas content, the basic gas parameters and coal quality indexes of 24 coal samples from 5 coal mines in the Hancheng area of Shanxi Province are measured by the laboratory measurement method. The raw coal gas content–gas desorption index of drilling cuttings (W–K1) relationship model is characterized by logarithmic function. Using SPSS data analysis software, a stepwise multiple linear regression method is used for statistical analysis. The results show that the factors that have a significant impact on the regression slope C in the W–K1 relationship model are gas adsorption constant (a), apparent density (ARD), initial velocity of gas diffusion (Δp) and consistent coefficient (f). The factors that have a significant impact on the regression constant D are Δp and atmospheric adsorption (Q). Then, the mathematical model of rapid prediction of coal seam gas content is determined. Compared with the measured values, the average absolute error rate is 12.84%, which meets the prediction requirements and provides a simple and easy method for rapid determination of coal seam gas content in coal mines in the Hancheng area.

Trigging stepwise-strand displacement amplification lights up numerous G-quadruplex for colorimetric signaling of serum microRNAs

MicroRNAs (miRNAs) play an important biomarker in various biological processes, especially cancer related, yet economic, simple, sensitive and specific methods for miRNA determination are still challenging. In this study, we have developed stepwise-strand displacement amplification (S-SDA)-based colorimetric sensing platform for let-7a miRNA detection in clinical serum samples. Our results demonstrated that the developed S-SDA-based method shows high sensitivity with a detection limit of 63.2 pM and a naked eye detection limit of 0.1nM. Moreover, the S-SDA amplifier is able to discriminate target miRNAs from their mutants with high accuracy and specificity. With its high sensitivity and selectivity, this method successfully identified healthy individuals from patients with colon cancer by detecting let-7a miRNAs in serum. We believe the colorimetric analysis method will provide a new paradigm for the detection of miRNA with different abundance and show great potential for clinical application in biomedical analysis and early clinical diagnosis.

Influence of the design constraints on the thickness optimization of glass panes to achieve lightweight insulating glass units in cruise ships

The increasing complexity and size in cruise ships demands for lightweight structures and practical but accurate design methods. Conventionally, the focus has been on the steel parts of the ship, as they make most of its weight. However, the proportions of other materials are increasing. Therefore, this study attempts to provide better understanding how one could reach the lightweight designs of insulating glass units (IGUs) in ships. These are windows where at least two glass panes are separated by a hermetically sealed cavity. They are thin-walled structures that benefit not only from the geometrically nonlinear behavior, but also from the load sharing. Considering these effects, their behavior is studied using the nonlinear Finite Element Method and Particle Swarm Optimization. Different design criteria are imposed on the thickness determination of the glass panes with different shapes. Rectangular, triangular, and circular shapes are considered. The results show that the triangular shapes have the least weight for a given area when the deflection criterion is the dominating one. When maximum principal stress is the thickness defining criterion, the shapes perform almost equally well. The ratio between the pane thicknesses had the most influence on the behavior of the IGU. As it increases, i.e., one pane is significantly thicker than the other, the load sharing percentage drops, but it provides the most lightweight solution. Closer it is to 1, more equally the structural stresses are divided between the panes, i.e., redundancy is achieved. Finally, it is possible to establish a simple but effective method for the thickness determination of these IGUs using the results of this study. However, more work is required, including numerical analysis and experimental testing.

Method of determining thermal diffusivity on the basis of measurements of linear displacements

An innovative, relatively simple method of non-stationary determination of thermal diffusivity with the use of linear displacement measurements is proposed. This method is dedicated mostly to materials with an extensive internal structure (porous building materials, i.e. concrete, ceramics, wood, etc.), where the thermal parameters should take into account the heterogeneity of the structure (relatively large samples are required). The main difference between the proposed method and the methods known from the literature is that in order to determine the thermal diffusivity, it is only necessary to measure changes in the length of the sample during cooling or heating. This is an alternative to methods based on direct or indirect measurement of the surface temperature of the sample. The proposed method was tested on samples made of plexiglass. The obtained results were compared with the reference results obtained from measurements with the use of commercial measuring equipment (Netzsch HFM 446), which allows to determine the thermal conductivity coefficient and specific heat with high accuracy. Good agreement of the obtained results was obtained. The uncertainty analysis of the proposed method showed that it is at the level of 3%, which is sufficient in the case of building materials.

Determination of polymyxin B in human plasma and epithelial lining fluid using LC-MS/MS and its clinical application in therapeutic drug monitoring

Polymyxin B (PB) is currently one of the last resort treatment options against carbapenem-resistant gram-negative bacterial pathogens. Pharmacokinetics/pharmacodynamics (PK/PD) guided therapeutic drug monitoring (TDM) of antibiotics is critical for optimizing dosage regimens to maximize efficacy, minimize toxicity, and delay the emergence of resistance. Currently, methods for determining PB in human plasma and epithelial lining fluid (ELF) are limited. In this study, we developed and validated a simple method for PB determination in human plasma and ELF using LC-MS/MS. Protein precipitation of the sample was conducted with 0.1% formic acid-acetonitrile. Polymyxin B1 and B2 were separated on a C18 column and detected within 4 min by the mass spectrometer in the positive mode coupled with multiple reaction monitoring. The calibration curve range was 0.156–10.0 and 0.0156–1.00 μg/mL in the plasma for polymyxin B1 and B2, respectively, and was 0.0625–2.00 and 0.00625–0.200 μg/mL for polymyxin B1 and B2, respectively in bronchoalveolar lavage fluid. The accuracy of the intra- and inter-assay studies ranged from 80.6% to 114.9%, and the coefficients of variation for intra- and inter-day assays were less than 14.8%. Among a considerable number of patients, the average steady-state plasma concentration of PB was suboptimal. Moreover, the exposure to PB in patients with acute kidney injury (AKI) was considerably higher than that in patients without AKI. Meanwhile, a higher concentration of PB in ELF could be achieved than that in plasma after PB nebulization treatment. The established method was proven to be rapid, simple, and suitable for TDM of PB and PK/PD studies in human plasma and ELF.

Spectrophotometric method for the Determination of Sulfathiazole Drug by Schiff's base Formation

This research involves the development of simple, sensitive and rapid spectrophotometric method for determination of sulfathiazole (STHZ) in aqueous solution. The method is based on the Schiff's base formation between the primary amino group of sulfathiazole and aldehyde group of the p-dimethyl aminobenzaldehyde reagent (p-DMAB) to produce a yellow colored complex having maximum absorption at 451 nm at pH 2.2. Beer's law is obeyed in the concentration range 2-24μg/ml of sulfathiazole , with a molar absorptivity 11259 L.mol-1.cm-1 and sandal index of 0.023 μg.cm-2 . The average recovery is 99.925%, relative standard deviation 0.68-0.81% and D.L of 0.1534 μg/ml . This method has been applied successfully to determination of sulfathiazole in veterinary injection liquid solution (bio prime).

Room temperature fabrication of magnetic covalent organic frameworks for efficient enrichment of parabens in water

A novel 4 + 2 covalent magnetic organic framework (COF) with core-shell structure was synthesized for the first time with N, N, N', N'-Tetrakis (4-aminophenyl)-1, 4- benzenediamine (TPDA) and 2, 6-Pyridinedicarboxaldehyde (PCBA) at room temperature. The synthesized magnetic TPDA-PCBA-COF has a large specific surface area and superparamagnetism, which makes it an ideal sorbent for trace analytes enrichment. To this end, we combined it with magnetic solid phase extraction (MSPE) to enrich trace parabens in environmental water. The parameters affecting the enrichment efficiency of magnetic solid phase extraction, such as the amount of Fe3O4@TPDA-PCBA-COF, extraction time, pH of samples, salt concentration, desorption solvent volume and desorption time, were optimized. A simple method for extraction and determination of parabens in water samples by MSPE combined with high performance liquid chromatography (HPLC) was established under optimized conditions. The validation results revealed that the linear ranges were at 1.0–5.0 × 102 ng mL−1 with R value between 0.9915 and 0.9999, the spiked recoveries were in the range of 82.8% to 99.9% and RSDs were lower than 10%. The method was further applied to the determination of parabens in water samples, with recoveries in the range of 82.2% to 110.0% and RSDs ≤ 7.7%. These results suggest that the magnetic TPDA-PCBA-COF could be used as a promising adsorbent for efficient extraction and quantitation of parabens in environmental water samples.

Determination Micro Spectrohotometric of Pyridoxine Hydrochloride and Nicotinamide via Derivative Spectrophotometry First and Second

A simple, sensitive and accurate spectrophotometric method for determination of PYR.HCl and NTA in pure and pharmaceutical forms. The method based on group of known digital data used to separate the response signals for sample contains the two components without need to separating via first and second derivative of spectra. The method obtained obeying to the Beers law in the concentration range between )5-45 µg.ml-1( for two components in the presence of PYR. HCl )15µg.ml-1( and NTA (5µg.ml-1) with another components at wavelength (210 nm ) respectively . The Rec % range was between ) 98.5354 - 103.4335 % (and RSD% (0.0864 - 0.1487 %), LOD) 1.0822 µg.ml-1, ( LOQ ( 3.6075 µg.ml-1 (PYR.HCl in presence of NTA, The Rec% range was between )96.1418 - 102.9273 % (and RSD% (0.2165–0.4933 % ), LOD (0.7273µg.ml-1 ,(LOQ (2.4252 µg.ml-1( NTA in presence of PYR. HCl .

Determination of Riboflavin and Cyanocobalamine Spectrophotometricaly via Area Under Curve Method

A simple, sensitive, accurate and economical spectrophotometric method for determination of Riboflavin (RIBO) and Cyanocobalamin (CCA) in pure and pharmaceutical forms was developed .The method based on the area under curve (AUC) in the region between 400-526 nm for RIBO and 538-562nm for CCA. The method obey Beers law in the concentration range between 10- 90 µg.ml-1 of RIBO and 6- 96 µg.ml-1 of CCA. The Rec% range was between 97.6542-103.5198 % and RSD% 0.5871-0.7542 % , LOD 0.2168 µg.ml-1, LOQ 0.8560 µg.ml-1 of RIBO. The Rec% range was between 99.7835-102.3990 % and RSD% 0.4811-0.8238 % and LOD 0.1381 µg.ml-1, LOQ 0.4606 µg.ml-1 of CCA .

A spectrophotometric method for the determination of tryptophan following oxidation by the addition of sodium hypochlorite pentahydrate.

Tryptophan (Trp) is an essential amino acid that functions in various biological processes and human daily health. As the significant functions of Trp become more apparent, its measurement is becoming increasingly important in various situations. Herein, we improved the Trp color reaction based on the Hopkins-Cole reaction and established a simple colorimetric method for Trp determination using several different reagents, including sodium hypochlorite pentahydrate and monosodium glutamate. The detection method can be performed using safe materials, rather than conventional toxic substances, and induces a crimson color change with an absorption peak at 525 nm, enabling the quantification of Trp by simple spectrophotometry in just 10 min. This assay exhibited a linear detection range from 10 to 100 mg/L (R2 = 0.9996). The average recoveries in the spiked cerebrospinal fluid ranged from 90.5% to 104.3%, with a relative standard deviation of 0.27% (n = 3, 29.40 mg/L Trp) to 1.19% (n = 3, 72.90 mg/L Trp). This novel spectrophotometric method may enable many researchers and laboratory technicians to detect Trp in various sample solutions without expensive analytical instruments or complicated operations.

A Simple Methods for Determination of Methylene Blue using Smartphone-Based as Digital Image Colorimetry

The advancement of smartphones that produce high-resolution photos has made their use even more developed. One application that is currently developing is a digital image produced as colorimetry. Digital image-based colorimetry is an easy and simple determination method and can be an alternative for analyzing dyes quantitatively. In this method, the color response of the digital image is analyzed, namely red-green-blue (RGB) with values from 0 to 255. This data is extracted from digital images using ImageJ 1.52a software for quantitative determination. In this study, 2 standard methods were used, namely external standards and standard addition to evaluating the most suitable method to obtain accurate measurements. In addition, 2 methods were used to determine the relationship of response to methylene blue levels. The 1st method used simple linear regression of each color red, green, or blue (univariate). The 2nd method is used in multivariate linear regression of the 3 colors red, green, and blue. The accuracy of the method was validated using UV-Vis spectrophotometry as the reference method. The results showed that the multivariate models produced very good accuracy, namely precision of up to 99 % compared to the simple regression method with the univariate. HIGHLIGHTS Smartphone cameras can be applied easily as a simple, fast, and inexpensive colorimetric method for quantitative analysis of methylene blue content The univariate models for external standard and standard addition methods showed up to 90 % precision for fish drug samples against UV-Vis spectrophotometric methods The multivariate models for the external standard method provide up to 99 % precision results for fish drug samples against UV-Vis spectrophotometric methods· GRAPHICAL ABSTRACT

A rapid and simple method for simultaneous determination of three breast cancer related microRNAs based on magnetic nanoparticles modified with S9.6 antibody

Cancer progression is typically associated with the simultaneous changes of multiple microRNA (miR) levels. Therefore, simultaneous determination of multiple miR biomarkers exhibits great promise in early diagnosis of cancers. This research seeks to discuss a simple biosensing method for the ultrasensitive and specific detection of the three miRs related to the breast cancer based on S9.6 antibody coated magnetic beads, titanium phosphate nanospheres, and screen-printed carbon electrode. To prepare signaling probes, three hairpin DNAs (hDNAs) were labeled with three encoding titanium phosphate nanospheres with large quantities of different heavy metal ions (zinc, cadmium, lead), which have been utilized to discriminate the signals of three microRNA targets in relation with the corresponding heavy metal ions. After that, these hairpin structures hybridize with miR-21, miR-155 and miR-10b to form miR-21/hDNA1, miR-155/hDNA2 and miR-10b/hDNA3 complexes, which were captured by S9.6 antibodies (one anti-DNA/RNA antibody) pre-modified on magnetic bead surface. Therefore, the specific preconcentration of targets from complex matrixes can be carried out using magnetic actuation, increasing the sensitivity and specificity of the detection. The biosensor was suitably applied for direct and rapid detection of multiple microRNAs in real sample. It was observed that there were no significant differences between the results obtained by the suggested method and qRT-PCR as a reference method. So, this method makes an ultrasensitive novel platform for miRNAs expression profiling in clinical diagnosis and biomedical research.

Determination of Acephate, Dinotefuran, and Emamectin Benzoate in a Pesticide Formulation: A Single-Laboratory Validation.

The advantage of simultaneous separation and quantification is the reduction of analysis time and consumption of solvents and reagents. The objective of the present investigation was to optimize and validate a novel, rapid, and simple reverse-phase high-performance liquid chromatographic method for the simultaneous determination of acephate, dinotefuran, and emamectin benzoate in a pesticide formulation. The chromatographic separation and quantification were accomplished by using Kromasil CN column (250 mm × 4.6 mm; 5 μm) with a mobile phase consisting of acetonitrile and water [0.1% (v/v) triethylamine, pH 2.7 with 10% (v/v) orthophosphoric acid] in the ratio of 50:50 (v/v) with a flow rate of 1.0 mL/min and diode array detection at the wavelength of (215 nm and 245 nm). The HPLC method was able to separate and quantify all the actives in the formulation by isocratic elution within 10 min. The method was fully validated in accordance with the SANCO and Collaborative International Pesticide Analytical Council guidelines concerning system suitability, specificity, linearity, precision, accuracy, and robustness. All the analytical parameters are within the range of acceptable limits in the guidelines. The validated method was successfully applied to a pesticide formulation. The novelty of the current research work lies in the development of the simple and rapid HPLC method for simultaneous determination of acephate, dinotefuran, and emamectin benzoate in wettable granular formulation.

Development, Validation and Greenness Assessment of Three Simple Spectrophotometric Methods for Determination of Two Combined Broad-Spectrum Antibacterial Agents

Development, Validation and Greenness Assessment of Three Simple Spectrophotometric Methods for Determination of Two Combined Broad-Spectrum Antibacterial Agents

137Cs direct measurement in water via LSC techniques

This work explores the screening technique of 137Cs concentration dissolved in water via the Cherenkov counting method on a Liquid Scintillation Counter Quantulus 1220. In the event of a nuclear emergency or the potential radioactive leakage from the power plants, the prompt detection of two long-lived fission products, 90Sr/90Y and 137Cs, is of the greatest radiological concern. Here we present an innovative, rapid, and simple LSC method for 137Cs content determination that enables quick evaluation of the radioactive contamination status of water samples without any sample pre-treatment. The novelty in the presented Cherenkov counting technique is the addition of ionic liquid 1-butyl-3-methylimidazolium salicylate in a sample vial. Its presence in the amount of ∼1 g increases efficiency up to ∼30% via a wavelength-shifting mechanism, thus reducing the detection limit of the method more than 4 times. Without the ionic liquid's addition, the method's main parameters were detection efficiency of 6.98(11)% and a detection limit of 2.6 Bq L−1 for 300 min of counting in a 20 mL sample volume. Interference with 90Sr/90Y, a radionuclide that can contribute to the Cherenkov radiation spectrum, was also investigated. The method of distinguishing individual radionuclides (137Cs and 90Sr/90Y) in the cumulative Cherenkov spectrum is presented as well.

Rapid Determination of Nitrate Nitrogen Isotope in Water Using Fourier Transform Infrared Attenuated Total Reflectance Spectroscopy (FTIR-ATR) Coupled with Deconvolution Algorithm.

Nitrate is a prominent pollutant in water bodies around the world. The isotopes in nitrate provide an effective approach to trace the sources and transformations of nitrate in water bodies. However, determination of isotopic composition by conventional analytical techniques is time-consuming, laborious, and expensive, and alternative methods are urgently needed. In this study, the rapid determination of 15NO3- in water bodies using Fourier transform infrared attenuated total reflectance spectroscopy (FTIR-ATR) coupled with a deconvolution algorithm and a partial least squares regression (PLSR) model was explored. The results indicated that the characteristic peaks of 14NO3-/15NO3- mixtures with varied 14N/15N ratios were observed, and the proportion of 15NO3- was negatively correlated with the wavenumber of absorption peaks. The PLSR models for nitrate prediction of 14NO3-/15NO3- mixtures with different proportions were established based on deconvoluted spectra, which exhibited good performance with the ratio of prediction to deviation (RPD) values of more than 2.0 and the correlation coefficients (R2) of more than 0.84. Overall, the spectra pretreatment by the deconvolution algorithm dramatically improved the prediction models. Therefore, FTIR-ATR combined with deconvolution and PLSR provided a rapid, simple, and affordable method for determination of 15NO3- content in water bodies, which would facilitate and enhance the study of nitrate sources and water environment quality management.

Development and Validation of a Simple HPLC-UV Assay Method for Determination of Levetiracetam Concentrations in Human Plasma

Levetiracetam (LEV) is a broad spectrum antiseizure medication that is used in various seizure types. There is evidence that therapeutic drug monitoring (TDM) of LEV is of value in selected patient populations, therefore determination of LEV plasma concentrations is essential. Herein we developed and validated a simple, reproducible, and practical method for the quantification of LEV concentrations in human plasma samples using high performance liquid chromatography (HPLC). Plasma samples (0.3 mL) deproteinization was done using acetonitrile. HPLC chromatographic separation of plasma samples was accomplished by reversed phase C18 column. The mobile phase constituted water and acetonitrile (90:10, v/v) ran at flow rate of 1 mL/min. Signal acquisition was conducted at a wavelength of 192 nm. Calibration curves showed excellent linearity (Correlation coefficient r2 > 0.99) over a concentration range of 3–80 μg/mL. Both inter and intraday assay accuracy and precision were less than 8% (except for the lowest limit of quantification was within 20%). Elution time was 15 min. The developed method excluded the use of buffers and utilized small volumes of plasma samples with simple mobile phase composition. Therefore, our method could be practically applied to routine TDM.

Simple analytical method for total biogenic amines content determination in wine using a smartphone.

A simple, fast, and green smartphone-based procedure for total biogenic amines content determination in wine was developed and validated. Sample preparation and analysis were simplified to make the method suitable for routine analyses even in resource-scarce settings. The commercially available S0378 dye and smartphone-based detection were used for this purpose. The developed method has satisfactory figures of merit for putrescine equivalent determination with R2 of 0.9981. The method's greenness was also assessed using the Analytical Greenness Calculator. Samples of Polish wine were analysed to demonstrate the applicability of the developed method. Finally, results obtained with the developed procedure were compared with those previously obtained with GC-MS in order to evaluate the equivalence of the methods.