scholarly journals Development and Validation of an Autonomous System for Measurement of Sunshine Duration

Sensors ◽  
2020 ◽  
Vol 20 (16) ◽  
pp. 4606
Author(s):  
Álvaro B. da Rocha ◽  
Eisenhawer de M. Fernandes ◽  
Carlos A. C. dos Santos ◽  
Júlio M. T. Diniz ◽  
Wanderley F. A. Junior
Keyword(s):  
Sunshine Duration ◽  
Low Cost ◽  
Electronic System ◽  
Operational Amplifiers ◽  
Solar Panels ◽  
Calculation Methods ◽  
Contrast Method ◽  
Microcontroller Unit ◽  
Development And Validation

This paper presented an autonomous electronic system for sunshine duration (SD) monitoring based on the contrast method and developed to operate on a horizontal surface. The prototype uses four photoresistors arranged at 90° in a 20 mm diameter circumference separated by a shading structure used to create a shadow pattern on the detection element. Photoresistors are inserted in individual signal conditioning circuits based on the association between Wheatstone bridges and operational amplifiers to provide an analog signal to the microcontroller unit. The determination of SD occurs through the implementation of fuzzy logic with numerical calculation methods to estimate the probability (f) of solar disk obstruction and estimate SD values. The system does not require additional adjustments after installation or use of energy sources for operation due to the use of an internal battery with charge recovery by solar panels. Experimental results of the proposed system were validated with the ones provided by a government meteorology station. Statistical analysis of the results showed a confidence index (c) greater than 90%, with a precision of 94.26%. The proposed system is a feasible low-cost solution to the available commercial systems for the measurement of sunshine duration.

Development and Validation of an Eco-Friendly and Low-Cost Method for the Quantification of Cefepime Hydrochloride in Powder for Injectable Solution Using Infrared (IR) Spectroscopy

2020 ◽  
Vol 16 (4) ◽  
pp. 456-464
Author(s):  
Danilo F. Rodrigues ◽  
Hérida R.N. Salgado
Keyword(s):  
Ir Spectroscopy ◽  
Low Cost ◽  
Pharmaceutical Preparations ◽  
Potassium Bromide ◽  
Pharmaceutical Products ◽  
Injectable Formulation ◽  
Ich Guidelines ◽  
Lactam Ring ◽  
Development And Validation

Background: A simple, eco-friendly and low-cost Infrared (IR) method was developed and validated for the analysis of Cefepime Hydrochloride (CEF) in injectable formulation. Different from some other methods, which employ organic solvents in the analyses, this technique does not use these types of solvents, removing large impacts on the environment and risks to operators. Objective: This study aimed at developing and validating a green analytical method using IR spectroscopy for the determination of CEF in pharmaceutical preparations. Methods: The method was validated according to ICH guidelines and the quantification of CEF was performed in the spectral region absorbed at 1815-1745 cm-1 (stretching of the carbonyl group of β- lactam ring). Results: The validated method showed to be linear (r = 0.9999) in the range of 0.2 to 0.6 mg/pellet of potassium bromide, as well as for the parameters of selectivity, precision, accuracy, robustness and Limits of Detection (LOD) and Quantification (LOQ), being able to quantify the CEF in pharmaceutical preparations. The CEF content obtained by the IR method was 103.86%. Conclusion: Thus, the method developed may be an alternative in the quality control of CEF sample in lyophilized powder for injectable solution, as it presented important characteristics in the determination of the pharmaceutical products, with low analysis time and a decrease in the generation of toxic wastes to the environment.

scholarly journals Development and Validation of an UHPLC Method for Ostarine Determination in Dietary Supplements

2019 ◽  
Vol 65 (2) ◽  
pp. 49-54
Author(s):  
Amalia Miklos ◽  
Amelia Tero-Vescan ◽  
Lénárd Farczádi ◽  
Daniela-Lucia Muntean
Keyword(s):  
Quantitative Determination ◽  
Dietary Supplements ◽  
Low Cost ◽  
Reversed Phase ◽  
European Pharmacopoeia ◽  
Average Mass ◽  
7Th Edition ◽  
Development And Validation ◽  
Mg Content

AbstractObjective: The purpose of this study was to develop a low-cost, yet sensitive and precise UHPLC method for the quantitative determination of ostarine from dietary supplements (DS) for athletes. The analytical performance of the method was verified on a DS legally acquired from a specialized website for athletes. The uniformity of mass and content of the ostarine DS was also verified.Methods: For the quantitative determination of ostarine a UHPLC method was developed and validated. The separation was performed using a reversed-phase C18 column, using a mixture of 75% methanol: 25% formic acid 0.1% in isocratic elution, at a flow rate of 0.5 ml/min. The uniformity of mass and content of DS was performed following the methodology described in the European Pharmacopoeia 7th Edition.Results: The validated method was specific and linear on the concentration range of 1-25 µg/ml and was precise and accurate at all concentration levels, according to the official guidelines for validating analytical methods. An average mass of 510 mg content was obtained for the ostarine capsules, with an RSD of 2.41%. Regarding the uniformity of the content, an average of 4.65 mg ostarine/capsule was obtained with an RSD of 1.05%.Conclusions: The developed UHPLC method was suitable, rapid, sensitive and allowed quantitative determination of active substance content in a DS with ostarine (92.91% ostarine/capsule from 5 mg ostarine/capsule declared by the manufacturer).

scholarly journals A Low-Cost, High-Precision Method for Ripple Voltage Measurement Using a DAC and Comparators

Electronics ◽  
2019 ◽  
Vol 8 (5) ◽  
pp. 586
Author(s):  
Jincheng Liu ◽  
Jiguang Yue ◽  
Li Wang ◽  
Chenhao Wu ◽  
Feng Lyu
Keyword(s):  
High Precision ◽  
High Speed ◽  
Low Cost ◽  
Estimation Method ◽  
Electronic System ◽  
Voltage Measurement ◽  
Pass Filter ◽  
Switched Mode Power Supply ◽  
Dc Component ◽  
Microcontroller Unit

As the core of electronic system, the switched-mode power supply (SMPS) will lead to serious accidents and catastrophes if it suddenly fails. According to the related research, the monitoring of ripple can acquire the health degree of SMPS indirectly. To realize low-cost, high-precision, and automatic ripple measurement, this paper proposes a new ripple voltage (peak-to-peak value) measuring scheme, utilizing a DAC and two high-speed comparators. Within this scheme, the DC component of SMPS output is blocked by a high-pass filter (HPF). Then, the filtered signal and the reference voltage from a DAC together compose the input of a high-speed comparator. Finally, output pulses of the comparator are captured by a microcontroller unit (MCU), which readjusts the output of the DAC by calculation, and this process is repeated until the DAC output is exactly equal to the peak (or valley) value of ripple. Moreover, in order to accelerate the measurement process, a peak estimation method is specially designed to calculate the output ripple peak (or valley) value of buck topology through merely two measurements. Then the binary search method is utilized to obtain a more exact value on the basis of estimative results. Additionally, an analysis of the measurement error of this ripple measurement system is executed, which shows that the theoretical error is less than 0.5% where the ripple value is larger than 500 mV. Furthermore, appropriate components are selected, and a prototype is manufactured to verify the validity of the proposed theory.

scholarly journals Portable and Low-Cost Respirometric Microsystem for the Static and Dynamic Respirometry Monitoring of Compost

Sensors ◽  
2019 ◽  
Vol 19 (19) ◽  
pp. 4132 ◽  
Author(s):  
Juliette F. Bermudez ◽  
Juan F. Saldarriaga ◽  
Johann F. Osma
Keyword(s):  
Laboratory Test ◽  
Organic Waste ◽  
New Technologies ◽  
Low Cost ◽  
Electronic System ◽  
Ease Of Use ◽  
Hierarchical Analysis ◽  
Standard Laboratory ◽  
The Cost

Composting is considered an option for the disposal of organic waste; however, the development of portable and low-cost systems for its monitoring is of high interest. Therefore, in this study, respirometric microsystems were designed and tested including two integrated oxygen sensors for the measurement of compost samples under static and dynamic conditions with high portability and ease of use. The cost of each sensor was calculated as 2 USD, while the cost of the whole respirometric microsystem was calculated as 6 USD. The electronic system for real-time monitoring was also designed and implemented. The designed systems were tested for over 6 weeks for the determination of compost quality using real samples. The respirometric microsystem was compared to a commercial respirometry system and a standard laboratory test using hierarchical analysis which included costs, portability accuracy, analysis time, and integration of new technologies. The analysis showed a global score of 6.87 for the respirometric microsystem compared to 6.70 for the standard laboratory test and 3.26 for the commercial system.

Development and Validation of an HPLC Method for the Simultaneous Determination of Fipronil, Chlorfenapyr, and Pyriproxyfen in Insecticide Formulations

2016 ◽  
Vol 99 (5) ◽  
pp. 1185-1190 ◽  
Author(s):  
Anum Hafeez ◽  
Iffat Abdul Tawab ◽  
Sajid Iqbal
Keyword(s):  
Simultaneous Determination ◽  
Method Development ◽  
Low Cost ◽  
Hplc Method ◽  
Good Resolution ◽  
Chromatographic Separations ◽  
Method Development And Validation ◽  
Development And Validation ◽  
Interday Precision

Abstract In this study, the analytical method development and validation of an HPLC assay for simultaneous determination of fipronil, chlorfenapyr, and pyriproxyfen in formulation products is described. On the basis of solubility and chromatographic separation with good resolution, acetonitrile–water (80 + 20) was selected as the mobile phase in isocratic mode with a flow rate of 1 mL/min. Chromatographic separations were performed on a Beckman C18 analytical column (4.6 mm × 15 cm, 5 μm particle size; Musa Jee & Sons, Karachi, Pakistan). The retention times for fipronil, chlorfenapyr, and pyriproxyfen were 3.70, 8.61 and 10.09 min, respectively. Calibration curves of all studied insecticides were linear in the concentration range of 20 to 800 μg/mL, with R2 > 0.997. The LODs of fipronil, chlorfenapyr, and pyriproxyfen were 15.1, 13.3, and 20.0 μg/mL, respectively, whereas the LOQs were 45.9, 40.3, and 60.6 μg/mL. Interday precision was RSD, % <2 for all formulation types, whereas intraday precision was <3. The accuracy of the proposed method was determined by interlaboratory comparison. The z-score for all formulation results were <2.The proposed method is low-cost, green, accurate, and precise and can suitably be used for the simultaneous quantitative determination of fipronil, chlorfenapyr, and pyriproxyfen in their formulations.

Validation of an analytical method based on QuEChERS and LC-MS/MS to quantify nine mycotoxins in plant-based milk

2021 ◽  
pp. 1-8
Author(s):  
L. Pinto ◽  
A. Santos ◽  
E. Vargas ◽  
F. Madureira ◽  
A. Faria ◽  
...  
Keyword(s):  
Ochratoxin A ◽  
Low Cost ◽  
Analytical Methodology ◽  
Relative Standard ◽  
Immunoaffinity Columns ◽  
Vegetable Milk ◽  
Aflatoxin B ◽  
Development And Validation ◽  
Proof Of Principle

Plant-based beverages (popularly known as vegetable milk) have become increasingly important in recent years. However, the nonexistence of information on mycotoxin contamination is noticeable. We herein describe the development and validation of an analytical methodology that employs QuEChERS and LC-MS/MS for the simultaneous determination of nine mycotoxins (aflatoxins B1, B2, G1, and G2, fumonisins B1 and B2, ochratoxin A, zearalenone, and citreoviridin) in seven types of vegetable milk (peanut, oat, rice, cashew, maize, soybean, and coconut). The method provided the following quantification limits, recoveries at the lowest validated concentration and relative standard deviations under repeatability conditions at the lowest validated concentration, respectively: aflatoxin B1 (0.023 μg/l, 84.98 and 9.23%); aflatoxin B2 (0.024 μg/, 93.00 and 4.85%); aflatoxin G1 (0.057 μg/l, 98.85 and 5.53%); aflatoxin G2 (0.031 μg/l, 96.64 and 4.08%); fumonisin B1 (2.166 μg/l, 75.55 and 16.78%); fumonisin B2 (1.105 μg/l, 70.47 and 11.89%); ochratoxin A (0.104 μg/l, 72.05 and 5.12%); zearalenone (8.093 μg/l, 107.10 and 6.37%); citreoviridin (1.305 μg/l, 97.25 and 7.28%). The method uses small amounts of samples, solvents, and other inexpensive reagents with no need for laborious clean-up and pre-concentration steps. Its attractive characteristics (simplicity, low cost compared to procedures that use immunoaffinity columns, and full compatibility with routine analyses) make it potentially valuable. As a proof-of-principle, the validated methodology was applied to seven commercial samples of different compositions showing that some were contaminated with aflatoxins and ochratoxin A.

Development and Validation of an analytical method for the determination of Ofloxacin and Benzyl alcohol in a Pharmaceutical mixture

2021 ◽  
pp. 2133-2138
Author(s):  
Ghadeer Balloul ◽  
Nikolay N. Boyko ◽  
Elena T. Zhilyakova ◽  
Solaiman Doba
Keyword(s):  
Benzyl Alcohol ◽  
Linear Dependence ◽  
Low Cost ◽  
Correlation Coefficients ◽  
Analytical Signal ◽  
Pure Substance ◽  
Apparent Concentration ◽  
Proportional Relationship ◽  
Development And Validation

The aim of the study is to develop a validated, rapid, simple and low-cost method for estimating ofloxacin and benzyl alcohol in a combined dosage. Materials and methods: Materials which were used ofloxacin pure substance and benzyl alcohol pure substance which were determined by UV spectrophotometer using ethanol 95% as a solvent and a blank. Results and discussion: Ofloxacin shows the absorption maxima at 300.0 ± 2.0 nm in ethanol 95% with an apparent concentration absorptivity of (30 to 90) µg/ml and benzyl alcohol shows the absorption maxima at 312.0 ± 2.0 nm in ethanol 95% with an apparent concentration absorptivity of (60 to 200) µg/ml, it was found that in the selected range of application of the method there is a directly proportional relationship between the concentration of ofloxacin and benzyl alcohol respectively, in the measured samples and the analytical signal, linear dependence is characterized by high correlation coefficients (R> 0.999)for both of drugs, which is considered acceptable for establishing strict linearity. Conclusion: The method has been verified as it has been proven simple, fast, accurate and low-cost method and does not require any expensive equipment for the analysis of Ofloxacin and benzyl alcohol separately and in a pharmaceutical mixture.

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