scholarly journals Multivariate analysis of images in spectrophotometric methods: Quantification of soil organic matter

2021 ◽  
Vol 12 (4) ◽  
pp. 377-381
Author(s):  
Pedro Augusto de Oliveira Morais ◽  
Diego Mendesde Souza ◽  
Beata Emoke Madari
Keyword(s):  
Organic Matter ◽  
Soil Organic Matter ◽  
Multivariate Calibration ◽  
Potassium Dichromate ◽  
Low Cost ◽  
Reference Method ◽  
Calibration Method ◽  
Spectrophotometric Methods ◽  
Color Histograms ◽  
Mathematical Algorithms

Soil organic matter (SOM) is usually quantified by Walkley-Black titration method or using a spectrophotometric method. This study proposes an alternative method for quantification of SOM using digital image from scanner and mathematical algorithms to replace titration and spectrophotometry procedures. For this, after SOM oxidation by potassium dichromate, digital images were acquired. Posteriorly, extraction of RGB color histograms from images have occurred, followed by the use of multivariate calibration method: partial least squares (PLS). Six soil samples were analyzed. We used the Walkley-Black method as reference. SOM was estimated by images using the PLS tool. The new method, besides being a fast, low cost, and more operational alternative, presented statistically equal results in relation to the reference method, as assessed by the Student t-test and F-test at 95 % confidence.

Impact of soil wetness on plant litter decomposition using low-cost soil moisture sensors and off-the-shelf tea bags

2020 ◽  
Author(s):  
Angelika Xaver ◽  
Taru Sandén ◽  
Heide Spiegel ◽  
Luca Zappa ◽  
Gerhard Rab ◽  
...  
Keyword(s):  
Organic Matter ◽  
Soil Moisture ◽  
Soil Organic Matter ◽  
Litter Decomposition ◽  
Environmental Variables ◽  
Low Cost ◽  
Plant Litter ◽  
Soil Moisture Sensors ◽  
Plant Litter Decomposition ◽  
The Relationship

<p>Soil organic matter plays a key role within the nutrient cycle, serves as an agent to improve soil structure, and is also known to impact concentrations of greenhouse gases and stabilize soil pollutants. Thus, the soil organic matter content and its potential losses through decomposition are of high interest, especially in the light of a changing climate. As the decomposition process is significantly influenced by climatic conditions, it is important to understand the relationship between decomposition and environmental variables. Previous studies primarily focused on determining the influence of air temperature and precipitation on litter decomposition, but the impact of soil moisture has hardly been investigated.</p><p>In this study, we evaluate the relationship between plant litter decomposition, using commercial tea bags (Green and Rooibos tea) as standardized plant litter, and soil moisture, observed with low-cost sensors used within the European citizen science project GROW Observatory (GROW; https://growobservatory.org/). The low-cost soil moisture sensors were placed alongside the tea bags at eight different locations, covering four different land cover types, within the Hydrological Open Air Laboratory (HOAL), a small agricultural catchment in Petzenkirchen, Austria. Data has been collected for two years providing decomposition rates (k) and stabilization factors (S) for the four different seasons of both years. Apart from soil moisture, we investigate air and soil temperature, precipitation and soil parameters as drivers for litter decomposition.</p><p>We will show preliminary results on the relationship between decomposition and different environmental variables, in particular soil moisture, throughout all seasons and various land cover classes.</p><p> </p><p>This study was funded by the GROW Observatory project of the European Union’s Horizon 2020 research and innovation programme (https://growobservatory.org/).</p>

scholarly journals Condensation Methods for the Determination of Darunavir in Pure and Pharmaceutical Formulations

2020 ◽  
Vol 13 (4) ◽  
pp. 394-401
Author(s):  
M.L.N. Acharyulu ◽  
P.V.S.R. Mohana Rao ◽  
I. Siva Ramakoti
Keyword(s):  
Regression Analysis ◽  
Acidic Medium ◽  
Low Cost ◽  
Condensation Reaction ◽  
Reference Method ◽  
Pharmaceutical Formulations ◽  
Molar Absorptivity ◽  
Spectrophotometric Methods

Two visible spectrophotometric methods were developed Aand B for the determination of Darunavir in pure and pharmaceutical formulations. The methods are based on condensation reaction with PDAB (Method-A) and ONB (Method-B) in presence of acidic medium with the primaryamine group in DNV. The coloured products exhibit absorption λmax at 639 nm and 452nm for methods A and B respectively. Regression analysis of Beer-Lambert plots showed good correlation in the concentration ranges 10-60μg/ml, 50-300 μg/ml, correlation co-efficients are 0.9983, 0.9989;Sandell’s sensitivities are9.9833 x 10-3, 3.0456 x 10-2(1 mole cm-1); and molar absorptivity values are5.4857 x 104,1.7981x 104 (μg cm-2) for methods-Aand B respectively. The proposed methods are applied to commercial available formulations and the results are statistically compared with those obtained by the UV reference method and validated by recovery studies. The results are found satisfactory and reproducible. These methods are applied successfully for the estimation of the DNV in the presence of other ingredients that are usually present in formulations. These methods offer the advantages of rapidity, simplicity and sensitivity and low cost without the need for expensive instrumentation and reagents.

scholarly journals FIRST-ORDER ULTRAVIOLET DERIVATIVE SPECTROPHOTOMETRIC METHODS FOR DETERMINATION OF RESERPINE IN ANTIHYPERTENSION TABLET

2012 ◽  
Vol 12 (3) ◽  
pp. 268-272 ◽  
Author(s):  
Latifah K Darusman ◽  
Mohamad Rafi ◽  
Wulan Tri Wahyuni ◽  
Rizna Azrianiningsari
Keyword(s):  
Limit Of Detection ◽  
Low Cost ◽  
Reference Method ◽  
Ml Estimation ◽  
Mean Values ◽  
First Order ◽  
Spectrophotometric Methods ◽  
Relative Standard ◽  
Limit Of Quantitation

A new ultraviolet derivative spectrophotometry (UVDS) method has been developed for determination of reserpine in antihypertension tablets. A first-order UVDS based on the measurement of the distance between peaks to baseline (DZ) at the wavelength of 312 nm was used. Evaluation of analytical performance showed that accuracy as percentage recovery was 99.18-101.13%, precision expressed as relative standard deviation (RSD) was 1.91% and linear correlation was also obtained 0.9998 in the range of 10-50 µg/mL. Estimation of limit of detection and limit of quantitation was 0.8868 µg/mL and 2.6874 µg/mL, respectively. As a reference method, HPLC methods from United States Pharmacopiea (USP) were used. Commercially tablets available were analyzed by the two methods. The content of reserpine in tablets was found 0.2260±0.0033 mg by UVDS and 0.2301±0.0051 mg by the USP methods. The result obtained from the two methods was compared statistically using F-test and t-test and showed no significant differences between the variance and mean values of the two methods at 95% confidence level. This method was faster, easier, low cost and gave result as well as the reference method published by USP.

scholarly journals EXPLORE THE CHARACTER OF SOIL SPECTRAL REFLECTANCE RELATE TO THE SOIL ORGANIC MATTER CONTENT

2019 ◽  
Vol 8 (3) ◽  
pp. 214
Author(s):  
Sari Virgawati ◽  
Muhjidin Mawardi ◽  
Lilik Sutiarso ◽  
Sakae Shibusawa ◽  
Hendrik Segah ◽  
...  
Keyword(s):  
Organic Matter ◽  
Soil Organic Matter ◽  
Spectral Reflectance ◽  
Near Infrared ◽  
Diffuse Reflectance Spectroscopy ◽  
Low Cost ◽  
Organic Matter Content ◽  
Nir Spectroscopy ◽  
Matter Content ◽  
Strong Negative Correlation

ABSTRACTThe visible and near-infrared (Vis-NIR) diffuse reflectance spectroscopy has emerged as a rapid and low-cost tool for extensive investigation of soil properties. The objective of this research was to explore how significant the relationship between the soil spectral reflectance and soil organic matter (SOM) content. Some soil samples in Yogyakarta were taken for SOM content and spectroscopy measurement. The SOM was analyzed using Walkley and Black method, while the spectral reflectance was determined using ASD Field-spectrophotometer by scanned the sample with Vis-NIR spectrum. Pearson’s coefficient showed that there was a strong negative correlation between SOM and soil spectral of certain wavelengths. Soil with less organic matter content performed high reflectance. Keywords: Soil organic matter; Vis-NIR spectroscopy; soil reflectance; Pearson’s correlation coefficient.

Soil Organic Matter

1962 ◽  
Vol 54 (5) ◽  
pp. 470-470
Author(s):  
T. M. McCalla
Keyword(s):  
Organic Matter ◽  
Soil Organic Matter
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