Quantification of deep soil carbon by a wet digestion technique

Soil Research ◽  
2017 ◽  
Vol 55 (1) ◽  
pp. 78 ◽  
Author(s):  
Podjanee Sangmanee ◽  
Bernard Dell ◽  
Richard J. Harper ◽  
David J. Henry
Keyword(s):  
Soil Carbon ◽  
Limit Of Detection ◽  
Soil Depth ◽  
Deep Soil ◽  
Limit Of Quantification ◽  
Wet Digestion ◽  
Digestion Technique ◽  
Carbon Recovery ◽  
Digestion Methods ◽  
Dry Combustion

Two wet digestion methods were evaluated using pure kaolinite as background for quantifying small concentrations of carbon (<0.05% total organic carbon (TOC)) in deep kaolinitic regolith in south-western Australia. The limit of detection and limit of quantification of the Walkley–Black method (0.015 and 0.050% TOC respectively) were approximately five times lower than those of the Heanes method (0.085 and 0.281% TOC respectively). Both methods showed excellent linearity (R2>0.99) using prepared standards (lignin, humic acid, cellulose and chitin mixed with kaolinite and their combinations), in the concentration range 0.008–1.000% TOC. However, the percentage carbon recovery values were underestimated for chitin. The Walkley–Black method (TOCWB, %) was evaluated with 94 calibration and 27 validation deep soil samples (1–35m soil depth) and compared with a dry combustion (Elementar) technique (TOCactual, %). The predictive equation (TOCactual=1.66TOCWB+0.018) (R2=0.91) obtained from the calibration set agreed well with the benchmark dry combustion values (root mean square error=0.017) and is recommended for quantification of deep soil carbon in other kaolinitic regoliths.

Effective remediation of diazinon from spent sheep dip wash by disposal on land

2007 ◽  
Vol 47 (1) ◽  
pp. 13 ◽  
Author(s):  
G. W. Levot
Keyword(s):  
Soil Profile ◽  
Soil Depth ◽  
Disposal Site ◽  
Deep Soil ◽  
Limit Of Quantification ◽  
Entire Volume ◽  
South Wales ◽  
Run Off ◽  
Australian Wool ◽  
Pre Treatment

Spent sheep dip wash (about 3500 L) containing 59 mg diazinon/L was evenly distributed onto a 450-m2 grassed, soil-bunded, sloping site near Cumnock in central New South Wales, Australia. The entire volume was contained within the bunded area but surface run-off created ponding in the lowest corner of the site. The mean concentration within the top 7 cm of soil was 2.32 mg/kg a day after application. By day 14, this had dropped to 0.4 mg/kg and by day 56, was below the limit of quantification (0.1 mg/kg). The half-life of diazinon in soil was estimated to be 7 days. Residues in the next 7 cm of soil depth were much lower and were below the limit of quantification in all samples collected at day 28 or later. This suggests that vertical leaching of diazinon within the soil profile did not occur despite more than 95 mm of rain during the trial interval. Throughout the 56-day trial interval, diazinon concentrations in the top 7 cm of soil 3 m downhill of the lowest corner of the dip disposal site were unchanged from background pre-treatment levels. No diazinon was detected in samples at 7–14 cm depth in the soil profile in this area. With neither vertical nor lateral movement of diazinon away from the initial treatment zone, we consider the disposal of spent diazinon sheep dips as described here, to be an acceptable and convenient option for Australian wool producers and dipping contractors. Suitable dip disposal sites should be situated away from sensitive locations in areas that have good grass cover over deep soil and that are contained by an effective bund. Stock and other animals should be excluded from these sensitive locations.

scholarly journals Soil carbon sequestration by three perennial legume pastures is greater in deeper soil layers than in the surface soil

2016 ◽  
Vol 13 (2) ◽  
pp. 527-534 ◽  
Author(s):  
X.-K. Guan ◽  
N. C. Turner ◽  
L. Song ◽  
Y.-J. Gu ◽  
T.-C. Wang ◽  
...  
Keyword(s):  
Carbon Sequestration ◽  
Soil Carbon ◽  
Soil Profile ◽  
Soil Depth ◽  
Arable Land ◽  
Growth Period ◽  
Bare Soil ◽  
Soil Carbon Sequestration ◽  
Deep Soil ◽  
Perennial Legume

Abstract. Soil organic carbon (SOC) plays a vital role as both a sink for and source of atmospheric carbon. Revegetation of degraded arable land in China is expected to increase soil carbon sequestration, but the role of perennial legumes on soil carbon stocks in semiarid areas has not been quantified. In this study, we assessed the effect of alfalfa (Medicago sativa L.) and two locally adapted forage legumes, bush clover (Lespedeza davurica S.) and milk vetch (Astragalus adsurgens Pall.) on the SOC concentration and SOC stock accumulated annually over a 2 m soil profile. The results showed that the concentration of SOC in the bare soil decreased slightly over the 7 years, while 7 years of legume growth substantially increased the concentration of SOC over the 0–2.0 m soil depth. Over the 7-year growth period the SOC stocks increased by 24.1, 19.9 and 14.6 Mg C ha−1 under the alfalfa, bush clover and milk vetch stands, respectively, and decreased by 4.2 Mg C ha−1 in the bare soil. The sequestration of SOC in the 1–2 m depth of the soil accounted for 79, 68 and 74 % of the SOC sequestered in the 2 m deep soil profile under alfalfa, bush clover and milk vetch, respectively. Conversion of arable land to perennial legume pasture resulted in a significant increase in SOC, particularly at soil depths below 1 m.

Spectrophotometeric Determination of Trifluoperazine HCL in Pure Forms and Pharmaceutical Preperations

2017 ◽  
Vol 9 (5) ◽  
Author(s):  
Mohammad Hamzah Hamzah ◽  
Rawa M M Taqi ◽  
Muna M. Hasan ◽  
Raid J. M. Al-Timimi
Keyword(s):  
Standard Method ◽  
Limit Of Detection ◽  
Molar Absorptivity ◽  
Dosage Forms ◽  
Oxidizing Agent ◽  
Optimum Conditions ◽  
Limit Of Quantification ◽  
Cerium Ion ◽  
Blank Solution

A simple and accurate spectrophotometric method for the determination of Trifluoperazine HCl in pure and dosage forms was developed. The method is based on the reaction between Trifluoperazine HCl and p-chloroaniline in the presence of cerium ion as oxidizing agent which lead to the formation of violate color product that absorbed at a maximum wavelength 570nm while the blank solution was pink. Under the optimum conditions a linear relationship between the intensity and concentration of TRF in the range 4-50μg/ml was obtained . The molar absorptivity 3.74×103 L.mol-1.cm-1 , Limit of detection (2.21μg/ml), while limit of quantification was 7.39μg/ml. The proposed analytical method was compared with standard method using t-test and F-test , the obtained results shows there is no significant differences between proposed method and standard method. Based on that the proposed method can be used as an alternative method for the determination of TRF in pure and dosage forms.

Recent Trends in Development of Nanomaterials Based Green Analytical Methods for Environmental Remediation

2020 ◽  
Vol 16 ◽  
Author(s):  
Sidra Amin ◽  
Amber R. Solangi ◽  
Dilawar Hassan ◽  
Nadir Hussain ◽  
Jamil Ahmed ◽  
...  
Keyword(s):  
Optical Sensors ◽  
Environmental Remediation ◽  
Environmental Chemistry ◽  
Limit Of Detection ◽  
Environmental Pollutants ◽  
Toxic Metal ◽  
Electrochemical Analysis ◽  
Good Choice ◽  
Nano Materials ◽  
Limit Of Quantification

Background: In recent years, the occurrence and fate of environmental pollutants has been recognized as one of the emerging issues in environmental chemistry. A survey documented about a wide variety of these pollutants, which are often detected in our environment and these are major cause of shortened life spans and the global warming. These pollutants include toxic metal, pesticides, fertilizers, drugs and dyes released into soil and major water bodies. The presence of these contaminants causes major disturbance in eco-system’s balance. To tackle these issues many technological improvements are made to detect minute contaminations. The latest issue being answered by the scientists is the use of green nano materials as sensors which are economical, instant and give much better results at low concentrations and can be used for the field measurements resulting in no dangerous by-product that could lead to more environmental contamination. Nano materials are known for their wide band gap, enhanced physical and optical properties with option of tuneablity as per need, by optimizing certain parameters. They are proved to be good choice for analytical/optical sensors with high sensitivity. Objective: This review holds information about multiple methods that use green nanomaterials for the analytical assessment of environmental pollutants. UV-Vis spectrophotometry and electrochemical analysis using green and reproducible nanomaterials are the major focus of this review article. To date, there are number of spectrophotometric and electro chemical methods available that have been used for the detection of environmental pollutants such as toxic metals, pesticides and dyes. Conclusion: The use of nanomaterials can drastically change the detection limits due to having large surface area, strong catalytic properties, and tunable possibility. With the use of nano materials, lower than the marked limit of detection and limit of quantification were seen when compared with previously reported work. The used nano-materials could be washed, dried, and reused, which makes the methods more proficient, cost effective and environmentally friendly.

Calcium/Copper alginate framework doped with CuO nano-particles as a novel adsorbent for micro-extraction of benzodiazepines from human serum

2020 ◽  
Vol 16 ◽  
Author(s):  
Nadereh Rahbar ◽  
Fatemeh Ahmadi ◽  
Zahra Ramezani ◽  
Masoumeh Nourani
Keyword(s):  
Human Serum ◽  
High Performance ◽  
Limit Of Detection ◽  
Solid Phase ◽  
Nano Particles ◽  
Limit Of Quantification ◽  
Analytical Methodology ◽  
Fiber Fabrication ◽  
Relative Standard ◽  
Green Procedure

Background: Sample preparation is one of the most challenging phases in pharmaceutical analysis, especially in biological matrices, affecting the whole analytical methodology. Objective: In this study, a new Ca(II)/Cu(II)/alginate/CuO nanoparticles hydrogel fiber (CCACHF) was synthesized through a simple, green procedure and applied for fiber micro solid phase extraction (FMSPE) of diazepam (DIZ) and oxazepam (OXZ) as model drugs prior to high-performance liquid chromatography-UV detection (HPLC-UV). Methods: Composition and morphology of the prepared fiber were characterized and the effect of main parameters on the fiber fabrication and extraction efficiency have been studied and optimized. Results: In optimal conditions, calibration curves were linear ranging between 0.1–500 µg L−1 with regression coefficients of 0.9938 and 0.9968. Limit of detection (LOD) (S/N=3) and limit of quantification (LOQ) (S/N=10) of the technique for DIZ and OXZ were 0.03 to 0.1 µg L−1. Within-day and between-day relative standard deviations (RSDs) for DIZ and OXZ were 6.0–12.5% and 3.3–9.4%, respectively. Conclusion: The fabricated adsorbent has been substantially employed to extraction of selected benzo-diazepines (BZDs) from human serum real specimens and the obtained recoveries were also satisfactory (82.1-109.7%).

Eco-Friendly Green Liquid Chromatographic Separations of a Novel Combination of Azelastine and Fluticasone in the Presence of their Pharmaceutical Dosage form Additives

2020 ◽  
Vol 16 (3) ◽  
pp. 277-286
Author(s):  
Amal A. El-Masry ◽  
Mohammed E. A. Hammouda ◽  
Dalia R. El-Wasseef ◽  
Saadia M. El-Ashry
Keyword(s):  
Lower Limit ◽  
Dosage Form ◽  
Limit Of Detection ◽  
Sodium Dodecyl ◽  
Uv Detection ◽  
Simultaneous Estimation ◽  
Limit Of Quantification ◽  
Chromatographic Separations ◽  
Pharmaceutical Dosage Form ◽  
Liquid Chromatographic

Background: The first highly sensitive, rapid and specific green microemulsion liquid chromatographic (MELC) method was established for the simultaneous estimation of fluticasone propionate (FLU) and azelastine HCl (AZL) in the presence of their pharmaceutical dosage form additives (phenylethyl alcohol (PEA) and benzalkonium chloride (BNZ)). Methods: The separation was performed on a C18 column using (o/w) microemulsion as a mobile phase which contains 0.2 M sodium dodecyl sulphate (SDS) as surfactant, 10% butanol as cosurfactant, 1% n-octanol as internal phase and 0.3% triethylamine (TEA) adjusted at pH 6 by 0.02 M phosphoric acid; with UV detection at 220 nm and programmed with flow rate of 1 mL/min. Results: The validation characteristics e.g. linearity, lower limit of quantification (LOQ), lower limit of detection (LOD), accuracy, precision, robustness and specificity were investigated. The proposed method showed linearity over the concentration range of (0.5-25 µg/mL) and (0.1-25 µg/mL) for FLU and AZL, respectively. Besides that, the method was adopted in a short chromatographic run with satisfactory resolution factors of (2.39, 3.78 and 6.74 between PEA/FLU, FLU/AZL and AZL/BNZ), respectively. The performed method was efficiently applied to pharmaceutical nasal spray with (mean recoveries ± SD) (99.80 ± 0.97) and (100.26 ± 0.96) for FLU and AZL, respectively. Conclusion: The suggested method was based on simultaneous determination of FLU and AZL in the presence of PEA and BNZ in pure form, laboratory synthetic mixture and its combined pharmaceutical dosage form using green MELC technique with UV detection. The proposed method appeared to be superior to the reported ones of being more sensitive and specific, as well as the separation was achieved with good performance in a relatively short analysis time (less than 7.5 min). Highly acceptable values of LOD and % RSD make this method superior to be used in quality control laboratories with of HPLC technique.

scholarly journals Soil Carbon Regulating Ecosystem Services in the State of South Carolina, USA

Land ◽  
2021 ◽  
Vol 10 (3) ◽  
pp. 309
Author(s):  
Elena A. Mikhailova ◽  
Hamdi A. Zurqani ◽  
Christopher J. Post ◽  
Mark A. Schlautman ◽  
Gregory C. Post ◽  
...  
Keyword(s):  
South Carolina ◽  
Ecosystem Services ◽  
Soil Carbon ◽  
Soil Depth ◽  
State Level ◽  
The United States ◽  
The State ◽  
Soil C ◽  
Low Country ◽  
Pee Dee

Sustainable management of soil carbon (C) at the state level requires valuation of soil C regulating ecosystem services (ES) and disservices (ED). The objective of this study was to assess the value of regulating ES from soil organic carbon (SOC), soil inorganic carbon (SIC), and total soil carbon (TSC) stocks, based on the concept of the avoided social cost of carbon dioxide (CO2) emissions for the state of South Carolina (SC) in the United States of America (U.S.A.) by soil order, soil depth (0–200 cm), region and county using information from the State Soil Geographic (STATSGO) database. The total estimated monetary mid-point value for TSC in the state of South Carolina was $124.36B (i.e., $124.36 billion U.S. dollars, where B = billion = 109), $107.14B for SOC, and $17.22B for SIC. Soil orders with the highest midpoint value for SOC were: Ultisols ($64.35B), Histosols ($11.22B), and Inceptisols ($10.31B). Soil orders with the highest midpoint value for SIC were: Inceptisols ($5.91B), Entisols ($5.53B), and Alfisols ($5.0B). Soil orders with the highest midpoint value for TSC were: Ultisols ($64.35B), Inceptisols ($16.22B), and Entisols ($14.65B). The regions with the highest midpoint SOC values were: Pee Dee ($34.24B), Low Country ($32.17B), and Midlands ($29.24B). The regions with the highest midpoint SIC values were: Low Country ($5.69B), Midlands ($5.55B), and Pee Dee ($4.67B). The regions with the highest midpoint TSC values were: Low Country ($37.86B), Pee Dee ($36.91B), and Midlands ($34.79B). The counties with the highest midpoint SOC values were Colleton ($5.44B), Horry ($5.37B), and Berkeley ($4.12B). The counties with the highest midpoint SIC values were Charleston ($1.46B), Georgetown ($852.81M, where M = million = 106), and Horry ($843.18M). The counties with the highest midpoint TSC values were Horry ($6.22B), Colleton ($6.02B), and Georgetown ($4.87B). Administrative areas (e.g., counties, regions) combined with pedodiversity concepts can provide useful information to design cost-efficient policies to manage soil carbon regulating ES at the state level.

scholarly journals Electrochemical Detection of Endosulfan Using an AONP-PANI-SWCNT Modified Glassy Carbon Electrode

Materials ◽  
2021 ◽  
Vol 14 (4) ◽  
pp. 723
Author(s):  
Kgotla K. Masibi ◽  
Omolola E. Fayemi ◽  
Abolanle S. Adekunle ◽  
Amal M. Al-Mohaimeed ◽  
Asmaa M. Fahim ◽  
...  
Keyword(s):  
Glassy Carbon Electrode ◽  
Glassy Carbon ◽  
Limit Of Detection ◽  
Modified Electrodes ◽  
Antimony Oxide ◽  
Current Response ◽  
Carbon Electrode ◽  
Trace Detection ◽  
Limit Of Quantification ◽  
Walled Carbon Nanotubes

This report narrates the successful application of a fabricated novel sensor for the trace detection of endosulfan (EDS). The sensor was made by modifying a glassy-carbon electrode (GCE) with polyaniline (PANI), chemically synthesized antimony oxide nanoparticles (AONPs), acid-functionalized, single-walled carbon nanotubes (fSWCNTs), and finally, the AONP-PANI-SWCNT nanocomposite. The electrochemical properties of the modified electrodes regarding endosulfan detection were investigated via cyclic voltammetry (CV) and square-wave voltammetry. The current response of the electrodes to EDS followed the trend GCE-AONP-PANI-SWCNT (−510 µA) > GCE-PANI (−59 µA) > GCE-AONPs (−11.4 µA) > GCE (−5.52 µA) > GCE-fSWCNTs (−0.168 µA). The obtained results indicated that the current response obtained at the AONP-PANI-SWCNT/GCE was higher with relatively low overpotential compared to those from the other electrodes investigated. This demonstrated the superiority of the AONP-PANI-SWCNT-modified GCE. The AONP-PANI-SWCNT/GCE demonstrated good electrocatalytic activities for the electrochemical reduction of EDS. The results obtained in this study are comparable with those in other reports. The sensitivity, limit of detection (LoD), and limit of quantification (LoQ) of AONP-PANI-SWCNT/GCE towards EDS was estimated to be 0.0623 µA/µM, 6.8 µM, and 20.6 µM, respectively. Selectivity, as well as the practical application of the fabricated sensor, were explored, and the results indicated that the EDS-reduction current was reduced by only 2.0% when interfering species were present, whilst average recoveries of EDS in real samples were above 97%.

scholarly journals Comparison of Drivers of Soil Microbial Communities Developed in Karst Ecosystems with Shallow and Deep Soil Depths

Agronomy ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 173
Author(s):  
Huiling Guan ◽  
Jiangwen Fan ◽  
Haiyan Zhang ◽  
Warwick Harris
Keyword(s):  
Microbial Community ◽  
Microbial Communities ◽  
Soil Depth ◽  
Phospholipid Fatty Acid ◽  
Soil Microbial Communities ◽  
Deep Soil ◽  
Soil System ◽  
Soil Microbial ◽  
Total Soil ◽  
Karst Ecosystems

Soil erosion is prevalent in karst areas, but few studies have compared the differences in the drivers for soil microbial communities among karst ecosystems with different soil depths, and most studies have focused on the local scale. To fill this research gap, we investigated the upper 20 cm soil layers of 10 shallow–soil depth (shallow–SDC, total soil depth less than 100 cm) and 11 deep–soil depth communities (deep–SDC, total soil depth more than 100 cm), covering a broad range of vegetation types, soils, and climates. The microbial community characteristics of both the shallow–SDC and deep–SDC soils were tested by phospholipid fatty acid (PLFAs) analysis, and the key drivers of the microbial communities were illustrated by forward selection and variance partitioning analysis. Our findings demonstrated that more abundant soil nutrients supported higher fungal PLFA in shallow–SDC than in deep–SDC (p < 0.05). Furthermore, stronger correlation between the microbial community and the plant–soil system was found in shallow–SDC: the pure plant effect explained the 43.2% of variance in microbial biomass and 57.8% of the variance in the ratio of Gram–positive bacteria to Gram–negative bacteria (G+/G−), and the ratio of fungi to total bacteria (F/B); the pure soil effect accounted for 68.6% variance in the microbial diversity. The ratio of microbial PLFA cyclopropyl to precursors (Cy/Pr) and the ratio of saturated PLFA to monounsaturated PLFA (S/M) as indicators of microbial stress were controlled by pH, but high pH was not conducive to microorganisms in this area. Meanwhile, Cy/Pr in all communities was >0.1, indicating that microorganisms were under environmental stress. Therefore, the further ecological restoration of degraded karst communities is needed to improve their microbial communities.

scholarly journals SaQuant: a real-time PCR assay for quantitative assessment of Staphylococcus aureus

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Colin Wood ◽  
Jason Sahl ◽  
Sara Maltinsky ◽  
Briana Coyne ◽  
Benjamin Russakoff ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Sensitivity And Specificity ◽  
Pathogen Detection ◽  
Limit Of Detection ◽  
Future Research ◽  
Limit Of Quantification ◽  
Pathogen Prevalence ◽  
Single Well ◽  
Effective Public Health ◽  
Detection And Quantification

Abstract Background Molecular assays are important tools for pathogen detection but need to be periodically re-evaluated with the discovery of additional genetic diversity that may cause assays to exclude target taxa or include non-target taxa. A single well-developed assay can find broad application across research, clinical, and industrial settings. Pathogen prevalence within a population is estimated using such assays and accurate results are critical for formulating effective public health policies and guiding future research. A variety of assays for the detection of Staphylococcus aureus are currently available. The utility of commercial assays for research is limited, given proprietary signatures and lack of transparent validation. Results In silico testing of existing peer-reviewed assays show that most suffer from a lack of sensitivity and specificity. We found no assays that were specifically designed and validated for quantitative use. Here we present a qPCR assay, SaQuant, for the detection and quantification of S. aureus as might be collected on sampling swabs. Sensitivity and specificity of the assay was 95.6 and 99.9 %, respectively, with a limit of detection of between 3 and 5 genome equivalents and a limit of quantification of 8.27 genome equivalents. The presence of DNA from non-target species likely to be found in a swab sample, did not impact qualitative or quantitative abilities of the assay. Conclusions This assay has the potential to serve as a valuable tool for the accurate detection and quantification of S. aureus collected from human body sites in order to better understand the dynamics of prevalence and transmission in community settings.

Sign in / Sign up

Export Citation Format

Share Document