scholarly journals Methods for Sample Collection, Storage, and Analysis of Freshwater Phosphorus

Water ◽  
2019 ◽  
Vol 11 (9) ◽  
pp. 1889 ◽  
Author(s):  
Yusef Kianpoor Kalkhajeh ◽  
Bahman Jabbarian Amiri ◽  
Biao Huang ◽  
Azad Henareh Khalyani ◽  
Wenyou Hu ◽  
...  
Keyword(s):  
Natural Waters ◽  
Monitoring Program ◽  
Sample Pretreatment ◽  
Freshwater Ecosystems ◽  
Sample Treatment ◽  
Sample Collection ◽  
P Fractions ◽  
Laboratory Methods ◽  
P Fractionation ◽  
Advantages And Disadvantages

Although phosphorus (P) is an essential nutrient for biological productivity, it can cause freshwater degradation when present at fairly low concentrations. Monitoring studies using continuous sampling is crucial for documenting P dynamics in freshwater ecosystems and to reduce the risk of eutrophication. Despite literature updates of developments of the analytical methods for measurement of P species in natural waters, there has been no comprehensive review addressing freshwater sample collection, sample preparation, and sample treatment to fractionate and characterize different forms of P. Therefore, this paper aims to elaborate the different techniques for freshwater sampling and to introduce alternative laboratory methods for sample preservation and P fractionation. The advantages and disadvantages of various sampling techniques, including the traditional manual and the recently developed automatic and passive methods, are presented to highlight the importance of collecting representative freshwater samples. Furthermore, we provide suggestions for sample pretreatment, including filtration, transportation, and storage steps to minimize microbial activity and to maximize the accuracy of measurement of various P fractions. Finally, the most common laboratory methods to measure dissolved and particulate as well as the organic and inorganic freshwater P fractions are efficiently provided. Using this guide, a comprehensive monitoring program of P dynamics in freshwater ecosystems can be developed and applied to improve water quality, particularly of P-rich freshwaters.

scholarly journals ASSESSMENT OF ECOLOGICAL STATE OF THE VELIKAYA RIVER DELTA BASED ON HYDROCHEMICAL INDICATORS AND STRUCTURE OF PHYTOPLANKTON

2017 ◽  
Vol 1 ◽  
pp. 82
Author(s):  
Tatiana Drozdenko ◽  
Sergei Mikhalap ◽  
Larisa Nikolskaya ◽  
Anna Chernova
Keyword(s):  
Water Quality ◽  
High Speed ◽  
Shannon Index ◽  
Freshwater Ecosystems ◽  
River Delta ◽  
Ecosystem Dynamics ◽  
Polluted Water ◽  
Ecological State ◽  
Sample Collection ◽  
Wide Range

The basis of the existence of freshwater ecosystems is phytoplankton, which produces most of the primary biological production, participates in repair processes and provides a wide range of ecosystem services. The short life cycle and high speed metabolism of microalgae make them ideal objects for ecological monitoring. The aim of the present study is to research the ecological state of the Velikaya river delta based on the species composition of phytoplankton community and some hydrochemical parameters. The sample collection for phytoplankton study and physicochemical measurements was carried out in summer 2016 at five stations representing different ecological locations of the Velikaya river delta. One hundred sixty five species taxa of microalgae belonging to 8 phylums were identified during the research: Bacillariophyta (37%), Chlorophyta (33.9%), Cyanophyta/Cyanobacteria (9.7%), Chrysophyta (6.1%), Euglenophyta (6.1%), Cryptophyta (3%), Dinophyta (3%), Xanthophyta (1.2%). The values of Shannon index indicate the average complexity of the microalgae communities structure. Values of Margalef index characterize the Velikaya river delta as an area of high species richness. Compared to the previous studies, a significant increase in the level of information diversity is observed, indicating an increase in the number of possible flows of substance and energy in the ecosystem. Dynamics of biogen substances in the water shows a slight increase of their concentrations. Ecological and geographical analysis proves that absolute dominance of cosmopolitan freshwater forms is typical for the algoflora of the Velikaya river delta. In relation to the pH-reaction inhabitants of neutral and slightly alkaline water dominate. Pantle–Buck saprobity index is applied for water quality assessment, which shows beta-mesosaprobic water quality in the ecosystem. Thus, the water of the Velikaya river delta could be referred to the category of moderately polluted water (class II of water quality). This is confirmed by the data of hydrochemical analysis.

scholarly journals ANALYSIS OF EXISTING METHODS FOR URANIUM-PLUTONIUM MIXED NITRIDE FUEL FAB-RICATION IN RUSSIA AND ABROAD

2020 ◽  
Vol 63 (6) ◽  
pp. 12-18
Author(s):  
Maxim S. Fedorov ◽  
Nikolay A. Baydakov ◽  
Alexander N. Zhiganov ◽  
Dmitry V. Zozulya
Keyword(s):  
High Voltage ◽  
Electric Pulse ◽  
Industrial Applications ◽  
Ceramic Technology ◽  
Laboratory Methods ◽  
Advantages And Disadvantages ◽  
Nitride Fuel ◽  
Powder Pressing ◽  
Uranium Nitride ◽  
Uranium Plutonium

This paper presents a review and a brief analysis of existing methods for producing mixed uranium nitride and plutonium, developed by both Russian and foreign scientists. The main parameters of the processes are considered, and their advantages and disadvantages are studied. Currently, the main areas of nitride fuel production are the metal hydride method and carbothermic reduction from the starting oxides. The methods are traditional ceramic technology. The starting products for the manufacture of nitride fuel powder can be either oxides (uranium dioxide and plutonium dioxide) or metals (uranium, plutonium and their alloys). To date, the technology for the manufacture of nitride fuel powder has not been finally selected. When considering existing methods, significant emphasis was placed on industrial applications and the simplicity of the hardware design processes. The laboratory methods are reflected in the work, which make it possible to simplify the process and reduce the costs of obtaining powders of mixed uranium and plutonium nitrides. However, they have significant difficulties in the technological implementation and low productivity of the processes. Of special interest among laboratory methods for producing mixed uranium and plutonium nitrides is the method of high-voltage electric pulse consolidation. This method allows sintering of tablets at the stage of powder pressing from mixed uranium and plutonium nitrides by passing a short high-voltage discharge with a power of several kW directly through the powder.

scholarly journals Rudjer Bošković Institute Radiocarbon Measurements VI

Radiocarbon ◽  
1981 ◽  
Vol 23 (3) ◽  
pp. 410-421 ◽  
Author(s):  
Dušan Srdoč ◽  
Adela Sliepčevic ◽  
Bogomil Obelic ◽  
Nada Horvatinčic
Keyword(s):  
Oxalic Acid ◽  
Soil Sample ◽  
Half Life ◽  
Sample Pretreatment ◽  
Radiocarbon Date ◽  
Sample Treatment ◽  
New Techniques ◽  
Counting Technique ◽  
Acid Sample ◽  
Modern Standard

The following radiocarbon date list contains dates of samples measured since our previous list (R, 1979, v 21, p 131-137). As before, age calculations are based on the Libby half-life 5570 ± 30 yr and reported in years before 1950. The modern standard is 0.95 of the activity of NBS oxalic acid. Sample pretreatment, combustion, and counting technique are essentially the same as described in R, 1971, v 13, p 135-140, supplemented by new techniques for groundwater processing (R, 1979, v 21, p 131-137) and for soil sample treatment (R, 1977, v 19, p 465-475).

Analysis of Pesticide Residues by Chemical Derivatization. V. Multiresidue Analysis of Eight Phenoxyalkanoic Acid Herbicides in Natural Waters

1977 ◽  
Vol 60 (5) ◽  
pp. 1070-1076 ◽  
Author(s):  
Haig Agemian ◽  
Alfred S Y Chau
Keyword(s):  
Natural Waters ◽  
Chromatographic Determination ◽  
Multiresidue Analysis ◽  
Boron Trichloride ◽  
Advantages And Disadvantages ◽  
Pentafluorobenzyl Bromide ◽  
Extraction Scheme ◽  
Liquid Chromatographic Determination ◽  
Liquid Chromatographic ◽  
Acid Herbicides

Abstract A multiresidue method is presented for the gas-liquid chromatographic determination of phenoxyalkanoic acid herbicides in natural waters. Extraction efficiencies of different organic solvents are considered in developing a solvent extraction scheme for these herbicides from water. Reactions for derivatizing these compounds by using pentafluorobenzyl bromide, boron trichloride-2-chloroethanol, and dicyclohexylcarbodiimide-2-chloroethanol were studied in order to obtain extracts with low blanks to provide the lowest detection limits. Advantages and disadvantages of the 3 methods are discussed. Retention times are twice as long for the pentafluorobenzyl (PFB) esters as for the 2-chloroethyl (2-Cl) esters under the same conditions, although electron capture sensitivity to the former was greater. The PFB esters are easier to form, but the 2-Cl reaction is more specific for these herbicides. Solutions from the boron trichloride reaction gave the cleanest blanks.

scholarly journals Factors influencing genotyping success and genotyping error rate of Eurasian otter (Lutra lutra) faeces collected in temperate Central Europe

2020 ◽  
Vol 67 (1) ◽  
Author(s):  
Marcia Sittenthaler ◽  
Eva Maria Schöll ◽  
Christoph Leeb ◽  
Elisabeth Haring ◽  
Rosemarie Parz-Gollner ◽  
...  
Keyword(s):  
Influential Factors ◽  
Lutra Lutra ◽  
Sample Treatment ◽  
Success Rates ◽  
Sample Collection ◽  
Allelic Dropout ◽  
Non Invasive ◽  
Eurasian Otter ◽  
Faecal Samples ◽  
Elusive Species

AbstractThe use of non-invasively collected DNA source material for genetic and genomic applications is usually characterized by low target DNA concentration and quality, genotyping errors and cost-intensive lab procedures. However, for otters (Lutrinae) as elusive species of conservation concern, genetic non-invasive sampling has become an important tool to study their ecology and demography. To increase cost-efficiency of monitoring programmes and to promote the expansion of genomic approaches to non-invasive samples, we aimed to refine sample collection and preparation. Therefore, we examined the effects of intrinsic sample characteristics (including diet), environmental conditions in the field and sample treatment in the molecular laboratory on the success of genotyping and allelic dropout (ADO) rates using microsatellite markers in 1970 fresh Eurasian otter (Lutra lutra) scats. Using fresh samples only, we probably eliminated one of the most important impediments of genotyping DNA from otter faecal samples beforehand. But, we observed higher genotyping success and lower ADO rates for anal glad secretions and faecal samples containing high proportions of mucus. Moist conditions during sample collection may promote DNA degradation and PCR inhibition, leading to decreased genotyping success rates. ADO was further affected by the type of extraction kit. However, a high proportion of variance remaining unexplained by our models implied that additional parameters were acting (amount of PCR inhibitors, non-uniform distribution of intestinal cells, efficiency of PCRs, specific microclimate at marking sites). We summarized influential factors maximizing genotyping quality of otter scats and give recommendations for sample collection, storage and DNA extraction based on our results and current literature.

Determination of Glyphosate Herbicide and (Aminomethyl)phosphonic Acid in Natural Waters by Liquid Chromatography Using Pre-Column Fluorogenic Labeling with 9-Fluorenylmethyl Chloroformate

1986 ◽  
Vol 69 (3) ◽  
pp. 458-461 ◽  
Author(s):  
Carl J Miles ◽  
Louis R Wallace ◽  
H Anson Moye
Keyword(s):  
Liquid Chromatography ◽  
Phosphonic Acid ◽  
Natural Waters ◽  
Sample Pretreatment ◽  
Fluorescence Detector ◽  
Rotary Evaporation ◽  
Glyphosate Herbicide ◽  
And Storage ◽  
Aminomethyl Phosphonic Acid

Abstract An analytical method has been developed for determination of glyphosate herbicide and its major metabolite, (aminomethyl)phosphonic acid (AMFA), in natural waters. Sample pretreatment consisted of filtration, addition of phosphate buffer, concentration by rotary evaporation, and a final filtration before derivatization with 9-fluorenylmethyl chloroformate. The derivatives were separated by anion exchange liquid chromatography and measured with a fluorescence detector. Standard curves were linear over 3 orders of magnitude and minimal detectable quantities were 10 ng/mL for glyphosate and 5 ng/mL for AMPA. The 20-fold concentration factor realized in sample preparation corresponds to ppb method detection limits for glyphosate and AMPA in natural waters. Recovery and storage studies were performed and are discussed.

scholarly journals Assessment of a portable clinical blood analyzer during space flight

1997 ◽  
Vol 43 (6) ◽  
pp. 1056-1065 ◽  
Author(s):  
Scott M Smith ◽  
Janis E Davis-Street ◽  
Tina B Fontenot ◽  
Helen W Lane
Keyword(s):  
Space Shuttle ◽  
Medical Data ◽  
Ionized Calcium ◽  
Sample Collection ◽  
Laboratory Methods ◽  
Remote Locations ◽  
Fluid Redistribution ◽  
Reliable Instrument ◽  
Orbiting Spacecraft ◽  
Control Samples

Abstract This study was designed to validate the utility of a commercial portable clinical blood analyzer (PCBA) in ground-based studies and on the space shuttle. Ionized calcium, pH, electrolytes, glucose, and hematocrit were determined. Results agreed well with those from traditional laboratory methods, and the PCBA demonstrated good between-day precision for all analytes. In-flight analysis of control samples revealed differences in one analyte (sodium). There were few changes in crew members’ results during flight, and these were expected. Potassium increased in flight compared with before flight, and potassium, pH, and hematocrit decreased after flight. Ionized calcium was decreased in flight and on landing day. Changes during flight were likely related to sample collection technique. Postflight changes likely reflected the fluid redistribution that occurs after exposure to weightlessness. These data confirm that the PCBA is a reliable instrument for most analytes, and can provide important medical data in remote locations, such as orbiting spacecraft.

The State and Future of Blood-Based Biomarkers in the Health and Retirement Study

2011 ◽  
Vol 14 (3) ◽  
Author(s):  
Thomas McDade
Keyword(s):  
Survey Design ◽  
Low Cost ◽  
Reproductive Function ◽  
Health And Retirement Study ◽  
Sample Collection ◽  
Advantages And Disadvantages ◽  
Methods Development ◽  
Wide Range ◽  
Primary Focus ◽  
Retirement Study

The Health and Retirement Study (HRS) is an important national resource for policy makers and investigators across a wide range of disciplines, and it is critical that the study collects the best information possible on the health status of its participants within the constraints of the survey design, and without compromising the integrity of the sample. Potential directions for the collection and analysis of biomarker data in future waves of HRS are discussed, with a primary focus on blood-based biomarkers. Advantages and disadvantages of various methods for collecting blood in the home are considered, with particular attention given to the strengths and weaknesses of dried blood spot (DBS) sampling. DBS sampling has been widely applied in recent biosocial surveys due to the low cost and burden associated with sample collection, but these benefits need to be weighed against challenges associated with quantification in the laboratory. Attention is also given to additional biomarkers that may be of relevance to HRS, and that would expand the survey’s current focus on obesity and metabolic syndrome. Measures of inflammation, pathogen exposure, reproductive function, stress, and epigenetic modifications are suggested as potentially productive future directions for the study. In addition, the analysis concludes with the following recommendations for HRS: Continue to collect DBS samples, but consider alternatives; implement enhanced procedures for quality control; calibrate DBS results against plasma values, and invest in methods development.

Hypothetical Situations and Particularistic Requests: A Test in Three Hospitals

1969 ◽  
Vol 28 (2) ◽  
pp. 119-127 ◽  
Author(s):  
L. Wager ◽  
George Miller
Keyword(s):  
Human Behavior ◽  
Practical Importance ◽  
Field Research ◽  
Hypothetical Situation ◽  
Social Scientists ◽  
Laboratory Methods ◽  
Laboratory Experimentation ◽  
Advantages And Disadvantages ◽  
Difficult Cases ◽  
Theoretical Import

Physical, biological, and social scientists are well aware that some events and processes in field research are more difficult to study directly than others. For this reason, problems of considerable theoretical import are sometimes neglected. The obstacles may arise from the relative infrequency and irregularity with which certain classes of events occur, the lower visibility of certain events to observations at the time and place they occur, or the costs of studying such classes of events. Yet the difficulties involved in no way reduce the theoretical or practical importance of these phenomena. It is precisely with respect to these difficult cases that social scientists find laboratory experimentation and the hypothetical situation in field research most useful. The relative advantages and disadvantages of laboratory methods for studying human behavior have been well documented. By comparison, the usefulness and limitations of the hypothetical situation technique as a viable alternative have been almost totally neglected.

scholarly journals Energy-loss magnetic chiral dichroism (EMCD): Magnetic chiral dichroism in the electron microscope

2008 ◽  
Vol 23 (10) ◽  
pp. 2582-2590 ◽  
Author(s):  
S. Rubino ◽  
P. Schattschneider ◽  
M. Stöger-Pollach ◽  
C. Hébert ◽  
J. Rusz ◽  
...  
Keyword(s):  
Circular Dichroism ◽  
Electron Microscope ◽  
Energy Loss ◽  
Magnetic Circular Dichroism ◽  
Magnetic Moments ◽  
Sample Collection ◽  
Experimental Conditions ◽  
Advantages And Disadvantages ◽  
A New Technique ◽  
Circular Dichroïsm

A new technique called energy-loss magnetic chiral dichroism (EMCD) has recently been developed [P. Schattschneider, et al. Nature441, 486 (2006)] to measure magnetic circular dichroism in the transmission electron microscope (TEM) with a spatial resolution of 10 nm. This novel technique is the TEM counterpart of x-ray magnetic circular dichroism, which is widely used for the characterization of magnetic materials with synchrotron radiation. In this paper we describe several experimental methods that can be used to measure the EMCD signal [P. Schattschneider, et al. Nature441, 486 (2006); C. Hébert, et al. Ultramicroscopy108(3), 277 (2008); B. Warot-Fonrose, et al. Ultramicroscopy108(5), 393 (2008); L. Calmels, et al. Phys. Rev. B76, 060409 (2007); P. van Aken, et al. Microsc. Microanal.13(3), 426 (2007)] and give a review of the recent improvements of this new investigation tool. The dependence of the EMCD on several experimental conditions (such as thickness, relative orientation of beam and sample, collection and convergence angle) is investigated in the transition metals iron, cobalt, and nickel. Different scattering geometries are illustrated; their advantages and disadvantages are detailed, together with current limitations. The next realistic perspectives of this technique consist of measuring atomic specific magnetic moments, using suitable spin and orbital sum rules, [L. Calmels, et al. Phys. Rev. B76, 060409 (2007); J. Rusz, et al. Phys. Rev. B76, 060408 (2007)] with a resolution down to 2 to 3 nm.

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