Determination of oxalate concentration in blood.

1988 ◽  
Vol 34 (8) ◽  
pp. 1540-1544 ◽  
Author(s):  
J Costello ◽  
D M Landwehr
Keyword(s):  
Direct Method ◽  
Biological Fluids ◽  
Direct Methods ◽  
Storage Conditions ◽  
Advantages And Disadvantages ◽  
Isotopic Methods ◽  
Basic Approaches ◽  
And Storage

Abstract The methods used for determination of oxalate in blood are reviewed, and the advantages and disadvantages of the two basic approaches--direct methods and in vivo isotope-dilution techniques--are compared. Possible reasons for the previous discrepancies between direct and isotopic methods are discussed, as are the effects of protein binding, sample handling, and storage conditions on oxalate values in plasma. Necessary precautions for obtaining reproducible results are presented. We recommend and critically review several direct methods, and describe the application of a direct method for oxalate determination in some other biological fluids.

scholarly journals Optimising storage conditions and processing of sheep urine for nitrogen cycle and gaseous emission measurements from urine patches

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Alice F. Charteris ◽  
Karina A. Marsden ◽  
Jess R. Evans ◽  
Harry A. Barrat ◽  
Nadine Loick ◽  
...  
Keyword(s):  
Freeze Drying ◽  
Storage Conditions ◽  
Chemical Components ◽  
Gaseous Emissions ◽  
Gaseous Emission ◽  
Grazing Systems ◽  
And Storage ◽  
Sheep Urine ◽  
Country Specific

AbstractIn grazing systems, urine patches deposited by livestock are hotspots of nutrient cycling and the most important source of nitrous oxide (N2O) emissions. Studies of the effects of urine deposition, including, for example, the determination of country-specific N2O emission factors, require natural urine for use in experiments and face challenges obtaining urine of the same composition, but of differing concentrations. Yet, few studies have explored the importance of storage conditions and processing of ruminant urine for use in subsequent gaseous emission experiments. We conducted three experiments with sheep urine to determine optimal storage conditions and whether partial freeze-drying could be used to concentrate the urine, while maintaining the constituent profile and the subsequent urine-derived gaseous emission response once applied to soil. We concluded that filtering of urine prior to storage, and storage at − 20 °C best maintains the nitrogen-containing constituent profile of sheep urine samples. In addition, based on the 14 urine chemical components determined in this study, partial lyophilisation of sheep urine to a concentrate represents a suitable approach to maintain the constituent profile at a higher overall concentration and does not alter sheep urine-derived soil gaseous emissions.

scholarly journals Determination of the Chemical Composition of Tea by Chromatographic Methods: A Review

2015 ◽  
Vol 4 (3) ◽  
pp. 56 ◽  
Author(s):  
Alexandr Ya Yashin ◽  
Boris V. Nemzer ◽  
Emilie Combet ◽  
Yakov I. Yashin
Keyword(s):  
Chemical Composition ◽  
Volatile Compounds ◽  
Black Tea ◽  
Storage Conditions ◽  
Organoleptic Evaluation ◽  
Chromatographic Methods ◽  
Tea Quality ◽  
Processing And Storage ◽  
And Storage

<p>Despite the fact that mankind has been drinking tea for more than 5000 years, its chemical composition has been studied only in recent decades. These studies are primarily carried out using chromatographic methods. This review summarizes the latest information regarding the chemical composition of different tea grades by different chromatographic methods, which has not previously been reviewed in the same scope. Over the last 40 years, the qualitative and quantitative analyses of high volatile compounds were determined by GC and GC/MS. The main components responsible for aroma of green and black tea were revealed, and the low volatile compounds basically were determined by HPLC and LC/MS methods. Most studies focusing on the determination of catechins and caffeine in various teas (green, oolong, black and pu-erh) involved HPLC analysis.</p> <p>Knowledge of tea chemical composition helps in assessing its quality on the one hand, and helps to monitor and manage its growing, processing, and storage conditions on the other. In particular, this knowledge has enabled to establish the relationships between the chemical composition of tea and its properties by identifying the tea constituents which determine its aroma and taste. Therefore, assessment of tea quality does not only rely on subjective organoleptic evaluation, but also on objective physical and chemical methods, with extra determination of tea components most beneficial to human health. With this knowledge, the nutritional value of tea may be increased, and tea quality improved by providing via optimization of the growing, processing, and storage conditions.</p>

scholarly journals Post-harvest content of free titratable acids in the grain of proso millet varieties (Panicum milliaceum L.), and changes during grain processing and storage

2010 ◽  
Vol 46 (Special Issue) ◽  
pp. S90-S95 ◽  
Author(s):  
V. Dvořáček ◽  
D. Janovská ◽  
L. Papoušková ◽  
E. Bicanová
Keyword(s):  
Dry Matter ◽  
Slight Modification ◽  
Storage Conditions ◽  
Panicum Miliaceum ◽  
Proso Millet ◽  
Grain Processing ◽  
Sensory Changes ◽  
Processing And Storage ◽  
And Storage

A triennial evaluation of the content of titratable acids (TA) in grain was carried out on 12 varieties of proso millet (<I>Panicum miliaceum </I>L.). The model variety, Mironovskoe 94, harvested in 2004, was used for the monitoring of sensory changes in TA content, in relationship to different storage conditions and the application of different grain processing methods. The Czech state norm (CSN 56 0512-9 1995) Determination of Titratable Acids, with a slight modification, was used as the standard method. The TA contents in dry matter varied between 39 and 78 mmol/kg of grain dry matter, and significant differences between varieties and experimental years were found. The method of proso millet processing had a key role in the final sensitivity to rancidity. The storage conditions had a much lower influence on TA content than the processing technology. The clearly detected sensory changes found in scoured grains corresponded with TA contents within the range of 90 to106 mmol/kg. The monitoring of the TA content can be considered as a suitable tool for the prediction of rancidity processes in millet grains.

scholarly journals Aflatoxin species: their health effects and determination methods in different foodstuffs

2012 ◽  
Vol 10 (3) ◽  
pp. 675-685 ◽  
Author(s):  
Sezgin Bakırdere ◽  
Selin Bora ◽  
E. Bakırdere ◽  
Fırat Aydın ◽  
Yasin Arslan ◽  
...  
Keyword(s):  
Health Effects ◽  
Analytical Techniques ◽  
The Other ◽  
Advantages And Disadvantages ◽  
Time Period ◽  
Long Time ◽  
Sensitive Determination ◽  
Determination Methods ◽  
And Storage

AbstractCarcinogenic and mutagenic properties of aflatoxin species are known in literature. Their intake over a long time period might be health-dangerous for human even at trace levels. It is well known that different foodstuffs can be contaminated by aflatoxin species through growing and storage. Due to the serious health effects, sensitive determination of aflatoxin species in any matrices related with the human being is very crucial at trace levels. In literature, there are sensitive techniques to analyze the different samples for the contents of their aflatoxin species. Each technique has some advantages and disadvantages over the other techniques. This review aims to summarize the different health effects of aflatoxin species, development of analytical techniques and applications of developed techniques in a variety of matrices.

A METHOD FOR THE SIMULTANEOUS DETERMINATION OF PROGESTERONE, ANDROSTENEDIONE, TESTOSTERONE AND DEHYDROEPIANDROSTERONE SULPHATE IN BIOLOGICAL FLUIDS

1968 ◽  
Vol 57 (3) ◽  
pp. 447-456 ◽  
Author(s):  
Asbjørn Aakvaag ◽  
Petter Fylling
Keyword(s):  
Simultaneous Determination ◽  
Biological Fluids ◽  
List Type ◽  
Human Ovary ◽  
Peripheral Plasma ◽  
High Concentrations ◽  
Venous Plasma ◽  
Ovarian Cyst Fluid

ABSTRACT A method is presented for the simultaneous determination of progesterone, androstenedione, testosterone and dehydroepiandrosterone sulphate in biological fluids. The method has been applied for the investigation of the secretion of these compounds by the ovary as well as their concentration in ovarian cyst fluid and peripheral plasma. The concentrations of the three androgens were all found to be higher in ovarian venous plasma than in peripheral plasma, and are thus shown to be secreted by the human ovary. High concentrations of progesterone were found in the ovarian vein blood when a corpus luteum was present. In some cases progesterone was also found to be secreted by the ovary during the follicular phase. The data are discussed and found to be in agreement with the suggestion that progesterone and androgens are secreted by different anatomical compartments of the human ovary in vivo.

Sensing bacteria but treating them well: Determination of optimal incubation and storage conditions

2008 ◽  
Vol 383 (1) ◽  
pp. 68-75 ◽  
Author(s):  
Eva Baldrich ◽  
Nuria Vigués ◽  
Jordi Mas ◽  
Francesc Xavier Muñoz
Keyword(s):  
Storage Conditions ◽  
And Storage ◽  
Optimal Incubation

scholarly journals Cobalt-lanthanum catalyst precursors for ammonia synthesis: determination of calcination temperature and storage conditions

2017 ◽  
Vol 19 (2) ◽  
pp. 61-66 ◽  
Author(s):  
Magdalena Zybert ◽  
Aleksandra Tarka ◽  
Bogusław Mierzwa ◽  
Wioletta Raróg-Pilecka
Keyword(s):  
Mass Spectrometry ◽  
Ammonia Synthesis ◽  
Textural Properties ◽  
Storage Conditions ◽  
Point Of View ◽  
Catalyst Precursor ◽  
Lanthanum Hydroxide ◽  
Co Precipitation ◽  
And Storage

Abstract A thermal decomposition of a cobalt-lanthanum catalyst precursor containing a mixture of cobalt and lanthanum compounds obtained by co-precipitation were studied using thermal analysis coupled with mass spectrometry (TG-MS). Studies revealed that the calcination in air at 500°C is sufficient to transform the obtained cobalt precipitate into Co3O4, but it leads to only partial decomposition of lanthanum precipitate. In order to obtain Co/La catalyst precursor containing La2O3 the calcination in air at the temperature about 800°C is required. However, it is unfavorable from the point of view of textural properties of the catalyst precursor. A strong effect of storage conditions on the phase composition of the studied cobalt-lanthanum catalyst precursor, caused by the formation of lanthanum hydroxide and lanthanum carbonates from La2O3 when contacting with air, was observed.

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