scholarly journals Passive sampling method for high-resolution concentration and isotopic composition of dissolved methane in Arctic lakes

2015 ◽  
Vol 14 (2) ◽  
pp. 69-78 ◽  
Author(s):  
Amy E. Goldman ◽  
Sarah B. Cadieux ◽  
Jeffrey R. White ◽  
Lisa M. Pratt
Keyword(s):  
High Resolution ◽  
Isotopic Composition ◽  
Passive Sampling ◽  
Sampling Method ◽  
Arctic Lakes ◽  
Dissolved Methane

scholarly journals Development of passive sampler POCIS for the analysis of polar pesticides in surface water

2015 ◽  
Vol 18 (2) ◽  
pp. 132-144
Author(s):  
Trang Thi Nhu Tran ◽  
Ty Thi Pham ◽  
Hai Lam Son Truong
Keyword(s):  
Surface Water ◽  
Environmental Factors ◽  
Pesticide Residues ◽  
Passive Sampling ◽  
Sampling Method ◽  
Passive Sampler ◽  
Polar Pesticides ◽  
Sampling Process ◽  
European Standards ◽  
First Time

The first time in Vietnam a passive sampling method has been developed to analyse the polar pesticides in surface water. The initial investigations of POCIS were performed for 7 polar pesticides as simazine,thiodicarb, carbofuran, chlortoluron, atrazine, isoproturon, and diuron. We determined the sampling rates RS for these substances ranged from 0.369 to 0.962 L day- 1. The obtained values of ku and RS showed the important influence of environmental factors such as flow on the ability to integrate polar pesticides in passive sampling process. This method can be applied to determine these 7 polar pesticides in surface water at trace levels according to European standards for pesticide residues in water (< 0.1 μg L-1).

scholarly journals High-resolution measurements of atmospheric molecular hydrogen and its isotopic composition at the West African coast of Mauritania

2012 ◽  
Vol 9 (12) ◽  
pp. 18799-18829
Author(s):  
S. Walter ◽  
A. Kock ◽  
T. Röckmann
Keyword(s):  
High Resolution ◽  
Isotopic Composition ◽  
Molecular Hydrogen ◽  
H2 Production ◽  
West African ◽  
Mixing Ratio ◽  
The West ◽  
Isotopic Signatures ◽  
West African Coast ◽  
African Coast

Abstract. Oceans are a net source of molecular hydrogen (N2) to the atmosphere, where nitrogen (N2) fixation is assumed to be the main biological production pathway besides photochemical production from organic material. The sources can be distinguished using isotope measurements because of clearly differing isotopic signatures of the produced hydrogen. Here we present the first ship-borne measurements of atmospheric molecular H2 mixing ratio and isotopic composition at the West African coast of Mauritania (16–25° W, 17–24° N). This area is one of the biologically most active regions of the world's oceans with seasonal upwelling events and characterized by strongly differing hydrographical/biological properties and phytoplankton community structures. The aim of this study was to identify areas of H2 production and distinguish H2 sources by isotopic signatures of atmospheric H2. Besides this a diurnal cycle of atmospheric H2 was investigated. For this more than 100 air samples were taken during two cruises in February 2007 and 2008, respectively. During both cruises a transect from the Cape Verde Island towards the Mauritanian Coast was sampled. In 2007 additionally four days were sampled with a high resolution of one sample per hour. Our results clearly indicate the influence of local sources and suggest the Banc d'Arguin as a pool for precursors for photochemical H2 production, whereas N2 fixation could not be identified as a H2 source during these two cruises. With our experimental setup we could demonstrate that variability in diurnal cycles is probably influenced and biased by released precursors for photochemical H2 production and the origin of air masses. This means for further investigations that just measuring the mixing ratio of H2 is insufficient to explain the variability of a diurnal cycle and support is needed, e.g. by isotopic measurements. However, measurements of H2 mixing ratios, which are easy to conduct online during ship cruises could be a helpful tool to easily identify production areas of biological precursors such as VOC's for further investigations.

scholarly journals A new method based on diffusive gradients in thin films for in situ monitoring microcystin-LR in waters

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Lei Yao ◽  
Alan D. Steinman ◽  
Xiang Wan ◽  
Xiubo Shu ◽  
Liqiang Xie
Keyword(s):  
Thin Films ◽  
Passive Sampling ◽  
Sampling Method ◽  
Binding Capacity ◽  
Accurate Method ◽  
In Situ Monitoring ◽  
Active Sampling ◽  
Binding Agent ◽  
Diffusive Gradients

AbstractThe passive sampling method of diffusive gradients in thin-films (DGT) was developed to provide a quantitative and time-integrated measurement of microcystin-LR (MC-LR) in waters. The DGT method in this study used HLB (hydrophilic-lipophilic-balanced) material as a binding agent, and methanol as an eluent. The diffusion coefficient of MC-LR was 5.01 × 10−6 cm2 s−1 at 25 °C in 0.45 mm thick diffusion layer. This DGT method had a binding capacity of 4.24 μg per binding gel disk (3.14 cm2), ensuring sufficient capacity to measure MC-LR in most water matrices. The detection limit of HLB DGT was 0.48 ng L−1. DGT coupled to analysis by HPLC appears to be an accurate method for MC-LR monitoring. Comparison of DGT measurements for MC-LR in water and a conventional active sampling method showed little difference. This study demonstrates that HLB-based DGT is a useful tool for in situ monitoring of MC-LR in fresh waters.

scholarly journals Passive Sampling Method for Total Volatile Organic Compounds in Indoor Air

2018 ◽  
Vol 21 (1) ◽  
pp. 41-49
Author(s):  
Takahiro ISHIZAKA ◽  
Ayato KAWASHIMA ◽  
Naoki HISHIDA ◽  
Noriaki HAMADA
Keyword(s):  
Volatile Organic Compounds ◽  
Organic Compounds ◽  
Indoor Air ◽  
Passive Sampling ◽  
Sampling Method ◽  
Total Volatile ◽  
Volatile Organic ◽  
Total Volatile Organic Compounds

scholarly journals High‐resolution food webs based on nitrogen isotopic composition of amino acids

2014 ◽  
Vol 4 (12) ◽  
pp. 2423-2449 ◽  
Author(s):  
Yoshito Chikaraishi ◽  
Shawn A. Steffan ◽  
Nanako O. Ogawa ◽  
Naoto F. Ishikawa ◽  
Yoko Sasaki ◽  
...  
Keyword(s):  
Amino Acids ◽  
High Resolution ◽  
Isotopic Composition ◽  
Food Webs ◽  
Nitrogen Isotopic Composition

High-resolution record of uranium isotopic composition of Paleo-Baikal water during the last 100 ka

2007 ◽  
Vol 414 (1) ◽  
pp. 630-633 ◽  
Author(s):  
N. A. Zhuchenko ◽  
E. P. Chebykin ◽  
E. L. Goldberg ◽  
O. G. Stepanova
Keyword(s):  
High Resolution ◽  
Isotopic Composition ◽  
Baikal Water
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