Huang R.-J.,Paul Scherrer Institute |
Huang R.-J.,National University of Ireland |
Huang R.-J.,Johannes Gutenberg University Mainz |
Li W.-B.,Xiamen University |
And 16 more authors.
Atmospheric Measurement Techniques | Year: 2014
In recent years low molecular weight alkylamines have been recognized to play an important role in particle formation and growth in the lower atmosphere. However, major uncertainties are associated with their atmospheric processes, sources and sinks, mostly due to the lack of ambient measurements and the difficulties in accurate quantification of alkylamines at trace level. In this study, we present the evaluation and optimization of two analytical approaches, i.e., gas chromatography-mass spectrometry (GC-MS) and ion chromatography (IC), for the determination of alkylamines in aerosol particles. Alkylamines were converted to carbamates through derivatization with isobutyl chloroformate for GC-MS determination. A set of parameters affecting the analytical performances of the GC-MS approach, including reagent amount, reaction time and pH value, was evaluated and optimized. The accuracy is 84.3-99.1%, and the limits of detection obtained are 1.8-3.9 pg (or 0.02-0.04 ng-3). For the IC approach, a solid-phase extraction (SPE) column was used to separate alkylamines from interfering cations before IC analysis. 1-2% (v/v) of acetone (or 2-4% (v/v) of acetonitrile) was added to the eluent to improve the separation of alkylamines on the IC column. The limits of detection obtained are 2.1-15.9 ng (or 0.9-6.4 ng m-3), and the accuracy is 55.1-103.4%. The lower accuracy can be attributed to evaporation losses of amines during the sample concentration procedure. Measurements of ambient aerosol particle samples collected in Hong Kong show that the GC-MS approach is superior to the IC approach for the quantification of primary and secondary alkylamines due to its lower detection limits and higher accuracy.
Mishra A.K.,Indian Central Soil Salinity Research Institute |
Singh J.,Indian Central Soil Salinity Research Institute |
Kumar V.,Center for Environmental Science and Technology |
Srivastava R.,Center for Environmental Science and Technology |
Srivastava S.,Allahabad University
Ecology, Environment and Conservation | Year: 2013
This study was carried out to investigate total carbon sequestration in ten dominant tree species grown in Rajiv Gandhi South Campus, Bañaras Hindu University, Barkaccha, Mirzapur, India having an area of 2760 acres. To estimate biomass from selective tree species, it is not advisable to cut them for this reason, non-destructive method is employed. The essential parameters required for the measurement of biomass and carbon stock is height, girth and wood density. Height measurement is based on shadow method and girth taken as Diameter at Breast Height (dbh) as 1.36 meter high above the ground. The study revealed that the height (0.70) and girth (0.93) showed positive correlation with carbon stock of selective tree species and has advantage over destructive method used for biomass and carbon stock estimation. Carbon storage in individual tree species varies from 0.04 tonnes (Acasia catechu) to 25.65 tonnes (Madhuca longifolia) © EM International.