In the other hand, in Puerto Morelos, during sampling campaign performed at the end of the mid-summer drought, NO 3 -levels were the highest and also higher than SO 4 2-concentrations, exceeding background level; and pH values observed were low. Excluding, Puerto Morelos, where other sources influenced the rain chemistry composition; all remaining sampling sites were clearly influenced by marine aerosol, showing ionic concentrations typical of sites with a minimal anthropogenic influence, and therefore, their ionic concentrations can be considered as representative of background values for this region. KEY WORDS:Tropical oceanic rain; coastal rainwater chemistry; Mexico. INTRODUCTIONTemporal and spatial trends in precipitation chemistry are affected by seasonal variations in biogenic emissions, local agricultural practices, long-range transport, local meteorology, marine salt, and episodes like hurricanes and volcanic activity. In coastal sites, sea-salt aerosol dominates precipitation chemistry, accounting for 95-100% of Na
<p>Separation, characterization and quantification of surfactants in different matrices is important due to the continuously increasing use of these products in industry and the adverse effects of their degradation products in the environment. However, surfactant separation and identification is a real challenge because of the wide chemical diversity of this type of compounds. In this report, HPLCUV or HPLC-Evaporative light scattering detector combined with electrospray ionization (infusion)-high resolution mass spectrometry (ESI-HRMS) was used for the study of main components in four commercial surfactants. In a second stage, size-exclusion chromatography and off-line ESI-MS were combined for quantification of surfactants in a synthetic latex sample by standard-additions method. This strategy allowed unambiguous determination of the structure of tensoactive agents in commercial products, and further use of obtained data for the selective determination of surfactants in the complex polymeric matrix of an industrial latex.</p>
The purpose of this research was to study the chemical composition of rainwater to assess the impact of marine aerosol and anthropogenic emissions by using back air-mass trajectories. Fieldwork was done from July to November 2004, in a coastal site probably impacted by gas and oil industry in Campeche, Mexico: San Antonio Cardenas. Na + , Cl -, and Mg 2+, were the most abundant ions, being sea-salt aerosol their unique source. A significant portion of K + and Ca 2+ originated from non-sea-salt sources; and the sulphate excess exceeded the background level reported for remote marine sites, suggesting that besides of marine aerosol, there was a significant contribution of SO 4 2-from anthropogenic sources. NO 3 -concentrations in San Antonio Cardenas exceeded the background level reported for coastal sites with minimal anthropogenic influence and showed a significant correlation with SO 4 2-, suggesting a common source. Agricultural practices are null, for this reason NH 4 + levels were low. Mean pH value was 4.64, this acidity showed a good correlation with SO 4 2-and NO 3 -levels, and with the local meteorology. A sour gas recompression plant located 10 km at NE from San Antonio Cardenas was identified as the main source of this strong acidity.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.