Environmental Analysis
US-EPA Monitors Quality of Ambient Air with MARGA
The US-EPA has signed a longterm contract for the supply of up to 40 MARGA systems for their CASTNET measurement network across the USA. There are an additional 9 MARGA systems located in Scotland(2),
South Korea(5), The Netherlands(1) and China(1).
MARGA (Monitor for AeRosols and Gases in ambient Air) is an ambient air monitoring system that is capable of measuring the gas
phase concentrations of NH3, HNO3, HCl, HNO2, and SO2, as well as the particulate matter (aerosol) concentrations of NO3-
, Cl- K+, Ca2+ and Mg2+ , SO42- , NH4+ , Na+ , . This unique instrument, developed by Applikon
Analytical in cooperation with the Dutch Energy Research Institute (ECN), draws in a 1 m3
volume of air each hour. The gases are then quantitatively (more than 99.7%) absorbed in a wetted rotating denuder (WRD) and the aerosols, which pass through the WRD, are trapped in a steam-jet aerosol collector (SJAC).
The trapped aerosols are quantitatively (more than 99.7%) separated from the airstream cyclone using condensational growth with supersaturated steam. The liquid streams from the WRD (dissolved gases) and SJAC (dissolved aerosols) are degassed and mixed with an internal standard before controlled injection into an anion and a cation ion chromatograph, both from Metrohm.
The determinations are continuously con- trolled by an internal calibration, performed by the addition of a standard solution (Li and Br). The instrument can operate for 7 days unattended and can be remote controlled via an internet connect-ion. The size of particulate matter (PM) can be selected by placing special designed
cyclones (e.g. PM10, PM2.5 or PM1.0) before the entrance of the sampling system.
For the worst samples you can imagine…
...the toughest IC systems available! Reader Reply Card no 21
Real-Time Determination of Anions and Cations in Aerosols by Ion Chromatography
Research on air pollution requires rapid and accurate measurements of inorganic species in ambient air. Coupling a Particle-Into-Liquid- Sampler (PILS) to Metrohm’s 850 Professional IC allows for quasi- continuous measurements with an unprecedented temporal resolu- tion of just 5 to 15 minutes.
The determination of anions and cations in atmospheric aerosols yields essential information concerning atmospheric transport and transform- ation processes. Until now these determinations have been carried out using filters. However, this method only allows to determine averages over a time span of 24 hours or even more. Moreover, the results can be compromised by desorption processes and chemical transformations.
In contrast to sampling devices relying on filters, using a PILS allows semi-continuous sam- pling of aerosols downstream from a denuder system. Subsequent to the removal of interfering gas-phase species, the remaining aerosol parti- cles are dissolved into water phase by means of supersaturated steam. Eventually, the liquid sample is transported to the IC for analysis. The key benefit of this method is a high temporal resolution of measurements of just 5 to 15 minutes. Changes in the ionic composition of ambient air can thus be recorded almost immediately allowing a much more precise correlation with meteorolo- gical and other data.
Reader Reply Card no 22
Loaded with particles? Presence of proteins? Filtration impossible? Metrohm Inline Sample Preparation (MISP) is the solution. Your Metrohm IC system gets the job done. Always! Metrohm IC – built for heavy duty, built to last.
www.professional-ic.com
New Generation of Microbore Colums for Environmentally Friendly Anion Chromatography
New legislation such as the «Clean Air and Water Act» and a general trend towards green chemistry stipulate the use of environmentally friendly chemical products and processes. Metrohm responds to this introducing a new generation of high capacity anion exchange columns. The new columns feature an inner diameter of only 2mm enabling lower eluent flow rates and less solvent consumption.
Moreover, environmentally benign carbonate/bicarbonate solutions are used with the columns for most anion separations. Not only the columns got thinner but also the suppressor module was scaled down, leading to reduced consumption of regenerant solution: for complete regeneration, as little as 2mL acid (1 mol/L) is sufficient and no exchange of cartridges or membranes is necessary.
Besides the ecological benefits, microbore columns require less frequent eluent preparation and thus improve accuracy and save time. Additionally, they get along with only small amounts of sample material and can be perfectly interfaced with various inline detectors.
Reader Reply Card no 20
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Reader Reply Card no 23
May/June 2010
IET
Ecknauer+Schoch ASW
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