Volume 51, No. 1, February 2017

Volume 51, No. 1, February 2017

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Description

Technical Articles

Comparing the material difference between four nitrogen sources affecting the performance of liquid chromatography with mass spectrometry.

Thalavaisundaram, S., Dolman, C.
Liquid chromatography with mass spectrometry (LC-MS) is a powerful technique that has very high sensitivity and selectivity to the detection of specifi substances. It is commonly used for the qualitative and quantitative analysis of a broad range of complex samples in agrochemical, food, environmental and pharmaceutical industries.  As environmental legislation tightens internationally the levels of detection are decreasing for a number of key environmental contaminants. This requires more sensitive equipment which relies upon high specifiations of key raw materials such as nitrogen in the LC-MSprocess. Nitrogen purity as well as relevant impurities (e.g. hydrocarbons, moisture) will have an impact on base line noise levels of the process reducing the sensitivity of the analytical equipment or even damaging the equipment. Four sources of nitrogen were assessed for base line noise utilising a SHIMADZU LC-MS these included ultra high purity nitrogen (99.999%), high purity nitrogen (99.99%), high purity bulk liquid nitrogen (99.95%) and nitrogen supplied by a Peak Genius 1051 generator. The results showed that the purity of the nitrogen used does have an impact on base line noise. The results of the work showed that users of LC-MS should use a nitrogen source that reflcts the sensitivity they require out of the analytical results.

Adsorbed non-polar organic species on inhalable γ-alumina particles.

Fleming, D., D’Angelo, A. M., Wilkinson, S., Fleming, D.
 Alumina refiing is a multi-billion-dollar industry in Western Australia (WA) where residents living in close proximity to the alumina refieries have raised concerns regarding health issues related to refiery emissions. Traditionally, alumina refiery gaseous or particulate matter emission levels are measured separately and do not include the combination of both, such as organics adsorbed on to particles. The adsorption and desorption of volatile organic compounds (VOCs) including n-hexane, benzene, toluene and o-, m-, p-xylene on/ from γ-alumina particles was investigated using thermal desorption gas chromatography mass spectrometry (TD-GCMS). Results from both adsorption and desorption studies show that these VOCs, found in alumina refiery emissions, adsorb and concentrate on γ-alumina particles and then desorb when the humidity is raised. Consequently, a new approach to determining exposure standards of inhaled air pollutants particles with adsorbed organic compounds may be required.

Air quality modelling of the Sydney Region using CCAM-CTM.

Duc, H. N., Trieu, T., Scorgie, Y., Cope, M., Thatcher, M.
This paper presents the results from an air quality modelling study in the Sydney region using a meteorological model, the Conformal Cubic Atmospheric Model (CCAM) and a dispersion model called the Chemical Transport Model (CTM). Both CCAM and CTM were developed by CSIRO and have been used to conduct pilot modelling studies, such as the Sydney particle Study (SPS) previously. In this study, the emission input data, which is based on the latest NSW 2008 emission inventory and consists of 15 different source type categories, is used to evaluate the CCAM-CTM model by comparing with observed meteorological and air quality data. The study period is February 2011, which was the focus of the SPS. The air quality outputs of interest were nitrogen oxides (NO, NO2), ozone (O3) and particles (PM10 and PM2.5). The results of this study show that the current version of CCAM-CTM used with the above emission data provides good prediction of NO, NO2, Ozone and PM2.5 but not PM10. Based on the results, future improvements of the CCAM-CTM air quality model are discussed and suggested.

Reports

  •  Air quality assessment in coal seam gas regions of the SuratBasin, Australia., Lawson, S.