Monitoring of atmospheric gaseous and particulate polycyclic aromatic hydrocarbons in South African platinum mines utilising portable denuder sampling with analysis by thermal desorption–comprehensive gas chromatography–mass spectrometry

Abstract

Concentrations of diesel particulate matter and polycyclic aromatic hydrocarbons (PAHs) in platinum mine environments are likely to be higher than in ambient air due to the use of diesel machinery in confined environments. Airborne PAHs may be present in gaseous or particle phases each of which has different human health impacts due to their ultimate fate in the body. Here we report on the simultaneous sampling of both phases of airborne PAHs for the first time in underground platinum mines in South Africa, which was made possible by employing small, portable denuder sampling devices consisting of two polydimethylsiloxane (PDMS) multichannel traps connected in series separated by a quartz fibre filter, which only require small, battery operated portable personal sampling pumps for air sampling. Thermal desorption coupled with comprehensive gas chromatography -mass spectrometry (TD-GCxGC-TofMS) was used to analyse denuder samples taken in three different platinum mines. The samples from a range of underground environments revealed that PAHs were predominantly found in the gas phase with naphthalene and mono-methylated naphthalene derivatives being detected at the highest concentrations ranging from 0.01 to 18 g m -3 . The particle bound PAHs were found in the highest concentrations at the idling load haul dump vehicle exhausts with a dominance of fluoranthene and pyrene. Particle associated PAH concentrations ranged from 0.47 to 260 ng m -3 and included benzo[k]fluoranthene, benzo[a]pyrene, indeno[1,2,3-cd]pyrene and benzo [ghi]perylene. This work highlights the need to characterise both phases in order to assess occupational exposure to PAHs in this challenging sampling environment.

Air Sampling: A Mini-denuder Sampling Device for Direct Desorption in an Inlet of a Gas Chromatograph for the Analyses of Airborne Gaseous Phase Pollutants and Airborne Particulate Phase Pollutants

“…However, the device can easily be applied quantitatively by spiking the denuder materials with known concentrations of chemical standards of interest for the quantification of analytes in air samples. 1,2 SHORT COMMUNICATION E. van Vuuren and Y. Naudé, 56 S. Afr. J.…”

“…1 Diffusion denuder samplers are employed to sample particulate phase and gas phase air pollutants. 1,2 Due to a difference in vapour and particle diffusivities diffusion denuders first separate the vapour phase to be retained on a sorptive surface from the particulate phase which passes through the denuder and is then collected on a downstream filter. 1,2 Denuder materials are solvent-extracted or thermally desorbed in commercial thermal desorber systems for subsequent analyses.…”

“…3 The PDMS multichannel trap was since utilized as a diffusion denuder for sampling of the insecticide DDT in contaminated indoor air and atmospheric polycyclic aromatic hydrocarbons (PAHs) in mines. 1,2 In these studies denuder materials were constructed in commercial thermal desorber glass tubes for desorption in thermal desorber systems with cryogenics. However, expensive thermal desorber systems and cryogenics may not be readily available in resourcepoor laboratories.…”

On-line coupling of thermal extraction with gas chromatography / tandem mass spectrometry for the analysis of semivolatile organic compounds in a few milligrams of indoor dust

“…Polar, thermolabile and weakly volatile compounds cannot be analyzed by thermal extraction. To the best of our knowledge, this technique has never been reported for the simultaneous determination of a large panel of SVOCs in indoor settled dust, but has already been used to measure polycyclic aromatic hydrocarbons (PAHs) [22][23][24][25][26][27][28][29][30][31][32][33][34][35][36] and many other SVOCs [37][38][39] in airborne particulate matter, a much less complex and heterogeneous matrix than settled dust.…”

Characterisation of semi-volatile hydrocarbon emissions from diesel engines

“…The challenge faced when characterising SVOCs stems from difficulties in quantitative collection and chemical analysis of these species. Traditional sampling methods for gaseousparticulate phase analytes employ high volume samplers that make use of a glass fibre filter that removes particles from the sample flow, and an adsorbent such as Tenax or polyurethane foam (PUF), to adsorb the gas phase analytes downstream of the filter (Geldenhuys et al, 2015). Although such high volume samplers are robust and easy to use in the field, they exhibit inherent limitations due to the sampling configuration and high volumetric flow rate (Forbes and Rohwer, 2015).…”