A meridional profile of the chemical composition of submicrometre particles over the East Atlantic Ocean : regional and hemispheric variabilities

Within the framework of SWEDARP (Swedish Antarctic Program) 92,93 an aerosol sampling program was carried out on board of M/S Palarbjorn which carried staff and material to the Nordic Antarctic Field exercises during the Austral summer 1992/1993. The cruise started 11 November 1992 from Oslo, went via Cape Town to Antarctica, and then back to Cape Town ,here the ship arrived on 4 January 1993. During the cruise, a meridional profile of physical and chemical submicrometre aerosol properties was derived covering the East Atlantic Ocean from 60degreesN to 70degreesS. The multicomponent aerosol data set combined with a trajectory analysis revealed a systematic meridional distribution of aerosol sources over the Atlantic that covered European and African continental Plumes and, South of 15degreesS, a largely biologically controlled marine aerosol. Median number concentrations calculated over the whole cruise spanned a factor of 20 between 2000 and 100 cm(-3), while total analyzed mass concentrations ranged between 7800 and 40 ng m(3). From the biologically dominated subset of the data in the southern hemisphere, relationships were developed that allowed an apportionment of the observed sulfate and ammonium concentration to biogenic and anthropogenic Sources over the whole meridional aerosol profile

Capillary electrophoresis-mass spectrometry at trial by Metabo-Ring: Effective electrophoretic mobility for reproducible and robust compound annotation

Capillary zone electrophoresis-mass spectrometry (CE-MS) is a mature analytical tool for the efficient profiling of (highly) polar and ionizable compounds. However, the use of CE-MS in comparison to other separation techniques remains underrepresented in metabolomics, as this analytical approach is still perceived as technically challenging and less reproducible, notably for migration time. The latter is key for a reliable comparison of metabolic profiles and for unknown biomarker identification that is complementary to high resolution MS/MS. In this work, we present the results of a Metabo-ring trial involving 16 CE-MS platforms among 13 different laboratories spanning two continents. The goal was to assess the reproducibility and identification capability of CE-MS by employing effective electrophoretic mobility (mu(eff)) as the key parameter in comparison to the relative migration time (RMT) approach. For this purpose, a representative cationic metabolite mixture in water, pretreated human plasma, and urine samples spiked with the same metabolite mixture were used and distributed for analysis by all laboratories. The mu(eff) was determined for all metabolites spiked into each sample. The background electrolyte (BGE) was prepared and employed by each participating lab following the same protocol. All other parameters (capillary, interface, injection volume, voltage ramp, temperature, capillary conditioning, and rinsing procedure, etc.) were left to the discretion of the contributing laboratories. The results revealed that the reproducibility of the mu(eff) for 20 out of the 21 model compounds was below 3.1% vs 10.9% for RMT, regardless of the huge heterogeneity in experimental conditions and platforms across the 13 laboratories. Overall, this Metabo-ring trial demonstrated that CE-MS is a viable and reproducible approach for metabolomics.Analytical BioScience