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REDMAAS (Red Española de DMAs Ambientales), the Spanish network of environmental Differential Mobility Analyzers (DMAs), currently consists of six research groups involved in the measurement of atmospheric aerosol size distributions by means of DMAs. The aim of this network is to guarantee the good quality and comparability of the routine measurements carried out at each different location and in diverse environments across Spain. In order to reach this objective, one of its main activities is an annual intercomparison of mobility size spectrometers used within the network (five units Scanning Mobility Particle Sizers (SMPS) and one Ultrafine Particle Monitor (UFPM)). Here we report the main results obtained during the 2010-1012 campaigns, including a study on particle deposition in dryers used in ambient air sampling systems. In general, all instruments showed a good performance with deviations in an accepted tolerance. The intercomparisons have been proven to be a useful exercise to detect instrument problems, such as incorrect calibrations. DMA calibration checks were performed with polystyrene latex (PSL) reference particles. Deviations of less than 1% were observed during the first year, which increased to a value of 4.7% during the last campaign. Some differences among the responses of different Condensation Particle Counter (CPC) models were encountered, being mainly connected to the intrinsic characteristics of each counter. The comparison of the UFPM with the CPCs has given good results. The SMPS intercomparisons, especially for particles Downloaded by [University of Otago] at 00:40 27 July 2015 ACCEPTED MANUSCRIPT ACCEPTED MANUSCRIPT3 above 20 nm, have been within +/-15% tolerances. Regarding the particle deposition in dryers used in sampling systems, particle penetration was lower than predicted by the recommended model. This result was probably due to the fact that not all the possible mechanisms were considered in the model.---

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SummaryA systematic investigation of operational buffer systems, sample preparation and instrument parameters for achieving the best possible performance for determining an homologous series of N-benzyl-N-alkyl-N,Ndimethylammonium chloride compounds by capillary zone electrophoresis with direct UV detection. The most effective separation was achieved within 3.5 min with the addition of acetonitrile (40 %) in a phosphate buffer (20 mM pH 5.2) using a 40 cm fused-silica capillary operating at 25 KV and 20 ~ Degassing of all electrolyte solutions and samples was very important. The linearity and repeatability for each compound were satisfactory. To improve detection limits, on-column sample preconcentration, sample stacking, was investigated achieving a tenfold enrichment factor and quantitation limits about 10 -7 M.

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