printed by Approaching a Universal Pneumatic Nebulizer Jerry Dulude (USA), Vesna Dolic and Peter Liddell (Australia), Glass Expansion ( Glass Expansion currently designs nebulizers to accommodate the recommended gas pressures and flows of the various spectrometer manufacturers. However, it is desirable to design a single nebulizer that when run under high pressure conditions will generate a finer mist and more of it. In this study a nebulizer was designed to operate at 60psi, markedly higher than that of a standard nebulizer. This nebulizer was compared to the standard for a variety of performance parameters on two different ICP-OES systems. INTRODUCTION Inter-Nebulizer Variation Figure 2: Inter-Nebulizer Study Results (60psi) To determine the effects of subtle changes in parameters, it is necessary to first establish the inter-nebulizer variability within a given design. Figure 2 demonstrates the inter-nebulizer variability for a group of 5 different 60 psi nebulizers of the same configuration at two different uptake rates. Note that even though the uptake rate has been decreased by a factor of 5, emission intensity counts are decreased by only about 20 to 25%. This is due to the much higher efficiency produced at lower uptake rates. A pneumatic nebulizer operated at 60psi offers significant improvements in perfor- mance over the standard nebulizer for two different ICP-OES manufacturers and models. Future work will center on the improvement in performance at lower uptake rates and the ability of these nebulizers to handle high dissolved solids samples. Figure 3: Effect of Pressure on Performance Signal Intensity (2ml/min uptake) Figure 4: Effect of Pressure on Performance- Short-term Stability (2ml/min uptake) Figure 5: Effect of Pressure on Performance- Long-term Stability (2ml/min uptake) Figure 6: Effect of Pressure on Performance- Detection Limit (0.4ml/min) EXPERIMENTAL Figure 1: Sample Intro System A Tracey™ Cyclonic spray chamber was used with a SeaSpray™ concentric glass nebulizer (both from Glass Expansion, Inc., Pocasset, MA and shown below in Figure 1). Standard conditions were used across the board on both a Varian Vista MPX and a Perkin Elmer Optima Both ICP-OES instruments were used with axial view for all lines. Figure 8: Effect of Pressure on Performance- Short-term Stability (0.4ml/min uptake) Figure 9: Effect of Pressure on Performance- Long-term Stability (2ml/min uptake) Figure 10: Effect of Pressure on Performance- Detection Limit (2ml/min uptake) DISCUSSION and CONCLUSIONS Figure 2 illustrates that the high reproducibility of various nebulizers of the same design enables detection of differences between nebulizers of a different design. Figures 3 through 6 show the improvements provided by the 60psi design in terms of intensity, stability, and detection limit for the Varian Vista MPX. This improvement is duplicated for the same parameters on the Perkin Elmer 2100 (Figures 7 through 10). Although all studies were conducted at both 0.4 and 2.0ml/min uptake rates, a clear difference was not always revealed for both. Therefore, in some cases, data is shown for one or the other. We are currently Investigating further to determine the source of these anomalies. PE OPTIMA 2100DV ICP-OES VARIAN VISTA MPX AXIAL ICP-OES TraceyCyclonicSprayChamber With Helix SeaSprayConcentricGlassNebulizer With EzyFit And EzyLok 60psi 30psi 30psi 60psi 60psi 30psi 30psi 60psi 60psi 30psi 60psi 30psi Figure 7: Effect of Pressure on Performance Signal Intensity (2ml/min uptake)