Demountable direct injection high efficiency nebulizer for inductively coupled plasma mass spectrometry

A low cost, demountable direct injection high efficiency nebulizer (d-DIHEN) is introduced that provides an adjustable solution capillary, allowing fundamental studies to improve operational characteristics of the micronebulizers, aerosol properties, and analytical figures of merit in inductively coupled plasma (ICP) spectrometries. Similar to the DIHEN and the large bore-DIHEN (LB-DIHEN), the d-DIHEN requires high RF power (1500 W), low nebulizer gas flow rates (approx. 0.16 l/min), and low solution uptake rates (1–100 μl/min) for optimal measurements in ICP mass spectrometry (ICPMS). In contrast to the DIHEN and LB-DIHEN, the optimum position for the d-DIHEN nozzle is located 5 mm (rather than 2 mm) below the end of the torch intermediate tube, thus reducing chances of accidental nebulizer tip meltdown. Compared with the DIHEN, the d-DIHEN produces smaller droplets with narrower droplet distributions and lower mean droplet velocities, characteristics important for improved sample–plasma interaction. Sensitivity, detection limits, and precision are superior with the d-DIHEN compared to conventional nebulizer-spray chamber arrangements and other direct injection nebulizers, especially at low solution uptake rates (<40 μl/min). In general, oxide ratios for the d-DIHEN and DIHEN are low and similar at solution uptake rates of 10 μl/min or less. Above 10 μl/min, the d-DIHEN provides lower oxide ratios than the DIHEN. For example, the oxide ratio for Ce increases from 0.6% to 3.8% (d-DIHEN) and 0.5 to 7.6% (DIHEN) as the solution uptake rate is increased from 5 to 85 μl/min. Doubly charged ratios for Ba are also lower for the d-DIHEN at all solution uptake rates compared to the DIHEN. The utility of the d-DIHEN is investigated in the analysis of a reference material (Lyphochek urine metals controls) at low (Level 1) and high (Level 2) concentration levels.