Nebulizer microconcentric high-efficiency

Figure 5 Micronebulizers (a) Meinhard high-efficiency nebulizer (HEN), (b) Cetac microconcentric nebulizer (MCN).

The disadvantage of microconcentric nebulizers is that they use an extremely tine capillary, which makes them not very tolerant to high concentrations of dissolved solids or suspended particles. Their high efficiency also means that most of the sample makes it into the plasma, and as a result can cause more severe matrix suppression problems. In addition, the higher level of matrix components entering the interface has the potential to cause cone blockage problems over extended periods of operation. For these reasons, they have been found to be most applicable for the analysis of samples containing low levels of dissolved solids. 

A type of concentric glass nebulizer which is operated at pressures of several tens of bars is known as a high efficiency nebulizer (HEN) [120]. More recently, microconcentric nebulizers have also been described, for which the internal vol-... 

Bjorn, E. and Freeh, W. (2001) Non-spectral interference effects in inductively coupled plasma mass spectrometry using direct injection high efficiency and microconcentric nebulization. J. Anal. At. Spectrom., 16, 4-11. 

The sample introduction from an LC column to ICP-MS is performed by a nebulizer. The usual nebulizers are pneumatic nebulizers, such as Meinhard, crossflow, or microconcentric nebulizers (MCNs). Additionally, there is the ultrasonic nebulizer (USN), the direct-injection nebulizer (DIN), and the hydraulic high-pressure nebulizer (HHPN). The nebuli-zation efficiency depends on nebulizer type and is typically low for Meinhard and crossflow nebulizers (only around 1—5 %, [23]), whereas it is high for the DIN and USN. 

Microflow or low-flow nebulizers, which were described in greater detail in Chapter 3, are being used more and more for routine applications. The most common ones used in ICP-MS are based on the microconcentric design, which operate at sample flows of 20-500 pL/min. Besides being ideal for small sample volumes, the major benefit of microconcentric nebulizers is that they are more efficient and produce smaller droplets than a conventional nebulizer. In addition, many microflow nebulizers use chemically inert plastic capillaries, which makes them well suited for the analysis of highly corrosive chemicals. This kind of flexibility has made low-flow nebulizers very popular, particularly in the semiconductor industry, where it is essential to analyze high-purity materials using a sample introduction system that is free of contamination." ... 

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