DIHEN

Figure 5.14 Schematics a) of DIHEN (j.E. Meinhard Associates, Santa Ana, CA) ().S. Becker, H.J. Dietze, ].A. McLean and A. Montaser, Anal. Chem., 71, 3077 (1999). Produced by permission of American Chemical Society) and b) of microconcentric nebulizer (MCN 100, CETAC Technologies, Ohama. Reproduced by permission of CETAC Technologies)...

Characteristics such as the solution uptake rate, the sensitivity and the limit of detection for uranium determination using several nebulizers (Meinhard, MicroMist nebulizer, Q-DIHEN,... 

For some applications, precipitation and co-precipitation, which is often incomplete, is utilized. As an example, for trace matrix separation the procedure for plutonium determination by ICP-SFMS in urine after trace matrix separation is summarized in Figure 6.29.86 87 The limit of detection for 239 Pu ultratrace determination in one litre of urine based on enrichment factor of 100 using the DIHEN in ICP-SFMS was 1.02- 10 18g mF1.86... 

The second type of direct injection nebulizer, called the direct injection high-efficiency nebulizer (DIHEN), is a specific type of the Meinhard HEN [38] that is inserted into the ICP torch in place of the center, injector tube. The main advantage of the DIHEN compared to the Cetac DEN is that a high-pressure pump is not needed to deliver sample to the nebulizer. An unusually low nebulizer gas flow rate (0.25 L/min) and high ICP power (1.5 kW) were found to provide optimal ICP-MS sensitivity when DIHEN is used [38]. 

Radioactive waste solution ICP-SFMS (Element, DIHEN) 226 Ra, 230jh, 230jh 233U, 23 Np, 238U, 2412 0.1 pgU (2" Am) 0.1 pgU (232Np) Mclean et a/. ... 

The addition of oxygen was found to be helpful when nebulizing effluents from HPLC containing organic eluents such as acetonitrile. This was useful when using ICP-MS for on-line detection in speciation as well as in trace-matrix separations. Here, however, it is useful to use desolvation, even in the case of low consumption, high efficiency nebulizers, such as the HEN or DIHEN. This can be done efficiently with membrane desolvation using Nafion membranes [148]. 

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