(US Patent #6166379)

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The DIHEN is based on the HEN described below.  There are several\ articles listed in the Reference List

The High Efficiency Nebulizer (HEN) available from Meinhard Glass Products is suitable for microsample analysis in HPLC and FIA as well as for more routine higher flow analyses, yet preserves the low cost and simplicity of design and operation that characterize the MEINHARD^® nebulizer.

The increase in efficiency is accomplished by increasing the kinetic\ energy of the nebulizing gas and by optimizing the liquid-to-gas mass ratio. These modifications are consistent with the trends predicted by the equation of Nukiyama and Tanasawa and subsequently more fully developed by Barry Sharp¹. Table I (below) compares the dynamic characteristics and geometric parameters of the HEN to those of the standard nebulizers. Table II lists the operating conditions under which the other experimental data reproduced in this article were taken.

* Data cited herein included in a paper by Dr. Hsiaoming Tan delivered at FACSS XIX, September 22, 1992.

The HEN operated at a sample flow rate of 0.08 mL/min achieves limits of detection comparable to those of a standard concentric nebulizer operated\ at a sample flow rate of 2.0 mL/min (see Table III). The HEN was tested at sample input rates ranging from 0.01 to 1.2 mL/min (see Figure I). Figures II and III compare the net signal intensities and percent RSD's of the HEN with those of the TR-50-C1 and TR-30-A3 when all three nebulizers are operated at 0.08 mL/min sample flow. The HEN exhibits both higher net signals and lower percent RSD's.

There are several other advantages to this high efficiency nebulizer. Washout times for the HEN is about 40 seconds, again quite comparable to that of the standard MEINHARD^® nebulizer. No high pressure pumping is needed for sample delivery as is required in some other high pressure, low flow nebulization systems. The sample input tube has a 0.125" outer diameter so that it can be used with standard chromatographic fittings, and a 0.026" inner diameter to minimize dead volume. The end of the input tube is ground flat and fire polished to provide a leak-free seal. And finally, the external configuration of the HEN allows for it to be easily interchanged with a standard nebulizer.

1. B. L. Sharp, J. Anal. Atomic Spectrom. 3, 613 and 939\ (1988)