Nebulizers Babington

Atomic emission spectroscopy can be employed, generally with an inductively coupled plasma for thermal excitation. The sample is introduced into the plasma as a mist of ultrafine droplets, and the monochromator and detector are set to measure the intensity of an atomic emission line characteristic of the element. This technique is powerful, general, sensitive, linear, and able to measure over 70 elements, and, as a result, is widely used. Response is typically linear over four orders of magnitude in concentration with relative standard deviations of 1 to 3%. In low-salt aqueous solutions, detection limits range from 10 to 1000 nanomolar without preconcentration. Significant problems with saline samples remain, but use of Babington nebulizers alleviates these problems somewhat. 

A device using an alternative principle to that of the jet and ultrasonic nebulizers has been described but has not been adopted to any extent. The Babington nebulizer, shown in Fig. 7, uses a principle that was first devised for fuel atomization [143]. Liquid (for the purposes of this discussion, a drug solution) is supplied to the outer surface of a hollow sphere. A thin film forms over the entire surface of the sphere. Compressed air supplied to the interior of the sphere expands through a small rectangular orifice at the top of the dome. Fine liquid particles form as escaping air ruptures a portion of the liquid film... 

In the pneumatic nebulizers used in atomic spectrometry, the liquid flow is usually of the order of 1 to a few mL/min and the full efficiency of the nebulizer (a few %) can actually be realized at gas flows of 2 L/min. However, even with gas flows below 2 L/min, droplet diameters as low as about 10 pm and injection velocities below about 10 m/ s are obtained. Pneumatic nebulization can be realized with a number of types of nebulizers. For flame emission and atomic absorption as well as for plasma spectrometry, they include concentric nebulizers, so-called cross-flow nebulizers, Babington nebulizers and fritted-disk nebulizers (Fig. 40) [95]. 

Fig. 40. Pneumatic nebulizers for plasma spectrometry. A concentric glass nebulizer, B cross-flow nebulizer, C Babington nebulizer, D fritted-disk nebulizer. (Reprinted with permission from Ref. [95].)...

Fig. 49. Particle size distributions of pneumatic nebulizers for ICP. MAK, high-pressure cross-flow nebulizer CGN, concentric glass nebulizer JAB, Jarrell—Ash Babington nebulizer JAC, Jarrell—.Ash fixed cross-flow nebulizer (Reprinted with permission from Ref. [139].)...

Nebulizers. The nebulizer converts a liquid into an aerosol of small droplets that can be transported to the plasma. Two approaches for aerosol formation are used commercially for ICPs, pneumatic nebulization, and ultrasonic nebulization. Pneumatic nebulizers use high-speed gas flows to create the aerosol. There are three commonly used pneumatic nebulizers the concentric nebulizer, the cross-flow nebulizer, and the Babington nebulizer. Pneumatic nebulizers produce a range of aerosol droplet sizes. Large droplets cannot be efficiently desolvated, so the aerosol is passed through a spray chamber to remove large droplets. As is the case with AAS, less than 5% of the original sample liquid actually reaches the plasma. 

Figure 5 Schematic of the (A) concentric nebulizer, (B) cross-flow nebulizer and (C) Babington nebulizer.

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