Nebulizer Reproducibility

Figure 8.4. Scheme of electrospray source with an ultrasonic nebulizer. (Reproduced with permission of the American Chemical Society, Ref [61].)... 

Fig. 33.9 (a) Schematic showing the principle of operation of an active vibrating mesh nebulizer (Reproduced from [71], With permission. Copyright 2007 Elsevier), (b) Photograph of an Aeroneb Professional Nebulizer System... 

Reproduced with permission of Wiley-VCH Verlag GmbH from [25]. (b) Cyclonic spray chamber. Reproduced with permission of Advanstar Communications from [27]. (c) Burgener nebulizer. Reproduced with permission ofWiley-VCH Verlag GmbH from [25]. 

The sample to be analyzed can be dissolved in an organic solvent, xylene or methylisobutyl ketone. Generally, for reasons of reproducibility and because of matrix effects (the surroundings affect the droplet size and therefore the effectiveness of the nebulization process), it is preferable to mineralize the sample in H2SO4, evaporate it and conduct the test in an aqueous environment. 

At best, expl power i a somewhat nebulous quantity. If we consider relative power as measured in a Ballistic Mortar or Trauzl Block, then OB correlates reasonably well with relative power, provided these comparisons are made for similar expls. This is illustrated in Fig 1, where Ballistic Mortar measurements axe respectively correlated with OB for nitro, nitramine, nitrate ester and aluminized expls. In general Ballistic Mortar measurements are more reproducible than Trauzl Block data. Consequently we have shown these in preference to Trauzl Block measurements. Correlation between Trauzl block data and OB are reported in Refs 1 8... 

Coupling of CE with MS is a difficult task, because of the incompatibility of the EOF (100 500 nl min ) and optimal ESI ionization conditions. Moreover, a stable current for reproducible electrophoretic separations must be ensured. Fortunately, both these problems can be solved by adding make-up solution (10 100 g min ), which also ensures an electric connection between the nebulizer and the tip of a capillary. 

Figure 4.8 Schematic of an electrospray probe with a concentric flow of nebulizing gas. From applications literature published by Micromass UK Ltd, Manchester, UK, and reproduced with permission.

Fig. 5.13 Strategy for 1-pot synthesis of crumpled RGO-metal/metal oxide hybrid via nebulization of aqueous GO/precursor solution prior to compression of GO and NP formation in tube furnace at 600-700 °C. Reproduced with permission from [200], (2012) American Chemical Society.

The significant enhancement of ion formation by a corona discharge as compared to a Ni source has already been implemented in early API sources. [139,140] The nature of the APCI plasma varies widely as both solvent and nebulizing gas contribute to the composition of the Cl plasma, i.e., APCI spectra can resemble PICI, CECI, NICI, or EC spectra (Chap. 7.2-7.4) depending on the actual conditions and ion polarity. This explains why APCI conditions suffer from comparatively low reproducibility as compared to other ionization methods. 

Fig. 11.28. Schematic of an APPl source, including the heated nebulizer probe, photoionization UV lamp and moimting bracket. Reproduced from Ref. [144] by permission. American Chemical Society, 2000.

FIGURE 8.5 Schematic representation of an API sonrce with a heated nebulizer interface for APCI. (Reproduced from Raffaelli, A., Atmospheric pressure chemical ionization (APCI), in Cappiello, A. (ed), Advances in LC-MS Instrumentation, vol. 72 Journal of Chromatography Library), Elsevier, Amsterdam, the Netherlands, 2007, 11-25. Copyright 2007. With permission from Elsevier.)... 

Schematic diagram of an ultrasonic nebulizer used for ICP-AES (reproduced with permission from the Perkin Elmer Corporation).

Figure 2.6 Ion intensity of Cs+ as a function of nebulizer gas flow rate for different sampling depths at rf power of 1.1 kW measured by ICP-MS. (M. A. Vaughan, C. fforlick and S. H. Tan, J. Anal. At. Spectrom. 2, 765 (1987). Reproduced by permission of the Royal Society of Chemistry).

Figure 5.1 Main parts of an inductively coupled plasma mass spectrometer sample introduction systems (left column), e.g., Meinhard or MicroMist nebulizer with cyclonic spray chamber, ultrasonic nebulizer, microconcentric nebulizer and laser ablation system (all from CETAC Technologies), ion source (middle column) and several types of mass spectrometers, (a) Agilent 7500 from Agilent, (b) Platform from CV Instruments, or (c) Element from Thermo Fisher Scientific. (Parts of this figure were reproduced with permission from CETAC Technologies, Agilent, CV Instruments and Thermo Tisher Scientific, respectively.)...

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)...

Figure 5.15 Experimental arrangement of microconcentric PFA nebulizer with heated cyclonic spray chamber and Peltier cooled multipass condenser APEX. (Reproduced by permission of Element Scientific Inc., Omaha).

Figure 5.16 Schematic of microconcentric nebulizer (Aridus II, CETAC Technologies, Ohama). (Reproduced by permission of CETAC Technologies.)...

Figure 5.19 Experimental arrangement of nanoflow injection in ICP-MS using the microflow nebulizer DS 5 with spray chamber together with a nanoinjection ventile a) schematic and (b) photograph, (j. S. Becker, Trends in Anal. Chem., 24, 243 (2005). Reproduced by permission of Elsevier.)...

Fig. 19 Detector block for the light-scattering detector. (1) nebulizer, (2) drift tube, (3) heated copper block, (4) light-scattering cell, (5) glass rod, (6) glass window, (7) diaphragm. (Reproduced from A. Stoly-hwo, H. Colin, and G. Guiochon, J. Chromatogr. 265 1 (1983) with permission.)...

From the late 1960s onwards, a number of research groups around the world began to investigate alternatives to pneumatic nebulization for sample introduction, in an attempt to overcome transport efficiency limitations. The most successful approaches were those which involved heating small, discrete liquid samples, and sometimes even solid samples, directly on a metal filament, boat, or cup which could be positioned reproducibly into a flame. However, since the temperature of the metal would be lower than that of the flame itself, the techniques were confined to the determination of relatively easily atomized elements such as arsenic, bismuth, cadmium, copper, mercury, lead, selenium, silver, tellurium, thallium, and zinc. 

In the early days of flame spectrometry, some very elaborate accessories were designed to give reproducible discrete sample nebulization.16,17 However, as the technique became more widely employed, the devices used became progressively simpler, often taking the form of small funnels with a capillary bore outlet connected directly to the nebulizer capillary.17 Even this is not really necessary, because all that is required is a small (1-2 ml capacity) beaker with a conical depression in the bottom. Conventional Auto Analyser sample cups work very well. The end of the flexible nebulizer aspiration tube is simply dipped into the droplet of solution in the cone. This is especially useful if, for example, such sample cups have been used for evaporative pre-concentration of water samples in a vacuum desiccator.19... 

Solid foods in powder form can be analyzed directly by means of LA- or ETV-ICP-MS to eliminate time-consuming sample dissolution procedures (see Table 8.2). However, this requires the preparation of homogeneous powdered samples and the subsequent analytical determination is not as straightforward as the one based on liquid sample introduction. Another way to perform direct analysis of solid foods is to grind and suspend them into slurries. The viability of slurry nebulization relies on the ability to prepare samples of fine particle size in a reproducible manner and on the adoption of suitable (e.g., high-solids) nebulizers. Otherwise, slurries can be analyzed by ETV-ICP-MS resorting to the ultrasonic slurry sampling technique [72-74]. 

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