Toluene nebulizers

Three different reactors were used to deposit CuInS2 films via AACVD. Reactor A, shown schematically in Fig. 6.11a, was primarily used in the parametric studies described below. This is a horizontal, atmospheric pressure, hot-wall reactor with a plate-type 2.5-MHz ultrasonic nebulizer from Sonaer Ultrasonics. The precursor (1.5-3.5g) was dissolved into distilled toluene (50-400 ml) and fed into the nebulizer using a syringe pump. The nebulizer... 

Aerosol Generator. The atomizer shown in Figure 7 was designed to produce aerosols of certain organic materials that are soluble only in easily vaporized solvents such as isopropanol or toluene. Difficulties were encountered when using other nebulizers because of continual concentration of the solution resulting from evaporation of the solvent, making it impossible to predict or control the test air concentration and the particle size. 

This is the direct-APPI approach, promoted by the group of Syage [66], In the observations and experimental setup of the group of Bruins [61], the direct-APPI process is not sufficiently efficient. Therefore, an easily ionizable compound, the dopant D, is added to the mobile phase or to the nebulizing gas to enhance the response. Toluene [61] or anisole [68] are frequently used as dopant. With a dopant, the APPI takes place via a charge-exchange reaction between the dopant molecular ion and the analyte molecule ... 

Duyck, C., Miekeley, N., Porto da Silveira, C. L., and Szatmari, P., Trace Element Determination in Crude Oil and Its Fractions by Inductively Coupled Plasma Mass Spectrometry Using Ultrasonic Nebulization of Toluene Solutions, Spectrochimica Acta Part B Atomic Spectroscopy, Vol. 57, 2002, pp. 1979-1990... 

Detection limits via either direct aspiration or pumped delivery are similar for the same solvent (toluene-pyridine), since nebulizer and spray chamber are identical. Precision of analysis, however, is considerably improved in the latter case. This observation was most pronounced when pyridine solutions of coal derived material were being examined rather than solutions of elemental standards. The relatively high viscosity of the concentrated coal derived solutions ( 5-7% w/w) no doubt leads to inconsistency in aspirated sample delivery. Relative standard deviations (RSD) were also improved on going from 10 second to 30 second integration times. Table II compares detection limits and RSD s in pyridine employing direct aspiration (10 second integrations) and pumped delivery (30 second integrations). The RSD s for most elements were less than 10% for the pumped delivery. 

The recent technique of nebulized spray pyrolysis (NSP) has been used to prepare aligned MWNTs bundles [62]. This technique consists in a spray generated by an ultrasonic atomizer. MWNTs with fairly uniform diameters, as well as ahgned MWNT bundles, have been obtained by using solutions of organometallic compounds, such as ferrocine, in benzene, toluene, and other hydrocarbon solvents. The advantage of NSP is the ease of scahng up to an industrial process where the reactants are fed into the furnace continuously. 

Hausler and Taylor [7] used 100 A /i-Styragel with toluene as eluent (0.5-1.0mLmin ) to separate metal salts of dialkylbenzene sulphonates in a petroleum-based matrix. A specially-designed nebulizer was used for ICP-AES detection. A mixture of four ferrocenes was clearly separated into four peaks, in the elution order bis(tetrapyrazolylborate) iron, 1, I -diacetylferrocene, acetylferrocene and ferrocene. Metal detection limits were similar to those obtained with aqueous samples. 

Duyck et al (2002) determined Ag, Al, Ba, Cd, Co, Cu, Fe, La, Mg, Mo and Mn in residual fuel oil and crude oils by ICP-MS after dilution of the samples in toluene, using ultrasonic nebulization. Good accuracy was reported for the determinations of the metals. Wondimu et al (2000) analysed residual fuel oil for Ag, Al, As, Ba, Bi, Ca, Cd, Co, Cr, Cu, Fe and Hg by ICP-MS after micro-wave acid decomposition. H2O2 was used after acid decomposition for better carbon removal. Lord (1991) determined Li, Al, Ti, V, Mn, Fe, Co, Ni, Cu, Zn, Sr, Mo, Ag, Cd, Sn, Sb, Ba and Pb in crude oils by ICP-MS with mciro-emulsion sample introduction. Kowalewska et al (2005) determined Cu in crude oils and crude oil distillation products by ICP-MS after ashing and micro-wave assisted decomposition of analyte and transferred to aqueous solution. Good recovery of Cu was reported. Kelly et al (2003) determined Hg in crude oils and refined products by cold Vapor ICP-MS after decomposition of the sample by closed system combustion. Botto (2002) analysed crude oil, petroleum naphthas and tars for Na, P, Ti, V, Mn, Fe, Co, Ni, Cu, Zn, As, Y, Mo, Cd, Sn, Sb,... 

Duyck, C. Miekeley, N. Silveira, C.L.P. Szatmari, P., (2002), Trace element determination in crude oil and its fractions by inductively coupled plasma mass spectrometry using ultrasonic nebulization of toluene solutions, Spectrodiim. Acta, 57B, 1979-1990. 

---