Radial viewing

Figure 8.6 Horizontal axially viewed torch and vertically oriented, radially viewed plasma configuration. Reproduced by permission of Varian, Inc.

Brenner, I.B. and Zander, A.T. (2000). Axially and radially viewed inductively coupled plasmas - a critical review. Spectrochimica Acta B55 1195-1240. 

Silva, F.Y., Trevizan, L. C., Silva, C. S., Nogueira, A. R. A., and Nobrega, J. A. (2002). Evaluation of inductively coupled plasma optical emission spectrometers with axially and radially viewed configurations. Spectrochimica Acta B 57 1905-1913. 

Vaisanen, A. and A. Hander. 2006. Optimization of operating conditions of axially and radially viewed plasmas for the determination of trace element concentrations form ultrasound-assisted digests of soil samples contaminated by lead pellets. Anal. Chim. Acta 570 93-100. 

ICP-OES atomic/ionic spectral lines must be within the range 160 - 800 nm. Gaseous elements, halogens, and carbon are not determined. There are poor detection limits for biologically important elements (As, Se, Pb, Th, etc.) in the radial viewing spectrometers. 

The structure repeats along the helical axis (vertical) at intervals of 34 A, which corresponds to 10 nucleotides on each chain. (B) Radial view, looking down the helix axis. 

Brenner IB, Zander A, Cole M, Wiseman A. Comparison of axially and radially viewed inductively coupled plasmas for multi-element analysis effect of sodium and calcium. J Anal Atom Spectrom 1997 12 897-906. 

The detection limits obtained by radial and axial observation were found to be up to one order of magnitude lower in the axial as compared with the radial viewing, as reported by Ivaldi and Tyson [393]. These results were obtained with an Echelle... 

Ivaldi and Tyson [393] reported that interferences caused by NaCl were found to be nearly twice as high in the case of axial viewing than in radial viewing and also atom to ion line intensity ratios were influenced more severely in the case of axial viewing. 

Figure 14.3 Plasmas obtained by inductively coupling or by microwaves, (a) Above left, (radial viewing to collect radial light). A radiofrequency current (between 27 and 50 MHz) that induces circulation of electrons in the inert gas drives the torch. The inner tube is used to inject the sample into the plasma. Right (for axial viewing), cooled device using fibre optic. The torch may consume up 10 to 15L/min of argon, which serves simultaneously as the ionization gas, nebulization gas and cooling gas (to avoid the torch melting ), (b) Below is a microwave plasma used at the outlet of a gas chromatograph for a specialized detector. These plasma sources must be stabilized for better reproducibility of the analyses.

Metal Wavelength (nm) Axial viewing Radial viewing... 

B) Radial view, looking down the helix axis. 

FIGURE 10-1 A typical ICP source. Position A shows radial viewing of the torch, and position B shows axial viewing. (From V. A. Fassel. Science. 1978.202,185. With permission. Copyright 1978 by the American Association for the Advancement of Science.)... 

In the analysis of simple solutions with known composition, for ICP-AES short term precision between 0.2 3 % relative standard deviation for analytes with concentrations ten times the detection Hmits may be achieved, while over several hours a 5 % RSD can be expected. This precision in combination with its robustness make ICP-AES superior to ICP-MS for the determination of minor and major components. With ICP-AES most elements (about 73) can be determined routinely at the 10 pg L level or better in solution with radial viewing. In favourable cases and/or axial viewing, detection Hmits < 1 pg can be achieved. Eor a single emission line, a Hnear range of four orders of magnitude may be easily attained and as many as six orders of magnitude can be observed in favourable cases. 

The detection system of ICP-AES is of two types simultaneous and sequential spectrometers with radial viewed torches in Fig. 3. A simultaneous type, where many elements can be determined in a single scan, is displayed in Fig. 3a, and a sequential type where one element in a scan is determined is in Fig. 3b. 

Table 2 Recommended wavelengths and estimated instrumental detection limits (IDLs) for radial view ICP/AES [2]...

---