Immersible cell

Immersion-cell continuous pH measurement, 14 33 Immersion cleaning, of metal surfaces,... 

Another drawback of the immersion cell concept is that the active area is badly defined, because of the meniscus formed at the electrolyte-air interface. The form of the meniscus greatly depends on whether the sample is hydrophilic or hydro-phobic, which again is a function of applied potential. This problem can be circumvented, if the active area of the sample is defined by a window in an inert layer, for example resist or CVD nitride, which is fully immersed into the electrolyte, as shown in Fig. 1.6 a. 

Fig. 1.6 Two different immersion cell designs optimized for special applications, (a) Set-up for fast removal and rinsing of a strip-shaped electrode by fast rotation of the shaft (solid arrow). This set-up is useful for measurements of transient electrode processes like...

Figure 11.15—Principle of a spectrophotometer fitted with an immersion probe. Monochromatic light from the spectrophotometer is guided toward an immersion cell and then brought back to the detector. The reference beam is also guided by a fibre optic.

The technique of immersing a known mass of outgassed solid, with no dissolution, in a given liquid and measuring the heat evolved, would appear to provide a means of determining A by a single measurement, provided that A u1 0 is known for the liquid-solid system. If the surface of the solid sample in the immersion cell is at least 1 m2, the amount of heat released is not difficult to measure with the microcalori-metric procedure described in Section 5.2.2. Thus, for the routine control of the specific surface areas of a series of well-defined samples, immersion microcalorimetry is a very useful technique. 

Figure 9.17 The principle of a spectrophotometer fitted with an immersion probe. Monochromatic light issuing from a spectrophotometer is guided towards an immersion cell and then returned to the detector. The route is confined by a fibre optic. Left transmission probe. Right ATR probe the sapphire prism has a refraction index greater than that of the solution. The schematic shows three reflections of the beam and its penetration into the solution (see explanation in Chapter 10, Section 10.9.3).

---