Figure 12.5(b)
Mass spectrometric confirmation of peak 12 as benzene.example, an automatic pipette may be used for sampling; a fraction collector in a chromatographic
separation; or an automatic sequence for making a measurement and recording data. By the use of
modern computer controlled robots it is becoming possible to fully automate such an analytical
sequence. Laboratory robots are discussed a little more fully at the end of the chapter. On the other hand
an analysis can be automated at all stages. Pioneers in automated wet analysis were Technicon Ltd with
their Autoanalyser. Subsequent developments and imitators have extended the scope of this system for
several hundred different analytes and matrices.
Figure 12.6 illustrates the outline of such an analysis. An automatic pipette extracts a preset volume of
the liquid sample (or solution) from a cup presented to it on a turntable. The measured sample is mixed
with the reagents in the appropriate proportions, and propelled through the instrument by the peristaltic
proportioning pump. This pump operates by means of moving bars, attached to a chain drive, which
sequentially compress the plastic sample and reagent tubes to drive the liquids forward through the
instrument. The incorporation of a succession of air bubbles at