Instant Notes: Analytical Chemistry

tive and repetitive tasks ranging from simple operations, such as weighing

samples, adding reagents or filtrations to multistep procedures for sample

cleanup by solvent or solid phase extractions. They are computer-controlled and

can be programmed and reprogrammed to perform sequences of operations

according to specific analytical requirements.

The spatial geometry of robots may be cylindrical, cartesian or anthropomor-

phic (mimicking human movements), the first form being the most common. A

typical laboratory work station with a computer-controlled cylindrical robot is

shown in Figure 2. Typical operations include:

● manipulation of glassware and other apparatus;

● weighing and dissolution of samples;

● addition of reagent solutions and solvents;

● control of heating, cooling and mixing;

● filtrations and extractions;

● instrument operation and control.

As for automation in general, robots release laboratory staff for more

demanding and nonrepetitive tasks, increase sample throughput, and contribute

to improved analytical precision and accuracy. They can also be designed to

work with hazardous materials so as to protect laboratory personnel from direct

contact with toxic or radioactive substances.

H2 – Automated procedures 329

Sensing electrode

Electronics

Control and

alarming

outputs

Reference

electrode

Constant

temperature

assembly

To waste

Mixer

Peristaltic

pump

3-way

solenoid

valve

Standardizing

solution

Reagent

Constant

head

chamber

Filtered

sample

Unfiltered

sample stream

Bypass filter

Fig.1. Schematic diagram of a potentiometric autotitration system. From Principles of Instrumental Analysis, 2nd edn,
by D.A. Skoog & D.M. West © 1980. Reprinted with permission of Brooks/Cole, an imprint of the Wadsworth Group, a
division of Thomson Learning.