 Gravimetry
Several methods exist to quantify analytes by measuring weights of products of
physical-chemical operations, among which precipitates are the most commonly used.
Volumetry
Volumetric or titration procedures are performed to accurately quantify the volume of
the titer reagent (usually measured by a burette) needed to react with an unknown quantity
of another reagent called analyte. The techniques most used are based on acid-base
reactions, oxidation-reduction, and formation of complexes and precipitates.
Potentiometry
Forms part of a broad range of techniques that use electrical measurements to quantify
chemical species.
Molecular and Atomic Spectrophotometry
The operational principle on which both techniques are based involves the interaction
of radiation with matter. This interaction produces certain effects, depending on the
radiation used. An apparatus measures the degree of interaction by comparing the intensity
of radiation before and after passing through the sample and its relationship with the
concentration of the absorbent species.
Carbon, Hydrogen, and Nitrogen (CHN) or Dry-combustion Analyzer
Changes in the composition of C, H, and N are measured on the basis of gas separation
by absorbers specific to water and carbon dioxide. Detection is through thermal
conductivity. Results are calculated by analyzing the pattern of check samples.
Continuous-flow Segmented Analyzer
The automated system for continuous-flow segmented analysis consists of a series of
individual modules, each a separate component that performs a specific task within a
programed sequence. The modules can be interchanged and reordered for different analytical
purposes. The system automatically introduces and prepares samples, and detects and
records sample concentration. A sampling capillary tube is submerged successively in each
container to take a given volume over a certain time interval. The sample is then fed into
the analyzer. |
