Thermal Conductivity Detector (TCD) Principle
Thermal conductivity detectors work on the principle of heat transfer by convection (gas cooling). Here, the assumption is that sample compounds will have different thermal properties than the carrier gas.…
Flame Ionization Detector (FID) Principle
Several different detector designs exist for process gas chromatographs. The two most common are the flame ionization detector (FID) and the thermal conductivity detector (TCD). Other detector types include the…
Online Gas Chromatograph Principle
The most common type of chromatography used in continuous process analysis is the gas chromatograph (abbreviated “GC”), so named because the mobile phase is a gas (or a vapor (…
Thin-Layer Chromatography : Manual Method
One of the manual chromatography methods taught to beginning chemists is thin-layer chromatography, also known as TLC. An illustrated sequence showing thin-layer chromatography appears here: As solvent wicks up the…
What is Chromatography ?
Imagine a major marathon race, where hundreds of runners gather in one place to compete. When the starting gun is fired, all the runners begin running the race, starting from…
pH measurement
Potentiometric pH measurement Color-change is a common pH test method used for manual laboratory analyses, but it is not well suited to continuous process measurement. By far the most common…
Electrodeless Conductivity Probes Principle
An entirely different design of conductivity cell called electrodeless uses electromagnetic induction rather than direct electrical contact to detect the conductivity of the liquid solution. This cell design enjoys the…
Four Electrode Conductivity Probes Principle
A very old electrical technique known as the Kelvin or four-wire resistance-measuring method is a practical solution to the problem of electrode fouling faced by two-electrode conductivity probes. Commonly employed…
Two Electrode Conductivity Probes Principle
We may measure the electrical conductivity of a liquid solution by passing an electric current through it. The most primitive form of conductivity sensor (sometimes referred to as a conductivity…
Conductivity Measurement
The electrical conductivity of liquids is an important analytical measurement in many industrial processes. This measurement is one of the more non-specific types of analytical technologies, because it does not…
