11.14 : 气相色谱法：检测器概述

In gas chromatography or GC, the detector is placed at the exit of the column to sense, identify, and quantify the separated components.

An ideal GC detector is nondestructive, generates a linear response over a wide range of concentrations, and can detect low analyte concentrations.

It may be universal, sensing all analytes, or selectively responsive to certain analytes.

The detector should be stable while remaining insensitive to changes in flow rate or temperature.

In GC, thermal conductivity, flame ionization, and electron capture detectors are commonly used.

While the TCD produces a signal for all solutes, it has a poor detection limit.

The FID provides a broader linear response range and has a lower detection limit than the TCD. However, the sample is destroyed.

Similarly, the ECD has an excellent detection limit but a relatively narrow linear range.

Ultimately, the choice of detector depends on the nature of the analyte.