Advantages of element specific detectors

The conductivity detector was set at a sensitivity that would have produced an acceptable signal for the selenium compounds in the absence of the other ions. Because of the high sensitivity setting on the detector and the high concentrations of chloride, sulfate, and phosphate relative to selenite and selenate, the recorder pen is off the chart for retention times between 8 and 25 minutes, and signals for selenite and selenate cannot be reliably located. However, when a graphite furnace atomic absorption spectrometer was employed as the selenium-specific 

High pressure liquid chromatography is frequently used to separate and identify trace element compounds. A common detector for liquid chromatographs is the differential refractive index detector that is not element-specific. To achieve separation, mobile phase gradients or sudden changes in the composition of mobile phases are frequently needed. The differential refractive index detector will often not be able to compensate for changes in the refractive index of the mobile phase and. 

Element-specific detectors can and have been used in conjunction with gas chromatographs, with ion chromatographs, and with high pressure liquid chromatographs to great advantage. Most of the element- 

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