Inductively coupled plasma atomic emission spectrometric detectors

5 Inductively coupled plasma atomic emission spectrometric detectors 

This technique has been found to be particularly useful for the determination in water of extremely low levels of a limited number of anions. 

The properties of an inductively coupled plasma closely approach those of an ideal source for the following reasons  

Greenfield et al. [36] were the first to recognise the analytical potential of the annular inductively coupled plasma. Wendt and Fassel [37] reported early experiments with a tear-drop shaped inductively coupled plasma but later described the medium power (l-3kW), 18mm annular plasma now favoured in modem analytical instruments [38]. 

The current generation of inductively coupled plasma emission spectrometers provide limits of detection in the range of 0.1-500pg Lin solution, a substantial degree of freedom from interference and a capability for simultaneous multi-element determination facilitated by a directly proportional response between the signal and the concentration of the analyte over a range of about five orders of magnitude. 

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AAS = atomic absorption spectrometry GC/FID = gas chromatography/f1ame ignition detector GC/FPD = gas chromatography/f1ame photometric detector ICP/AES = inductively coupled plasma atomic emission spectroscopy ICP/MS = inductively coupled plasma with mass spectrometric detection... 

Luminescence molecular detectors have also been used for online monitoring of dissolution tests and the characterization of toxic residues using bioluminescence assays. Atomic (atomic absorption spectroscopy, inductively coupled plasma-atomic emission spectroscopy (ICP-AES)) detectors have been coupled to robotic stations either through a continuous system acting as interface or by direct aspiration into an instrument from a sample vial following treatment by the robot. Mass spectrometric and nuclear magnetic resonance (NMR) detectors... 

Atomic emission detector (AED), electrochemical detection (ELCD), electron capture detection (ECD), evaporative light scattering detector (ELSD, including condensation nuclea-tion-CN), fluorescence detector (FLD, including laser-induced fluorescence), inductively coupled plasma-mass spectormetry (ICP-MS), mass spectrometry (MSD), MS/MS, MS(n), thermoionic detector (NPD), spectrometric detection (UV, Vis, DAD) ... 

The association of a spectrometer with the liquid chromatograph is usually for the purpose of structure elucidation of the eluted solute, a procedure that will be discussed in a later chapter. The association of tui atomic spectrometer with the liquid chromatograph, in contrast, is almost exclusively for the specific detection of the metalic and semi-metalic elements. The atomic spectrometer is a highly specific detector, and for element detection perhaps more so than the electrochemical detector. However, in general, a flame atomic absorption spectrometric (AAS) system is not as sensitive. If an atomic emission spectrometer or an atomic fluorescence spectrometer is employed then multi-element detection is possible. The inductively coupled plasma spectrometer can also, under some circumstances, provide multi-element detection but all three instruments are extremely expensive particularly in terms of an LC detector. It follows that most LC/AAS combinations employ a flame atomic absorption spectrometer or occasionally an atomic spectrometer fitted with a graphite furnace. Furthermore the spectrometer is usually set to monitor one element only, throughout the development of any given separation. 

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