Flow-Injection Inductively Coupled Plasma Atomic Emission Spectrometry with a Multielement Photodiode-Array Spectrometer

A multichannel photodiode-array spectrometer was used to monitor the transient multielement atomic-emission signal generated by an inductively coupled plasma utilizing flow-injection sample introduction. The linearity, dynamic range, sensitivity, and precision of the technique were assessed for three different sample-loop volumes (110,290, and 500 µL). With a fixed, optimized integration time, a linear dynamic range of 3.5 orders of magnitude was established for five elements—Cd, Cr, Cu, Mg, and Zn—when the 290- and 500-µL sample loops were used. Because the lateral dispersion of the transient sample plug was low and because efforts were made to optimize the signal-to-background ratio by synchronizing the integration period of the photodiode-array detector with the transient signal, detection limits for the flow-injection system were comparable with those obtained with the use of continuous-nebulization sample introduction. An interface is described which enables temporal synchronization of the transient flow-injection signal with the signal integration period of the photodiode array.