A simultaneous multielement non-dispersive atomic-fluorescence spectrometer using modulated sources and frequency discrimination of fluorescence signals.
Commercial radiofrequency-excited electrodeless discharge lamps can be run from a square-wave modulated power supply so as to give a low level of continuous emission when modulated in the frequency range 3-10 kHz. Use of a different modulation frequency and lock-in amplifier for each lamp allows multielement non-dispersive atomic-fluorescence spectrometry to be performed. Very low detection limits have been obtained for arsenic, selenium, tin and mercury. The use of low-cost electronic components in the system largely offsets the high cost of the individual excitation power supplies and tuned a.c. detectors.
D'ulivo
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Istituto di Chimica Analitica Strumentale del C.N.R.-Istituto di Chimica Analitica dell'Università Di Pisa, Via Risorgimento 35, 56100 Pisa, Italy.
Papoff
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Festa
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