Applicability of a multiple-mode diode laser in flame atomic absorption spectroscopy

A multiple-mode laser diode is used to supply the primary radiation for atomic absorption spectroscopy (AAS). The multiple wavelength characteristics of the laser allow peak ratio measurements and possible background correction by the monitoring of the absorption spectrum with a diode-array spectrometer. In this demonstration, lithium is used as the analyte and air/acetylene flame is used as the atom reservoir. The detection sensitivity (1% absorption) is 20 ng/mL and the detection limit (2 σ of blank) is 4 ng/mL; these values are comparable to those of the conventional flame AAS with the use of a hollow cathode lamp as the source radiation.