Matrix Effect of Alkali and Alkaline Earth Metal Halides on Fluorescence Quantum Yield of Indium in Laser‐Induced Fluorescence Flame Spectrometry

Abstract

As in ter fered with by al kali and al ka line earth metal halides added as the ma trix in an acet y lene/air flame, the flu o res cence quan tum yield of In as the analyte in a la ser-induced flu o res cence (LIF) flame spec trom e try has been thor oughly char ac ter ized. The flu o res cence quan tum yield is de ter mined by a ra t io of F to A, where F is the mea sured flu o res cence of In and A is the dif fer ence be tween the ab sorp tion sig nals re corded for the analyte and the blank so lu tions. The nor mal ized flu o res cence sig nal is treated to pre vent de vi a tions due to vari a tions of the at om iza tion ef fi ciency un der the con di tions with and with out the ma trix added. The flu o rescence quan tum yield is mea sured to be al most in de pend ent of the ma trix con cen tra tion up to 500 ppm ( g/mL) stud ied, un der con di tions of ei ther op ti cal unsaturation or sat u ra tion. By con sid er ing a quench ing ef fect induced by elec tron-atom col li sions, the cal cu lated flu o res cence quan tum yields are con sis tent with our ob serva tions.