Increase of the signal LIBS by electric field for Ca analysis in soils

CARLOS A. RINALDI; BOGGIO, NORBERTO G; VOROBIOFF, JUAN

México

Encuentro; Colloquium Spectroscopicum Internationale XLI & I Latin American Meeting on LIBS; 2019

UNAM - CSI XLI - I LAMLIBS Organizing Committe.

One of the limitations for the detection of elements by LIBS is the intensity of the signal. There are several ways to improve the LIBS emission. For example the use of multiple laser pulses, the introduction of buffer gas around in theplasma and the application of a magnetic field. Mayo et al applied an electric field to measure the amount of mass extracted by pulse and also the application of an electric field produces more intense and sustained spectral lines overtime. Following the ideas proposed by Mohamed A. Hairth et al, in this work we developed a system to increase the signal intensity using a low power electric field. In Fig.1 the increase in the LIBS signal intensity in the emission rangecorresponding to Zn atom is shown. The effect of an electric field of 50 V/cm can produce a signal increase of 100%.In Fig. 2 is observed that the same electric field (50 V/cm) produces an increase on the Ca(II) ions emission signals of about one order of magnitude.This results are in agreement with those obtained by Hairth et al.6 and show that the electric field had a pronounced effect on the emission intensities of the ionic lines under forward biasing (negative target).The effect on atomic lines is lower than ionic lines under forward biasing. In this work we demonstrated that it is feasible to improve the limit of detection (LOD) of the LIBS technique using a low power electric field.