Limit of detection (LOD) for macronutrients, micronutrients and trace elements in fertilizers using single and double pulse LIBS

Laser induced breakdown spectroscopy (LIBS) in single pulse (SP) and double pulse (DP) configuration in collinear beam geometry at atmospheric air pressure was used to determine the limit of detection (LOD) for the macronutrients Ca, Mg and P, the micronutrients Fe, Na, Mn and Zn and the trace elements Al, Cr, Cu and V in 26 samples of organic and inorganic fertilizers of different matrix composition. Inductively coupled plasma optical emission spectroscopy (ICP-OES) was used as a reference technique. A comparative study was performed to optimize key parameters, such as excitation wavelength, delay time and interpulse, for improving LIBS performance in the SP and DP configurations. Results show a considerable improvement in linear correlation between the DP LIBS signal and element concentration measured by ICP-OES compared to SP LIBS. LOD values obtained by DP LIBS increased up to five times as compared to SP LIBS. In general, LIBS results show a marked improvement in the simultaneous quantitative determination of various elements in organic and inorganic fertilizers.