Direct Determination of Ca, K and Mg in Cassava Flour Samples by Laser-Induced Breakdown Spectroscopy (LIBS)

This study aims to develop a method for direct determination of Ca, K, and Mg in cassava flour samples by laser-induced breakdown spectroscopy (LIBS). LIBS instrumental parameters were evaluated using factorial design with a central point. The variables evaluated were delay time (0.0; 1.0 and 1.8 μs) and fluence (81; 2037 and 4074 Jcm−2): both were tested in three different values. The best results obtained were with a delay time of 1.8 μs and a fluence of 4074 Jcm−2. The proposed calibration model obtained using LIBS data presented a good correlation with reference values obtained by inductively coupled plasma atomic emission spectrometry (ICP OES). The predictive capabilities, based on the standard error of validation (SEV), were 117, 530 and 77 mg kg−1 for Ca, K, and Mg, respectively. The proposed LIBS method was applied to the analysis of 90 cassava flour samples, and the results showed concentrations of Ca, K, and Mg of 352–1845, 1285–3187, and 320–1242 mg kg−1, respectively.