Application of Laser‒induced breakdown spectroscopy coupled with pulsed Laser ablation time‒of‒flight mass spectrometry for the characterization of Bentonite Clay Mineral

In this work, laser-induced breakdown spectroscopy (LIBS) coupled with pulsed laser ablation time-of-flight mass spectrometry (PLA‒TOFMS) is applied as a fast, micro-destructive, and complementary diagnostic method for the qualitative detection and quantitative measurements of the Bentonite clay mineral material. LIBS provides in situ, direct multi-element identification with no or nominal sample preparation, requiring only microgram surface ablation, whereas PLA‒TOFMS is a versatile analytical technique for elemental and molecular characterization and can provide isotopic information depending on the mass resolution and experimental conditions. The LIBS and PLA‒TOFMS analysis established that the clay sample is mainly composed of oxygen (O), silicon (Si), and aluminum (Al), with additional contributions at minor level from various elements such as iron (Fe), carbon (C), sodium (Na), magnesium (Mg), potassium (K), and calcium (Ca), suggesting a characteristic aluminosilicate clay matrix. A calibration-free laser-induced breakdown spectroscopy (CF‒LIBS) approach was used for the sample quantification measurements. The LIBS analytical limitations, including line self-absorption, matrix effects, and signal uncertainties, were addressed and minimized through normalization and cross-validation with those of the results obtained using PLA‒TOFMS. Furthermore, the Bentonite sample was also examined using the EDX and XRF techniques based on K α , K β , and L α characteristic emissions to cross-validate LIBS and PLA‒TOFMS analyses. The study suggests that the integration of LIBS with PLA‒TOFMS, EDX, and XRF provides a rapid and reliable analytical framework for the compositional analysis of Bentonite clay mineral material.