Application of the experimental design in the optimization of a procedure for antimony (Sb) remediation in environmental samples employing mesoporous array.

This study describes the sustainable and eco-friendly synthesis of the silica-based mesoporous structure from the use of alternative amorphous silica extracted from rice husk ash (RHA). The mesoporous material was called MCM-48 (RHA), and its application as adsorbent to the antimony (Sb) remediation in environmental samples was tested. The adsorbent was prepared by an efficient and sustainable hydrothermal method, which exhibited an amorphous framework with type IV isotherms and type H1 hysteresis, and surface area, total pore volume, and pore diameter values of 820.

Multiway Calibration Strategies in Laser-Induced Breakdown Spectroscopy: A Proposal.

In this study, a new approach to laser-induced breakdown spectroscopy (LIBS) data modeling using multiway algorithms was investigated. Two case studies, parallel factor analysis (PARAFAC) and unfolded-partial least-squares with residual bilinearization (U-PLS/RBL) algorithms were used in (1) the determination of Al, Cu, and Fe in samples of reference material of printed circuit board (PCB) from electronic waste and (2) the determination of Ca, K, and Mg in samples of a human mineral supplement, where depth was used to obtain multidimensional data in the first case and delay-time in the second. In addition, univariate calibration was applied and compared with the multiway approaches.

Forensic analysis of hand-written documents using laser-induced breakdown spectroscopy (LIBS) and chemometrics.

With the use of Laser Induced Breakdown Spectroscopy (LIBS), fast and semi non-destructive elemental analysis of ball-point pen writings has been performed directly from paper surfaces, aiming to obtain maximum differentiation between pens with a minimum number of pulses. The instrumental variables, the delay time, laser pulse energy and number of pulses per point, were evaluated through factorial design and optimum values were obtained through a quadratic regression model. Several atomic emission lines were tested as fingerprints in order to improve the differentiation between the tested inks and the range of 212-228 and 324-328 nm, which corresponds to Cu emission, demonstrated to be the best alternative as a discriminatory factor for two pens of the same color.