Development of Method Based on Dispersive Liquid-Liquid Microextraction Air-Assisted for Multi-Element Determination of Cadmium and Manganese in Sugarcane Spirit (Brazilian cachaça) by FAAS

In this work, a new method was developed for multi-element determination of Cd and Mn in samples of sugarcane spirit (cachaca) by FAAS using the air-assisted dispersive liquid-liquid microextraction (AA-DLLME). After univariate and multivariate optimizations (mixture design), the experimental conditions were as follows: 5.2 mL of sample at pH 8.5, 0.7 mL 10% (w/v) NaCl solution, 120 μL of trichlorethylene (extraction solvent) containing 1-(2-pyridylazo)-2-naphthol (PAN) at 0.05% (w/v) as chelating agent, six cycles of stirring the mixture with a glass syringe, and 3 min of centrifugation. In these conditions, the calibration curve obtained for Cd was Abs = 0.0158CCd + 0.0333, with R2 0.9951 and for Mn was Abs = 0.0011CMn + 0.0142 and R2 0.9911. The limits of detection, enrichment factor, and consumption index were, respectively, 0.51 μg L−1, 79 and 0.07 mL for Cd, and 1.64 μg L−1, 18, and 0.28 mL for Mn. Precision was evaluated at concentrations of 5 and 10 μg L−1, and RSD% (N = 10) was 0.97% and 6.6% for Cd and 2.8% and 4.5% for Mn, respectively. Addition and recovery tests in samples of Brazilian cachaca were performed to evaluate the accuracy, and recoveries were 87% to 120%, with concentrations found between 1.20 and 3.05 μg L−1 for Cd and between 6.98 and 14.4 μg L−1 for Mn. The developed method proved to be sensitive, efficient, simple, fast, and having low reagent consumption, and of applicability not previously reported in the literature.