Atomic absorption spectrometric (AAS) measurements
Flame atomic absorption spectrometric determination of manganese was performed based on a previous method described in the literature [23]. A GBC 932AA (Melbourne, Australia) flame atomic spectrophotometer (FAAS) equipped with the respective hollow cathode lamp was employed for the determination of Mn in bioethanol samples. The flow rates of air and acetylene were 3.5 and 1.5 L min-1. Other conditions were wavelength (297.5 nm), slit width (0.2 nm), lamp current (5.0 mA), and height of observation (15 mm). An analytical curve between 0.1 and 2.0 mg L-1 was obtained with a detection limit of 10 μg L-1 of Mn (II).