A Shimadzu GC 17-A gas chromatograph (Kyoto, Japan) was used with a Shimadzu QP-5050A mass spectrometer, in electron impact mode (70 eV). A DB-Wax column (60 m × 0.25 mm; 0.50 μm film thickness;
Agilent, Santa Clara, CA) was used to separate EC. The temperature of injector and detector interface was maintained at 220 °C. The GC oven was programmed as follows: the initial temperature was 90 °C (2 min), then it was raised to 150 °C at a rate of 10 °C min−1, then raised to 230 °C at a rate of 40 °C min−1, and held for 10 min at this temperature. Injected volume was 2.0 μL (splitless). The carrier gas was helium (5.0) at a flow rate of 1.0 mL min−1. The acquisition mode was SIM, monitoring ions m/z 62, 74 and 89. Quantification was done by comparing chromatographic results of samples in an analytical curve obtained through an check details PCI-32765 purchase EC 99% solution (1.0 mg mL−1
in 40% ethanol; New Química) diluted to obtain a concentration range of 5–5000 μg L1. Detection (LOD) and quantification (LOQ) limits of analysis were 15 and 50 μg L−1, respectively. There was no observed difference between samples collected in each reactor used for chemical analysis in each repetition (June, August, October). Consequently, the end result of all analyses conducted was expressed as the average of three samples, obtained by repetition. Fig. 1 shows the alcoholic content of samples analysed. It was possible to observe a regular pattern in alcoholic content between repetitions: up to 8 L (head) samples were approximately 65% (v/v) in second alcohol; up to 128 L (heart) this content decreased to 35% (v/v) in alcohol; in the tail (133 at 148 L) the alcoholic content fell to less than 20% when distillation was stopped. After mixing collected fractions in the “heart” the final product (cachaça) possessed an alcoholic content of nearly 44% (v/v), in accordance with Brazilian law. Table 1 shows
the results of the copper analysis in the evaluated fractions. Brazilian legislation requires that its content in cachaça should be lower than 5.0 mg L−1 and it could be observed that the heart fraction was in accordance with the legislation. As shown in the table the head fractions did not fulfil the demands of legislation, and the copper content in the tail was very close to the legislation’s limit. This result corroborates the need to separate head and tail from the heart fraction to ensure cachaça quality. Cachaça is usually distilled in copper retorts and copper contamination can take place, as is confirmed by our results. The distillation in copper apparatus is, however, necessary to guarantee good sensorial properties in the product, due to the catalytic effects for the formation of flavour compounds ( Neves et al., 2007).