General characteristics of the brands, including the distillation method, were obtained from local inspecting authorities and from label information. All brands of pot still cachaças were single-distilled. Detailed information on distillation was collected during visits to five pot still distilleries,
which were selected on the basis of their low or high levels of EC and interest in participating in the project. Ethyl carbamate (99.0%), for calibration, and propyl carbamate (98.0%), used as an internal standard, were purchased from Chem Service (West Chester, USA) and Aldrich (Milwaukee, USA), respectively. The analytical solutions were dissolved in LC grade ethanol (Merck, Darmstadt, Germany) at 40% (v/v). An AAS Tritisol® copper standard (Merck, Darmstadt, Germany) was employed to prepare the analytical Sunitinib cell line curves in the determination of copper. Distilled water, subsequently passed through a Milli-Q system, was used to prepare the samples. Preparation of calibration curves MAPK Inhibitor Library and EC analysis by GC–MS were carried out as described by Nóbrega et al. (2009). The limits of detection (LOD) and quantitation (LOQ) were 10 and 40 μg/l of EC, respectively. The alcoholic strengths (% volume
at 20 °C) of the spirits were determined according to Nóbrega et al. (2009). The copper content was determined by flame atomic absorption spectrometry (Perkin–Elmer model Analyst 200, Germany), as described by OIV (1994). A sample (50 ml) was placed in an open 100 ml beaker and then evaporated under controlled heating (∼95 °C) until 10 ml of the sample volume remained. After cooling at room temperature (∼20 °C), the sample was transferred to a 50 ml volumetric Vasopressin Receptor flask, made to volume with ultrapure water, and then analysed. The calibration curves were constructed by using an external standard method. Table 1 shows the EC concentrations (in increasing order), alcoholic strength, and copper concentrations of 13 pot still and 20 column still cachaças brands produced in Pernambuco State. With respect to copper, an average of 2.2 mg/l was found, with three brands exceeding the limit established by MAPA (5 mg/l;
DOU, 2005) for this contaminant (Table 1). Copper levels were included in this research as result of unexpected data that emerged on profiling pot still distilleries in Pernambuco (see Section 3.2), particularly the use of different construction materials (copper and stainless steel) in distillation apparatus. Taking into account that these differences could have an impact on copper levels, and possibly on EC, we decided to investigate the metal in all the samples (Table 1). It is worth recalling that all profiled distilleries in our previous study (Nóbrega et al., 2009) used pot stills made entirely of copper. Copper has been shown to play an important catalytic role in cyanide conversion into EC in cachaça (Aresta et al., 2001 and Bruno et al.