Trapping of polycyclic aromatic hydrocarbons in vehicle exhaust using an in-tube extraction device for analysis by gas chromatography-barrier ionization discharge detection.

This work presents a methodology for polycyclic aromatic hydrocarbons (PAHs) trapping from vehicular emissions using an in-tube extraction device (IT-FEx). Trapping selectivity studies were conducted, evaluating the interaction profile between the aromatic compounds and the polymeric phase (composed of polydimethylsiloxane and internal to the IT-FEx devices), as in an aqueous equilibrium system (25 min of sampling), and as in gaseous dynamic phase (30 s of sampling), regarding a qualitative evaluation. The adsorption profiles were similar, with greater affinity for medium-sized PAHs (four aromatic rings) than for the smaller (one to three rings) and larger (five to six rings).

Optimization and validation of a method for the determination of the refractive index of milk serum based on the reaction between milk and copper(II) sulfate to detect milk dilutions.

We report the use of a method to determine the refractive index of copper(II) serum (RICS) in milk as a tool to detect the fraudulent addition of water. This practice is highly profitable, unlawful, and difficult to deter. The method was optimized and validated and is simple, fast and robust.

Arsenic mobility in sediments from Paracatu River Basin, MG, Brazil.

Paracatu River Basin, Minas Gerais, Brazil, houses long areas of irrigated agriculture and gold-, lead-, and zinc-mining activities. This region has a prevalence of sulfide minerals and a natural occurrence of high levels of arsenopyrite. In this work, surface water, groundwater, sediments and local vegetable samples were collected in October 2010 and November 2011 and were analyzed to evaluate arsenic (As) distribution, mobility, and transport in these environmental compartments.