Arylnitroalkenes as scavengers of macrophage-generated oxidants.

Oxygen and nitrogen derived molecules mediated oxidation and nitration have been involved in several pathological conditions. Conversely, nitric oxide and hydrogen peroxide are important signalization intermediates, whose concentrations are tightly regulated by specialized enzyme repertoires and should remain undisturbed by the addition of exogenous antioxidant molecules, as already demonstrated by intervention studies with antioxidant vitamins. Our goal was to develop specific antioxidants able to scavenge peroxynitrite anion, as well the radicals derived from the homolytic decomposition of its conjugated acid, nitrogen dioxide and hydroxyl radical.

Simultaneous determination of CFC-11, CFC-12 and CFC-113 in seawater samples using a purge and trap gas-chromatographic system.

We have optimized the analytical parameters of a homemade instrument for the simultaneous measurement of the chlorofluorocarbons CCl(2)F(2) (CFC-12), CCl(3)F (CFC-11) and C(2)Cl(3)F(3) (CFC-113) in seawater. Seawater samples are flame sealed into 60 ml glass ampoules avoiding any contact with the atmosphere and stored in cold, dark condition until analysis. In the laboratory, after cracking the ampoule in an enclosed chamber filled with ultra-pure nitrogen, the seawater sample is transferred to a stripping chamber, where ultra-pure nitrogen is used to purge the dissolved CFCs from the seawater.

Inductively coupled plasma optical emission spectrometric determination of trace elements in sediments after sequential selective extraction: effects of reagents and major elements on the analytical signal.

The interfering effects due to the reagents and matrix elements associated with a four step sequential extraction procedure on ICPOES determination of trace elements were investigated in a systematic way. The emission lines were selected in order to include the most interesting elements for environmental studies (Zn, Pb, Ni, Cr, V and Cu) and the concentrations ranged according with the values occurring in the real samples. In order to distinguish between chemical and physical interfering effects, the Mg 280.

Trace metals speciation in coastal particulate matter for marine environmental studies in Antarctica.

Solid speciation of some trace metals (Pb, Cd, Fe, Mn, Cu) having environmental relevance was studied in coastal particulate sampled during the Austral Spring 2000/2001. A nearshore station situated in the Gerlache Inlet of Terra Nova Bay (Ross Sea, Antarctica) was sampled from November to February. Samples were collected using the in situ filtration system FIS500, equipped with polycarbonate membrane filters having different pore sizes (10 microm, 2 microm and 0.

Multivariate optimization of an axially-viewed inductively coupled plasma multichannel-based emission spectrometer for the analysis of environmental samples.

An experimental design procedure was applied to optimize the operating conditions of an axially-viewed inductively coupled plasma emission spectrometer instruments equipped with echelle optics with cross dispersion and charge transfer device. The multivariate effect of carrier gas flow rate and r.f.