Alfredo Lo Balbo

Liquid chromatography/electrochemical detection of phenols at a Poly[Ni-(Protoporphyrin IX)] chemically modified electrode

Abstract Poly(Ni-(Protoporphyrin IX)) modified glassy carbon electrodes showed an enhanced response for the oxidation of different phenolic compounds ( p -chlorophenol, p -nitrophenol and phenol). It can also suppress the oxidation of more polar substances such as ascorbic acid and potassium hexacyanoferrate(II). These substantial improvements in the sensitivity and selectivity of liquid chromatography with electrochemical detector (LCEC) for the determination of phenols can be obtained by using electrodes thus coated. The method gives a linear range up to 1.3 μg ml −1 and a detection limit of 13 ng ml −1 for p -nitrophenol. The dynamic behaviour of the detector is evaluated with respect to the solute concentration and flow rate. The surface coating is highly stable under the hydrodynamic conditions prevailing in the flow cell.

Linear Scan Stripping Voltammetry at Glassy-Carbon Based Thin Mercury Film Electrodes for Determination of Trace Aluminium in Dialysis Fluids.

Abstract Linear scan cathodic stripping voltammetry at glassy-carbon based thin mercury film electrodes is a simple and inexpensive alternative for determining trace Al(III) in dialysis fluids. The efficiency of a variety of ligands (SVRS, Cupferron and Blue Black Eriochrome R) was evaluated comparing their voltamperometric response by application of a linear scan mode, after preconcentration into the mercury film electrode as Al(III) complexes. The best results were obtained when Cupferron was used as ligand, since its stripping current compares favourably in terms of sensitivity and resolution. The sharply defined cathodic peak at -1.3 V, corresponding to the reduction of the interfacial accumulated complex, could be used for quantitation. The response is linear up to 50 μg/l; correlation coefficient, 0.995. The relative standard deviation (at 20 μg/l level) is 3.5%, a detection limit of 0.5μg/l was estimated from the signal to noise characteristics of the response for 5 μg/l, which compares favourably ...

Small-scale studies towards a rational use of bioaugmentation in an Antarctic hydrocarbon-contaminated soil

Abstract Bioaugmentation is a controversial strategy. In this work, the effect of the inoculum size and the absence of natural microflora on the efficiency of hydrocarbon removal were studied. Two levels of inoculum (106 and 109 CFU g-1) were applied to soil microcosms containing sterile (S6 and S9) and non-sterile (NS6 and NS9) oil contaminated Antarctic soil. Community controls (CC) and biostimulated autochthonous microflora (BAM) were also included. Total heterotrophic aerobic (THAB) and hydrocarbon degrading (HDB) bacteria as well as total petroleum hydrocarbons (TPH) were analysed. At day 0, THAB and HDB counts (CFU g-1) showed no differences among CC, BAM and NS6 but significantly higher values were observed in NS9 and S9. At day 60, three different levels of HDB were observed. The lower level was represented by CC (106 CFU g-1), a second group (5 x 107 CFU g-1) was represented by BAM, NS6, NS9 and S6, and the third level was constituted by S9 (1 x 109 CFU g-1). TPH values at day 60 decreased significantly in all systems excluding the controls. NS6, NS9, S6 and S9 were not different from those corresponding to BAM. Results suggest that the bioaugmentation of a chronically diesel fuel-contaminated Antarctic soil is unlikely to be profitable or beneficial.

Freon: Accidental ingestion and gastric perforation

Introduction. Freons generally have a low order of toxicity, but exposure to relatively high concentrations (>100 ppm) may produce adverse effects on health. Currently, intoxication reports are unintentional inhalation of CFCs. We report an unintentional ingestion of a mixture of CFCs and the results of a rat study. Case Report. A 43-year-old man was admitted to the Emergency Department with a chief complaint of acute abdominal pain that developed minutes after he ingested a clear liquid in a water glass, which contained a mixture of Freon and water. Subsequent surgical evaluation revealed perforation of the stomach and necrosis of the stomach wall. He developed a transient rise in his hepatic transaminases, which resolved spontaneously, and fully recovered from his surgery. Methods. A murine model of the injury was created to evaluate threshold concentration and effect of time on injury grade. Results. Injury grade increased with delay to histologic analysis from 8 to 24 hours after exposure to Freon. Increasing amounts of Freon also increased the lesion grade score. Conclusions. Patients ingesting Freon need to be closely evaluated for risk of gastric damage and perforation.