Francesco Pantani

Determination of carbonyl compounds in water by derivatization-solid-phase microextraction and gas chromatographic analysis

The solid-phase microextraction (SPME) technique was evaluated for the determination of 23 carbonyl compounds in water. The carbonyl compounds in water were derivatized with omicron-(2,3,4,5,6-pentafluorobenzyl)-hydroxylamine hydrochloride (PFBHA), extracted with SPME from liquid or headspace and analyzed by GC with electron capture detection (GC-ECD). The effects of agitation techniques and the addition of salt (NaCl) on extraction, the absorption-time and absorption-concentration profiles were examined. The precision of the SPME technique for the determination of carbonyl compounds was evaluated with spiked bidistilled water, ozonated drinking water, and rain water. The relative standard deviations obtained from different spiked water matrix were similar, and in the range of 5.7-21.1%. The precision can be further improved by using an internal standard. With 4 ml of water sample, the limits of detection for most of the tested carbonyl compounds using liquid or headspace SPME-GC-ECD were similar and in the range of 0.006-0.2 micrograms/l, except for glyoxal and methylglyoxal, which showed low sensitivity when using headspace SPME. In the analysis of an ozonated drinking water sample, the SPME techniques gave comparable results to those of the conventional liquid-liquid extraction method.

Direct acetylation followed by solid-phase disk extraction and GC-ITDMS for the determination of trace phenols in water

SummaryA rapid, accurate and sensitive method is described for the analysis of phenolic compounds, including phenol, alkylphenols, halogenated phenols and nitrophenols in tap, ground and river water samples. The method consists in direct acetylation of the aqueous phenols with acetic anhydride, extraction of the phenol acetates with a C18 disk and analysis by gas chromatography with an ion-trap detector mass spectrometer. Using this method, the sample preparation time was approximately 1.5 h for six 1-L water samples, and recoveries for most of the phenolic compounds studied were more than 80% at concentration levels of 0.1 and 1.0μg L−1. The detection limits were in the range 2 to 15 ng L−1 for phenol, alkylphenols and halogenated phenols, and 25 to 50 ng L−1 for nitrophenols.

Chemical characterization of cloud episodes at a ridge site in Tuscan Appennines, Italy

Cloudwater samples were collected from November 1992 to March 1995 in Vallombrosa, a mountain site of the Tuscan Apennines (central Italy). Chemical analyses show that all examined inorganic ions contributed significantly to the total ionic content (TIC). The ratio SO42−/NO4− ranged from 0.92 to 3.46 and was >1 for 86% of samples. There is a wide range in the chemical composition of the cloudwater. The total ionic content ranged from 640 to 7476 μeq l−1 and pH from 3.17 to 6.22. The liquid water content (LWC) ranged from 0.06 to 0.94 g m−3 and electrical conductivity from 47 to 485 μΩ−1. The total ionic content decreases while the liquid water content increases. Also analyzed were soluble trace metals (Fe, Pb, Cu, Mn, Cd, Al), synthetic anionic surfactants and the methanesulphonic acid. Chemical analyses evidenced in some cases a high concentration of organic matter. The meteorological analysis for a few samples of individual passages was carried out for the possibility of establishing a correspondence between meteorological events and chemical composition. The sources (marine, crustal and anthropogenic) of chemical components were deduced.

Spectrophotometric determination of noble metals with tin(II) in bromide solutions

Abstract In presence of tin(II) bromide, noble metals give coloured products which are suitable for spcctrophotometric determinations. The colours are red (platinum), yellow-orange (rhodium), yellow-brown (palladium), yellow (iridium) and violet (gold) They are extracted, except for gold, with isoamyl alcohol Platinum, rhodium and palladium can be separated from irdium, and rhodium and platinum from palladium. Rhodium and platinum can be determined simultaneously.

The polarographic behaviour of rhodium(III) chlorocomplexes

Abstract It has been experimentally proved, by coulombometric measurements, that Rhodium(III) chlorocomplexes are reduced to metal at dropping mercury electrode, and we have given evidence of the reversibility of reduction process. Further, it has been studied the variation of the half wave potential as a function of chloroions activity in acid solution. The formation constants of complexed ions: RhCl+2RhCl2+RhCl3RhCl4−RhCl5−2RhCl6−3 have been computed and the following values derived: K 1 = 2.8 · 10 2 , K 1 = 3.5 · 10 4 , K 3 = 8.3 · 10 3 K 4 = 1.2 · 10 7 , K 5 = 5.6 · 10 4 , K 3 = 2.7 · 10 8

Multi-residue pesticide analysis in soil by solid-phase disk extraction and gas chromatography/ion-trap mass spectrometry

Abstract A rapid and reproducible multi-residue analysis was developed for the simultaneous determination of 46 pesticides belonging to triazines. organophosphorus and organochlorine compounds, carbamates, anilides. anilines, and amides in various soil samples. Soil samples including its natural water contents were extracted with a mixture of methanol/water (3/1. v/v). The aqueous methanol extracts were directly transferred to an extraction reservoir containing 1 L of reagent water and subjected to clean-up and enrichment by an SPE membrane workstation on Empore C18 disks. The analytes were eluated, concentrated and analyzed without additional treatment by gas chromaiography/ion-trap mass spectrometry (GC-ITDMS). Recoveries of the analytes using this procedure ranged from 65 to 102% measured at 20–200 μg/kg spiked levels for 41 pesticides tested. With 10 g of soil sample, the detection limits were between 0.5 and 25 μg/kg. The disk SPE procedure was compared to the soxhlet extraction, and comparable recov...

Residual heavy metal (Cu and Cd) removal byIris Pseudacorus

The uptake of Cu and Cd by the roots ofIris pseudacorus and its transport to rhizome and leaves were examined using solutions containing 0.5 and 5.0 mg L−1 of Cu and Cd. Heavy metal accumulation was measured while replacing the metal absorbed by the plants with daily introduction to restore the initial concentrations. The heavy metal accumulation by Iris p. was 1.01 g Cu and 0.69 g Cd kg−1 of fresh plant at the end of the tests for the solutions of 5.0 mg L−1 metal concentration, respectively.

Detergents as a condition of pollution from coastal marine aerosol

Abstract Experimental evidence of damage of a Pinus pinea foliage by detergent surfactants in aerosol from marine water solutions is shown. Typical natural non-detergent surfactants from the coastal marine environment, such as humic acids, do not cause per se damage although they could become a vehicle of polluting agents in marine aerosols. Taking into account that the damage mechanism due to the detergents can be generalized to all type of coastal vegetation, this damage is suggested in a first instance as an indication of marine pollution.

Elemental leaching from quercus ilex L. in response to simulated acidic fog

Quercus ilex L. seedlings were intermittently exposed to simulated acidic and non-acidic fogs in 6-hr events for 16 times. After a 1-mo break, treatments were carried out again for a 5 day period. Strong acidity neutralization, weak acidity release and cation leaching from foliage and stem were determined. Leaching of Al, Cu, Mn, Fe, Cd, Pb, Ca, Mg, and K increased in response to acid treatment. This effect was less marked for Na. A positive correlation between H− uptake and cation leaching was found. Cationic release and neutralization of strong acidity increased after breaks in acid treatment, but this faculty and the amount of leached cations and neutralized acidity decreased with time. The stem showed a higher cation loss and higher buffer capacity than the leaves.

A POLAROGRAPHIC AND SPECTROPHOTOMETRIC INVESTIGATION OF RHODIUM(III) BROMOCOMPLEXES

In bromide solutions and in the presence of 0.03% gelatin, Rh/sup 3+/ yields well-developed polarographic waves. The process is a practically reversible three-electron reduction. Several bromocomplexes appear to be in solution at the same time when the pH is lower than 3. Two maxima are observed in the absorption spectrum. Stabillty constaints of the complexed forms were computed and resolution of the spectra was achieved. The results were confirmed by electrophoresis and anion-exchange resins. (auth)