A. Di Muccio

Application of solid-phase partition cartridges in the determination of fungicide residues in vegetable samples

Disposable, ready-to-use cartridges filled with a macroporous diatomaceous material are used to extract in a single step fungicide residues with dichloromethane from aqueous acetone extracts of vegetables. This procedure takes the place of some functions (such as separating funnel partition, drying over anhydrous sodium sulphate and clean-up) usually performed by separate steps in classical schemes. Fourteen fungicides (dichloran, vinclozolin, chlorthalonil, triadimefon, dichlofluanide, procymidone, hexaconazole, captan, folpet, ditalimfos, iprodione, captafol, pyrazophos and fenarimol) were determined using the described procedure with recoveries between 83 and 107% at spiking levels ranging for the different compounds from 0.04 to 0.40 mg/kg. Crops subjected to the described procedure included lettuce, strawberry, apple, yellow pepper and peach, and gave extracts containing a mass of co-extractives between 5 and 30 mg. Compared with classical schemes, the described procedure is simple, less labour intensive, allows parallel handling of several extracts and does not require preparation and maintenance of equipment. Troublesome emulsions such as those frequently observed in separating funnel partitioning do not occur.

Simplified clean-up for the determination of benzimidazolic fungicides by high-performance liquid chromatography with UV detection

Abstract A method was developed that allows the determination of benomyl, carbendazim (MBC), thiophanate methyl (TFM) as carbendazim and thiabendazole (TBZ) by HPLC with UV detection. After extraction and cyclization of TFM into MBC, the conversion of benomyl into MBC is carried out by absorbing the raw extract on a ready-to-use, disposable column of a macroporous Kieselghur-type material and percolating 0.1 M HCl through it. Benzimidazolic residues are partitioned into the acid solution whereas most of the co-extractives are retained on the column. The final clean-up is performed on a strong cation-exchange (SCX) cartridge. The determination of MBC and TBZ is carried out by HPLC-UV detection on a polymeric reversed-phase column eluted with a water-ecetonitrile (70 : 30). Recoveries of MBC and TBZ from pear, apple, orange, grape, kiwi, tomato and lettuce, spiked at levels of 0.22 and 0.88 mg/kg, were satisfactory (70%). The main features of the method include high selectivity towards MBC and TBZ, reduced consumption of reagents and solvents, reduced handling operations, lack of emulsions and the use of disposable items.

Solid-matrix partition for separation of organochlorine pesticide residues from fatty materials

A fast, single step and efficient partition between n-hexane and acetonitrile on ready-to-use, disposable cartridges of Kieselghur-type material has been developed for the separation of organochlorine (OC) pesticide residues from oils and fats. The extract is cleaned up with Florisil minocolumn chromatography, followed by a solid-matrix sulphuric acid treatment. Carry-over of lipid material through the partition step is lower comapared to conventional, separatory-funnel partition. Recovery of eighteen OC pesticides from 1.0 g olive oil was between 72% and 104% at spiking levels between 0.01 and 0.15 mg/kg for the different compounds.

Distribution of hydrocarbons in bovine tissues

Liver, heart, kidneys, muscle and adipose (perirenal and subcutaneous) tissues were collected from six animals for analysis of their hydrocarbon composition. Qualitative and quantitative determinations were carried out by gas chromatography and combined gas chromatography-mass spectrometry. Although differing in the proportions, a homologous series of n-alkanes ranging from n-C12 to n-C31 was found in all the samples examined. The isoprenoid hydrocarbons phytane and phytene (phyt-1-ene and phyt-2-ene) were also identified.

Vertical Mobility of Soil Contaminants: Preliminary Results of a Survey on the Herbicide Atrazine

Abstract Atrazine is considered a potential contaminant of water bodies, where it has been repeatedly detected. Its use in Italy is almost limited to the Northern part of the country where corn monocultures are common. Northern Italy is characterized by the presence of an area with soil quite permeable and where ground waters are often present at not very deep levels. In this area well waters, which represent the main source of drinking water, have been frequently found contaminated by atrazine. A program has been started aimed at studying the role of soil nature and local factors in the process of groundwater contamination. Two atrazine application rates were used at two sites with loamy and loamy-sandy soils. Results clearly show a different mobility of atrazine in the two soil types. Since the two sites have similar organic carbon levels, the major proportion of clay to sand and the lower pH of loamy soil may explain the lower vertical mobility of atrazine in this soil. Work is in progress to study atr...

Screening for coumatetralyl in soft drinks by solid-matrix extraction and high-performance liquid chromatography with diode-array detection.

A method was developed for the rapid determination coumatetralyl in cola- and orange-type soft drinks, which includes extraction using solid-matrix column, clean-up by silica cartridge chromatography and reversed-phase high-performance liquid chromatography with diode-array detection. The recovery of coumatetralyl from 50 ml of soft drinks was better than 80% at spiking levels down to 50 micrograms/kg (ppb).

Occurrence and distribution of n-alkanes in sucking-calf tissues

Samples of subcutaneous and perirenal fat, muscle, heart, liver, kidney, and spleen from eleven 4-month-old sucking calves were analyzed for their hydrocarbon composition. Qualitative and quantitative determinations were carried out by gas chromatography. Ranges of total hydrocarbons and odd-even hydrocarbon distribution for each tissues are reported. In general, a predominance of odd-numbered hydrocarbons in the high carbon number range was observed. As compared to adult bovines, calf tissues, with the exception of adipose tissues, show higher amounts of total hydrocarbons.

Residue Levels in Apples and Pears Field-Treated with Two Experimental Chlorothalonil Formulations

Chlorothalonil is a well-known product largely used in several countries against a broad spectrum of pathogenic fungi which affect economically important crops (I, 2, 3). Chlorothalonil has been recently considered by I.A.R.C. (4). In Italy, Chlorothalonil is included in a list of pesticides presently under revision. A deeper and updated knowledge about its toxicological and environmental properties will improve the evaluation of risks related to the use of that pesticide. In this framework t he determination of the residues in crops treated with Chlorothalonil formulations was performed. As new types of Chlorothalonil formulations become available, itis essential to check both their efficacy and their residue levels after treatment. Two different types of experimental Chlorothalonil formulations bave been tested in a field treatment carried out by the Regional Plant Protection Service (Bologna, Italy) on apple and pears cultivations. This paper presents the levels of Chlorothaloni! residues in treated apple and pear samples, harvested afte�9 several time intervals, under the experimenta! conditions described below.

Lack of in vitro oxidation of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) in the presence of laccase from Polyporus versicolor fungus

Abstract An investigation has been carried out to assess whether Polyporus versicolor laccase could catalyze in vitro transformation of 2,3,7,8-tetrachloro-dibenzo-p-dioxin (TCDD) under a number of different experimental conditions of incubation including homogeneous or heterogeneous phase, variable durations, addition of phenol, variable dissolved oxygen concentrations and TCDD/laccase ratios. No significant degradation of TCDD was detected.