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La disinfestazione dei prodotti agricoli essiccati (frutta secca, cereali, thé, caffè, camomilla, tabacco ecc.), mediante fumigazione con fosfina, rappresenta una pratica ampiamente adoperata. Tale processo è realizzato mediante l’utilizzo di formulati a base di Fosfuro di Magnesio o Fosfuro di Alluminio, in forma di pelletts. Questi formulati, nelle normali condizioni di uso, reagiscono con l’umidità dell’aria, generando fosfina allo stato gassoso, dotata di una elevata azione disinfestante. I pelletts, durante l’esposizione all'aria, sfioriscono generando un sottile residuo polverulento che ostacolando la diffusione dell'umidità atmosferica, rallenta la reazione per la produzione di fosfina. Per questo motivo, dopo il normale periodo di fumigazione di cinque giorni, il residuo polverulento contiene ancora 1-2 % di principio attivo; pertanto il residuo, secondo la normativa vigente, è da considerarsi, tossico e nocivo. Da quanto esposto risulta evidente che l' esaurimento totale del principio attivo in un tempo ragionevole si può ottenere rimescolando continuamente il residuo polverulento. In aggiunta la velocità della produzione di fosfina dipende dalla quantità di acqua presente e dalla temperatura. In sintesi i parametri che consentono di esaurire completamente il principio attivo e di ridurre i tempi di reazione da cinque giorni a due giorni sono : rimescolamento, aggiunta di acqua al principio attivo e suo riscaldamento durante la fase di reazione. E' stato progettato e realizzato un dispositivo che prevede l' impiego dei parametri sopra riportati. Il dispositivo, di facile uso, consente di esaurire in maniera completa il principio attivo e di ridurre il tempo di produzione di fosfina da 5 giorni a 2 giorni. In aggiunta, il dispositivo risulta particolarmente conveniente nelle fumigazioni in periodi freddi.

Citrus liqueurs are typical alcoholic beverages produced in the italian Region Campania. The determination of teh alcohol percentage in the alcoholic extract of citrus peel and of obtained liqueurs by density measurements using the official methods does not lead in general to accurate results. This paper proposes a simple procedure that leads to accurate results using the official methods by measuring the density on a distillate of both the alcoholic extract of citrus peel and of the derived citrus liqyeurs previously clarified by filtration to separate the essential oils.

The work describes an analytical procedure that allows the quantitative determination by gas-chromatography of the concentration of the components of the essentil oils in the extracts and in the lemon liquors. This would allow to standardize the preparation of the liquors by knowing the concentration of the essential oils responsible for the aroma in the lemon liquor. The results are highly reproducible and analitically verified.

In questo lavoro è stata messa a punto una procedura di smaltimento della polvere di tabacco nel terreno come ammendante. La concentrazione della nicotina è stata monitorata nel tempo per studiarne il tempo di decacimento.

The interference of triglycerides in the analysis of sterols and their esters in fats can be eliminated by transesterification of the sample dissolved in n-hexane with a solution of sodium hydroxide 2 mol/L. Since the analytes are distributed equally in n-hexane and in methanol, better results can be obtained by accurate measurements of the volumes, and processing the standards as the samples. Triglycerides and steryl esters are transesterified quantitatively by a solution of sodium hydroxide 2 mol/L using diethyl ether as solvent. At 40°C, ten minutes are sufficient to complete the reaction. The sterols are determined in fats using a mass spectrometer detector, at concentrations as low as 5 mg/Kg. Using FID, it was possible to analyze sterols present in concentrations higher than 100 mg/Kg.

In this paper we present an innovative device designed and constructed to improve the fumigation process for stored foodstuffs with the use of phosphine gas in sealed chambers. The device allowed a considerable reduction in phosphine production time (from about 5 to 7 days for traditional systems to 2 days for the equipment considered), maintaining the system below the inflammability threshold, and at the same time achieving the total exhaustion of aluminum (or magnesium) phosphide so as to avoid toxic residues at the end of the process. With the standard device currently available on the market, after the normal 5–7 day fumigating period, the powder residue contains as much as 1–2% (w/w) of phosphide. Thus the residues, according to current legislation, have to be considered toxic and harmful. To overcome this disadvantage, appropriate modifications were made to the cylindrical tray used for the fumigation process: a nebulizer was installed, which has the function of increasing the moisture of the air spreading around the phosphide pellets and allowing a more rapid reaction with phosphide. Moreover, the cylindrical tray was also heated by means of an electrical resistance, and temperature was checked by a thermostat, so as to always obtain the same efficiency, independently of outside temperature, for both hot and cold periods, since reaction speed depends on the system temperature considered. In addition, a control device for air saturation allows condensation processes to be avoided. Using the modified cylindrical tray we performed tests to determine the best values of humidity and temperature for the process concerned, avoiding phosphine concentrations that might result in a fire hazard, and the remixing of phosphide pellets inside the cylindrical tray. Our experimental data allowed us to obtain a mathematical model used to gain an insight into the process in question.

This article gives a description of the setup in a laboratory of a pilot system to reduce phosphine following the smoking process of foodstuffs. At present, this fumigant is released into the atmosphere and causes serious damage to the environment due to its transformation into aggressive compounds. However, phosphine may prove a good alternative to methyl bromide, which will legally be used as a fumigant until the year 2002, provided it is made inert after the smoking process and transformed into nontoxic and easily disposable substances. Oxidant solutions containing potassium permanganate or potassium bichromate in suitable concentrations proved moderately effective in reducing phosphine. The addition of traces of silver nitrate as a catalyst to the oxidant solutions increased the efficiency in reducing the fumigant, although not completely. Thus it was necessary to use a recycling system to decontaminate air from phosphine, as such an apparatus ensures the complete reduction of phosphine. The mathematical function describing how the concentration of phosphine varies in the smoking chamber also makes it possible to estimate the time necessary to reduce a phosphine concentration from any initial value to a fixed final value.