Ivano Camoni

Selective, solid-matrix dispersion extraction of organophosphate pesticide residues from milk

A rapid procedure has been developed that allows a single-step, selective extraction and cleanup of organophosphate (OP) pesticide residues from milk dispersed on solid-matrix diatomaceous material filled into disposable cartridges by means of light petroleum saturated with acetonitrile and ethanol. Recovery experiments were carried out on homogenized commercial milk (3.6% fat content) spiked with ethanolic solutions of 24 OP pesticides, viz., ethoprophos, diazinon, dimethoate, chlorpyrifos-methyl, parathion-methyl, chlorpyrifos-ethyl, malathion, isofenphos, quinalphos, ethion, pyrazophos, azinphosethyl, heptenophos, omethoate, fonofos, pirimiphos-methyl, fenitrothion, parathion, chlorfenvinphos, phenthoate, methidathion, triazophos, phosalone, azinphos-methyl, at levels ranging for the different OP pesticides from 0.02 mg/kg to 1.11 mg/kg. Average recoveries of four replicates were in the range 72-109% for the different OP pesticides, with relative standard deviations (R.S.D.) from ca. 1 to 19%, while dimethoate and omethoate were not recovered. Coextracted fatty material amounted to an average of about 4.0 mg/ml of milk. The extraction procedure requires about 30 min. The main advantages are that extraction and cleanup are carried out in a single step, emulsions do not occur, several samples can be run in parallel by a single operator, reusable glassware is not needed and simple operations are required.

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.

Organochlorine Pesticide and Polychlorinated Biphenyl Residues in Human Milk from Rome (Italy) and Surroundings

Organochlorine (OC) pesticides and polychlorinated biphenyls (PCBs) in human milk have been the subject of many studies. Surveys carried out in Italy are all eight years old with the exception of the latest work. Because of recent improvements in analytical methodology, the authors believe an up-to-date study would provide additional information. Thus, this paper presents a survey of the levels of human milk contamination, in Rome and surroundings, by organochlorine pesticides and PCBs. This survey is a part of a larger monitoring program covering also geographical areas outside of Rome.

Clean-up of aqueous acetone vegetable extracts by solid-matrix partition for pyrethroid residue determination by gas chromatography—electron-capture detection

Disposable, ready-to-use cartridges filled with macroporous diatomaceous material are used to carry out a partition clean-up that, in a single step, is capable of transferring pesticide residues from aqueous acetone extracts into light petroleum-dichloromethane (75:25, v/v). This procedure takes the place of some functions (such as separatory-funnel partition, drying over anhydrous sodium sulphate and partial adsorption clean-up) usually performed by separate steps in classical schemes. Fourteen pyrethroid pesticides, including tefluthrin, tetramethrin, cyphenothrin, cyfluthrin, flucythrinate, tau-fluvalinate, deltamethrin, bioallethrin, fenpropathrin, lambda-cyhalothrin, permethrin, alpha-cypermethrin, esfenvalerate and tralomethrin were determined using the described procedure with satisfactory recoveries for most of them, at spiking levels ranging from 0.08 to 0.82 mg/kg for the different compounds. Crops subjected to the described procedure included strawberry, apple, and orange gave extracts containing a mass of co-extractives that was 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 the preparation and maintenance of equipment. Troublesome emulsions such as those frequently observed in separation funnel partitioning do not occur.

Clean-up procedure for the extraction of soil samples in the determination of 2,3,7,8-tetrachlorodibenzo-p-dioxin.

This paper describes the method which was developed in relation to analytical work connected with microbial and physico-chemical degradation experiments on 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD). Soil samples are best extracted with methanol plus methylene chloride. Microbial preparations are extracted with light petroleum after boiling with methanolic potassium hydroxide. The clean-up consists of a sulphuric acid treatment and chromatography on a multilayer column (Celite + H2SO4/silica gel) followed by alumina column chromatography. The clean-up procedure proved to be suitable for soil samples and microbial preparations even when large quantities of organic matter (hydrocarbons, oils, surfactants) were present.

Estimation of dietary intake of pesticide residues by the Italian population during 1997

In 1997 the Italian monitoring programme for pesticide residues in food comprised 7951 samples of 152 different foods for which a total of 275 pesticides were analysed. For 90 pesticides, the National Estimated Daily Intakes (NEDIs) were calculated by using the 90th percentile value and the food consumption data for the general Italian population. The calculated NEDIs were found to represent only a small portion of the respective Acceptable Daily Intake (ADI).

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).

LABORATORY INVESTIGATION FOR THE MICROBIOLOGICAL DEGRADATION OF 2,3,7,8-TETRACHLORODIBENZO-p-DIOXIN IN SOIL BY ADDITION OF ORGANIC COMPOST

ABSTRACT The persistence of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) in soil has been studied under laboratory conditions. The effect of addition to the soil of an organic compost rich in both organic matter and microbial flora has been investigated in the soil from Seveso, accidentally polluted by TCDD and in a TCDD free soil to which a known amount of TCDD was applied. In both experiments the initial concentration of TCDD was at level of 0.1 mg/Kg. The TCDD was periodically monitored over 480 days. At this time 73% to 77% of the initially present TCDD was recovered in both experiments. Data show that the addition of organic compost had no appreciable influence on the degradation of TCDD. Soil samples were extracted with methanol followed by dichloromethane and the extracts were cleaned-up by column chromatography. Determination of TCDD was carried out by GLC/ECD and confirmed by GLC/MS.

Survey of ethylenethiourea (ETU) in ethylenebis(dithiocarbamate) (EBDC) fungicides

Ethylenethiourea (ETU) has been recognized as a compound with adverse toxicological properties. It may occur in ethylenebis(dithiocarbamate) (EBDC) fungicides as a by-product and/or a degradation product. Restrictions have been issued by the Italian Health Authority to keep the level of ETU in EBDC formulations under 0.5% (on an EBDC technical product basis). A survey was carried out on 85 samples of commercial formulations from the Italian market to verify compliance with the above limitation. ETU was extracted by methanol and determined by gas chromatography with a flame ionization detector. Three of the 85 samples (3.5%) exceeded the limit of 0.5% established by the Italian legislation for ETU.

Exposure to agricultural treatment residues: Some simple statistical considerations based on monitoring data for ethoxyquin on apples

The data examined here concern ethoxyquin levels, mainly measured in apple samples from the retail market. In this study about three hundred measurements, carried out on apples in Northern-Central Italy and recently published, are examined, with the purpose of defining the main characteristics of value statistical distribution and variability and to optimize sampling criteria. The analysis did not indicate the presence of significantly high levels or consequently significantly high risks; nevertheless, it pointed out some important aspects in data collection and evaluation. First, it appeared that the statistical distribution of data is typically nonsymmetrical, non-Gaussian, and characterized by a tail extending toward the high values. The logarithmic transformation of data appeared useful in order to obtain a Gaussian distribution. As a rule, the data variability appeared to be high. The frequency and distribution of values above the analytical threshold resulted in significant change, both in time and in space. The percentage of positive values (above the analytical threshold) appeared to vary up to a factor of 2-3, as analogously did their geometric mean.(ABSTRACT TRUNCATED AT 250 WORDS)