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F Vergori

Publications and source records attributed to F Vergori.

6 recordsLinked to original sources
PubMed1997

Selective extraction of pyrethroid pesticide residues from milk by solid-matrix dispersion.

A rapid procedure has been developed that allows a single-step, selective extraction and clean-up of pyrethroid (PYR) pesticide residues from milk dispersed on solid-matrix diatomaceous material filled into disposable cartridges and eluted by means of light petroleum saturated with acetonitrile and ethanol. The extract was cleaned up by high-performance size-exclusion chromatography. Determinations were carried out by gas chromatography with electron-capture detection. Recovery experiments were carried out on homogenized commercial milk (3.6% fat content) that was spiked with solutions of 14 PYR pesticides, viz., tefluthrin, tetramethrin, cyphenothrin, cyfluthrin, flucythrinate, fluvalinate, deltamethrin, bioallethrin, fenpropathrin, lambda-cyhalothrin, permethrin, alpha-cypermethrin, esfenvalerate and tralomethrin, at levels ranging from 0.04 to 0.41 mg/kg for the different PYR pesticides. Average recoveries were in the range 60-119% for the different PYR pesticides, with relative standard deviations from ca. 2.5 to 14.4%. Coextracted fatty material amounted to an average of ca. 5 mg/ml of milk. The sole extraction step requires about 30 min. The main advantages of the procedure are that extraction of PYR pesticides (with a minimum carry over of fat) is performed 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.

Animals↗
PubMed1997

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.

Acetone↗
PubMed1991

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).

4-Hydroxycoumarins↗
PubMed1990

Single-step multi-cartridge clean-up for organophosphate pesticide residue determination in vegetable oil extracts by gas chromatography.

A multi-cartridge system has been developed which, in a single step, performs the extraction and clean-up of organophosphate (OP) pesticide residues from oils and fatty extracts. A solution in hexane containing up to 1.8 g of lipidic material is loaded on to an Extrelut-3 column to which a silica-gel cartridge and a C18 silica cartridge have been connected in series. The OP pesticide residues are eluted with 15 ml of acetonitrile. Carry-over of fatty material is in the range 2-5 mg per 1.8 g of different oils, which makes the final solution amenable to capillary gas chromatography. Recoveries of 23 OP pesticides were in the range 82-111%. The whole procedure takes ca. 20 min and compares favourably with current procedures.

Chromatography, Gas↗
PubMed1988

Selective, on-column extraction of organochlorine pesticide residues from milk.

A rapid procedure has been developed that allows a single-step, selective extraction of organochlorine pesticide (OCP) residues from milk on solid-matrix disposable columns by means of acetonitrile-saturated light petroleum. Recovery experiments were carried out on homogenized milk (3.6% fat content) spiked with an ethanolic solution of nine OCPs, viz., HCB, alpha-HCH, beta-HCH, gamma-HCH, heptachlor epoxide, dieldrin, endrin, p,p'-DDE and p,p'-DDT, at levels ranging from 0.002 mg/kg for alpha-HCH to 0.008 mg/kg for p,p'-DDT. Average recoveries of four replicates were 77% for HCB and almost quantitative (94-113%) for the other pesticides, with relative standard deviations from 2.9 to 7.3%. Coextracted fatty material amounted to about 5 mg/ml of milk before the clean-up. The described procedure also showed a satisfactory performance with milk powder. The extraction procedure requires about 60 min. The main advantages are that 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.

Animals↗