Aflatoxins levels in dried fruits and nuts from Rabat-Salé area, Morocco

Abstract The occurrence of aflatoxins (AFs) in dried fruits and nuts available in Rabat-Sale area (Morocco) was surveyed in this study. One hundred samples of dried fruits and nuts, purchased from retail shops and local markets from January to October 2006, were analyzed for AFs content by immunoaffinity (IAC) clean-up with liquid chromatography and fluorescence detection. Results showed that the incidences of total aflatoxins (AFT) and aflatoxin B1 (AFB1) in peanut, dried raisins, dried figs, walnut, and pistachio were 5%, 20%, 30%, 30% and 45% and 5%, 20%, 5%, 30% and 45%, respectively. The highest contamination levels of AFB1 were found in one walnut sample (2500 μg/kg) and one pistachio…

Determination of aminoglycoside and macrolide antibiotics in meat by pressurized liquid extraction and LC-ESI-MS

A simple method for the simultaneous determination of dihydrostreptomycin, spectinomycin, spiramycin, streptomycin, tilmicosin, and tylosin in meat has been developed using pressurized liquid extraction and LC-triple quadrupole MS (LC-ESI-MS/MS). The pressurized liquid extraction operational parameters were optimized and no protein precipitating and fat removing steps were required. A gradient HPLC separation was developed with ion-pair mobile phases consisting of aqueous 1 mM heptafluorobutyric acid water and methanol. Protonated molecules were used as precursor ions for CID. Data acquisition under MS/MS was achieved by applying multiple reaction monitoring of three fragment ion transition…

SOLID-PHASE EXTRACTION OF PESTICIDES FROM WATER SAMPLES

Incidence of ochratoxin A in rice and dried fruits from Rabat and Salé area, Morocco.

One hundred samples of dried fruits (20 dried raisins, 20 walnuts, 20 peanuts, 20 dried figs and 20 pistachios) and 20 samples of rice purchased from retail shops in the Rabat and Salé area in Morocco were analysed for ochratoxin A (OTA) by immunoaffinity clean-up (IAC) and liquid chromatography (LC) with fluorescence detection. The limit of quantification (LOQ) (S/N = 10:1) of OTA was 0.02 ng g(-1) in rice, 0.03 ng g(-1) in pistachio, peanut and walnut, and 0.03 ng g(-1) in dried raisins and dried figs. The incidences of occurrence of OTA in dried raisins, walnuts, peanuts, dried figs and rice were 30, 35, 25, 65 and 90%, respectively. Analytical results showed that pistachio samples conta…

Analysis of Polychlorinated Biphenyls in Aqueous Samples Using C18 Glass Column Extraction

Abstract A method for polychlorinated biphenyl (PCB) trace extraction from contaminated water at the part-pertrillion levels is described. This procedure involves quantitative adsorption of PCBs on Cis glass microcolumns. PCBs are retained on the surface and subsequently eluted with n-hexane (5 mL) before gas chromatography. Recovery of water fortified with PCBs was 83.6-108.5%. Compared to liquid-liquid extraction methods, the Cis glass microcolumns give comparable results, lessen solvent costs, and are less time-consuming.

Monitoring Alternaria mycotoxins and pesticide residues in tomato by dispersive liquid–liquid microextraction coupled to gas chromatography–tandem mass spectrometry

BEHAVIOUR OF GRAPHITIZED CARBON BLACK IN THE EXTRACTION OF POLAR NON-IONIC NITROGEN-CONTAINING PESTICIDES. A CHECKING OF HYPOTHESES

Graphitized Carbon Black (GCB) extractive cartridges are evaluated for on-line coupling with a C8 analytical column to determine eleven carbamates and one carboximide pesticide from spiked deionized water at the 1.2 μg/L level. Several experiments were carried out to ascertain whether GCB saturation, pesticide degradation on the surface, existence of by-pass channels, mobility among the bulk cartridge, or strong retention on the surface interfere with the determination of pesticides. Problems in on-line CGB elution are partially solved by modifying the acetonitrile/water gradient to contain a front of 100% acetonitrile for a few seconds. Eluting the same GCB cartridges off-line with dichlor…

Solid phase techniques in the extraction of pesticides and related compounds from foods and soils

The application of SPE technology to the isolation of pesticides and related compounds from food and soils has grown enormously in the last decade. Much of this growth has been due to the relative ease of sample handling and the wide range of solid supports currently available for a variety of applications. The aim of this review is to present the methods for solid phase extraction (SPE) of pesticide residues from soils and foods. There are three main areas according to the type of approach used to handle the sample: solid phase extraction, solid phase clean-up (SPC), and matrix solid phase dispersion (MSPD). This review covers milk products, fatty foods, fruits, vegetables, and soils. Soli…

Limited survey for the presence of aflatoxins in foods from local markets and supermarkets in Valencia, Spain.

Aflatoxin B1 (AFB1), B2 (AFB2), G1 (AFG1) and G2 (AFG2) were extracted by matrix solid-phase dispersion with C18 silica and acetonitrile as the eluting solvent, analysed by liquid chromatography with fluorescence detection and confirmed by liquid chromatography with mass spectrometry using an electrospray interface in 58 samples grouped as cereals, dried fruits, herbs and spices, pulses, snacks, and nuts and nut products collected from local markets and supermarkets in Valencia, Spain. All samples analysed by the proposed method were previously studied with an enzyme-linked immunosorbent assay as a screening protocol for the fast detection of mycotoxins. The samples containing residues (3/5…