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ABSTRACT: Nowadays, bee products are being produced in an environment polluted by different sources of contamination, such as pesticides, which can be transported by honey bees to the hive and incorporated into honey. In addition, the increasing consumption of honey has demanded efficient quality control for this product. In this study, the determination of the pesticides fipronil, imidacloprid, thiamethoxam, dimethoate, carbendazin, tebuconazole, amitraz, τ-fluvalinate and 5-hydroxymethylfurfural (HMF) which are used as indicators of honey quality, was carried out simultaneously. For the sample preparation, the optimized QuEChERS method was used and the determinations were done by LC-APCI-MS/MS. The LOQs of the method ranged between 0.005 and 1.0mgkg(-1). For the recovery calculations and method evaluation a working curve was drawn. All the analytical curves showed r values higher than 0.99. The recoveries ranged between 70% and 112%, with RSD lower than 20% for all compounds. The matrix effect was evaluated, and most of the compounds showed signal enrichment. The applicability of the method for honey from different flowers was verified, and the method showed robustness and recoveries in the range 70-120% established for all compounds in samples belonging to different blossoms. HMF was detected in all samples, with concentrations ranging between 4.6 and 51.7mgkg(-1); it was below the maximum concentration allowed by the legislation.
Talanta 09/2012; 99:380-6. · 3.79 Impact Factor
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ABSTRACT: A new method for the determination of clomazone, fipronil, tebuconazole, propiconazole, and azoxystrobin in samples of rice paddy soil is presented. The extraction of the pesticides from soil samples was performed by using a modified quick, easy, cheap, effective, rugged, and safe (QuEChERS) method. Some extraction conditions such as salt addition, sample acidification, use of buffer, and cleanup step were evaluated. The optimized method dealt with a single extraction of the compounds under study with acidified acetonitrile, followed by the addition of MgSO(4) and NaCl prior to the final determination by liquid chromatography-atmospheric chemical pressure ionization-tandem mass spectrometry. Validation studies were carried out in soil samples. Recoveries of the spiked samples ranged between 70.3 and 120% with relative standard deviation lower than 18.2%. The limits of quantification were between 10 and 50 μg kg(-1). The method was applied to the analysis of real samples of soils where rice is cultivated.
Journal of Agricultural and Food Chemistry 11/2011; 59(22):11918-26. · 2.82 Impact Factor
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Ana P S Votto,
Beatriz S Domingues,
Michele M de Souza,
Flavio M R da Silva Júnior, Sergiane S Caldas,
Daza M V B Filgueira,
Rosilene M Clementin,
Ednei G Primel,
Adriana L Vallochi,
Eliana B Furlong,
Gilma S Trindade
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ABSTRACT: Onion (Allium cepa) is being studied as a potential anticancer agent, but little is known regarding its effect in multidrug resistance (MDR) cells. In this work, the cytotoxicity of crude onion extract (OE) and fractioned extract (aqueous, methanolic and ethyl acetate), as well as some onion compounds (quercetin and propyl disulfide) were evaluated in Lucena MDR human erythroleukemic and its K562 parental cell line. The capacity of OE to induce apoptosis and/or necrosis in these cells, the possible participation of oxidative stress and DNA damage were also assessed. Similar sensitivities were obtained for both tumoral cells, however only OE caused significant effects in the cells. In K562 cells, a significant increase of apoptosis was verified while the Lucena cells experienced a significant increase of necrosis. An antioxidant capacity was verified for OE discarding oxidative damage. However, OE provoked similar significant DNA damage in both cell lines. Thus, the OE capacity to overcome the MDR phenotype suggests anti-MDR action of OE.
Biological research 01/2010; 43(4):429-37. · 1.03 Impact Factor
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ABSTRACT: A rapid, simple and sensitive liquid chromatographic method has been developed to assay ciclopirox olamine in raw material
and topical solution. The analysis used a reversed-phase C18 end-capped column, with UV detection at 305nm and pre-column derivatization with dimethyl sulphate. A linear response (r
2>0.999) was observed in the range of 0.4–200μgmL−1. The method showed good recoveries for the raw material and topical solution and the relative standard deviation intra and
inter-day were ≤2.00%. Validation parameters such as specificity and robustness were also determined. The proposed method
provided an accurate and precise analysis of ciclopirox olamine in raw material and topical solution.
Chromatographia 01/2008; 67(11):967-971. · 1.20 Impact Factor
