Coordination polymer adsorbent for matrix solid-phase dispersion extraction of pesticides during analysis of dehydrated Hyptis pectinata medicinal plant by GC/MS

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Otimização e validação de método cromatográfico para determinação de 17 'beta'- estradiol, estrona e estriol em solo tratado com esterco animal e iodo de ETE

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Exposição à mistura de pesticidas em baixas doses: validação de método e aplicação a tecido adiposo de animais de experimentação (ratos Lewis)

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Matrix Effects on Water Analysis for Alkylphenols Using Solid Phase Extraction Gas Chromatography-Mass Spectrometry

Gas chromatography with mass spectrometry is frequently used for the quantification of many classes of substances, including alkylphenols. Alkylphenol polyethoxylates are nonionic surfactants used in a wide variety of industrial and consumer applications. Alkylphenol polyethoxylates can degrade to alkylphenols, which are endocrine disruptors. In analytical validation procedures, the most common parameters studied are the detection and quantification limits, linearity, and recovery; however, the matrix effects are sometimes neglected. Although some investigators have evaluated matrix effects, there is no consensus on how to evaluate them during method validation. In this study, the matrix effects of alkylphenol polyethoxylates (nonylphenol monoethoxylate, nonylphenol diethoxylate, octylphenol monoethoxylate, octylphenol diethoxylate) and alkylphenols (nonylphenol and octylphenol) were studied using solid phase extraction and gas chromatography-mass spectrometry analysis. For alkylphenol polyethoxylates, the matrix effects ranged from 16 to 4692%, whereas for alkylphenols (nonylphenol and octylphenol), the effects were insignificant. Therefore, constructing an analytical curve in the matrix for alkylphenol polyethoxylates is essential. © 2013 Copyright Taylor and Francis Group, LLC.

Monitoring pharmaceuticals photo-Fenton degradation process by using Solid Phase Extraction and liquid chromatography

The recovery of the pharmaceuticals bezafibrate and tetracycline from water was evaluated, using Solid Phase Extraction (SPE) with the aim of applying this technique to interrupt the pharmaceuticals' photodegradation by photo-Fenton process for further analysis. Sep-Pack C-18, Strata X, and Oasis HLB cartridges were evaluated. Oasis HLB showed the most satisfactory recovery and repeatability results: 98% (CV - 1%) for bezafibrate (20.0 mg L-1) and 76% (CV = 1%) for tetracycline (25.0 mg L-1). There was not a significant decrease in recovery at lower concentrations of the pharmaceuticals, and neither when present in Sewage Treatment Plant (STP) effluent matrix.

Determination of organochlorine pesticides and polychlorinated biphenyls residues in municipal solid waste compost by gas chromatography with electron-capture detection

A simple and efficient method for the simultaneous gas chromatographic determination of ten organochlorine pesticides (alpha-HCH, beta-HCH, gamma-HCH, p,p'-DDT, o,p'-DDT, p,p'-DDD, p,p'-DDE, aldrin, endrin, and dieldrin) and six congeners of PCBs (PCB 28, 52, 118, 138, 153, and 180) in municipal solid waste compost is described. The procedure involves a solid-phase dispersion matrix using celite as dispersant sorbent, alumina as clean up sorbent and hexane-dichloromethane (7:3, v/v) mixture as eluting solvent. An additional purification step with copper was necessary to eliminate sulphur. Analysis of the sample was performed by GC-ECD. The method was validated with fortified samples at two concentration levels (0.025 and 0.05 mg kg(-1)). Average recovery ranged from 77 to 121% with relative standard deviation between 1 and 18%. The detection limits, which ranged from 0.003 to 0.01 mg kg-1, were lower than those established by the Baden-Wurttemberg directive (0.033 mg kg(-1)).

Polysiloxane-poly(propylene oxide) hybrid discs as solid phase in anti-HCV detection using a recombinant core protein

In this work, siloxane-poly(propylene oxide) discs (PPO disc) prepared using the sol-gel process were used as solid phase in enzyme-linked immunosorbent assays (ELISA) for the detection of anti-hepatitis C virus (HCV) antibodies. The HCV RNA from serum (genotype 1b) was submitted to the RT-PCR technique and subsequent amplification of the HCV core 408 pb. This fragment was cloned into expression vector pET42a and expressed in Escherichia coli as recombinant protein with glutathione S-transferase (GST). Cell cultures were grown and induced having a final concentration of 0.4 x 10(-3) mol L-1 of IPTG. After induction, the cells were harvested and the soluble fraction was analyzed using polyacrilamide gel 15% showing a band with an approximate molecular weight of 44 kDa, the expected size for this GST-fused recombinant protein. The recombinant protein was purified and continued by immunological detection using HCV-positive serum and showed no cross-reactivity with positive samples for other infectious diseases. An ELISA was established using 1.25 ng of recombinant protein per PPO disc, a dilution of 1: 10,000 and 1:40 for a peroxidase conjugate and serum, respectively, and solutions of hydrogen peroxide and 3,3',5,5'-tetra-methylbenzidine in a ratio of 1: 1. The proposed methodology was compared with the ELISA conventional polystyrene-plate procedure and the performance of the PPO discs as a matrix for immunodetection gave an easy synthesis, good performance and reproducibility for commercial application. (c) 2007 Elsevier B.V. All rights reserved.

Banana Peel Applied to the Solid Phase Extraction of Copper and Lead from River Water: Preconcentration of Metal Ions with a Fruit Waste

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Preconcentration and determination of Cu(II) in a fresh water sample using modified silica gel as a solid-phase extraction adsorbent

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Solid-phase peptide synthesis in highly loaded conditions

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Determination of sugar cane herbicides in soil and soil treated with sugar cane vinasse by solid-phase extraction and HPLC-UV

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Determination of carbofuran and 3-hydroxycarbofuran residues in coconut water by solid-phase extraction and liquid chromatography with UV detection

A simple method was developed to determine carbofuran and 3-hydroxycarbofuran in coconut water. The procedure involved solid-phase extraction using C-18 cartridges with acetonitrile for elution. The analysis of these compounds was carried out by liquid chromatography with UV detection at 275 nm using a gradient solvent system. The method was validated with fortified samples at different concentration levels (0.01-2.5 mu g/mL). Average recoveries ranged from 81 to 95% with relative standard deviation between 1.6 and 12.5%. Each recovery analysis was repeated at least five times. Detection limits ranged from 0.008 to 0.01 mu g/mL. The analytical procedure was applied to coconut water samples from palms submitted to treatment with commercial formulation under field conditions.