A procedure using disposable pipette tips adapted for solid-phase extraction, known as DPX SPE, was used as an alternative way for the chromium determination in wastewater samples. DPX-SPE consists of a device which allows a dynamic contact between the sample and the solid-phase. A residue obtained from the processing of coffee beans, denominate coffee silverskin, was used as a new adsorbent. Characterization techniques revealed properties of lignocellulosic materials with potential application for chromium adsorption. The parameters including adsorbent mass (25.00 mg), elution solvent (0.1 mol L-1 HCl, 200 μL) and pH (2.0) were optimized. Thus, 1.00 mL of deionized water for conditioning, 4.00 mL of sample, 2 extraction cycles and 1 elution cycle were the employed conditions. Enrichment factor of 12, limit of detection of 6.00 µg L-1 and relative standard deviation (RSD) 1.3% (n = 3) were obtained. The method proved to be fast, cheap, environmentally friendly, and simple, providing good recoveries (104-113%), and it was satisfactorily applied in real samples.

Food safety is a constant and necessary concern due to the worldwide increase of the food demand. The monitoring of quality parameters demands the development of accurate, easy and fast procedures. The aim of this work was to develop a cheap, miniaturized and trustworthy salting-out assisted liquid-liquid extraction (SALLE) procedure for the determination of pesticides in wines. Sample and acetonitrile were mixed and the addition of NaCl and CH3COONa were used for separation of aqueous and organic phases. After centrifugation, the organic phase was directly injected into a liquid chromatograph. The developed SALLE procedure consumed at least 25-fold less reagent compared to conventional QuEChERS procedure. Additionally, the d-SPE step of the QuEChERS method was suppressed, without efficiency losses. The developed procedure was compared to the conventional methodology and no significant difference was observed. It was successfully applied to the determination of three pesticides in wines by liquid chromatography. Low consumption of sample and solvent, low residues generation, simple instrumentation are notable advantages. The suppression of the d-SPE step simplified the process and the risk of analyte losses.

This work presents a simple electrochemical method for 2-naphthylamine (2NAP) determination in perfume by differential-pulse voltammetry (DPV) employing a boron-doped diamond (BDD) electrode cathodically treated. Simple dilution of sample in supporting electrolyte was performed before electrochemical analysis. A borate buffer solution of pH 10.0 containing 20% (v/ (LOD) of 0.0046 µmol L-1 with a linear range between 0.5 and 90 µmol L-1, and RSD < 2.9%, respectively. Recovery values for spiked samples with 2NAP were between 102 and 104%. The proposed method is feasible to be applied for 2NAP detection and quantification on perfume samples with simple sample preparation.

RESUMO Objetivou-se avaliar o efeito térmico na mudança comportamental e fisiológica de novilhas girolando, por meio da análise de componentes principais. A pesquisa foi conduzida na região Agreste do estado de Pernambuco, Brasil. Foram utilizadas três novilhas submetidas ao sistema de pastejo contínuo. Para determinação do efeito térmico sobre os animais, foram registradas as variáveis temperatura de bulbo seco e umidade relativa do ar, o que permitiu determinar o índice de temperatura e umidade e a entalpia específica. As variáveis fisiológicas monitoradas foram a frequência respiratória, temperatura retal e temperatura de pelame. Os indicadores comportamentais quantificados foram andando, bebendo, comendo, ruminando e ócio, para determinação da porcentagem de tempo despendido em cada comportamento. As variáveis do estudo foram submetidas a análise exploratória e descritiva, para inferência do grau de associação dos componentes principais. A análise multivariada permitiu estabelecer o grau de pertinência entre os sinais fisiológicos e padrões comportamentais associado ao ambiente térmico, que indicaram adaptação das novilhas ao pastejo contínuo, mesmo em condições meteorológicas críticas.

ABSTRACT The objective of this study was to evaluate the thermal effect on the behavioral and physiological changes of Girolando heifers by means of principal components analysis. The research was conducted in the Agreste region of the state of Pernambuco, Brazil. Three heifers submitted to the continuous grazing system were used. For the determination of the thermal effect on the animals, the variables dry bulb temperature and relative air humidity were recorded, which allowed to determine the temperature and humidity index and the specific enthalpy. The physiological variables monitored were the respiratory rate, rectal temperature and skin temperature. The quantified behavioral indicators were walking, drinking, eating, ruminating and leisure, to determine the percentage of time spent in each behavior. The variables of the study were submitted to exploratory and descriptive analysis, in order to infer the degree of association of the main components. The multivariate analysis allowed to establish the degree of pertinence between the physiological signs and behavioral patterns associated with the thermal environment, which indicated heifers adaptation to continuous grazing, even in critical meteorological conditions.

This paper presents a simple and low-cost capillary electrophoresis method for ultra-fast simultaneous determination of naphazoline (NPZ) and one of the following active ingredients: diphenhydramine (DIP), pheniramine (PHEN) or chlorpheniramine (CPHEN). The proposed method is based on capillary electrophoresis with capacitively coupled contactless conductivity detection (CE-C4D) equipped with a short length capillary column (10 cm). One sample can be analyzed every 35 s (ca. 100 injections per hour) with resolutions between peaks greater than 1.4. The optimized background electrolyte (BGE) was composed by 20 mmol L-1 histidine and 10 mmol L-1 3,4-dimethoxycinnamic acid (pH = 9.5, adjusted with NaOH). Limits of detection were 25 µmol L-1 for NPZ, DIP, and PHEN and 13 µmol L-1 for CPHEN. The results obtained with the developed procedure were compared to those obtained by high-performance liquid chromatography (HPLC) and no statistically significant differences were observed (95% confidence level).

ABSTRACT Coupling solid-phase extraction (SPE) to flow systems has promoted a synergistic development. Whereas SPE mechanization leads to improved precision and higher sample throughput, as well as diminishes systematic errors and contamination risks, analyte concentration and separation from the sample matrix provides a remarkable impact on detectability and selectivity in flow analysis. Historical aspects, main cornerstones, tips for system design, and recent applications are critically reviewed, in the context of analyte(s) separation/concentration, sample clean-up, and release of sorbed chemical species involving both packed (e.g. mini-columns, cartridges, and disks) or fluidized (e.g. beads and magnetic materials) particles. Novel (bio)sorbents, selective synthetic materials, and stationary phases for low-pressure chromatography are also discussed. Moreover, the feasibility of SPE for sample treatment before chromatographic separation, as well as the exploitation of direct measurements on the solid phase (optosensing) are emphasized.