New approach for direct analysis of opaque solutions with high content of suspended solids: Determination of calcium and phosphate in raw sugarcane juice.

This paper presents a new analytical approach for element concentration determination in samples containing significant concentrations of dissolved and suspended interferences. The proposed system enables to segregate of the complex matrix, species of interest from other interferences with a minimum requirement of reagents and energy. For this purpose, a new cleanup chamber design was implemented with cationic and anionic resins employed under membrane form and the tangential flow of the solution avoided the drawbacks commonly attributed to the packed and fluidized bed columns, such as the formation of preferred paths, increasing hydrodynamic pressure and clogging.

Ethanol determination in fermented sugarcane substrates by a diffusive micro-distillation device.

The determination of ethanol in fermented substrates is an important parameter for monitoring the production of distilled beverage samples. The correct measurement of its content has a direct impact on the profitability of the process. In this work, a diffusive micro-distillation device (DMDD) is proposed that allows the determination of ethanol directly in the fermented or distilled beverages samples.

Synthesis and characterization of struvite derived from poultry manure as a mineral fertilizer.

Animal manure is an important source of nutrients for crop production, but environmental issues can restrict its direct use. Thermochemical processing these manures may be an alternative to concentrate nutrients and reduce the final volume for agriculture application. We aimed here to evaluate the viability of extracting nutrients from chicken manure using a thermochemical process which reduces the volume of transported nutrients, targeting phosphorus (P) recovery as precipitated struvite, without add external source of P.

An automatic titration setup for the chemiluminometric determination of the copper complexation capacity in opaque solutions.

An automatic titration setup exploiting flow analysis was proposed for the evaluation of the copper complexation capacity of highly opaque substances (milk and humic substances). The binary search approach was implemented in a flow-batch analyzer, in order to add the in-line selected titrant (e.g.

YTOX: a rapid toxicity test based on the dehydrogenase activity of Saccharomyces cerevisiae for detection of contaminants in water samples.

A simple generic toxicity method (test) is proposed using baker's yeast to mediate the reduction of the colourless triphenyltetrazolium chloride (TTC) to red, 1,3,5-triphenyl formazan, which can be extracted by dimethyl sulfoxide (DMSO), enabling the identification of reducible toxic compounds (e.g. cadmium, fipronil) in water for consumption.

Cadmium sorption and extractability in tropical soils with variable charge.

The availability of cadmium (Cd) for plants and its impact in the environment depends on Cd sorption in soil colloids. The study of Cd sorption in soil and its fractionation is an interesting tool for the evaluation of Cd affinity with soil pools. The objective with this study was to evaluate Cd sorption and desorption in tropical soils with variable charge (three Oxisols), in a Mollisol and in two Entisols with diverse physical, chemical, and mineralogical attributes.

Fluidized particles in flow analysis: potentialities, limitations and applications.

In flow analysis, solid particles (sorbents, reagents or catalysts) have been used for e.g. analyte separation/concentration, sample clean-up, speciation analysis, enzymatic assays, analysis relying on slight soluble reagents, and kinetics studies related to adsorption/release of species.

Temporal Changes in Cadmium Speciation in Brazilian Soils Evaluated Using Cd LIII-Edge XANES and Chemical Fractionation.

Chemical speciation of soil cadmium (Cd) dictates its mobility and potential toxicity in the environment. Our objective was to compare temporal changes in speciation of Cd(II) reacted with samples from six Brazilian soils having varying Cd(II) sorption capacities. Cadmium L-edge X-ray absorption near edge structure (XANES) analysis showed there were short-term changes in speciation after reaction with 4.

Sulphate radical generation through interaction of peroxymonosulphate with Co(II) for in-line sample preparation aiming at spectrophotometric flow-based determination of phosphate and phosphite in fertilizers.

An advanced oxidative process relying on the interaction of peroxymonosulphate and cobalt(II) was implemented for generating the sulphate radicals in flow analysis, in order to accomplish in-line sample preparation thus improving the spectrophotometric determination of phosphate and phosphite in liquid foliar fertilizers. To this end, a flow-batch system with a heated chamber was designed. The sample was handled twice, with and without the step of phosphite oxidation to phosphate, and the formed orthophosphate was quantified after interaction with the vanadate-molybdate reagent.

A critical review on photochemical conversions in flow analysis.

Photochemical conversions are cost-effective and environmental friendly processes that require mild experimental conditions and avoid generation of highly acidic wastes. Treated samples are then compatible with most of the analytical techniques. These characteristics become more relevant when the photoconversions are accomplished to flow analysis, thus allowing exploitation of incomplete reactions, the effective use of the photogenerated unstable radicals and in-line sample treatment.

Fabrication of glass microchannels by xurography for electrophoresis applications.

This communication describes a simple and cost-effective method for fabricating glass microchannels by wet chemical etching using masks made by xurography in vinyl adhesive films. Analytical performance of microfluidic devices fabricated using the new approach was evaluated by microchip electrophoresis coupled to capacitively coupled contactless conductivity detection (C(4)D) and laser-induced fluorescence (LIF) detection.

Multivariate classification of cigarettes according to their elemental content determined by inductively coupled plasma optical emission spectrometry.

In this paper we describe our study on the characterization of cigarette samples according to their mineral content. Acid digestion assisted by microwaves was employed, and inductively coupled plasma optical emission spectrometry was the analytical technique used for the determination of Al, Ba, Ca, Cu, Fe, K, Mg, Mn, Na, P and Sr in conventional, light, and flavorized cigarettes. Multivariate techniques, such as hierarchical clusters analysis (HCA) and principal-component analysis (PCA), were applied to discriminate among different types of cigarettes.