Modified Polysulfone Nanofibers for the Extraction and Preconcentration of Lead from Aqueous Solutions.

Since lead is a highly toxic metal, it is necessary to detect its presence in different samples; unfortunately, analysis can be complicated if the samples contain concentrations below the detection limit of conventional analytical techniques. Solid phase extraction is a technique that allows the carrying out of a pre-concentration process and thus makes it easy to quantify analytes. This work studied the efficiency of sorption and preconcentration of lead utilizing polysulfone (PSf) fibers grafted with acrylic acid (AA).

Ternary Quantum Dots in Chemical Analysis. Synthesis and Detection Mechanisms.

Ternary quantum dots (QDs) are novel nanomaterials that can be used in chemical analysis due their unique physicochemical and spectroscopic properties. These properties are size-dependent and can be adjusted in the synthetic protocol modifying the reaction medium, time, source of heat, and the ligand used for stabilization. In the last decade, several spectroscopic methods have been developed for the analysis of organic and inorganic analytes in biological, drug, environmental, and food samples, in which different sensing schemes have been applied using ternary quantum dots.

Application of Multivariate Statistical Analysis to Simultaneous Spectrophotometric Enzymatic Determination of Glucose and Cholesterol in Serum Samples.

A method using UV-Vis spectroscopy and multivariate tools for simultaneous determination of glucose and cholesterol was developed in this paper. The method is based on the development of the reaction between the analytes (cholesterol and glucose) and enzymatic reagents. The spectra were analyzed by partial least squares regression and artificial neural networks.

Flow based determination of Cr(VI) by adsorptive cathodic stripping voltammetry on an immobilized magnetic poly(ionic liquid) modified electrode.

In this work an electrochemical procedure for Cr(VI) flow based determination in tap water is presented. An AdCSV method was developed using a screen printed electrode modified with magnetic poly(1-allyl-3-methylimidazolium) chloride and the procedure does not require the addition of complexing agents in the solution unlike the methodologies reported so far for Cr(VI) determination. The flow based system is described and the control variables were studied in detail and optimized using a Taguchi parameters design.

Size exclusion chromatography (SEC-HPLC) as an alternative to study thrombin inhibition.

In vitro analysis of anticoagulant compounds with a potential use as antithrombotic drugs, has been traditionally performed using techniques like spectrophotometry, turbidimetry, as well as electrochemical and clinical assays. Although, these techniques have some disadvantages such as: the inability to measure the total biological activity of thrombin, interferences and, sometimes, the quantitative determination of the inhibition ratio is not accurate. In the present work, the conversion of fibrinogen to fibrin was monitored by molecular exclusion chromatography (SEC-HPLC) in three different reaction systems.