EMQAL: Erasmus Mundus Master in Quality in Analytical Laboratories

The Erasmus Mundus Master in Quality in Analytical Laboratories (EMQAL) is a two-year Joint Master Degree. The course is funded by the European Commission through the Erasmus Mundus Programme, providing a number of attractive scholarships for European and non-European students. EMQAL prepares professionals for analytical laboratories, focusing on laboratory management and quality systems, along with complementing their technical knowledge. The EMQAL aims at training students in the most relevant issues concerning quality systems and management in analytical laboratories, and to become an expert in: Quality management, Analytical methods and Data Analysis. EMQAL promotes mobility. The students will attend one academic year of lectures in one of the European universities of the EMQAL consortium, and a 12 months master thesis at other European university, with the possibility to spend three-months in one of the non-EU partners. The language of instruction and examination is English. Further information is available at www.emqal.org

Multivariate standard addition for the analysis of overlapping voltammetric signals in the presence of matrix effects: Application to the simultaneous determination of hydroquinone and catechol

A multivariate version of the classical univariate standard addition method is tested as a proof of concept for the voltammetric analysis of complex samples generating overlapped signals in the presence of significant matrix effects. The proposed strategy applies a multivariate calibration method such as partial least squares (PLS) to the full voltammograms measured for the sample alone and after combined additions of a series of standard solutions (one for every analyte). Then, a calibration model is built and further applied to the prediction of the concentration added to a blank, i.e., a full voltammetric signal measured in the absence of analytes. The absolute value of such predicted concentration is taken as the concentration of the analyte in the sample. The method has been successfully tested in different natural water samples spiked with hydroquinone and catechol and appears to be a promising tool for the analysis of overlapped signals in complex matrices

Mercury films on commercial carbon screen-printed devices for the analysis of heavy metal ions: a critical evaluation

The suitability of mercury films on commercial screen-printed electrodes for the analysis of heavy metal ions is critically tested for the particular case of Pb(II)-ions. Although determination is possible by anodic stripping voltammetry with a reasonable detection limit (8.9 µg L-1), important drawbacks are noticed as a consequence of the heterogeneous deposition of mercury on the rough surface of screen-printed devices

A chemically-bound glutathione sensor bioinspired by the defense of organisms against heavy metal contamination: Optimization of the immobilization conditions

The influence of the experimental conditions (glutathione concentration and incubation time and temperature) concerning the covalent immobilization of glutathione via carbodiimide coupling on the behavior of a glutathione modified screen-printed carbon electrode obtained by electrografting is evaluated. The optimized parameters fasten the modification process and improve the performance of the sensor as compared to the usual procedure. This suggests the convenience of a tailored preparation of metal sensors based on metal-binding biomolecules such as glutathione

A screen-printed voltammetric electronic tongue for the analysis of complex mixtures of metal ions

A voltammetric electronic tongue was constituted by four screen-printed modified electrodes: a carbon nanofiber modified electrode, an ex-situ antimony film electrode prepared from carbon nanofiber modified electrode, and two carbon nanofiber electrodes chemically modified withCys and GSH. The tongue was successfully applied to the analysis of a complex mixture of metal ions (4 analytes and 2 interferences) by differential pulse anodic stripping voltammetry. Each sensor was firstly studied for the determination of each metal separately confirming that all electrodes showed differentiated response for the metals. The obtained voltammetric signals provided by the sensor array were processed by Partial Least Squares regression (PLS) to resolve the overlapped nature of the obtained multimetal stripping measurements. This PLS model was built considering a hierarchical model in order to reduce the large amount of data. The method was applied to synthetic mixtures of Cd(II), Pb(II), Tl(I), and Bi(III) in the presence of Zn(II) and In(III) at the levels of μg L-1 and successfully validated with correlation coefficients of both calibration and prediction higher than 0.9 obtained from predicted vs. expected concentration graphs. Moreover, the simultaneous determination of Cd(II), Pb(II), Tl(I), and Bi(III) in the presence of Zn(II) and In(III) in a spiked tap water was also satisfactory achieved, providing comparable results to those obtained by ICP-MS

Glutathione modified screen-printed carbon nanofiber electrode for the voltammetric determination of metal ions in natural samples

This work reports the development of a glutathione modified electrode via electrografting on a screen-printed carbon nanofiber substrate (GSH-SPCNFE). GSH-SPCNFE was compared to a classical screen-printed carbon electrode modified with glutathione (GSH-SPCE) for the simultaneous voltammetric determination of Cd(II) and Pb(II). Their electrochemical characterization and analytical performance suggest that SPCNFE could be a much better support for GSH immobilization. The applicability of GSH-SPCNFE for the determination of low concentration levels of Pb(II) and Cd(II) ions in environmental samples was successfully tested in a certified wastewater reference material by means of stripping voltammetry with a very high reproducibility and good trueness

Penicillamine-modified sensor for the voltammetric determination of Cd(II) and Pb(II) ions in natural samples

A new penicillamine-GCE was developed based on the immobilization of D-penicillamine on aryl diazonium salt monolayers anchored to the glassy carbon electrode (GCE) surface and it was applied for the first time to the simultaneous determination of Cd(II) and Pb(II) ions by stripping voltammetric techniques. The detection and quantification limits at levels of µg L-1 suggest that the penicillamine-GCE could be fully suitable for the determination of the considered ions in natural samples

Simultaneous determination of Tl(I) and In(III) using a voltammetric sensor array

A sensor array consisting of a chemically modified sensor in which 4-carboxybenzo-18-crown-6 was immobilized onto a screen-printed carbon nanofiber-modified electrode (crown-6-SPCNFE) and an ex-situ antimony film deposited on a screen-printed carbon nanofiber-modified electrode (ex-situ-SbSPCNFE) was applied for the resolution of the strong overlapped signals resulting from the simultaneous determination of Tl(I) and In(III) by stripping voltammetry. A Partial Least Squares model was constructed and good calibration curves of predicted vs. expected concentrations of the considered metal ions, with correlation coefficients higher than 0.98 for both training and test sets, were obtained. These results provided by the sensor array were compared with those obtained by a single electrode. Moreover, this sensor array was successfully applied for the voltammetric determination of both Tl(I) and In(III) in tap water, providing comparable results to those obtained by ICP-MS measurements

New approaches to antimony film screen-printed electrodes using carbon-based nanomaterials substrates

Three different commercial carbon nanomaterial-modified screen-printed electrodes based on graphene, carbon nanotubes and carbon nanofibers were pioneeringly tested as electrode platforms for the plating with Sb film. They were microscopically and analytically compared to each other and to the most conventional unmodified carbon screen-printed electrode (SPCE). The obtained detection and quantification limits suggest that the in-situ antimony film electrode prepared from carbon nanofibers modified screen-printed electrode (SbSPCE-CNF) produces a better analytical performance as compared to the classical SPCE modified with antimony for Pb(II) and Cd(II) determination, approving its appropriateness for measuring low μg L(-1) levels of the considered metals. In-situ SbSPCE-CNF was successfully used for the simultaneous determination of Pb(II) and Cd(II) ions, by means of differential pulse anodic stripping voltammetry, in a certified reference estuarine water sample with a very high reproducibility and good trueness

Voltammetric determination of antihypertensive drug hydrochlorothiazide using screen-printed electrodes modified with L- glutamic acid

This work deals with the development of screen-printed carbon electrodes modified with L-glutamic acid via two different approaches: electropolymerization (SPCE/PGA) and aryl diazonium electrochemical grafting (SPCE/EGA). SPCE/PGA and SPCE/EGA were analytically compared in the determination of hydrochlorothiazide (HCTZ) by differential pulse voltammetry. Both electrochemical characterization and analytical performance indicate that SPCE/EGA is a much better sensor for HCTZ. The detection and quantification limits were at the level of micromol L-1 with a very good linearity in the studied concentration range. In addition, the proposed SPCE/EGA was successfully applied for the determination of HCTZ in an anti-hypertensive drug with high reproducibility and good trueness