Laboratorio Of Desarrollo Analitico Y Quimiometria Ladaq

Buenos Aires, Argentina

Laboratorio Of Desarrollo Analitico Y Quimiometria Ladaq

Buenos Aires, Argentina

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Kuligowski J.,University of Valencia | Galera M.M.,University of Almeria | Garcia M.D.G.,University of Almeria | Culzoni M.J.,Laboratorio Of Desarrollo Analitico Y Quimiometria Ladaq | And 4 more authors.
Talanta | Year: 2011

Multivariate science based calibration (SBC) has been applied to the resolution of overlapped peaks in liquid chromatography with diode array detection (LC-DAD). Complex river water samples spiked with 11 pharmaceutical substances resulted in poorly resolved chromatograms containing additional peaks from interfering matrix compounds and a change in the background absorbance due to the mobile phase gradient. Applying the present multivariate approach it was possible to resolve all 11 analytes from overlapping peaks, obtaining linear calibration lines (R2 > 0.96). Recovery percentages on spiked samples ranged between 74.6 and 113.5%, which are quite satisfactory taking into account the low concentration ranges considered to 1-7 μg L-1. © 2010 Elsevier B.V. All rights reserved.


Goicoechea H.C.,Laboratorio Of Desarrollo Analitico Y Quimiometria Ladaq | Culzoni M.J.,Laboratorio Of Desarrollo Analitico Y Quimiometria Ladaq | Garcia M.D.G.,University of Almeria | Galera M.M.,University of Almeria
Talanta | Year: 2011

This overview covers the different chemometric strategies linked to chromatographic methodologies that have been used and presented in the recent literature to cope with problems related to incomplete separation, the presence of unexpected components in the sample, matrix effect and changes in the analytical signal due to pre-treatment of sample. Among the different chemometric strategies it focuses on pre-treatment of data to correct background and time shift of chromatographic peaks and the use of second-order algorithms to cope with overlapping peaks from analytes or from analytes and interferences in liquid chromatography coupled to diode array, fast-scanning fluorescence spectroscopy and mass spectrometry detectors. Finally the review presents the strategies used to deal with changes in the analytical response as result of matrix effect in liquid and gas chromatography, as well as the use of standardization strategies to correct modifications in the analytical signal as a consequence of sample pre-treatment in liquid chromatography. © 2010 Elsevier B.V. All rights reserved.


Schenone A.V.,Laboratorio Of Desarrollo Analitico Y Quimiometria Ladaq | Culzoni M.J.,Laboratorio Of Desarrollo Analitico Y Quimiometria Ladaq | Campiglia A.D.,University of Central Florida | Goicoechea H.C.,Laboratorio Of Desarrollo Analitico Y Quimiometria Ladaq
Analytical and Bioanalytical Chemistry | Year: 2013

In this work, we present the development of a method for the determination of doxorubicin in plasma samples in the presence of an unexpected component (riboflavin) by using total synchronous fluorescence spectroscopic data matrices. To the best of our knowledge, this is the first time that the second-order advantage is obtained with this kind of data. Two strategies including unfolding the data and: (a) processing with multivariate curve resolution coupled to alternating least-squares as first-order data or (b) processing with unfolded partial least-squares and exploiting the second-order advantage by the residual bilinearization procedure were considered. The calibration set was built with human plasma samples spiked with doxorubicin, while the validation set was prepared with human plasma samples spiked with both doxorubicin and riboflavin, a drug whose spectrum highly overlaps with the one corresponding to doxorubicin. Both methodologies reached good indicators of accuracy: recoveries of ca. 100 ± 8 % and REP of ca. 5 %; and precision: coefficient of variations between 7 and 9 %. [Figure not available: see fulltext.] © 2013 Springer-Verlag Berlin Heidelberg.


Vera-Candioti L.,CONICET | Teglia C.M.,CONICET | Camara M.S.,Laboratorio Of Desarrollo Analitico Y Quimiometria Ladaq
Electrophoresis | Year: 2016

A dispersive liquid–liquid microextraction procedure was developed to extract nine fluoroquinolones in porcine blood, six of which were quantified using a univariate calibration method. Extraction parameters including type and volume of extraction and dispersive solvent and pH, were optimized using a full factorial and a central composite designs. The optimum extraction parameters were a mixture of 250 μL dichloromethane (extract solvent) and 1250 μL ACN (dispersive solvent) in 500 μL of porcine blood reached to pH 6.80. After shaking and centrifugation, the upper phase was transferred in a glass tube and evaporated under N2 steam. The residue was resuspended into 50 μL of water–ACN (70:30, v/v) and determined by CE method with DAD, under optimum separation conditions. Consequently, a tenfold enrichment factor can potentially be reached with the pretreatment, taking into account the relationship between initial sample volume and final extract volume. Optimum separation conditions were as follows: BGE solution containing equal amounts of sodium borate (Na2B4O7) and di-sodium hydrogen phosphate (Na2HPO4) with a final concentration of 23 mmol/L containing 0.2% of poly (diallyldimethylammonium chloride) and adjusted to pH 7.80. Separation was performed applying a negative potential of 25 kV, the cartridge was maintained at 25.0°C and the electropherograms were recorded at 275 nm during 4 min. The hydrodynamic injection was performed in the cathode by applying a pressure of 50 mbar for 10 s. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim


Culzoni M.J.,Laboratorio Of Desarrollo Analitico Y Quimiometria Ladaq | Culzoni M.J.,CONICET | Mancha De Llanos A.,University of Extremadura | De Zan M.M.,Laboratorio Of Desarrollo Analitico Y Quimiometria Ladaq | And 5 more authors.
Talanta | Year: 2011

This work presents the development of a liquid chromatographic method based on modeling entire fast scan fluorimetric detection second-order data with the multivariate curve resolution alternating least squares algorithm, for the simultaneous determination of five marker pteridines in urine samples. The modeling strategy involves the building of a single MCR-ALS model composed of matrices augmented in the spectral mode, i.e. time profiles remain invariant while spectra may change from sample to sample. This approach allowed us to separate and determine the whole analytes at once. The developed approach enabled us to determine five of the most important metabolic disorder marker pteridines: biopterin, neopterin, isoxanthopterin, pterin and xanthopterin, three of them presenting emission spectra with the same emission wavelength maxima. In addition, some of these analytes present overlapped time profiles. As a consequence of using the entire data sets, a considerable reduction of the data processing experimental time can be achieved. Results are compared with a previous strategy in which data were split in five different regions, and information about the figures of merit of the new strategy compared with the previously reported strategy is reported. © 2011 Elsevier B.V. All rights reserved.


Schenone A.V.,Laboratorio Of Desarrollo Analitico Y Quimiometria Ladaq | Culzoni M.J.,Catedra de Quimica Analitica II | Marsili N.R.,National Hellenic Research Foundation | Goicoechea H.C.,Laboratorio Of Desarrollo Analitico Y Quimiometria Ladaq
Food Chemistry | Year: 2013

The performance of MCR-ALS was studied in the modeling of non-linear kinetic-spectrophotometric data acquired by a stopped-flow system for the quantitation of tartrazine in the presence of brilliant blue and sunset yellow FCF as possible interferents. In the present work, MCR-ALS and U-PCA/RBL were firstly applied to remove the contribution of unexpected components not included in the calibration set. Secondly, a polynomial function was used to model the non-linear data obtained by the implementation of the algorithms. MCR-ALS was the only strategy that allowed the determination of tartrazine in test samples accurately. Therefore, it was applied for the analysis of tartrazine in beverage samples with minimum sample preparation and short analysis time. The proposed method was validated by comparison with a chromatographic procedure published in the literature. Mean recovery values between 98% and 100% and relative errors of prediction values between 4% and 9% were indicative of the good performance of the method. © 2012 Elsevier Ltd. All rights reserved.


Gholivand M.-B.,Razi University | Jalalvand A.R.,Razi University | Jalalvand A.R.,Laboratorio Of Desarrollo Analitico Y Quimiometria Ladaq | Goicoechea H.C.,Laboratorio Of Desarrollo Analitico Y Quimiometria Ladaq | And 2 more authors.
Talanta | Year: 2015

For the first time, interaction of vitamin B7 (VB7) with bovine serum albumin (BSA) was investigated with the aim of developing a method for the analysis of BSA. The interaction of VB7 with BSA was investigated by cyclic voltammetry (CV), linear sweep voltammetry (LSV), and differential pulse voltammetry (DPV) at a multi-walled carbon nanotubes-modified glassy carbon electrode (MWCNTs/GCE). The recorded electrochemical data was combined with UVvis and fluorescence (F) spectroscopic data into a row- and column-wise augmented matrix and resolved by multivariate curve resolution-alternating least squares (MCR-ALS) as an efficient chemometric tool, and this assisted in the further elucidation of the above interaction. Also, with aid of MCR-BANDS method, the absence of rotational ambiguity was verified in the obtained results and we confirmed that the obtained results were unambiguous and reliable. The binding of VB7 to BSA was also modeled by molecular docking methods. Excellent agreement was found between the experimental and computational results. The differences of DPV responses of VB7 in the absence and presence of BSA (ΔI) were found to be linearly related to BSA concentration between 0.5×10-9 mol L-1 and 35.0×10-9 mol L-1, and a limit of detection (LOD, 3Sb/b) of 0.22×10-9 mol L-1 was calculated. Finally, the DPV method was further applied to the determination of serum albumin (SA) in serum samples obtained from Holstein cows and the results were in good agreement with those obtained by a medical diagnostic laboratory whose method was based on traditional cellulose acetate electrophoresis. The MWCNTs/GCE showed enhanced electron transfer kinetics, large electroactive surface area, and was highly sensitive, selective, and stable towards SA determination. The satisfactory analytical performance of the proposed method would make it potentially advantageous for a broad range of biosensing and clinical applications. © 2014 Elsevier B.V.


Gholivand M.-B.,Razi University | Jalalvand A.R.,Razi University | Jalalvand A.R.,Laboratorio Of Desarrollo Analitico Y Quimiometria Ladaq | Goicoechea H.C.,Laboratorio Of Desarrollo Analitico Y Quimiometria Ladaq | And 3 more authors.
Talanta | Year: 2015

For the first time, an analytical methodology based on differential pulse voltammetry (DPV) at a glassy carbon electrode (GCE) and integration of three efficient strategies including variable selection based on ant colony optimization (ACO), mathematical pre-processing selection by genetic algorithm (GA), and sample selection (SS) through a distance-based procedure to improve partial least squares-1 (PLS-1, ACO-GA-SS-PLS-1) multivariate calibration (MVC) for the simultaneous determination of five opium alkaloids including morphine (MOP), noscapine (NOP), thebaine (TEB), codeine (COD), and papaverine (PAP) was used and validated. The baselines of the DPV signals were modeled as a smooth curve, using P-splines, a combination of B-splines and a discrete roughness penalty. After subtraction of the baseline we got a signal with a two-component probability density. One component was for the peaks and it was approximated by a uniform distribution on the potential axis. The other component was for the observed noise around the baseline. Some sources of bi-linearity deviation for electrochemical data were discussed and analyzed. The lack of bi-linearity was tackled by potential shift correction using correlation optimized warping (COW) algorithm. The MVC model was developed as a quinternary calibration model in a blank human serum sample (drug-free) provided by a healthy volunteer to regard the presence of a strong matrix effect which may be caused by the possible interferents present in the serum, and it was validated and tested with two independent sets of analytes mixtures in the blank and actual human serum samples, respectively. Fortunately, the proposed methodology was successful in simultaneous determination of MOP, NOP, TEB, COD, and PAP in both blank and actual human serum samples and its results were satisfactory comparable to those obtained by applying the reference method based on high performance liquid chromatography-ultraviolet detection (HPLC-UV). © 2014 Published by Elsevier B.V.


Gholivand M.-B.,Razi University | Jalalvand A.R.,Razi University | Jalalvand A.R.,Laboratorio Of Desarrollo Analitico Y Quimiometria Ladaq | Goicoechea H.C.,Laboratorio Of Desarrollo Analitico Y Quimiometria Ladaq | Skov T.,Copenhagen University
Talanta | Year: 2014

For the first time, an ultrasensitive impedimetric buprenorphine hydrochloride (BN) biosensor based on immobilization of bovine serum albumin (BSA) onto multi-walled carbon nanotubes (MWCNTs)/glassy carbon electrode (BSA/MWCNTs/GCE) has been developed using initial characterization by computational methods and complementing them by experimental observations. Computational results showed that the BSA hydrophobically binds to MWCNTs which is energetically favorable and leads to spontaneous formation of the stable BSA/MWCNTs nanobiocomposite (bioconjugate). Computational results also showed that the interaction of BN with BSA is mainly driven by hydrophobic interactions. The interactions of BSA with MWCNTs and BN with BSA were also monitored by fluorescence and UV-vis spectroscopic techniques, and their results were consistent with the computational results. Morphology and electrochemical properties of the fabricated composite electrodes were examined by scanning electron microscopy (SEM), cyclic voltammetry (CV), and electrochemical impedance spectroscopy (EIS). Besides complementing the computational studies, experimental results showed that the addition of MWCNTs to the surface of the GCE greatly facilitated the electron transfer reactions, and also showed that the presence of BSA inhibits the interfacial electron transfer in some extent due to the non-conductive properties of BSA. On the other hand, the presence of BN may form an electroactive complex with BSA which accelerates the interfacial electron transfer and leads to obvious Faradaic impedance changes. The Faradaic impedance responses were linearly related to BN concentration between 5.0 nM and 72.0 nM and a limit of detection (LOD, 3Sb/b) of 1.5 nM was achieved. Finally, the proposed biosensor was successfully applied to determination of BN in urine samples of both healthy and addict volunteers. The results were satisfactory and comparable to those obtained by applying the reference method based on high performance liquid chromatography-ultraviolet detection (HPLC-UV). It is expected that the distinctive features of BSA/MWCNTs nanobiocomposite would make it potentially advantageous for a broad range of biosensing, and clinical applications. © 2014 Elsevier B.V.


Gholivand M.-B.,Razi University | Jalalvand A.R.,Razi University | Jalalvand A.R.,Laboratorio Of Desarrollo Analitico Y Quimiometria Ladaq | Goicoechea H.C.,Laboratorio Of Desarrollo Analitico Y Quimiometria Ladaq
Electrochimica Acta | Year: 2014

A computationally designed impedimetric pregabalin (PGB) biosensor based on immobilization of bovine serum albumin (BSA) onto graphene/glassy carbon electrode (BSA/Gr/GCE) has been developed using initial characterization by computational methods and complementing them by experimental observations. Computational results showed that the BSA hydrophobically binds to Gr which is energetically favorable and leads to the spontaneous formation of the stable nanobiocomposite (BSA/Gr), and also showed that the interaction of PGB with BSA is mainly driven by hydrogen bonding and hydrophobic interactions. The interactions of BSA with Gr and PGB with BSA were also monitored by fluorescence and UVvis spectroscopic techniques, and their results were consistent with the computational results. The electrochemical properties of the fabricated composite electrodes were examined by cyclic voltammetry (CV) scanning electron microscopy (SEM), and electrochemical impedance spectroscopy (EIS) techniques. Besides complementing the computational studies, experimental results showed that the addition of Gr to the surface of the electrode facilitated the electron transfer reactions, and also showed that the presence of BSA inhibits the interfacial electron transfer in some extent due to the non-conductive properties of BSA. The presence of the PGB may form an electroinactive complex with BSA which decelerates the interfacial electron transfer leading to obvious faradaic impedance changes. The faradaic impedance responses were linearly related to PGB concentration between 10.0 nM and 280.0 nM and the limit of detection (LOD) was calculated to be 3.0 nM (3Sb/b). Finally, the proposed biosensor was successfully applied to determination of PGB in human serum samples. The results were satisfactory and comparable to those obtained by applying the reference method based on high performance liquid chromatography (HPLC). The results confirmed that the proposed biosensor has good sensitivity, selectivity, stability, repeatability, reproducibility, and regeneration ability for PGB determination. © 2014 Published by Elsevier Ltd.

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