References of "Talanta"
     in
Bookmark and Share    
Full Text
Peer Reviewed
See detailComprehensive plasma profiling for the characterization of graft-versus-host disease biomarkers
De Bock, Muriel; BEGUIN, Yves ULg; Leprince, Pierre ULg et al

in Talanta (2014), 125

Acutegraft-versus-hostdisease(aGVHD)remainsalife-threateningcomplicationofhematopoieticstem cell transplantation(HSCT)thereforelimitingitsapplication.TooptimizethemanagementofaGVHDand reduce therapy ... [more ▼]

Acutegraft-versus-hostdisease(aGVHD)remainsalife-threateningcomplicationofhematopoieticstem cell transplantation(HSCT)thereforelimitingitsapplication.TooptimizethemanagementofaGVHDand reduce therapy-relatedtoxicity,earlyspecific markersareneeded.Themainobjectiveofthisstudywas to uncoverdiagnosticbiomarkersbycomparingplasmaproteinprofiles ofpatientsatthetimeofacute GVHDdiagnosiswiththoseofpatientsundergoingHSCTwithoutaGVHD.Additionalanalysisofsamples taken 15daysbeforeaGVHDdiagnosiswasalsoperformedtoevaluatethepotentialofournewly discoveredbiomarkersforearlydiagnosis.Togetcomplementaryinformationfromplasmasamples, we usedthreedifferentproteomicapproaches,namely2D-DIGE,SELDI-TOF-MSand2D-LC-MSE. Weidentified andconfirmed bythemeansofindependenttechniques,thedifferentialexpression of severalproteinsindicatingsignificantly increasedinflammation responseanddisturbanceinthe coagulation cascade.Thevariationoftheseproteinswasalreadyobserved15daysbeforeGVHD diagnosis, suggestingthepotentialearlydetectionofthediseasebeforesymptomsappearance. Finally,logisticregressionanalysisdeterminedacompositebiomarkerpanelcomprising fibrinogen, fragment of fibrinogenbetachain,SAA,prothrombinfragments,apolipoproteinA1andhepcidinthat optimallydiscriminatedpatientswithandwithoutGVHD.Theareaunderthereceiveroperating characteristiccurvedistinguishingthese2groupswas0.95. [less ▲]

Detailed reference viewed: 27 (13 ULg)
Full Text
Peer Reviewed
See detailAnalysis of collagen preservation in bones recovered in archaeological contexts using NIR Hyperspectral Imaging
Vincke, Damien; Miller, Rebecca ULg; Stassart, Edith ULg et al

in Talanta (2014), 125

The scope of this article is to propose an innovative method based on Near Infrared Hyperspectral Chemical Imaging (NIR-HCI) to rapidly and non-destructively evaluate the relative degree of collagen ... [more ▼]

The scope of this article is to propose an innovative method based on Near Infrared Hyperspectral Chemical Imaging (NIR-HCI) to rapidly and non-destructively evaluate the relative degree of collagen preservation in bones recovered from archaeological contexts. This preliminary study has allowed the evaluation of the potential of the method using bone samples from the Early Upper Palaeolithic, Mesolithic and Neolithic periods at the site of Trou Al'Wesse in Belgium. NIR-HCI, combined with chemometric tools, has identified specific spectral bands characteristic of collagen. A chemometric model has been built using Partial Least Squares Discriminant Analysis (PLS-DA) to identify bones with and without collagen. This enables the evaluation of the degree of collagen preservation and homogeneity in bones within and between different strata, which has direct implications for archaeological applications (e.g., taphonomic analyses, assemblage integrity) and sample selection for sub- sequent analyses requiring collagen. Two archaeological applications are presented: comparison between sub-layers in an Early Upper Palaeolithic unit, and evaluation of the range of variability in collagen preservation within a single Holocene stratum. [less ▲]

Detailed reference viewed: 22 (2 ULg)
Full Text
Peer Reviewed
See detailDetermination of 4-aminophenol in a pharmaceutical formulation using Surface Enhanced Raman scattering: from development to method validation
De Bleye, Charlotte ULg; Dumont, Elodie ULg; Rozet, Eric ULg et al

in Talanta (2013), 116

A Surface Enhanced Raman Scattering (SERS) method able to quantify 4-aminophenol in a pharmaceutical formulation based on acetaminophen, also called paracetamol, was developed and, for the first time ... [more ▼]

A Surface Enhanced Raman Scattering (SERS) method able to quantify 4-aminophenol in a pharmaceutical formulation based on acetaminophen, also called paracetamol, was developed and, for the first time, successfully validated. In this context, silver nanoparticles were synthesized according to the method described by Lee-Meisel and used as SERS substrate. The repeatability of the silver colloid synthesis was tested using different methods to characterise the size and the zeta potential of silver nanoparticles freshly synthesized. To optimize the SERS samples preparation, a design of experiments implicating concentrations of citrate-reduced silver nanoparticles and aggregating agent was performed in order to maximize the Raman signal enhancement. Finally, an approach based on tolerance intervals and accuracy profiles was applied in order to thoroughly validate the method in a range of concentrations comprised from 3 to 15 µg mL-1 using normalized band intensities. The standard addition method was selected as method calibration. Therefore, measurements were carried out on 4-aminophenol spiked solutions of the pharmaceutical formulation. Despite the well-known stability and reproducibility problems of SERS, the validation was performed using two operators and 5 batches of nanoparticles, one for each validation day. [less ▲]

Detailed reference viewed: 69 (43 ULg)
Full Text
Peer Reviewed
See detailDiscrimination of grassland species and their classification in botanical families by laboratory scale NIR hyperspectral imaging: preliminary results
Dale, Laura ULg; Thewis, André ULg; Boudry, Christelle ULg et al

in Talanta (2013), 116

The objective of this study was to discriminate by a NIR line scan hyperspectral imaging, taxonomic plant families comprised of different grassland species. Plants were collected from semi-natural meadows ... [more ▼]

The objective of this study was to discriminate by a NIR line scan hyperspectral imaging, taxonomic plant families comprised of different grassland species. Plants were collected from semi-natural meadows of the National Apuseni Park, Apuseni Mountains, Gârda area (Romania) according to botanical families. Chemometric tools such as PLS-DA were used to discriminate distinct grassland species, and assign the different species to botanical families. Species within the Poacea family and Other Botanical Families could be distinguished (R2=0.91 and 0.90, respectively) with greater accuracy than those species in the Fabacea family (R2=0.60). A correct classification rate of 99% was obtained in the assignment of the various species to the proper family. Moreover a complete study based on wavelength selection has been performed in order to identify the chemical compound related to each botanical family and therefore to the possible toxicity of the plant. This work could be considered as a first step for the development of a complete procedure for the detection and quantification of possible toxic species in semi-natural meadows used by grazing animals. [less ▲]

Detailed reference viewed: 40 (10 ULg)
Full Text
Peer Reviewed
See detailFast method for the simultaneous quantification of toxic polyphenols applied to the selection of genotypes of yam bean (Pachyrhizus sp.) seeds.
Lautié, Emmanuelle; Rozet, Eric ULg; Hubert, Philippe ULg et al

in Talanta (2013), 117

The purpose of the research was to develop and validate a rapid quantification method able to screen many samples of yam bean seeds to determine the content of two toxic polyphenols, namely pachyrrhizine ... [more ▼]

The purpose of the research was to develop and validate a rapid quantification method able to screen many samples of yam bean seeds to determine the content of two toxic polyphenols, namely pachyrrhizine and rotenone. The analytical procedure described is based on the use of an internal standard (dihydrorotenone) and is divided in three steps: microwave assisted extraction, purification by solid phase extraction and assay by ultra high performance liquid chromatography (UHPLC). Each step was included in the validation protocol and the accuracy profiles methodology was used to fully validate the method. The method was fully validated between 0.25mg and 5mg pachyrrhizin per gram of seeds and between 0.58mg/g and 4mg/g for rotenone. More than one hundred samples from different accessions, locations of growth and harvest dates were screened. Pachyrrhizine concentrations ranged from 3.29mg/g to lower than 0.25mg/g while rotenone concentrations ranged from 3.53mg/g to lower than 0.58mg/g. This screening along with principal component analysis (PCA) and discriminant analysis (DA) analyses allowed the selection of the more interesting genotypes in terms of low concentrations of these two toxic polyphenols. [less ▲]

Detailed reference viewed: 11 (0 ULg)
Full Text
Peer Reviewed
See detailDetermination of inhibitory potency of argatroban toward thrombin by electrophoretically mediated microanalysis
Pochet, Lionel; Servais, Anne-Catherine ULg; Farcas, Elena ULg et al

in Talanta (2013), 116

Developing an EMMA method for enzymatic assay remains a challenge, particularly using UV detection. Indeed, it is necessary to optimize the separation conditions while allowing the enzymatic reaction to ... [more ▼]

Developing an EMMA method for enzymatic assay remains a challenge, particularly using UV detection. Indeed, it is necessary to optimize the separation conditions while allowing the enzymatic reaction to occur within the capillary respecting kinetic constraints and achieving enough sensitivity. In this work, such EMMA methodology was set up to evaluate the inhibitory potency of drugs toward thrombin, a serine protease implicated in the coagulation cascade. To achieve our goal, the separation buffer, the injection sequence, the internal standard and the chromogenic substrate were investigated. The newly developed system was then assessed determining the kinetic Km constant for the selected substrate and compared with the results obtained with a continuous spectrophotometer cell assay. Secondly, the Ki inhibitory constant of the thrombin inhibitor argatroban was determined and found in agreement with the published value. [less ▲]

Detailed reference viewed: 22 (8 ULg)
Full Text
Peer Reviewed
See detailAnalysis of the diastereoisomers of alliin by HPLC
DETHIER, Bérénice ULg; Laloux, Morgan ULg; Hanon, Emilien et al

in Talanta (2012), 101

Garlic has been known for its therapeutic effects for centuries and is used worldwide as a functional food. The concentration of the active molecules could be enhanced by a better knowledge of their ... [more ▼]

Garlic has been known for its therapeutic effects for centuries and is used worldwide as a functional food. The concentration of the active molecules could be enhanced by a better knowledge of their biosynthesis. The precursor of these compounds, alliin (a sulfur amino-acid) has been obtained by chemical synthesis. However, this synthesis route also leads to a diastereoisomer as co-product. This work describes the development of an analytical method which allows the separation and quantification of the two diastereoisomers in order to determine in which proportion the natural form can be produced. The HPLC method which was optimized and validated by accuracy profile exploits an original stationary phase consisting of porous graphitic carbon (PGC). Furthermore, the developped method was used to separate the diastereoisomers of methiin, another garlic cysteine sulfoxide, and to analyse and aqueous extract of garlic. The ability to quantify the amount of natural alliin is valuable for further work on garlic molecules and their application for health protection. [less ▲]

Detailed reference viewed: 65 (24 ULg)
Full Text
Peer Reviewed
See detailChemometrics and chromatographic fingerprints to discriminate and classify counterfeit medicines containing PDE-5 inhibitors.
Deconinck, Eric; Sacre, Pierre-Yves ULg; Courselle, Patricia et al

in Talanta (2012), 100

Chromatographic fingerprints recorded for a set of genuine and counterfeit samples of Viagra® and Cialis® were evaluated for their use in the detection and classification of counterfeit samples of these ... [more ▼]

Chromatographic fingerprints recorded for a set of genuine and counterfeit samples of Viagra® and Cialis® were evaluated for their use in the detection and classification of counterfeit samples of these groups of medicines. Therefore several exploratory chemometric techniques were applied to reveal structures in the data sets as well as differences among the samples. The focus was on the differentiation between genuine and counterfeit samples and on the differences between the samples of the different classes of counterfeits as defined by the Dutch National Institute for Public Health and the Environment (RIVM). In a second part the revealed differences between the samples were modelled to obtain a predictive model for both the differentiation between genuine and counterfeit samples as well as the classification of the counterfeit samples. The exploratory analysis clearly revealed differences in the data for the genuine and the counterfeit samples and with projection pursuit and hierarchical clustering differences among the different groups of counterfeits could be revealed, especially for the Viagra® data set. For both data sets predictive models were obtained with 100% correct classification rates for the differentiation between genuine and counterfeit medicines and high correct classification rates for the classification in the different classes of counterfeit medicines. For both data sets the best performing models were obtained with Least Square-Support Vector Machines (LS-SVM) and Soft Independent Modelling by Class Analogy (SIMCA). [less ▲]

Detailed reference viewed: 35 (3 ULg)
Full Text
Peer Reviewed
See detailSimultaneous measurement of protein-bound 3-chlorotyrosine and homocitrulline by LC-MS/MS after hydrolysis assisted by microwave: application to the study of myeloperoxidase activity during hemodialysis.
Delporte, Cedric; Franck, Thierry ULg; Noyon, Caroline et al

in Talanta (2012), 99

A high degree of uremia is common in patients with end-stage renal disease and has been linked to the development of chronic inflammation and cardiovascular diseases. In conditions where transplantation ... [more ▼]

A high degree of uremia is common in patients with end-stage renal disease and has been linked to the development of chronic inflammation and cardiovascular diseases. In conditions where transplantation is not possible, uremia can be reduced by hemodialysis although the repeated interventions have been implicated in loss of renal function, partially as a result of chronic inflammation and/or oxidative stress processes. In this context, it has been suggested that myeloperoxidase (MPO) can contribute to the oxidative stress during hemodialysis and to the cardiovascular risk. Protein damages due to MPO activity have never been assessed during hemodialysis although two of its reaction products, 3-chlorotyrosine and homocitrulline, are of interest. Indeed, the first one is a specific product of MPO activity and the formation of the second one could be catalyzed by MPO. In order to analyze these products in plasma proteins, a total hydrolysis method followed by liquid chromatography mass spectrometry analysis was developed. Different conditions of hydrolysis were tested and the optimized procedure was assessed for complete hydrolysis and artifactual chlorination. Finally, the method was used for analyzing 3-chlorotyrosine and homocitrulline in plasma proteins during a hemodialysis session in fifteen patients and data were related to measurements of MPO concentration and activity. Both increases in MPO activity and protein-bound 3-chlorotyrosine were observed, highlighting the involvement of MPO in oxidative stress during hemodialysis and further demonstrating the link between hemodialysis and cardiovascular diseases. [less ▲]

Detailed reference viewed: 25 (0 ULg)
Full Text
Peer Reviewed
See detailComments on “Uncertainty profiles for the validation of analytical methods” by Saffaj and Ihssane
Rozet, Eric ULg; Ziemons, Eric ULg; Marini Djang'Eing'A, Roland ULg et al

in Talanta (2012), 88

Saffaj et al., recently proposed an uncertainty profile for evaluating the validity of analytical methods using the statistical methodology of γ-confidence β-content tolerance intervals. This profile ... [more ▼]

Saffaj et al., recently proposed an uncertainty profile for evaluating the validity of analytical methods using the statistical methodology of γ-confidence β-content tolerance intervals. This profile assesses the validity of the method by comparing the method measurement uncertainty to a pre defined acceptance limit stating the maximum uncertainty suitable for the method under study. Several years earlier as stated by these authors a SFSTP (Société Française des Sciences et Techniques Pharmaceutique) commission has developed a similar profile called accuracy profile used to assess the validity of analytical methods. This accuracy profile also uses the methodology of statistical tolerance intervals, but β-expectation tolerance intervals. The uncertainty profile of Saffaj et al. and the accuracy profile of the SFSTP commission are both fulfilling the same final purpose. The core question is finally what statistical tolerance interval to use ? The aim of this letter to the editor is to discuss this question and provide arguments that β-expectation tolerance intervals should be prefered to assess the validity of the method as this type of interval give the guarantee that each future results has high probability to fall within pre-specified acceptance limits. [less ▲]

Detailed reference viewed: 83 (13 ULg)
Full Text
Peer Reviewed
See detailReply to the responses on the comments on “Uncertainty profiles for the validation of analytical methods” by Saffaj and Ihssane
Rozet, Eric ULg; Ziemons, Eric ULg; Marini Djang'Eing'A, Roland ULg et al

in Talanta (2012), 100

Saffaj et al., recently proposed an uncertainty profile for evaluating the validity of analytical methods using the statistical methodology of γ-confidence β-content tolerance intervals. This profile ... [more ▼]

Saffaj et al., recently proposed an uncertainty profile for evaluating the validity of analytical methods using the statistical methodology of γ-confidence β-content tolerance intervals. This profile assesses the validity of the method by comparing the method measurement uncertainty to a pre defined acceptance limit stating the maximum uncertainty suitable for the method under study. In this letter we comment on the response (T. Saffaj, B. Ihssane, Talanta 94 (2012) 361-362) these authors have made to our previous letter (E. Rozet, E. Ziemons, R.D. Marini, B. Boulanger, Ph. Hubert, Talanta 88 (2012) 769–771). In particular, we demonstrate that β-expectation tolerance intervals are prediction intervals, we show that β-expectation tolerance intervals are highly usefull for assessing analytical methods validation and for estimating measurement uncertainty and finally we show what are the differences and implications for these two topics (validation and uncertainty) when using either the methodology of β-expectation tolerance intervals or the γ-confidence β-content tolerance tolerance interval one. [less ▲]

Detailed reference viewed: 37 (6 ULg)
Full Text
Peer Reviewed
See detailNew approach to quantitative analysis of benzo[a]pyrene in food supplements by an immunochemical column test
Beloglazova, Natalia; Goryacheva, Irina; De Saeger, Sarah et al

in Talanta (2011), 85

Detailed reference viewed: 29 (9 ULg)
Full Text
Peer Reviewed
See detailPre-study and in-study validation of a SPE-LC-MS-MS method for the determination of 5-S-cysteinyldopa, a melanoma biomarker, in human plasma.
Martin, Gaelle; Mansion, François ULg; Houbart, Virginie ULg et al

in Talanta (2011), 84(2), 280-6

The incidence of malignant melanoma has increased over the past decades, particularly in Caucasian population. This disease presents defavourable prognosis in terms of survey, especially when detection ... [more ▼]

The incidence of malignant melanoma has increased over the past decades, particularly in Caucasian population. This disease presents defavourable prognosis in terms of survey, especially when detection occurs at the metastatic phase. Reliable analytical methods for biomarker determination are thus an interesting tool in pathology detection and follow-up. In this context, a method using SPE-LC-ESI-MS-MS for the determination of 5-S-cysteinyldopa (5-SCD) in human plasma was optimized. The presence of matrix effect was investigated in details while 5-SCD stability was studied according to FDA requirements for the validation of bioanalytical methods. Pre-study and in-study validations of the entire method were then successfully performed by applying the approach based on total measurement error and accuracy profiles over a concentration ranges from 1.6 to 200 ng/ml. Good results with respect to accuracy, trueness and precision were obtained. The maximum risk of observing future measurements falling outside the acceptance limits during routine analysis was also estimated. [less ▲]

Detailed reference viewed: 41 (8 ULg)
Full Text
Peer Reviewed
See detailDevelopment and validation by accuracy profile of a method for the analysis of monoterpenes in indoor air by active sampling and thermal desorption-gas chromatography-mass spectrometry
Marlet, Christelle ULg; Lognay, Georges ULg

in Talanta (2010), 82(4), 1230-1239

The technique of thermal desorption (TD)-GC/MS was evaluated for the measurement of monoterpenes in indoor air. The validation strategy was intentionally oriented towards routine use and the reliability ... [more ▼]

The technique of thermal desorption (TD)-GC/MS was evaluated for the measurement of monoterpenes in indoor air. The validation strategy was intentionally oriented towards routine use and the reliability of the method rather than extreme performance. For this reason, validation by accuracy profile was chosen. The accuracy profile procedure, which is based on the concept of total error (bias + standard deviation), guarantees that a known proportion of future results obtained with the method will be within acceptance limits. For all the compounds tested in the present study, α-pinene, α-terpineol, β-pinene, d-limonene, Δ3-carene, camphene, 1,8-cineole, p-cymene, linalool, but not in the case of carvone, the accuracy profile procedure established that at least 95% of the future results obtained would be within the ±15% acceptance limits of the validated method over the whole defined concentration range. Other parameters, such as selectivity, recovery, repeatability, stability of the molecules of interest and the effect of temperature, were also determined. The performance of the described method was finally evaluated by the analysis of indoor air from new timber frame constructions. [less ▲]

Detailed reference viewed: 31 (7 ULg)
Full Text
Peer Reviewed
See detailDevelopment and validation of a quantitative method for the selective determination of tin species in tin octoate by differential pulse polarography
Hubert, Cédric ULg; Ziemons, Eric ULg; Rozet, Eric ULg et al

in Talanta (2010), 80(3), 1413-1420

Tin octoate is used as a catalyst in the synthesis of polydimethylsiloxane (PDMS), a room temperature vulcanizing (RTV) silicone rubber. This rubber is largely used in the medical field due to its great ... [more ▼]

Tin octoate is used as a catalyst in the synthesis of polydimethylsiloxane (PDMS), a room temperature vulcanizing (RTV) silicone rubber. This rubber is largely used in the medical field due to its great biocompatibility. In this framework, a high-speed and costless analytical method for the determination of stannic ions, Sn(IV), in the presence of stannous ions, Sn(II), has been developed. The separation of these two ions was carried out using differential pulse polarography (DPP). For this purpose, the tin species contents in the catalyst is quantitatively extracted under inert condition to avoid any changes in the ratio Sn(IV)/Sn(II). Polarography showed well-shaped oxidation and reduction peaks respectively at −650 and −860 mV for stannous ions. The peak of the stannic ion was well separated and appeared at −1210 mV. Many parameters such as extraction process, extraction time, pH, chelating agents and polarographic conditions were optimized. We have also demonstrated that no oxidation of the stannous ions occurred during the sample preparation. The dosing range considered in this study extends between 10 and 40 μg/mL, corresponding to 6.8% and 27.2% of the degradation product (Sn(IV)) in the catalyst, regarding to the sampling. Finally this method was successfully validated using the total error concept. [less ▲]

Detailed reference viewed: 171 (53 ULg)
Full Text
Peer Reviewed
See detailBuilding the quality into pellet manufacturing environment - feasibility study and validation of an in-line quantitative near infrared (NIR) method
Mantanus, Jérôme ULg; Ziemons, Eric ULg; Rozet, Eric ULg et al

in Talanta (2010), 83

The present study focuses on the implementation of an in-line quantitative near infrared (NIR) spectroscopic method for determining the active content of pharmaceutical pellets. The first aim was to non ... [more ▼]

The present study focuses on the implementation of an in-line quantitative near infrared (NIR) spectroscopic method for determining the active content of pharmaceutical pellets. The first aim was to non-invasively interface a dispersive NIR spectrometer with four realistic particle streams existing in the pellets manufacturing environment. Regardless of the particle stream characteristics investigated, NIR together with principal component analysis (PCA) was able to classify the samples according to their active content. Further, one of these particle stream interfaces was non-invasively investigated with a FT-NIR spectrometer. A predictive model based on Partial Least Squares (PLS) regression was able to determine the active content of pharmaceutical pellets. The NIR method was finally validated with an external validation set for an API concentration range from 80 to 120 % of the targeted active content. The prediction error of 0.9 % (root mean standard error of prediction, RMSEP) was low, indicating the accuracy of the NIR method. The accuracy profile on the validation results, an innovative approach based on tolerance intervals, demonstrated the actual and future performance of the in-line NIR method. Accordingly, the present approach paves the way for real-time release-based quality system. [less ▲]

Detailed reference viewed: 161 (54 ULg)
Full Text
Peer Reviewed
See detailActive content determination of non-coated pharmaceutical pellets by near infrared spectroscopy: Method development, validation and reliability evaluation
Mantanus, Jérôme ULg; Ziemons, Eric ULg; Lebrun, Pierre ULg et al

in Talanta (2010), 80

A robust near infrared (NIR) method able to quantify the active content of pilot non-coated pharmaceutical pellets was developed. A protocol of calibration was followed, involving 2 operators, independent ... [more ▼]

A robust near infrared (NIR) method able to quantify the active content of pilot non-coated pharmaceutical pellets was developed. A protocol of calibration was followed, involving 2 operators, independent pilot batches of non-coated pharmaceutical pellets and two different NIR acquisition temperatures. Prediction models based on Partial Least Squares (PLS) regression were then carried out. Afterwards, the NIR method was fully validated for an active content ranging from 80 to 120% of the usual active content using new independent pilot batches to evaluate the adequacy of the method to its final purpose. Conventional criteria such as the R2, the Root Mean Square Error of Calibration (RMSEC), the Root Mean Square Error of Prediction (RMSEP) and the number of PLS factors enabled the selection of models with good predictive potential. However, such criteria sometimes fail to choose the most fitted for purpose model. Therefore, a novel approach based on accuracy profiles of the validation results was used, providing a visual representation of the actual and future performances of the models. Following this approach, the prediction model using signal pre-treatment Multiplicative Scatter Correction (MSC) was chosen as it showed the best ability to quantify accurately the active content over the 80–120% active content range. The reliability of the NIR method was tested with new pilot batches of non-coated pharmaceutical pellets containing 90 and 110% of the usual active content, with blends of validation batches and industrial batches. All those batches were also analyzed by the HPLC reference method and relative errors were calculated: the results showed low relative errors in full accordance with the results obtained during the validation of the method, indicating the reliability of the NIR method and its interchangeability with the HPLC reference method. [less ▲]

Detailed reference viewed: 174 (42 ULg)
Full Text
Peer Reviewed
See detailIsotope coded protein label quantification of serum proteins--comparison with the label-free LC-MS and validation using the MRM approach.
Turtoi, Andrei ULg; Mazzucchelli, Gabriel ULg; De Pauw, Edwin ULg

in Talanta (2010), 80(4), 1487-95

Protein quantification based upon mass spectrometry is gaining ground in diverse applications of biological and clinical relevance. The present article focuses on one of the most complex biological fluids ... [more ▼]

Protein quantification based upon mass spectrometry is gaining ground in diverse applications of biological and clinical relevance. The present article focuses on one of the most complex biological fluids - serum - and provides a novel ICPL based quantification protocol. The results are compared to a label-free (data independent alternate scanning) absolute quantification method. The validation is performed using MRM based protein quantification technique. Regarding the ICPL approach, serum samples used in this study were depleted of high abundant proteins, labeled with ICPL and fractionated according to their respective pI (3-5, 5-7 and 7-12). The samples were further subjected to tryptic digestion followed by treatment with the Glu-C enzyme. The peptides were analyzed on a 2D-nano-LC system using four different concentrations of salt injections (45, 75, 150 and 500 mM ammonium acetate). The LC system was connected on-line with the electrospray ion-trap mass spectrometer. For the label-free quantification the serum samples were depleted and digested with trypsin. A proteome-wide comparison was performed using highly reproducible LC and data independent alternate scanning in conjunction with a high mass accuracy orthogonal time-of-flight mass spectrometer. Selected proteins, found by both methods, were validated using the MRM approach. For this purpose non-depleted tryptically digested serum samples were analyzed by LC coupled with a triple-quadrupole MS. The relative protein quantification using ICPL and mass spectrometry allowed for the detection of approximately 200 proteins, whereas about 2/3 of those contained the ICPL label and could therefore be quantified. Label-free approach used no fractionation, less sample and was able to identify and quantify over 110 proteins. The identified proteins covered generally 3-4 orders of magnitude of protein concentration in human serum. Changes in relative abundance of eight proteins were validated using MRM. This study, for the first time, shows the ability of the relative protein quantification based upon ICPL and 2D-LC-MS/MS to quantify serum biomarkers. It provides two additional label-free approaches that could validate and bring additional value to the label-based results, offering a starting point for comprehensive proteomics studies aiming at revealing biomarkers of clinical relevance. [less ▲]

Detailed reference viewed: 194 (49 ULg)
Full Text
Peer Reviewed
See detailComparison of three methods for fractionation and enrichment of low molecular weight proteins for SELDI-TOF-MS differential analysis
De Bock, Muriel ULg; De Seny, Dominique ULg; Meuwis, Marie-Alice ULg et al

in Talanta (2010), 82

In most diseases, the clinical need for serum/plasma markers has never been so crucial, not only for diagnosis, but also for the selection of the most efficient therapies, as well as exclusion of ... [more ▼]

In most diseases, the clinical need for serum/plasma markers has never been so crucial, not only for diagnosis, but also for the selection of the most efficient therapies, as well as exclusion of ineffective or toxic treatment. Due to the high sample complexity, prefractionation is essential for exploring the deep proteome and finding specific markers. In this study, three different sample preparation methods (i.e., highly abundant protein precipitation, restricted access materials (RAM) combined with IMAC chromatography and peptide ligand affinity beads) were investigated in order to select the best fractionation step for further differential proteomic experiments focusing on the LMW proteome (MW inferior to 40,000 Da). Indeed, the aim was not to cover the entire plasma/serum proteome, but to enrich potentially interesting tissue leakage proteins. These three methods were evaluated on their reproducibility, on the SELDI-TOF-MS peptide/protein peaks generated after fractionation and on the information supplied. The studied methods appeared to give complementary information and presented good reproducibility (below 20%). Peptide ligand affinity beads were found to provide efficient depletion of HMW proteins and peak enrichment in protein/peptide profiles. [less ▲]

Detailed reference viewed: 75 (19 ULg)
Full Text
Peer Reviewed
See detailA new statistical method for the automated detection of peaks in UV-DAD chromatograms of a sample mixture
Debrus, Benjamin ULg; Lebrun, Pierre ULg; Ceccato, Attilio ULg et al

in Talanta (2009), 79

One of the major issues within the context of the fully automated development of chromatographic methods consists of the automated detection and identification of peaks coming from complex samples such as ... [more ▼]

One of the major issues within the context of the fully automated development of chromatographic methods consists of the automated detection and identification of peaks coming from complex samples such as multi-component pharmaceutical formulations or stability studies of these formulations. The same problem can also occur with plant materials or biological matrices. This step is thus critical and time-consuming, especially when a Design of Experiments (DOE) approach is used to generate chromatograms. The use of DOE will often maximize the changes of the analytical conditions in order to explore an experimental domain. Unfortunately, this generally provides very different and “unpredictable” chromatograms which can be difficult to interpret, thus complicating peak detection and peak tracking (i.e. matching peaks among all the chromatograms). In this context, Independent Components Analysis (ICA), a new statistically based signal processing methods was investigated to solve this problem. The ICA principle assumes that the observed signal is the resultant of several phenomena (known as sources) and that all these sources are statistically independent. Under those assumptions, ICA is able to recover the sources which will have a high probability of representing the constitutive components of a chromatogram. In the present study, ICA was successfully applied for the first time to HPLC–UVDAD chromatograms and it was shown that ICA allows differentiation of noise and artifact components from those of interest by applying clustering methods based on high-order statistics computed on these components. Furthermore, on the basis of the described numerical strategy, itwas also possible to reconstruct a cleaned chromatogram with minimum influence of noise and baseline artifacts. This can present a significant advance towards the objective of providing helpful tools for the automated development of liquid chromatography (LC) methods. It seems that analytical investigations could be shortened when using this type of methodologies. [less ▲]

Detailed reference viewed: 175 (47 ULg)