1
|
An optimized methodology for the determination of multiclass organic ultraviolet sunscreens and metabolites in human milk through chromatographic and chemometric resolution. Talanta 2024; 270:125560. [PMID: 38128275 DOI: 10.1016/j.talanta.2023.125560] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2023] [Revised: 12/11/2023] [Accepted: 12/13/2023] [Indexed: 12/23/2023]
Abstract
Organic UV filters (UVFS) are used to mitigate the dermal effects associated with health risks from UV radiation, making them essential in personal care products. UVFS are frequently identified in environmental samples due to their high lipophilicity and persistence, underscoring the urgency of comprehensive assessments and regulatory measures aimed at safeguarding ecosystems and human health. The present study reports a multiclass analytical method for determining 16 UV sunscreens and metabolites in breast milk based on an ultrasound-assisted-dispersive liquid-liquid micro-extraction (UA-DLLME) with further chromatographic and chemometric resolution. The experimental conditions of the UA-DLLME were optimized through the implementation of the Design of Experiment tools. To model the responses, least-squares and artificial neural network methodologies were implemented. The optimal conditions were found by employing the desirability function. The samples were analyzed through reverse-phase liquid chromatographic separation, UV diode array, and fast-scanning fluorescence detection. The chromatographic analysis enabled the resolution of 16 analytes in a total time of 13.0 min. Multivariate curve resolution-alternating least-square (MCR-ALS) modelling was implemented to resolve analytes that were not fully resolved and to determine analytes that coeluted with endogenous components of the breast milk samples. An enrichment factor of 5-fold concentration was obtained with this methodology, reaching recoveries between 65 % and 105 % for 13 multiclass UV sunscreens and metabolites in breast milk samples with RSD % and REP % lower than 12 %.
Collapse
|
2
|
Analytical techniques and chemometrics approaches in authenticating and identifying adulteration of paprika powder using fingerprints: A review. Microchem J 2022. [DOI: 10.1016/j.microc.2022.107382] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
|
3
|
Binding the gap between experiments, statistics, and method comparison: A tutorial for computing limits of detection and quantification in univariate calibration for complex samples. Anal Chim Acta 2022; 1209:339342. [PMID: 35569842 DOI: 10.1016/j.aca.2021.339342] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2021] [Revised: 11/26/2021] [Accepted: 11/29/2021] [Indexed: 11/30/2022]
Abstract
The present tutorial aims to review the most frequently reported criteria for the calculation of the limits of detection (LOD) and quantification (LOQ) in univariate calibration, summarizing their fundamentals, advantages, and limitations. The current criteria for estimating LOD and LOQ are based on diverse theoretical and/or empirical assumptions and require different amounts of experimental data, making the calculation rather complex in some cases. Moreover, alternative forms for calculating LOD/LOQ frequently lead to dissimilar results. This scenario might worsen in the case of complex analytical systems. Throughout this tutorial, different forms of calculating LOD/LOQ are illustrated using previously reported experimental datasets in the environmental chemistry field as examples. The influence of the sample matrix during the estimation of LOD/LOQ parameters is investigated through one calibration approache. The discrepancies in the obtained results with different criteria for the calculation of LOD/LOQ are highlighted. Finally, general guidelines and recommendations regarding experimental and data processing issues are proposed, aiming to promote fair criteria for the comparison of different analytical methodologies in terms of prediction ability and detection capability.
Collapse
|
4
|
First-order discrimination of methanolic extracts from plums according to harvesting date using fluorescence spectra. Quantification of polyphenols. Microchem J 2021. [DOI: 10.1016/j.microc.2021.106533] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
|
5
|
Photo-assisted ozonation of cefuroxime with solar radiation in a CPC pilot plant. Kinetic parameters determination. Sep Purif Technol 2021. [DOI: 10.1016/j.seppur.2021.118514] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
|
6
|
Untargeted classification for paprika powder authentication using visible – Near infrared spectroscopy (VIS-NIRS). Food Control 2021. [DOI: 10.1016/j.foodcont.2020.107564] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
|
7
|
Four- and five-way excitation-emission luminescence-based data acquisition and modeling for analytical applications. A review. Anal Chim Acta 2019; 1083:41-57. [PMID: 31493809 DOI: 10.1016/j.aca.2019.06.059] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2019] [Revised: 06/26/2019] [Accepted: 06/27/2019] [Indexed: 01/23/2023]
Abstract
The latest advances in both theory and experimental procedures on third-order/four-way and fourth-order/five-way calibration methods are discussed. This report is focused on excitation-emission (fluorescence and phosphorescence) matrices generation, employing different variables as the third data mode (time retention in chromatography, pH gradient, fluorescence/phosphorescence lifetime, kinetics, or other chemical treatments). Fully capitalizing on the second-order advantage, it has been possible to develop appealing analytical applications in spite of the complexity of the data. Extraction of the significant chemical information about the system under study as well as the individual abundance of the contributing constituents after proper higher-order data decomposition has allowed to analytical researchers performing quantitative analysis of complex samples. The experimental works reported up to the present are introduced and discussed in order to illustrate concepts. Throughout this work, the analytical benefits achieved by modeling third- and fourth-order data are exposed, attempting to contribute to the ongoing debate in the chemometric community regarding the existence and the true nature of the third-order advantage.
Collapse
|
8
|
Combination of fluorescence excitation emission matrices in polar and non-polar solvents to obtain three- and four- way arrays for classification of Tempranillo grapes according to maturation stage and hydric status. Talanta 2019; 199:652-661. [DOI: 10.1016/j.talanta.2019.03.002] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2018] [Revised: 02/28/2019] [Accepted: 03/01/2019] [Indexed: 12/29/2022]
|
9
|
Classification of pre-dyed textile fibers exposed to weathering and photodegradation by non-destructive excitation-emission fluorescence spectroscopy paired with discriminant unfolded-partial least squares. Forensic Chem 2019. [DOI: 10.1016/j.forc.2018.11.001] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
|
10
|
Modeling second-order data for classification issues: Data characteristics, algorithms, processing procedures and applications. Trends Analyt Chem 2018. [DOI: 10.1016/j.trac.2018.07.022] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
|
11
|
Phenanthrene metabolites determination in human breast and cow milk by combining elution time-emission fluorescence data with multiway calibration. Talanta 2018; 188:299-307. [DOI: 10.1016/j.talanta.2018.05.096] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2018] [Revised: 05/24/2018] [Accepted: 05/28/2018] [Indexed: 12/15/2022]
|
12
|
Detection and quantification of extra virgin olive oil adulteration by means of autofluorescence excitation-emission profiles combined with multi-way classification. Talanta 2018; 178:751-762. [DOI: 10.1016/j.talanta.2017.09.095] [Citation(s) in RCA: 57] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2017] [Revised: 09/27/2017] [Accepted: 09/30/2017] [Indexed: 11/27/2022]
|
13
|
Combination of Liquid Chromatography with Multivariate Curve Resolution-Alternating Least-Squares (MCR-ALS) in the Quantitation of Polycyclic Aromatic Hydrocarbons Present in Paprika Samples. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2016; 64:8254-8262. [PMID: 27717286 DOI: 10.1021/acs.jafc.6b03852] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
This work presents a strategy for quantitating polycyclic aromatic hydrocarbons (PAHs) in smoked paprika samples. For this, a liquid chromatographic method with fluorimetric detection (HPLC-FLD) was optimized. To resolve some interference co-eluting with the target analytes, the second-order multivariate curve resolution-alternating least-squares (MCR-ALS) algorithm has been employed combined with this liquid chromatographic method. Among the eight PAHs quantified (fluorene, phenanthrene, anthracene, pyrene, chrysene, benzo[a]anthracene, benzo[b]fluoranthene, and benzo[a]pyrene) by HPLC-FLD, only in the case of fluorene, pyrene, and benzo[b]fluoranthene was it necessary to apply the second-order algorithm for their resolution. Limits of detection and quantitation were between 0.015 and 0.45 mg/kg and between 0.15 and 1.5 mg/kg, respectively. Good recovery results (>80%) for paprika were obtained via the complete extraction procedure, consisting of an extraction from the matrix and the cleanup of the extract by means of silica cartridges. Higher concentrations of chrysene, benzo[a]anthracene, benzo[b]fluoranthene, and benzo[a]pyrene were found in the paprika samples, with respect to the maximal amounts allowed for other spices that are under European Regulation (EU) N° 2015/1933.
Collapse
|
14
|
Highly Selective and Ultrasensitive Turn-on Luminescence Chemosensor for Mercury (II) Determination Based on the Rhodamine 6G Derivative FC1 and Au Nanoparticles. SENSORS 2016; 16:s16101652. [PMID: 27782059 PMCID: PMC5087440 DOI: 10.3390/s16101652] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/23/2016] [Accepted: 09/28/2016] [Indexed: 11/25/2022]
Abstract
A method for the detection and quantitation of Hg2+ in aqueous samples by fluorescence spectroscopy is presented. It consists of a turn-on sensor developed by coupling Gold nanoparticles (AuNPs) with the rhodamine 6G derivative FC1, in which the response is generated by a mercury-induced ring-opening reaction. The AuNPs were included in order to improve the sensitivity of the method towards the analyte, maintaining its high selectivity. The method was validated in terms of linearity, precision and accuracy, and applied to the quantitation of Hg2+ in Milli-Q and tap water with and without spiked analyte. The limit of detection and quantitation were 0.15 μg·L−1 and 0.43 μg·L−1, respectively, constituting a substantial improvement of sensitivity in comparison with the previously reported detection of Hg2+ with free FC1.
Collapse
|
15
|
Isocratic LC–DAD–FLD method for the determination of flavonoids in paprika samples by using a rapid resolution column and post-column pH change. Talanta 2016; 152:15-22. [DOI: 10.1016/j.talanta.2016.01.041] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2015] [Revised: 01/18/2016] [Accepted: 01/22/2016] [Indexed: 12/27/2022]
|
16
|
Nondestructive Total Excitation–Emission Fluorescence Microscopy Combined with Multi-Way Chemometric Analysis for Visually Indistinguishable Single Fiber Discrimination. Anal Chem 2016; 88:2967-75. [DOI: 10.1021/acs.analchem.6b00264] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
|
17
|
Unfolded and Multiway Partial Least-Squares with Residual Multilinearization. DATA HANDLING IN SCIENCE AND TECHNOLOGY 2015. [DOI: 10.1016/b978-0-444-63527-3.00008-4] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/03/2022]
|
18
|
Second- and higher-order data generation and calibration: A tutorial. Anal Chim Acta 2014; 806:8-26. [DOI: 10.1016/j.aca.2013.11.009] [Citation(s) in RCA: 120] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2013] [Revised: 10/30/2013] [Accepted: 11/03/2013] [Indexed: 10/26/2022]
|
19
|
AUTOMATIC EVALUATION AND DATA GENERATION FOR ANALYTICAL CHEMISTRY INSTRUMENTAL ANALYSIS EXERCISES. QUIM NOVA 2014. [DOI: 10.5935/0100-4042.20140242] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
|
20
|
Determination of Mercuric Ion in Water Samples with a LED Exciting and CCD Based Portable Spectrofluorimeter. ACTA ACUST UNITED AC 2011. [DOI: 10.4236/ajac.2011.25068] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
|
21
|
Fluorescent determination of Hg2+ in water and fish samples using a chemodosimeter based in a Rhodamine 6G derivative and a portable fiber-optic spectrofluorimeter. APPLIED SPECTROSCOPY 2010; 64:520-527. [PMID: 20482971 DOI: 10.1366/000370210791211600] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
A fluorimetric chemodosimeter (FC1), based on a Rhodamine 6G derivative, is proposed for the recognition of Hg(2+) ions in water and fish samples. The reagent shows a highly selective and sensitive reaction with Hg(2+), giving rise to strong fluorescence emission at 555 nm. The obvious color change of the solution from colorless to pink upon the addition of Hg(2+) demonstrates that FC1 can be used for "naked-eye" detection of Hg(2+) in water effluents. The fluorescence intensity is proportional to the amount of Hg(2+) at ng mL(-1) levels, and it is capable of distinguishing between safe and toxic levels of inorganic mercury in drinking water and fish samples. The procedure has been implemented in a portable instrument composed of a 515 nm light-emitting diode (LED) excitation source, two fiber optics, and a charge-coupled device (CCD) camera as detector, connected to a portable computer for data acquisition and analysis, intended for in situ determination of mercury, offering a viable alternative to a conventional spectrofluorimeter. The proposed method has been applied to different water and fish samples with satisfactory results.
Collapse
|
22
|
Determination of marker pteridins and biopterin reduced forms, tetrahydrobiopterin and dihydrobiopterin, in human urine, using a post-column photoinduced fluorescence liquid chromatographic derivatization method. Anal Chim Acta 2009; 648:113-22. [PMID: 19616696 DOI: 10.1016/j.aca.2009.06.045] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2009] [Revised: 06/17/2009] [Accepted: 06/17/2009] [Indexed: 11/18/2022]
Abstract
A liquid chromatographic method for the simultaneous analysis of marker pteridins and biopterin reduced forms, in urine samples is proposed. A Zorbax Eclipse XDB-C18 column was used for the chromatographic separation, using a 98/2 (v/v), citrate buffer (pH 5.5)-acetonitrile mobile phase, in isocratic mode. A post-column photoderivatization was carried out with an on-line photoreactor, located between a diode array detector (DAD) and a fast scanning fluorescence detector (FSFD). Neopterin (NEO), biopterin (BIO), pterin (PT) and dihydrobiopterin (BH2) were determined by measuring native fluorescence, using the photoreactor in OFF-mode, and tetrahydrobiopterin (BH4) was determined by measuring of the induced fluorescence of the generated photoproducts, using the photoreactor in ON-mode. In addition, Creatinine (CREA), as a reference of metabolites excrection in urine, was simultaneously determined using the DAD detector. Detection limits were 0.2, 13.0, 0.3, 0.3 and 3.5 ng mL(-1), for NEO, BH2, BIO, PT and BH4, respectively, and 0.4 microg mL(-1) for CREA. Ratio values for NEO/CREA, PT/CREA, BH4/CREA, BH2/CREA, NEO/BIO and BIO(total)/CREA, in urine samples, of healthy children and adults, phenylketonuric children and infected mononucleosis children, are reported. A comparative study, about the mean values obtained for each of the compounds, by the present procedure and by the classical iodine oxidation method (Fukushimas method), has been performed, in urine samples belonging to healthy volunteers. The values obtained were BH4/CREA: 0.41, BH2/CREA: 0.31 and BIO(total)/CREA: 0.73, by the proposed method, and BH4/CREA: 0.35, BH2/CREA: 0.20 and BIO(total)/CREA: 0.48, by iodine oxidation method.
Collapse
|
23
|
Determination of danofloxacin in milk combining second-order calibration and standard addition method using excitation–emission fluorescence data. Food Chem 2009. [DOI: 10.1016/j.foodchem.2008.08.032] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
|
24
|
Nonlinear four-way kinetic-excitation-emission fluorescence data processed by a variant of parallel factor analysis and by a neural network model achieving the second-order advantage: malonaldehyde determination in olive oil samples. Anal Chem 2008; 80:7248-56. [PMID: 18752340 DOI: 10.1021/ac8007829] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Four-way data were obtained by recording the kinetic evolution of excitation-emission fluorescence matrices for the product of the Hantzsch reaction between the analyte malonaldehyde and methylamine. The reaction product, 1,4-disubstituted-1,4-dihydropyridine-3,5-dicarbaldehyde, is a highly fluorescent compound. The nonlinear nature of the kinetic fluorescence data has been demonstrated, and therefore the four-way data were processed with parallel factor analysis combined with a nonlinear pseudounivariate regression, based on a quadratic polynomial fit, and also with a recently introduced neural network methodology, based on the combination of unfolded principal component analysis, residual trilinearization, and radial basis functions. The applied chemometric strategies are not only able to adequately model the nonlinear data but also to successfully determine malonaldehyde in olive oil samples. This is possible since the experimentally recorded four-way data, modeled with the above-mentioned advanced chemometric approaches, permit the achievement of the second-order advantage. This allows us to predict the analyte concentration in a complex background, in spite of the nonlinear behavior and in the presence of uncalibrated interferences. The present work is a new example of the use of higher-order data for the resolution of a complex nonlinear system, successfully employed in the context of food chemical analysis.
Collapse
|
25
|
Multiway Partial Least-Squares Coupled to Residual Trilinearization: A Genuine Multidimensional Tool for the Study of Third-Order Data. Simultaneous Analysis of Procaine and Its Metabolitep-Aminobenzoic Acid in Equine Serum. Anal Chem 2007; 79:6949-58. [PMID: 17688323 DOI: 10.1021/ac070596+] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
A new third-order multivariate calibration approach, based on the combination of multiway-partial least-squares with a separate procedure called residual trilinearization (N-PLS/RTL), is presented and applied to multicomponent analysis using third-order data. The proposed chemometric algorithm is able to predict analyte concentrations in the presence of unexpected sample components, which require strict adherence to the second-order advantage. Results for the determination of procaine and its metabolite p-aminobenzoic acid in equine serum are discussed, based on kinetic fluorescence excitation-emission four-way measurements and application of the newly developed multiway methodology. Since the analytes are also the reagent and product of the hydrolysis reaction followed by fast-scanning fluorescence spectroscopy, the classical approach based on parallel factor analysis is challenged by strong linear dependencies and multilinearity losses. In comparison, N-PLS/RTL appears an appealing genuine multiway alternative that avoids the latter complications, yielding analytical results that are statistically comparable to those rendered by related unfolded algorithms, which are also able to process four-way data. Prediction was made on validation samples with a qualitative composition similar to the calibration set and also on test samples containing unexpected equine serum components.
Collapse
|
26
|
Separation of fifteen quinolones by high performance liquid chromatography: Application to pharmaceuticals and ofloxacin determination in urine. J Sep Sci 2007; 30:1242-9. [PMID: 17623463 DOI: 10.1002/jssc.200600536] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
A simple chromatographic method is described for assaying 15 quinolones and fluoroquinolones (pipemidic acid, marbofloxacin, enoxacin, ofloxacin, norfloxacin, ciprofloxacin, danofloxacin, lomefloxacin, enrofloxacin, sarafloxacin, difloxacin, oxolinic acid, nalidixic acid, flumequine and piromidic acid), in urine and pharmaceutical samples. The determination was achieved by LC using an RP C18 analytical column. A mobile phase composed of mixtures of methanol-ACN-10 mM citrate buffer at pH 3.5 and 10 mM citrate buffer at pH 4.5, delivered under an optimum gradient program, at a flow rate of 1.5 mL/min, allows to accomplish the chromatographic separation in 26 min. For detection, diode-array UV-Vis at 280 nm and fluorescence detection set at excitation wavelength/emission wavelength: 280/450, 280/ 495, 280/405 and 320/360 nm were used. Detection and quantification limits were between 0.3-18 and 0.8-61 ng/mL, respectively. The method was validated in terms of interday (n = 6) and intraday (n = 6) precision and accuracy. The procedure was successfully applied to the analysis of human and veterinary pharmaceuticals. Also, ofloxacin was determined in human urine samples belonging to a patient undergoing treatment with this active principle, among others.
Collapse
|
27
|
Second-Order Advantage Achieved by Unfolded-Partial Least-Squares/Residual Bilinearization Modeling of Excitation−Emission Fluorescence Data Presenting Inner Filter Effects. Anal Chem 2006; 78:8051-8. [PMID: 17134139 DOI: 10.1021/ac061369v] [Citation(s) in RCA: 61] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
A second-order multivariate calibration approach, based on a combination of unfolded-partial least-squares with residual bilinearization (U-PLS/RBL), has been applied to fluorescence excitation-emission matrix data for multicomponent mixtures showing inner filter effects. The employed chemometric algorithm is the most successful one regarding the prediction of analyte concentrations when significant inner filter effects occur, even in the presence of unexpected sample components, which require strict adherence to the second-order advantage. Results for simulated fluorescence excitation-emission data are described, in comparison with the classical approach based on parallel factor analysis and other second-order algorithms, including generalized rank annihilation, bilinear least squares combined with residual bilinearization and multivariate curve resolution-alternating leastsquares. A set of experimental data was also studied, in which calibration was performed with fluorescence excitation-emission matrices for samples containing mixtures of chrysene (the analyte of interest) and benzopyrene (which produced strong inner filter effect across the useful wavelength range). Prediction was made on validation samples with a qualitative composition similar to the calibration set, and also on test samples containing an unexpected component (pyrene). In this latter case, U-PLS/RBL showed a unique success for the analysis of the calibrated component chrysene, achieving the useful second-order advantage.
Collapse
|
28
|
Abstract
This paper reports, for the first time, a liquid chromatographic method for the simultaneous determination of three frequently co-administered active principles, two antibiotics, ciprofloxacin (CIPRO) and cloxacillin (CLOXA) belonging to the fluoroquinolones and beta-lactam families, respectively, and ibuprofen (IBU), a non-steroidal anti-inflammatory drug. The chromatographic separation was performed on a C-18 analytical column, using isocratic elution with methanol-acetonitrile-pH 3 formate buffer (CT = 0.1 M) (15:12:73, v/v/v) for 3 min and, after that, a linear gradient with methanol-acetonitrile (88:12, v/v) for 8 min. Several absorption spectra were obtained for each peak using a DAD detector. Chromatograms at the maximum absorption wavelength for each analyte, 220 nm for both IBU and CLOXA, and 280 nm for CIPRO were selected as the most suitable. The proposed chromatographic method requires about 15 min per sample. The presence of a urine background was tested and no interference was found. The method was satisfactorily applied to the determination of CIPRO, CLOXA, and IBU, in fortified urine, and in urine samples from a patient undergoing treatment with these three active principles, among others. Limits of quantification in urine were 1.00, 1.70, and 2.87 microg/mL for CIPRO, CLOXA, and IBU, respectively.
Collapse
|
29
|
Second-Order Advantage Achieved with Four-Way Fluorescence Excitation−Emission−Kinetic Data Processed by Parallel Factor Analysis and Trilinear Least-Squares. Determination of Methotrexate and Leucovorin in Human Urine. Anal Chem 2004; 76:5657-66. [PMID: 15456283 DOI: 10.1021/ac0493065] [Citation(s) in RCA: 100] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Four-way fluorescence data recorded by following the kinetic evolution of excitation-emission fluorescence matrices (EEMs) have been analyzed by parallel factor analysis and trilinear least-squares algorithms. These methodologies exploit the second-order advantage of the studied data, allowing analyte concentrations to be estimated even in the presence of an uncalibrated fluorescent background. They were applied to the simultaneous determination of the components of the anticancer combination of methotrexate and leucovorin in human urine samples. Both analytes were converted into highly fluorescent compounds by oxidation with potassium permanganate, and the kinetics of the reaction was continuously monitored by recording full EEM of the samples at different reaction times. A commercial fast scanning spectrofluorometer has been used for the first time to measure the four-way EEM kinetic data. The rapid scanning instrument allows the acquisition of a complete EEM in 12 s at a wavelength scanning speed of 24 000 nm/min. The emission spectra were recorded from 335 to 490 nm at 5-nm intervals, exciting from 255 to 315 nm at 6-nm intervals. Ten successive EEMs were measured at 72-s intervals, to follow the fluorescence kinetic evolution of the mixture components. Good recoveries were obtained in synthetic binary samples and also in spiked urine samples. The excitation, emission, and kinetic time profiles recovered by both chemometric techniques are in good agreement with experimental observations.
Collapse
|
30
|
Two multivariate strategies applied to three-way kinetic spectrophotometric data for the determination of mixtures of the pesticides carbaryl and chlorpyrifos. APPLIED SPECTROSCOPY 2004; 58:83-90. [PMID: 14727724 DOI: 10.1366/000370204322729504] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Two pesticides, carbaryl and chlorpyrifos, have been simultaneously determined using second-order kinetic spectrophotometric measurements upon alkaline oxidative degradation. In spite of the complexity of the system and of the serious spectral overlap among the reagents and products, calibration and prediction is possible thanks to the power of second-order multivariate techniques. Strategies such as parallel factor analysis (PARAFAC) and multivariate curve resolution coupled to alternating least-squares (MCR-ALS) have been employed, which adequately exploit the second-order advantage. They allow for a correct determination of the analytes both in synthetic binary samples and in a commercial formulation, in this latter case even in the presence of unmodeled interferents. Multi-way partial least-squares (n-PLS) produced good results only on synthetic binary mixtures but could not be applied to a commercial sample because it contained an uncalibrated component.
Collapse
|
31
|
Interference-free analysis using three-way fluorescence data and the parallel factor model. Determination of fluoroquinolone antibiotics in human serum. Anal Chem 2003; 75:2640-6. [PMID: 12948131 DOI: 10.1021/ac026360h] [Citation(s) in RCA: 86] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Three-way fluorescence data and multivariate calibration based on parallel factor analysis (PARAFAC) are combined for the simultaneous quantitation of three fluoroquinolone anitibiotics (norfloxacin, enoxacin, and ofloxacin) in human serum samples. The three analytes can be adequately determined with limits of detection of 0.2, 3.0, and 0.5 microg L(-1), respectively, with minimum experimental effort. The selected analytical methodology fully exploits the so-called second-order advantage of the employed three-way data, allowing obtaining individual concentrations of calibrated analytes in the presence of any number of uncalibrated (serum) components. In contrast to PARAFAC, less satisfactory results were obtained with a multidimensional partial least-squares (nPLS) model trained with the same calibration set.
Collapse
|
32
|
Determination of theophylline in blood serum by UV spectrophotometry and partial least-squares (PLS-1) calibration. Anal Chim Acta 1999. [DOI: 10.1016/s0003-2670(98)00834-4] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
|
33
|
Room-temperature phosphorescence of acenaphthene in aerated solutions in the presence of bromoalcohols and γ-cyclodextrin. Anal Chim Acta 1998. [DOI: 10.1016/s0003-2670(98)00270-0] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
|
34
|
Simultaneous fluorimetric determination of acetylsalicylic acid metabolites in urine by partial least squares multivariate calibration. ACTA ACUST UNITED AC 1995. [DOI: 10.1007/bf00322961] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
|
35
|
Fluorimetric Determination of Sulfametoxazole in Pharmaceutical Preparations in Combination with Trimethoprim by Inclusion in β-Cyclodextrin/Urea. ANAL LETT 1994. [DOI: 10.1080/00032719408002639] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
|
36
|
Spectrofluorimetric determination of nalidixic acid based on host–guest complexation with γ-cyclodextrin. Analyst 1994. [DOI: 10.1039/an9941901215] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
|
37
|
Spectrophotometric determination of mixtures of iron(III) and manganese(II) by complexation with 3-indolylacetohydroxamic acid and principal component regression multivariate calibration. Analyst 1994. [DOI: 10.1039/an9941901537] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
|
38
|
Determination of 1-naphthylamine and the related pesticides, naptalam and antu, in river-water by high-performance liquid chromatography. Application to the study of the degradation processes of naptalam. Analyst 1994. [DOI: 10.1039/an9941901151] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
|
39
|
Retention behavior of β-cyclodextrin complexes of anthracene and pyrene using reversed-phase liquid chromatography. J Chromatogr A 1992. [DOI: 10.1016/0021-9673(92)80311-h] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
|
40
|
Analysis of mixtures of oxytetracycline and riboflavine by first-derivative synchronous spectrofluorimetry. Analyst 1991. [DOI: 10.1039/an9911600291] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
|
41
|
Simultaneous determination of molybdenum and tungsten by first-derivative synchronous spectrofluorimetry. Analyst 1989. [DOI: 10.1039/an9891401297] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
|
42
|
Simultaneous determination of aluminium and zinc by first- and second-derivative synchronous fluorimetry. Analyst 1988. [DOI: 10.1039/an9881301435] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
|
43
|
|
44
|
Spectrofluorimetric determination of beryllium in rocks, alloys and steels with nuclear fast red. Analyst 1987. [DOI: 10.1039/an9871200645] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
|
45
|
|
46
|
Simultaneous determination of beryllium and magnesium with 1-hydroxy-2-carboxyanthraquinone by first-derivative spectrophotometry. Analyst 1987. [DOI: 10.1039/an9871201391] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
|