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Inner filter effect in fluorescence spectroscopy: As a problem and as a solution. JOURNAL OF PHOTOCHEMISTRY AND PHOTOBIOLOGY C-PHOTOCHEMISTRY REVIEWS 2019. [DOI: 10.1016/j.jphotochemrev.2019.100318] [Citation(s) in RCA: 97] [Impact Index Per Article: 19.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
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2
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Kumar K, Tarai M, Mishra AK. Unconventional steady-state fluorescence spectroscopy as an analytical technique for analyses of complex-multifluorophoric mixtures. Trends Analyt Chem 2017. [DOI: 10.1016/j.trac.2017.09.004] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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3
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Ryder AG, Stedmon CA, Harrit N, Bro R. Calibration, standardization, and quantitative analysis of multidimensional fluorescence (MDF) measurements on complex mixtures (IUPAC Technical Report). PURE APPL CHEM 2017. [DOI: 10.1515/pac-2017-0610] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
AbstractThis IUPAC Technical Report describes and compares the currently applied methods for the calibration and standardization of multi-dimensional fluorescence (MDF) spectroscopy data as well as recommendations on the correct use of chemometric methods for MDF data analysis. The paper starts with a brief description of the measurement principles for the most important MDF techniques and a short introduction to the most important applications. Recommendations are provided for instrument calibration, sample preparation and handling, and data collection, as well as the proper use of chemometric data analysis methods.
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Affiliation(s)
- Alan G. Ryder
- Nanoscale Biophotonics Laboratory, School of Chemistry, National University of Ireland, Galway, Ireland
| | - Colin A. Stedmon
- National Institute for Aquatic Resources, Technical University of Denmark, DK-2800, Kgs.Lyngby, Denmark
| | - Niels Harrit
- Nanoscience Center, H. C. Ørsted Institute, Universitetsparken 5, University of Copenhagen, DK-2100, Copenhagen, Denmark
| | - Rasmus Bro
- Department Food Science, Faculty of Life Sciences, University Copenhagen, DK-1958, Frederiksberg, Denmark
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Mabood F, Boqué R, Folcarelli R, Busto O, Jabeen F, Al-Harrasi A, Hussain J. The effect of thermal treatment on the enhancement of detection of adulteration in extra virgin olive oils by synchronous fluorescence spectroscopy and chemometric analysis. SPECTROCHIMICA ACTA. PART A, MOLECULAR AND BIOMOLECULAR SPECTROSCOPY 2016; 161:83-87. [PMID: 26963728 DOI: 10.1016/j.saa.2016.02.032] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/05/2015] [Revised: 01/25/2016] [Accepted: 02/28/2016] [Indexed: 06/05/2023]
Abstract
In this study the effect of thermal treatment on the enhancement of synchronous fluorescence spectroscopic method for discrimination and quantification of pure extra virgin olive oil (EVOO) samples from EVOO samples adulterated with refined oil was investigated. Two groups of samples were used. One group was analyzed at room temperature (25 °C) and the other group was thermally treated in a thermostatic water bath at 75 °C for 8h, in contact with air and with light exposure, to favor oxidation. All the samples were then measured with synchronous fluorescence spectroscopy. Synchronous fluorescence spectra were acquired by varying the wavelength in the region from 250 to 720 nm at 20 nm wavelength differential interval of excitation and emission. Pure and adulterated olive oils were discriminated by using partial least-squares discriminant analysis (PLS-DA). It was found that the best PLS-DA models were those built with the difference spectra (75 °C-25 °C), which were able to discriminate pure from adulterated oils at a 2% level of adulteration of refined olive oils. Furthermore, PLS regression models were also built to quantify the level of adulteration. Again, the best model was the one built with the difference spectra, with a prediction error of 3.18% of adulteration.
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Affiliation(s)
- F Mabood
- Department of Biological Sciences & Chemistry, College of Arts and Sciences, University of Nizwa, Oman.
| | - R Boqué
- Department of Analytical Chemistry and Organic Chemistry, Universitat Rovira i Virgili, Tarragona, Spain
| | - R Folcarelli
- Department of Chemistry, University of Rome "Sapienza", P.e Aldo Moro 5, I-00185 Rome, Italy
| | - O Busto
- Department of Analytical Chemistry and Organic Chemistry, Universitat Rovira i Virgili, Tarragona, Spain
| | - F Jabeen
- Department of Chemistry, University of Malakand, KPK, Pakistan
| | - Ahmed Al-Harrasi
- UoN Chair of Oman Medicinal Plants and Marine Products, University of Nizwa, Sultanate of Oman
| | - J Hussain
- Department of Biological Sciences & Chemistry, College of Arts and Sciences, University of Nizwa, Oman
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Mu T, Chen S, Zhang Y, Chen H, Guo P, Meng F. Classification of Motor Oil Using Laser-Induced Fluorescence and Phosphorescence. ANAL LETT 2015. [DOI: 10.1080/00032719.2015.1086777] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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Mabood F, Boqué R, Folcarelli R, Busto O, Al-Harrasi A, Hussain J. Thermal oxidation process accelerates degradation of the olive oil mixed with sunflower oil and enables its discrimination using synchronous fluorescence spectroscopy and chemometric analysis. SPECTROCHIMICA ACTA. PART A, MOLECULAR AND BIOMOLECULAR SPECTROSCOPY 2015; 143:298-303. [PMID: 25748285 DOI: 10.1016/j.saa.2015.01.119] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/07/2014] [Revised: 12/15/2014] [Accepted: 01/31/2015] [Indexed: 06/04/2023]
Abstract
We have investigated the effect of thermal treatment on the discrimination of pure extra virgin olive oil (EVOO) samples from EVOO samples adulterated with sunflower oil. Two groups of samples were used. One group was analyzed at room temperature (25°C) and the other group was thermally treated in a thermostatic water bath at 75°C for 8h, in contact with air and with light exposure, to favor oxidation. All samples were then measured with synchronous fluorescence spectroscopy. Fluorescence spectra were acquired by varying the excitation wavelength in the region from 250 to 720nm. In order to optimize the differences between excitation and emission wavelengths, four constant differential wavelengths, i.e., 20nm, 40nm, 60nm and 80nm, were tried. Partial least-squares discriminant analysis (PLS-DA) was used to discriminate between pure and adulterated oils. It was found that the 20nm difference was the optimal, at which the discrimination models showed the best results. The best PLS-DA models were those built with the difference spectra (75-25°C), which were able to discriminate pure from adulterated oils at a 2% level of adulteration. Furthermore, PLS regression models were built to quantify the level of adulteration. Again, the best model was the one built with the difference spectra, with a prediction error of 1.75% of adulteration.
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Affiliation(s)
- Fazal Mabood
- Department of Biological Sciences & Chemistry, College of Arts and Sciences, University of Nizwa, Oman.
| | - Ricard Boqué
- Department of Analytical Chemistry and Organic Chemistry, Universitat Rovira i Virgili, Tarragona, Spain
| | - Rita Folcarelli
- Department of Chemistry, University of Rome "Sapienza", P.e Aldo Moro 5, I-00185 Rome, Italy
| | - Olga Busto
- Department of Analytical Chemistry and Organic Chemistry, Universitat Rovira i Virgili, Tarragona, Spain
| | - Ahmed Al-Harrasi
- Department of Biological Sciences & Chemistry, College of Arts and Sciences, University of Nizwa, Oman
| | - Javid Hussain
- Department of Biological Sciences & Chemistry, College of Arts and Sciences, University of Nizwa, Oman
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Groza RC, Calvet A, Ryder AG. A fluorescence anisotropy method for measuring protein concentration in complex cell culture media. Anal Chim Acta 2014; 821:54-61. [PMID: 24703214 DOI: 10.1016/j.aca.2014.03.007] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2014] [Revised: 03/06/2014] [Accepted: 03/07/2014] [Indexed: 01/09/2023]
Abstract
The rapid, quantitative analysis of the complex cell culture media used in biopharmaceutical manufacturing is of critical importance. Requirements for cell culture media composition profiling, or changes in specific analyte concentrations (e.g. amino acids in the media or product protein in the bioprocess broth) often necessitate the use of complicated analytical methods and extensive sample handling. Rapid spectroscopic methods like multi-dimensional fluorescence (MDF) spectroscopy have been successfully applied for the routine determination of compositional changes in cell culture media and bioprocess broths. Quantifying macromolecules in cell culture media is a specific challenge as there is a need to implement measurements rapidly on the prepared media. However, the use of standard fluorescence spectroscopy is complicated by the emission overlap from many media components. Here, we demonstrate how combining anisotropy measurements with standard total synchronous fluorescence spectroscopy (TSFS) provides a rapid, accurate quantitation method for cell culture media. Anisotropy provides emission resolution between large and small fluorophores while TSFS provides a robust measurement space. Model cell culture media was prepared using yeastolate (2.5 mg mL(-1)) spiked with bovine serum albumin (0 to 5 mg mL(-1)). Using this method, protein emission is clearly discriminated from background yeastolate emission, allowing for accurate bovine serum albumin (BSA) quantification over a 0.1 to 4.0 mg mL(-1) range with a limit of detection (LOD) of 13.8 μg mL(-1).
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Affiliation(s)
- Radu Constantin Groza
- Nanoscale Biophotonics Laboratory, School of Chemistry, National University of Ireland, Galway, Ireland
| | - Amandine Calvet
- Nanoscale Biophotonics Laboratory, School of Chemistry, National University of Ireland, Galway, Ireland
| | - Alan G Ryder
- Nanoscale Biophotonics Laboratory, School of Chemistry, National University of Ireland, Galway, Ireland.
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8
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Kumar K, Mishra AK. Analysis of dilute aqueous multifluorophoric mixtures using excitation-emission matrix fluorescence (EEMF) and total synchronous fluorescence (TSF) spectroscopy: a comparative evaluation. Talanta 2013; 117:209-20. [PMID: 24209332 DOI: 10.1016/j.talanta.2013.09.002] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2013] [Revised: 08/31/2013] [Accepted: 09/02/2013] [Indexed: 10/26/2022]
Abstract
Excitation-emission matrix fluorescence (EEMF) and total synchronous fluorescence (TSF) spectroscopy are two conceptually different fluorescence techniques that have been used to map the fluorescence responses of the fluorophores present in a multifluorophoric mixture. EEMF was introduced four decades back and most of the fluorimeters have the suitable computer program which allows the acquisition EEMF spectra. Recently introduced TSF spectroscopy has been shown to possess good application potential in analytical fluorimetry and has started attracting the attention of analytical chemists. TSF data structure, however, is intrinsically different from EEMF data structure and a better understanding of TSF data structure is crucial to utilising its application potential. In the present work, a comprehensive comparative study between EEMF and TSF spectroscopic data set was performed by taking aqueous mixtures containing low concentrations of benzo[a]pyrene, chrysene, and pyrene as test case. The EEMF and TSF data structures were clearly explained by taking pyrene as an example. The effects of Rayleigh and Raman scattering on the quality of EEMF and TSF data sets were studied. EEMF and TSF data sets of dilute aqueous mixtures of benzo[a]pyrene, chrysene, and pyrene were subjected to three chemometric techniques PARAFAC, N-PLS, and MCR-ALS analysis. TSF data set in particular was found to be highly attuned to MCR-ALS analysis. Obtained results of chemometric analyses on EEMF and TSF data sets show that TSF data of dilute aqueous mixtures provides more accurate spectral and concentration information than EEMF data sets. Therefore, TSF spectroscopy could be considered as an alternate to the EEMF for the analyses of dilute multifluorophoric mixtures.
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Affiliation(s)
- Keshav Kumar
- Department of Chemistry, Indian Institute of Technology-Madras, Chennai-600036, India
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9
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Rapid quantification of tryptophan and tyrosine in chemically defined cell culture media using fluorescence spectroscopy. J Pharm Biomed Anal 2012; 71:89-98. [DOI: 10.1016/j.jpba.2012.08.002] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2012] [Revised: 08/01/2012] [Accepted: 08/05/2012] [Indexed: 11/19/2022]
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10
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Kumar K, Mishra AK. Application of parallel factor analysis to total synchronous fluorescence spectrum of dilute multifluorophoric solutions: addressing the issue of lack of trilinearity in total synchronous fluorescence data set. Anal Chim Acta 2012; 755:37-45. [PMID: 23146392 DOI: 10.1016/j.aca.2012.10.024] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2012] [Revised: 09/25/2012] [Accepted: 10/16/2012] [Indexed: 10/27/2022]
Abstract
In recent years, total synchronous fluorescence (TSF) spectroscopy has become popular for the analysis of multifluorophoric systems. Application of PARAFAC, a popular deconvolution tool, requires trilinear structure in the three-way data array. The present work shows that TSF based three-way array data set of dimension sample × wavelength × Δλ does not have trilinear structure and hence it should not be subjected to PARAFAC analysis. This work also proposes that a TSF data set can be converted to an excitation-emission matrix fluorescence (EEMF) like data set which has trilinear structure, so that PARAFAC analysis can be performed on it. This also enables the retrieval of PARAFAC-separated component TSF spectra.
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Affiliation(s)
- Keshav Kumar
- Department of Chemistry, Indian Institute of Technology-Madras, Chennai, India.
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Andrade-Eiroa Á, de-Armas G, Estela JM, Cerdà V. Critical approach to synchronous spectrofluorimetry. I. Trends Analyt Chem 2010. [DOI: 10.1016/j.trac.2010.04.010] [Citation(s) in RCA: 59] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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12
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Andrade-Eiroa Á, de-Armas G, Estela JM, Cerdà V. Critical approach to synchronous spectrofluorimetry. II. Trends Analyt Chem 2010. [DOI: 10.1016/j.trac.2010.05.002] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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13
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Ryan PW, Li B, Shanahan M, Leister KJ, Ryder AG. Prediction of Cell Culture Media Performance Using Fluorescence Spectroscopy. Anal Chem 2010; 82:1311-7. [DOI: 10.1021/ac902337c] [Citation(s) in RCA: 60] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Paul W. Ryan
- Nanoscale Biophotonics Laboratory, School of Chemistry, National University of Ireland, Galway, Galway, Ireland, Centre for Bioanalytical Sciences, School of Chemistry, National University of Ireland, Galway, Galway, Ireland, and Process Analytical Sciences, Bristol-Myers Squibb, Syracuse, New York
| | - Boyan Li
- Nanoscale Biophotonics Laboratory, School of Chemistry, National University of Ireland, Galway, Galway, Ireland, Centre for Bioanalytical Sciences, School of Chemistry, National University of Ireland, Galway, Galway, Ireland, and Process Analytical Sciences, Bristol-Myers Squibb, Syracuse, New York
| | - Michael Shanahan
- Nanoscale Biophotonics Laboratory, School of Chemistry, National University of Ireland, Galway, Galway, Ireland, Centre for Bioanalytical Sciences, School of Chemistry, National University of Ireland, Galway, Galway, Ireland, and Process Analytical Sciences, Bristol-Myers Squibb, Syracuse, New York
| | - Kirk J. Leister
- Nanoscale Biophotonics Laboratory, School of Chemistry, National University of Ireland, Galway, Galway, Ireland, Centre for Bioanalytical Sciences, School of Chemistry, National University of Ireland, Galway, Galway, Ireland, and Process Analytical Sciences, Bristol-Myers Squibb, Syracuse, New York
| | - Alan G. Ryder
- Nanoscale Biophotonics Laboratory, School of Chemistry, National University of Ireland, Galway, Galway, Ireland, Centre for Bioanalytical Sciences, School of Chemistry, National University of Ireland, Galway, Galway, Ireland, and Process Analytical Sciences, Bristol-Myers Squibb, Syracuse, New York
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15
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Nevin A, Cather S, Burnstock A, Anglos D. Analysis of protein-based media commonly found in paintings using synchronous fluorescence spectroscopy combined with multivariate statistical analysis. APPLIED SPECTROSCOPY 2008; 62:481-489. [PMID: 18498688 DOI: 10.1366/000370208784344523] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
The spectrofluorimetric analysis of protein-based binding media, which are commonly found as painting materials, is based on the detection of emissions from amino acids, as well as fluorescent degradation products that develop with aging. Laser-induced fluorescence spectroscopy, fluorescence excitation emission spectroscopy, and time-resolved fluorescence spectroscopy have all been employed in efforts to discriminate between commonly found proteinaceous binding media, including egg white, egg yolk, milk, and casein, as well as collagen-based glues from rabbit skin, ox bone, parchment, and fish. However, synchronous fluorescence spectroscopy (SFS), a rapid means of recording fluorescence properties of samples, has not been reported for the differentiation between binding media. This work focuses on the analysis of a large set of naturally aged films of different protein-based binding media using SFS with a range of different offsets between excitation and emission monochromators between 30-60 nm. An interpretation of synchronous fluorescence spectra of binding media is presented and is followed by an assessment and classification of a database of recorded spectra using multivariate analysis. Importantly, following SFS analysis of films of binding media, principal component analysis is used to differentiate among all the proteinaceous media considered on the basis of clustering of data. This application is thus a novel and nondestructive means for differentiation between protein-based binding media.
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Affiliation(s)
- Austin Nevin
- Courtauld Institute of Art, University of London, Somerset House, Strand, London WC2R 0RN, UK.
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Bugden JBC, Yeung CW, Kepkay PE, Lee K. Application of ultraviolet fluorometry and excitation-emission matrix spectroscopy (EEMS) to fingerprint oil and chemically dispersed oil in seawater. MARINE POLLUTION BULLETIN 2008; 56:677-685. [PMID: 18304589 DOI: 10.1016/j.marpolbul.2007.12.022] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/05/2007] [Revised: 12/11/2007] [Accepted: 12/28/2007] [Indexed: 05/26/2023]
Abstract
Excitation-emission matrix spectroscopy (EEMS) was used to characterize the ultra violet fluorescence fingerprints of eight crude oils (with a 14,470-fold range of dynamic viscosity) in seawater. When the chemical dispersant Corexit 9500 was mixed with the oils prior to their dispersion in seawater, the fingerprints of each oil changed primarily as an increase in fluorescence over an emission band centered on 445 nm. In order to simplify the wealth of information available in the excitation-emission matrix spectra (EEMs), two ratios were calculated. A 66-90% decrease in the slope ratio was observed with the addition of Corexit. When the slope ratios were reduced in complexity to intensity ratios, similar trends were apparent. As a result either of the ratios could be used as a simple and rapid means of identifying and monitoring chemically dispersed oil in the open ocean.
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Affiliation(s)
- J B C Bugden
- Centre for Offshore Oil and Gas Environmental Research, Fisheries and Oceans Canada, Bedford Institute of Oceanography, 1 Challenger Drive, P.O. Box 1006, Dartmouth, NS, Canada B2Y 4A2.
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Owens P, Ryder AG, Blamey NJF. Frequency Domain Fluorescence Lifetime Study of Crude Petroleum Oils. J Fluoresc 2008; 18:997-1006. [DOI: 10.1007/s10895-008-0330-5] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2007] [Accepted: 01/22/2008] [Indexed: 11/29/2022]
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Poulli KI, Mousdis GA, Georgiou CA. Synchronous fluorescence spectroscopy for quantitative determination of virgin olive oil adulteration with sunflower oil. Anal Bioanal Chem 2006; 386:1571-5. [PMID: 16953317 DOI: 10.1007/s00216-006-0729-2] [Citation(s) in RCA: 63] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2006] [Revised: 07/26/2006] [Accepted: 07/31/2006] [Indexed: 10/24/2022]
Abstract
Adulteration of extra virgin olive oil with sunflower oil is a major issue for the olive oil industry. In this paper, the potential of total synchronous fluorescence (TSyF) spectra to differentiate virgin olive oil from sunflower oil and synchronous fluorescence (SyF) spectra combined with multivariate analysis to assess the adulteration of virgin olive oil are demonstrated. TSyF spectra were acquired by varying the excitation wavelength in the region 270-720 nm and the wavelength interval (Deltalambda) in the region from 20 to 120 nm. TSyF contour plots for sunflower, in contrast to virgin olive oil, show a fluorescence region in the excitation wavelength range 325-385 nm. Fifteen different virgin olive oil samples were adulterated with sunflower oil at varying levels (0.5-95%) resulting in one hundred and thirty six mixtures. The partial least-squares regression model was used for quantification of the adulteration using wavelength intervals of 20 and 80 nm. This technique is useful for detection of sunflower oil in virgin olive oil at levels down to 3.4% (w/v) in just two and a half minutes using an 80-nm wavelength interval.
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Affiliation(s)
- Konstantina I Poulli
- Chemistry Laboratory, Agricultural University of Athens, 75 Iera Odos, 118 55 Athens, Greece
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Ryder AG, Przyjalgowski MA, Feely M, Szczupak B, Glynn TJ. Time-resolved fluorescence microspectroscopy for characterizing crude oils in bulk and hydrocarbon-bearing fluid inclusions. APPLIED SPECTROSCOPY 2004; 58:1106-1115. [PMID: 15479528 DOI: 10.1366/0003702041959505] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Time-resolved fluorescence data was collected from a series of 23 bulk crude petroleum oils and six microscopic hydrocarbon-bearing fluid inclusions (HCFI). The data was collected using a diode laser fluorescence lifetime microscope (DLFLM) over the 460-700 nm spectral range using a 405 nm excitation source. The correlation between intensity averaged lifetimes (tau) and chemical and physical parameters was examined with a view to developing a quantitative model for predicting the gross chemical composition of hydrocarbon liquids trapped in HCFI. It was found that tau is nonlinearly correlated with the measured polar and corrected alkane concentrations and that oils can be classified on this basis. However, these correlations all show a large degree of scatter, preventing accurate quantitative prediction of gross chemical composition of the oils. Other parameters such as API gravity and asphaltene, aromatic, and sulfur concentrations do not correlate well with tau measurements. Individual HCFI were analyzed using the DLFLM, and time-resolved fluorescence measurements were compared with tau data from the bulk oils. This enabled the fluid within the inclusions to be classified as either low alkane/high polar or high alkane/low polar. Within the high alkane/low polar group, it was possible to clearly discriminate HCFI from different locales and to see differences in the trapped hydrocarbon fluids from a single geological source. This methodology offers an alternative method for classifying the hydrocarbon content of HCFI and observing small variations in the trapped fluid composition that is less sensitive to fluctuations in the measurement method than fluorescence intensity based methods.
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Affiliation(s)
- Alan G Ryder
- National Centre for Biomedical Engineering Science, Department of Chemistry, National University of Ireland-Galway, Galway, Ireland.
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