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Total reflection X-ray fluorescence spectrometry – A versatile tool for ultra-micro analysis of objects of cultural heritage  [PDF]
Alex von Bohlen
E-Preservation Science , 2004,
Abstract: A short introduction into total reflection X-ray fluorescence spectrometry (TXRF) is given. Some aspects of development, including theory, technical advances and publications covering the last 30 years are summarised. The main fields of TXRF applications, trace analysis of elements, micro analysis of solids and surface analysis are presented. A special section describes in detail a gentle micro-sampling method that can be used for the analysis of objects of cultural heritage. The versatility and efficiency of TXRF combined with the micro-sampling of solids for restoration, preservation and art historical tasks are demonstrated using new applications. These examples concern pigment analysis of paintings, analysis of iron gall inks in ancient manuscripts and historical violin varnishes. References are given for further examples. More than 50 references, mainly dedicated to TXRF analysis of art objects, are included.
Development of a method for the determination of ultra-trace level mercury in adipose tissue by cold vapour atomic fluorescence spectrometry  [PDF]
Keith E. Levine,Reshan A. Fernando,M. Lang,Amal Essader,Robert W. Handy,Bradley J. Collins
Journal of Analytical Methods in Chemistry , 2000, DOI: 10.1155/s1463924600000146
Abstract: A method for the determination of total mercury in rat adipose tissue by cold vapour atomic fluorescence spectrometry (CVAFS) has been developed. Adipose samples were initially subjected to a lyophilization procedure in order to facilitate the homogenization and accurate weighing of small tissue aliquots (~50 mg). A closed vessel microwave digestion procedure using a mixture of sulphuric and nitric acids was used to liberate mercury from the adipose matrix. All mercury species were quantitatively oxidized to Hg(II) by a potassium bromate/bromide oxidation, then reduced to Hg(0) vapour by stannous chloride prior to fluorescence detection. The CVAFS exhibited a linear range of 10 pg Hg/ml to 120 pg Hg/ml. The method detection limit in solution was 2 pg Hg/ml, or 1 ng Hg/g adipose tissue, based on a nominal 50 mg sample and a final volume of 25 ml. A reference material from the National Research Council of Canada (DOLT-2, trace metals in dogfish liver) was prepared in quadruplicate in order to assess the accuracy and precision of the method. Mercury in this material was recovered at 2.22 ± 0.08 μ g/g, which is 104% of the certified level (2.14 ± 0.10 μ g/g).
Determination of inorganic species of Sb and Te in cereals by hydride generation atomic fluorescence spectrometry
Reyes, Mariela N. M;Cervera, Maria L;Guardia, Miguel de la;
Journal of the Brazilian Chemical Society , 2011, DOI: 10.1590/S0103-50532011000200002
Abstract: a non-chromatographic fast, sensitive and easy method has been developed for the determination of sb(iii), sb(v), te(iv) and te(vi) in cereal samples. the procedure is based on ultrasound assisted extraction and determination by hydride generation atomic fluorescence spectrometry (hg afs). preliminary studies were made in order to get the best extraction efficiency using 1 mol l-1 phosphoric acid, 1 mol l-1 nitric acid, aqua regia, 1 mol l-1 sulfuric acid and 6 mol l-1 hydrochloric acid. the extraction with aquaregia showed a clear interconversion of the species during the process, being h2so4 the best extractant with efficiencies greater than 90% from the total content of sb and te quantified previously and without species interconversion. this point was checked by recovery experiments at different spiked levels. the method provided limits of detection values from 0.1 to 0.5 ng g-1 with relative standard deviation values from 5.4 to 9.2% of 10 independent analysis of samples containing few ng g-1 of sb and te species.
Total Scanning Fluorescence Characteristics of Coals and Implication to Coal Rank Evaluation  [PDF]
Junjia Fan,Keyu Liu,Yiwen Ju,Shaobo Liu,Lili Gui
Journal of Geological Research , 2012, DOI: 10.1155/2012/692865
Abstract: Total Scanning Fluorescence (TSF), as a kind of new fluorescence technique, has great significance and wide application in identifying hydrocarbon inclusions of reservoirs, hydrocarbon migration pathways and palaeo-current oil-water interfaces. Total scanning fluorescence (TSF) is characterized by high efficiency, requiring low sample amount and high accuracy. Vitrinite reflectance (Ro) is one of significant parameters for determining coal ranks, it cannot only reflect coalification features, but also provide a favorable indicator for coal ranks. In order to establish a relationship between vitrinite reflectance (Ro) and the characteristic parameters derived from total scanning fluorescence (TSF), fourteen coal samples (coal powder without separating macerals) collected from Qinshui basin and Huaibei coalfield are tested by TSF technique and vitrinite reflectance (oil immersion), respectively. It shows that TSF parameters are related to vitrinite reflectance value, although TSF parameters and fluorescence intensity of coals differ in Qinshui basin and Huaibei coalfield. Research indicates that more factors should be taken into consideration for coal sample TSF testing in the future so as to obtain an empirical formula relationship between Ro and TSF parameters. 1. Introduction to Total Scanning Fluorescence (TSF) Technique Fluorescence spectroscopy is a technique that has had wide application in characterizing hydrocarbon mixtures. Ultraviolet (UV) fluorescence is inherently more selective for aromatic compounds than conventional absorption measurements and at least an order of magnitude more sensitive. Fluorescence methods are particularly useful for the detection and measurement of organic compounds containing one or more aromatic functional groups. Since all oils contain a significant amount of aromatic compounds, with one to four (or more) aromatic rings and their alkylated analogues, oils exhibit distinctive fluorescence “fingerprints.” These “fingerprints,” used in conjunction with other analyses, can provide significant information for typing oils, shale extracts, and sea bottom sediment extracts [1]. Fluorescence analysis technique is significant in identifying hydrocarbon inclusion, hydrocarbon migration pathway, and palaeocurrent water-oil interface [2–4]. It includes three items, quantitative grain fluorescence (QGF), quantitative grain fluorescence-extract (QGF-E), and total scanning fluorescence (TSF). TSF technique is used in this study. TSF which developed from 1980s, was used to test aromatic hydrocarbon and concentration. This method of
Automatic Discrimination of the Geographical Origins of Milks by Excitation-Emission Fluorescence Spectrometry and Chemometrics
Lu Xu,De-Hua Deng,Chen-Bo Cai,Hong-Wei Yang
Journal of Analytical Methods in Chemistry , 2011, DOI: 10.1155/2011/323196
Abstract: This paper presents the automatic discrimination of geographical origins of milks from Western Yunnan Plateau areas and eastern China by excitation-emission fluorescence spectrometry and chemometrics. Genuine plateau milks (=60) and milks from eastern China (=89) are scanned in the regions of 180–300 nm for excitation and 200–800 nm for emission. Different options of data analysis are investigated and compared in terms of their performance in discriminating milks of different geographical origins: (1) two-way partial least squares discriminant analysis (PLSDA) based on excitation and emission spectra, respectively; (2) two-way PLSDA based on fusion of excitation and emission spectra; (3) three-way PLSDA based on excitation-emission matrix spectra. The two-way PLSDA methods with excitation spectra, emission spectra, and fusion of excitation and emission spectra correctly classify 91.3%, 88.6%, and 95.3% of the milk samples, respectively; while the total accuracy of three-way PLSDA is 96.0%. The results demonstrate the two-way data combining excitation and emission spectra are sufficient to characterize and identify the plateau milks. Considering both model accuracy and the analytical time required, two-way PLS-DA with fusion of excitation and emission spectra is recommended as a reliable and quick method to discriminate plateau milks from ordinary milks.
A Concept for a Sensitive Micro Total Analysis System for High Throughput Fluorescence Imaging  [PDF]
Arthur Rabner,Yosi Shacham
Sensors , 2006, DOI: 10.3390/s6040341
Abstract: This paper discusses possible methods for on-chip fluorescent imaging forintegrated bio-sensors. The integration of optical and electro-optical accessories, accordingto suggested methods, can improve the performance of fluorescence imaging. It can boostthe signal to background ratio by a few orders of magnitudes in comparison to conventionaldiscrete setups. The methods that are present in this paper are oriented towards buildingreproducible arrays for high-throughput micro total analysis systems (μTAS). The firstmethod relates to side illumination of the fluorescent material placed into micro-compartments of the lab-on-chip. Its significance is in high utilization of excitation energyfor low concentration of fluorescent material. The utilization of a transparent μLED chip,for the second method, allows the placement of the excitation light sources on the sameoptical axis with emission detector, such that the excitation and emission rays are directedcontroversly. The third method presents a spatial filtering of the excitation background.
Quantitative Analysis of FeMo Alloys by X-Ray Fluorescence Spectrometry  [PDF]
Sung-Mo Jung
American Journal of Analytical Chemistry (AJAC) , 2014, DOI: 10.4236/ajac.2014.512085
Abstract: A quantitative analysis method of molybdenum in FeMo alloys by X-ray spectrometry using borate fusion technique was compared with that with pressed pellet. The complete pre-oxidation of FeMo alloys for the preparation of homogeneous fused discs was achieved by employing an automated fusion machine equipped with specially designed O2-blowing nozzles, which used lithium tetra-borate as flux with the addition of lithium nitrate (LiNO3) as oxidizer. The calibration curves of Mo and Fe were used in the quantitative analysis of standard materials and unknown plant samples with satisfactory accuracy and precision, utilizing the corrections of the matrix effects and line overlap. It was confirmed that the newly proposed method of preparing fused glass discs of FeMo alloys can replace the conventional wet chemical analyses requiring the labor intensive and time consuming procedure.
Plasma free and total carnitine measured in children by tandem mass spectrometry
Osorio, J.H.;Pourfarzam, M.;
Brazilian Journal of Medical and Biological Research , 2002, DOI: 10.1590/S0100-879X2002001100003
Abstract: free and total carnitine quantification is important as a complementary test for the diagnosis of unusual metabolic diseases, including fatty acid degradation disorders. the present study reports a new method for the quantification of free and total carnitine in dried plasma specimens by isotope dilution electrospray tandem mass spectrometry with sample derivatization. carnitine is determined by looking for the precursor of ions of m/z = 103 of n-butylester derivative, and the method is validated by comparison with radioenzymatic assay. we obtained an inter- and intra-day assay coefficient of variation of 4.3 and 2.3, respectively. free and total carnitine was analyzed in 309 dried plasma spot samples from children ranging in age from newborn to 14 years using the new method, which was found to be suitable for calculating reference age-related values for free and total carnitine (less than one month: 19.3 ± 2.4 and 23.5 ± 2.9; one to twelve months: 28.8 ± 10.2 and 35.9 ± 11.4; one to seven years: 30.7 ± 10.3 and 38.1 ± 11.9; seven to 14 years: 33.7 ± 11.6, and 43.1 ± 13.8 μm, respectively). no difference was found between males and females. a significant difference was observed between neonates and the other age groups. we compare our data with reference values in the literature, most of them obtained by radioenzymatic assay. however, this method is laborious and time consuming. the electrospray tandem mass spectrometry method presented here is a reliable, rapid and automated procedure for carnitine quantitation.
Plasma free and total carnitine measured in children by tandem mass spectrometry  [cached]
Osorio J.H.,Pourfarzam M.
Brazilian Journal of Medical and Biological Research , 2002,
Abstract: Free and total carnitine quantification is important as a complementary test for the diagnosis of unusual metabolic diseases, including fatty acid degradation disorders. The present study reports a new method for the quantification of free and total carnitine in dried plasma specimens by isotope dilution electrospray tandem mass spectrometry with sample derivatization. Carnitine is determined by looking for the precursor of ions of m/z = 103 of N-butylester derivative, and the method is validated by comparison with radioenzymatic assay. We obtained an inter- and intra-day assay coefficient of variation of 4.3 and 2.3, respectively. Free and total carnitine was analyzed in 309 dried plasma spot samples from children ranging in age from newborn to 14 years using the new method, which was found to be suitable for calculating reference age-related values for free and total carnitine (less than one month: 19.3 ± 2.4 and 23.5 ± 2.9; one to twelve months: 28.8 ± 10.2 and 35.9 ± 11.4; one to seven years: 30.7 ± 10.3 and 38.1 ± 11.9; seven to 14 years: 33.7 ± 11.6, and 43.1 ± 13.8 μM, respectively). No difference was found between males and females. A significant difference was observed between neonates and the other age groups. We compare our data with reference values in the literature, most of them obtained by radioenzymatic assay. However, this method is laborious and time consuming. The electrospray tandem mass spectrometry method presented here is a reliable, rapid and automated procedure for carnitine quantitation.
Trace element distribution in human teeth by x-ray fluorescence spectrometry and multivariate statistical analysis  [PDF]
Cristiana Oprea,Pavel J. Szalanski,Marina V. Gustova,Ioan A. Oprea,Violeta L. Buzguta
Physics , 2014,
Abstract: X-ray fluorescence spectrometry (XRFS) was used as a multielement method of evaluation of individual whole human tooth or tooth tissues for their amounts of trace elements. Measurements were carried out on human enamel, dentine, and dental cementum, and some differences in tooth matrix composition were noted. In addition, the elemental concentrations determined in teeth from subjects of different ages, nutritional states, professions and gender, living under various environmental conditions and dietary habits, were included in a comparison by multivariate statistical analysis (MVSA) methods. By factor analysis it was established that inorganic components of human teeth varied consistently with their source in the tissue, with more in such tissue from females than in that from males, and more in tooth incisor than in tooth molar.
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