Quantitative elemental analysis of bacterial polyphosphate bodies using scanning transmission electron microscopy and energy-dispersive x-ray spectroscopy

1996 ◽  
Vol 54 ◽  
pp. 802-803
Author(s):  
J. Goldberg ◽  
H. Gonzalez ◽  
T.E. Jensen ◽  
W.A. Corpe
Keyword(s):  
Elemental Composition ◽  
Bulk Sample ◽  
Energy Dispersive ◽  
Mode Analysis ◽  
Objective Lens ◽  
X Ray ◽  
Scanning Transmission ◽  
Tem Mode ◽  
Cell Components ◽  
Polyphosphate Bodies

The elemental composition of polyphosphate bodies (PPB's) has been determined qualitatively previously using energy dispersive x-ray spectrometers (EDX) and in bodies isolated from cells. In this present study we determine in several bacteria their quantitative elemental composition using EDX in conjunction with a STEM.Bacteria were grown as previously described or were collected from natural sources. Portions of each sample were air dried on formvar coated grids. Separate samples were fixed and embedded in Epon. For x-ray analysis cells of interest were first located using the TEM mode. The microscope was then switched to the STEM mode. Analysis of cell components was carried out in the spot mode (75 kV) of the STEM. The spot diameter at 100,000x is approximately 20nm. The objective lens current was adjusted so a total x-ray count of 600 to 1,000 cps was attained for the 100 sec. count time. Spectra were collected on a PGT IMIX (EDX). The data was analyzed using a bulk sample analysis program (ZAF method) in standardless mode (w/w). Latex spheres of known density (1.05 g per cu cent) and volume were analyzed to obtain a standard (mass/weight).

Quantitative Analysis of Metal Sequestering in Different Cell Components of Gloeocapsa alpicola in the Overplus Phase

2000 ◽  
Vol 6 (S2) ◽  
pp. 908-909
Author(s):  
J.J. Goldberg ◽  
T.E. Jensen
Keyword(s):  
Quantitative Analysis ◽  
Elemental Composition ◽  
Growth Phase ◽  
Energy Dispersive ◽  
Logarithmic Growth Phase ◽  
X Ray ◽  
Tem Mode ◽  
Cell Components ◽  
Polyphosphate Bodies ◽  
Logarithmic Growth

The elemental composition of polyphosphate bodies (PPB's) and other components of the cell have previously been determined by using energy dispersive X-ray spectrometers(EDX). In this present study we perform a quantitative analysis of normally grown cells and cells that were grown in the overplus phenomenon.Cells of Gloeocapsa alpicola were grown in modified Fitzgerald's media and harvested after a logarithmic growth phase of 14 days. The overplus cells were grown, as has been previously described. The cells were exposed to 20ppm of Al, Cd, Cu, Mn, Ni, Pb, and Zn, as well as a control, for one hour. The cells were then air dried on formvar coated grids or fixed and embedded in EPON according to Luft's procedure.For Xn-ay analysis cells were first located using the TEM mode, and then the microscope was switched to the STEM mode. Analyses of cell components were carried out using the spot mode (75Kv).

Quantitative Elemental Analysis of the Components of Pb Exposed Cells Of Plectonema Boryanum Using Regular and Overplus Cells: an Energy Disspersive X-Ray Spectroscopy Study

1998 ◽  
Vol 4 (S2) ◽  
pp. 262-263
Author(s):  
J.J. Goldberg ◽  
T.E. Jensen
Keyword(s):  
Quantitative Analysis ◽  
Mode Analysis ◽  
Spectroscopy Study ◽  
Plectonema Boryanum ◽  
Logarithmic Growth Phase ◽  
X Ray ◽  
Tem Mode ◽  
Cell Components ◽  
Polyphosphate Bodies ◽  
Logarithmic Growth

The elemental composition of polyphosphate bodies (PPB’s) and other components of the cell have previously been determined by using energy dispersive X-ray spectrometers(EDX). In this present study we perform a quantitative analysis or normally grown cells and cells that were grown in the overplus phenomenon.Cells of Plectonema boryanum were grown in modified Fitzgerald's media and harvested after a logarithmic growth phase of 14 days. The overplus cells were grown as has been previously described2. The cells were exposed to l00ppm of lead, as well as other metals separately, for one hour. The cells were then fixed and embedded in EPON according to Luft's procedure.For X-ray analysis cells were first located using the TEM mode, and then the microscope was switched to the STEM mode. Analysis of cell components were carried out using the spot mode (75Kv).

Microanalysis of precipitates in a ferritic steel

1978 ◽  
Vol 36 (1) ◽  
pp. 618-619
Author(s):  
J.M. Titchmarsh
Keyword(s):  
Ferritic Steel ◽  
Particle Identification ◽  
Energy Dispersive ◽  
Objective Lens ◽  
Ferritic Steels ◽  
Replica Technique ◽  
X Ray ◽  
Large Numbers ◽  
Scanning Transmission ◽  
Made In

The advances in recent years in the microanalytical capabilities of conventional TEM's fitted with probe forming lenses allow much more detailed investigations to be made of the microstructures of complex alloys, such as ferritic steels, than have been possible previously. In particular, the identification of individual precipitate particles with dimensions of a few tens of nanometers in alloys containing high densities of several chemically and crystallographically different precipitate types is feasible. The aim of the investigation described in this paper was to establish a method which allowed individual particle identification to be made in a few seconds so that large numbers of particles could be examined in a few hours.A Philips EM400 microscope, fitted with the scanning transmission (STEM) objective lens pole-pieces and an EDAX energy dispersive X-ray analyser, was used at 120 kV with a thermal W hairpin filament. The precipitates examined were extracted using a standard C replica technique from specimens of a 2¼Cr-lMo ferritic steel in a quenched and tempered condition.

Energy Dispersive X-Ray Measurements of thin Metal Foils

1976 ◽  
Vol 34 ◽  
pp. 426-427
Author(s):  
J. Bentley ◽  
E. A. Kenik
Keyword(s):  
Materials Science ◽  
Energy Dispersive Spectrometer ◽  
Thin Foil ◽  
Thin Metal ◽  
Energy Dispersive ◽  
Thin Specimen ◽  
X Ray ◽  
Metal Foils ◽  
Small Probe ◽  
Scanning Transmission

Instruments combining a 100 kV transmission electron microscope (TEM) with scanning transmission (STEM), secondary electron (SEM) and x-ray energy dispersive spectrometer (EDS) attachments to give analytical capabilities are becoming increasingly available and useful. Some typical applications in the field of materials science which make use of the small probe size and thin specimen geometry are the chemical analysis of small precipitates contained within a thin foil and the measurement of chemical concentration profiles near microstructural features such as grain boundaries, point defect clusters, dislocations, or precipitates. Quantitative x-ray analysis of bulk samples using EDS on a conventional SEM is reasonably well established, but much less work has been performed on thin metal foils using the higher accelerating voltages available in TEM based instruments.

Comparison of high-angle take-off and low-angle take-off EDX detector geometry of the HF-2000 FE-TEM

1993 ◽  
Vol 51 ◽  
pp. 252-253
Author(s):  
Y. Sato ◽  
T. Hashimoto ◽  
M. Ichihashi ◽  
Y. Ueki ◽  
K. Hirose ◽  
...  
Keyword(s):  
Quantitative Analysis ◽  
Field Emission ◽  
Solid Angle ◽  
Energy Dispersive ◽  
Objective Lens ◽  
X Rays ◽  
High Angle ◽  
X Ray ◽  
Detector Geometry

Analytical TEMs have two variations in x-ray detector geometry, high and low angle take off. The high take off angle is advantageous for accuracy of quantitative analysis, because the x rays are less absorbed when they go through the sample. The low take off angle geometry enables better sensitivity because of larger detector solid angle.Hitachi HF-2000 cold field emission TEM has two versions; high angle take off and low angle take off. The former allows an energy dispersive x-ray detector above the objective lens. The latter allows the detector beside the objective lens. The x-ray take off angle is 68° for the high take off angle with the specimen held at right angles to the beam, and 22° for the low angle take off. The solid angle is 0.037 sr for the high angle take off, and 0.12 sr for the low angle take off, using a 30 mm2 detector.

Field-Emission Scanning Electron Microscopy and Energy-Dispersive X-Ray Analysis to Understand the Role of Tannin-Based Dyes in the Degradation of Historical Wool Textiles

2014 ◽  
Vol 20 (5) ◽  
pp. 1534-1543 ◽  
Author(s):  
Annalaura Restivo ◽  
Ilaria Degano ◽  
Erika Ribechini ◽  
Josefina Pérez-Arantegui ◽  
Maria Perla Colombini
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Elemental Composition ◽  
Field Emission ◽  
Cross Sections ◽  
Morphological Changes ◽  
Energy Dispersive ◽  
X Ray ◽  
Edx Analysis ◽  
Scanning Electron

Abstract:An innovative approach, combining field-emission scanning electron microscopy (FESEM) with energy dispersive X-ray spectroscopy (EDX) analysis, is presented to investigate the degradation mechanisms affecting tannin-dyed wool. In fact, tannin-dyed textiles are more sensitive to degradation then those dyed with other dyestuffs, even in the same conservation conditions.FESEM-EDX was first used to study a set of 48 wool specimens (artificially aged) dyed with several raw materials and mordants, and prepared according to historical dyeing recipes. EDX analysis was performed on the surface of wool threads and on their cross-sections. In addition, in order to validate the model formulated by the analysis of reference materials, several samples collected from historical and archaeological textiles were subjected to FESEM-EDX analysis.FESEM-EDX investigations enabled us to reveal the correlation between elemental composition and morphological changes. In addition, aging processes were clarified by studying changes in the elemental composition of wool from the protective cuticle to the fiber core in cross-sections. Morphological and elemental analysis of wool specimens and of archaeological and historical textiles showed that the presence of tannins increases wool damage, primarily by causing a sulfur decrease and fiber oxidation.

Energy Dispersive X-Ray Spectrometry of Gold-Silver-Copper Standards for Comparison with Historic Gold Objects

1990 ◽  
Vol 185 ◽  
Author(s):  
S.M. White ◽  
R.J. Koestler ◽  
C. Blair ◽  
N. Indictor
Keyword(s):  
Elemental Composition ◽  
Ternary Mixtures ◽  
Energy Dispersive ◽  
X Ray ◽  
Silver Copper ◽  
Gold Silver

AbstractSeven ternary mixtures of gold(80-95%)-silver(4-15%)-copper(1-15%) were prepared as standards for the determination of elemental composition by energy dispersive X-ray spectrometry (EDS). Two geometric forms (flat and oblate) of the standards were prepared for comparison to the analyses of historic gold objects. Surface analyses were performed. Polished sections of the standards were also analysed Comparison between two methods for collecting EDS data is reported. The analyses are discussed in terms of developing a generalized methodology for estimating elemental composition of museum artifacts.

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