Calcium measurements with electron probe X-ray and electron energy loss analysis

Journal Article · Thu Mar 01 00:00:00 EST 1990 · Environmental Health Perspectives; (USA)

DOI:https://doi.org/10.1289/ehp.908457· OSTI ID:7063973

LeFurgey, A; Ingram, P ^[1]

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1. Duke Univ., Durham, NC (USA)

This paper presents a broad survey of the rationale for electron probe X-ray microanalysis (EPXMA) and the various methods for obtaining qualitative and quantitative information on the distribution and amount of elements, particularly calcium, in cryopreserved cells and tissues. Essential in an introductory consideration of microanalysis in biological cryosections is the physical basis for the instrumentation, fundamentals of X-ray spectrometry, and various analytical modes such as static probing and X-ray imaging. Some common artifacts are beam damage and contamination. Inherent pitfalls of energy dispersive X-ray systems include Si escape peaks, doublets, background, and detector calibration shifts. Quantitative calcium analysis of thin cryosections is carried out in real time using a multiple least squares fitting program on filtered X-ray spectra and normalizing the calcium peak to a portion of the continuum. Recent work includes the development of an X-ray imaging system where quantitative data can be retrieved off-line. The minimum detectable concentration of calcium in biological cryosections is approximately 300 mumole kg dry weight with a spatial resolution of approximately 100 A. The application of electron energy loss (EELS) techniques to the detection of calcium offers the potential for greater sensitivity and spatial resolution in measurement and imaging. Determination of mass thickness with EELS can facilitate accurate calculation of wet weight concentrations from frozen hydrated and freeze-dried specimens. Calcium has multiple effects on cell metabolism, membrane transport and permeability and, thus, on overall cell physiology or pathophysiology. Cells can be rapidly frozen for EPXMA during basal or altered functional conditions to delineate the location and amount of calcium within cells. 72 references.

• OSTI ID: 7063973
• Journal Information: Environmental Health Perspectives; (USA), Vol. 84; ISSN 0091-6765
• Country of Publication: United States
• Language: English

Related Subjects

59 BASIC BIOLOGICAL SCIENCES
CALCIUM
CHEMICAL ANALYSIS
ANIMAL CELLS
ANIMAL TISSUES
CRYOBIOLOGY
ELECTRON MICROPROBE ANALYSIS
MAN
REVIEWS
SPATIAL RESOLUTION
X-RAY DIFFRACTION
X-RAY SPECTRA
ALKALINE EARTH METALS
ANIMALS
BIOLOGY
BODY
COHERENT SCATTERING
DIFFRACTION
DOCUMENT TYPES
ELEMENTS
MAMMALS
METALS
MICROANALYSIS
PRIMATES
RESOLUTION
SCATTERING
SPECTRA
TISSUES
VERTEBRATES
550201* - Biochemistry- Tracer Techniques