Plasma chemistry applied to Electron Microscopy (EM) preparation procedures
A selection of published work covering a range of applications using plasma chemistry as a preparation technique. The references are listed at the bottom of the page.
Analysis of paint pigment distribution
Paint on microscope slides is ashed in Oxygen for progressively longer
periods with intermittent weight and surface sampling by EM replication
techniques. Pigment distribution through the film thickness can be evaluated
in an "onion peel" fashion. Also applicable to accelerated weathering
of paint finishes.
Evaluation of implants in primates
A range of Tantalum samples prepared in a variety of ways were implanted
and then evaluated in relation to effects on surrounding tissue by a variety
of techniques, including EM. Samples treated in an Oxygen plasma prior
to implanting showed high surface energy and bio-adhesion compared to
untreated samples.
Plasma ashing of paper
SEM studies of paper. Oxygen ashing over progressive periods of up to
30 minutes indicated the gradual destruction of cellulose while the Kaolin
filler remains unaffected.
Replica EM studies of Polyamide structure
Use of Oxygen plasma for differential etching of ordered and disordered
regions in organic samples. Rates of etching reduced from lower molecular
weight substances through disordered (amorphous) regions to ordered (crystalline)
regions. This allowed identification by replica EM of simultaneous presence
of single crystals and spherilites in Polamide 68.
Replica EM studies of latexes of Acrylic Copolymers
Using replica EM and Oxygen ashing it was shown that latex particles of
Polyalkylacrylates and Alkylacrylate-Methacrylic Acid Copolymers are aggregates
of primary globules, the size of the globules depends upon the polymer.
EM studies of Polyethylene Tetraphthalates films and fibres
Oxygen ashing in conjunction with replica EM revealed supra molecular
structure with correlation between EM and X-ray diffraction data. Oxygen
ashing: followed by SEM examination allowed identification of three types
of internal flaw in bright fibres. Results showed high concentrations
of Titanium Dioxide in regions containing voids, and highly ordered polymers
which had previously been assumed to be defusants.
Quantitative bulk analysis by TEAM of biological microsamples
100um sections of Wistar rat hearts were Oxygen plasma ashed and then
dissolved and sprayed onto grids. The droplets were then individually
analysed. The method was found to retain volatiles such as Sulphur
and possibly Chlorine. Ashing times when compared to high temperature
ashing are considerably reduced.
Detection of inorganic materials in biological samples
Plasma ashed coal samples and Wandering Jew leaf observed using SEM and
EDS showed 3-5 fold improvement in detection levels fr Sulphur and Iron
and also revealed particulates not previously observed.
Microincineration for EM localization of biological materials
A review of high temperature ashing and plasma ashing of various materials
Review of techniques for SEM and Electron Probe Microanalysis
Amongst many applications the following are highlighted:- microelectronic
failure analysis; grain boundary composition in mineralogical specimens
containing silicates and carbonaceous material; discovery if microvoids
and flaws in Carbon reinforcing fibres; differential etching of polymers;
formation of 3-dimensional ash skeletons; studies of modular graphite
inclusions in cast iron; mineral staining of brain tissue followed by
Oxygen ashing.
Low temperature ultra microincineration of thin sectioned tissue
Plasma incineration used to determine the morphological localization of
structure bound mineral and metallic elements within biological cells
at TEM levels.
Ultrastructure of cell organelles in thick plasma-etched sections
1um sections of fixed and embedded kidney tissue when surface etched by
Oxygen plasma, allowed etch resistant cell components to be imaged with
clarity. Resolution was better that other preparation technique for SEM
of internal structures of cells and organelles in bulk samples of tissue.
TEM-EDS of silica in cell walls of rye grass
A comparison of preparation methods, including plasma ashing, to determine
amounts of Silicon in cell wall material.
Plasma ashing moths and insects prior to EM and XES
Oxygen ashing of insects allowed the removal of organic material but left
the structure intact. This allowed area sectioning for subsequent analysis.
X-ray microanalysis of Epon sections after Oxygen plasma ashing
Improved X-ray detectability of elements retained in ash by lowered background
counts. Method removes Osmium fixative and Chlorine to reveal hidden Phosphorous
peak; pattern fidelity allows microanalytical resolution of 0.1um.
SEM of embedded biological specimens surface plasma etched
As a general technique for SEM, Oxygen plasma etching thick sections of
a wide variety of different types of embedded tissue yields specimens
that show a resolution that is considerably better than that obtainable
by most other methods; particularly for viewing internal structure of
cells and organelles in bulk structure
Measuring the concentration of Asbestos fibres in air samples
Oxygen plasma used to remove high levels of airborne organic contaminants
and to remove filter paper prior to TEM sizing.
Identification second counting of Asbestos fibres on membrane filters
Methods are described whereby Asbestos fibres can be counted by phase
contrast microscopy and identified on the same membrane filter by optical
and SEM techniques. Airborne concentration of different Asbestos types
in mixed clouds can therefore be estimated.
References
Analysis of paint pigment distribution
Paint Research Association Newsletter April 1979 no. 12
Tissue response to surface treated Tantalum implants. Preliminary
observations in primates
Michael A Meenaghan. Journal of Biomedical Materials Research. Vol 12,
631443 (1979)
Plasma Ashing of paper
Source unknown
Improved gas-discharge etching techniques in the Electron Microscope
studies of Polyamide structures.
L I Bezruk. Vysokomol. Soyed. A10: No. 6 1434-1437, 1968
Particle and film structures of films of some latexes of acrylic
copolymers
V I Yeliseyeva. Vosokomol. Soyed A9: No 11 2478-2481, 1967
Oxygen etching method of making an Electron Microscopy study of Polyethylene
Tetraphthalate films
K Z Gumargaliveva. Vosokomol. Soyed. 8: No. 10 1742-1744, 1966
Studies of plasma-etched Polyethylene Terephthalate fibres by SEM
and energy-dispersive X Ray microanalysis
P R Blakey & M O Alfy. Letter to Journal of Textile Institute 1978
No 1
The application of X-ray analysis in Transmission Electron Analytical
Microscope (TEAM) to the quantitative bulk analysis of biological microsamples
T W Davies & A J Morgan. Journal of Microscopy Vol 107, part 1, May
1976. pp 47-54
Detection of inorganic materials in biological samples
Source unknown
Microincineration techniques for electron-microscopic localization
of biological minerals
Richard S Thomas. W Region Research Lab, Agricultural Research Service,
US Dept, of Ag. Albany Ca. USA
Use of chemically reactive gas plasma in preparing specimens for
SEM and Electron Probe Microanalysis
Richard S Thomas. SE.M/1974 part I proc 7th SEM Symph –April/1974
Low temperature ultra-microincineration of thin section tissue
Wayne Hohman & Harold Shraer. Journal of Cell Biology, Volume 55 1972
pp 328-354
Ultra-microincineration of thin-sectioned tissue
Principles and Techniques of EM-1976
Ultrastructure of cell organelles by Scanning Electron Microscopy
of thick sections surface-etched by an Oxygen plasma
W J Humphreys. Journal of Microscopy Vol 116 July 1979.
Silica in the mesophyll cell walls of Italian Rye Grass
D Dinsdale Ann. Bot 44 73-77 1979
Ashing moths and various insects
J Bowden (pr comm) Rothampstead Research Station. July 1979
X-ray microanalysis of Epon sections after Oxygen plasma microincineration
Tudor Barnard and R S Thomas Journal of Microscopy Vol 113 Pt 3 Aug 1978.
pp269-276
Scanning Electron Microscopy of biological specimens surface-etched
by an Oxygen plasma
W J Humphreys. Scanning Electron Microscopy 1979/11. Asbestos counting
method using TEM. Ontario Research Foundation.
In situ identification of Asbestos fibres collected on membrane filters
for counting
N P Vaugham and S J Rooker. Ann. Occup. Hyg. Vol 24 No 3 pp281-290 1981.
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