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Freeze Dry in the LV SEM

Observation of hydrated specimens

Pre-treatment of specimens Many specimens can be observed

without any pre-treatment. The conventional chemical fixation can be

applied for specimens that deform in vacuum after the freeze dry

preparation.

Freezing Deformation of internal structures caused by freezing

has little effect on surface structures observed by an SEM.

Specimens are frozen for approximately one minute in liquid nitrogen.

Freeze dry A frozen specimen is observed using the low vacuum

mode. The pressure in the specimen chamber reaches low vacuum

in one minute. Temperature of the frozen specimen rises and the ice

is removed by sublimation. In general, a specimen is dried and ready

for observation in a few minutes.

Observation The dried specimen can be observed in the low vac-

uum mode.

JEOL has developed a simple and quick method for observation of

water-containing specimens. The freeze-dry method in the LV SEM

removes water with minimal specimen deformation. This method is

especially effective for specimens that are difficult to prepare with the

conventional critical point drying method, such as fresh water plank-

ton, sea water plankton, cryptosporidium, hair root of plant, and mite.



10m

m

0.5

m

0.1

m

1mm

100

m100m

The Procedure is Simple and Quick.

Observation in Low Vacuum SEM

Cleaning

Rinse in water

Freeze in liquid nitrogen

Freeze dry in Low Vacuum SEM

Collection of specimen

Freeze dry in Low Vacuum SEM

Chemical fixation

Flower with a bug

Cross section of an apple 15kV

Cryptospordium muris, Freeze dried in LV SEM

Specimen courtesy of Tokyo Metropolitan Institute of

Public Health.

Nematode, Chemically fixed, dehydrated, replaced with t-butyl

alcohol, freeze dried in LV SEM

Specimen courtesy of Prof. E. Kondo, Saga University, Japan.

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Sharp EL-6490 Manual de usuario Pagina 15

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