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Tousimis Critical Point Dryers Overview


Tousimis is a well respected manufacturer if critical point dryers (CPD). They have been at the forefront of developing Critical Point Dryers for over 50 years and were one of the first companies to offer CPD systems. The core business of Tousimis still is development and manufacturing of CPD systems. During the more than 40 years of CPD development and manufacturing at Tousimis, many unique innovations have flown into the renowned Tousimis SAMDRI CPD systems. Tousimis currently offers a choice of 7 CPD systems for microscopy and structural applications to cover a wide range of samples.

Tousimis AutoSAMDRI-931, standard chamber, automatic critical point dryer 230V / 50Hz EM-Tec TC1 TEM calibration standard oriented gold crystal Tousimis AutoSAMDRI-931, large chamber, automatic critical point dryer 230V / 50Hz

AutoSAMDRI-931.GL CPD standard
Ø32x32mm chamber.
Touch screen operation
create/store recipes

AutoSAMDRI-931.GL CPD medium
Ø64x32mm chamber.
Touch screen operation
create/store recipes.

AutoSAMDRI-931.GL CPD with large
Ø86x32mm chamber.
Touch screen operating
create/store recipes.

 

Tousimis SAMDRI-815, Series A fully automatic critical point dryer 230V / 50Hz

 

Tousimis SAMDRI-815B, Series A fully automatic critical point dryer with extra large chamber, 230V / 50Hz
EM-Tec TS3 TEM combined test specimen standard

AutoSAMDRI-815 Series A,
fully automatic CPD with standard Ø32mmx32mm chamber

 

AutoSAMDRI-815B Series A,
fully automatic CPD with extra large Ø114mmx32mm chamber

SAMDRI-795 semi-automatic CPD with Ø32mmx32mm chamber

Tousimis SAMDRI-PVT-3D advanced manual critical point dryer 230V / 50Hz

 

Tousimis SOTER condenser to capture waste alcohol
EM-Tec TC3 TEM EDX calibration standard thin Cu foil on Al grid

SAMDRI-PVT-3D manual CPD with Ø32mmx32mm chamber

SOTER condenser to capture waste alcohol

CPD accessories,
sample holders and inserts



Principles of critical point drying (CPD)

              
              Carbon_dioxide_pressure-temperature_phase_diagram

 

Critical point drying is a process to remove liquids in such a way that the internal external structure is not damaged during the drying process. Applications for critical point drying are preparation of biological samples for scanning electron microscopy (SEM), production of aerogel, decaffeination of coffee and production of micromechanical systems. The Tousimis critical point dryers offered on this page are designed for EM sample preparation. CPD aims to prepare biological structures in their original (living) state.

When biological samples are air dried, the liquid changes to gas (evaporate) at a certain rate, while at the same time the amount of liquid is reduced at the same rate. When this happens in a sample, surface tension in the liquid body pulls against any structures the liquid is in contact with. Delicate structures collapse; the sample structure is destroyed and can't be studied. To avoid this, the sample needs to dried above the critical point through the super-critical region.  The super-critical fluid has no distinction between gas and fluid (equal densities) and therefore no liquid to gas boundary phase.

Fluids suitable for critical point drying are:

 Fluid

Critical point temperature

Critical point pressure

 

°C

Bar

PSI

 Acetone

235.0

47.7

681.7

 CO2

31.1

73

1072

 Ethanol

243.1

63.1

915.2

 IPA

235.0

53.0

768.7

 Methanol

240.0

78.7

1141.5

 Water

374.0

217.7

3157.8

 Freon

25.0

37.5

550

       

CO2 is ideal for the CPD process because of the low temperature of the critical point, readily miscible with alcohol, non-flammable, non-toxic, globally abundant with low costs.
In CPD sample preparation, water in the fixated sample has been replaced with alcohol and alcohol is added to the cooled CPD processing chamber. High pressure liquid CO2 (LCO2) is used to replace the alcohol and after this the sample is completely immersed in the super-critical CO2. The LCO2 is then heated until the temperature goes beyond the critical point. After that,  the pressure can be gradually reduced, allowing the gaseous CO2 to escape and leaving an intact dry sample. Before examining the sample in the SEM, it needs to be coated with thin layer of precious metal to make it conductive.
Critical point dried samples shown great actual details and provide ample signal after coating. CPD processing often provides better imaging and allows to store samples for future investigations. These are important advantages compared to imaging with variable pressure with increased water vapour pressure.


 

REM Zubehör

TEM Zubehör

Kalibrierung

Probe Vorbereitung

AFM / SPM

  REM Probenteller
  Kohlenstoffklebepads
  Adapter für Probenteller
  Adapter für Probentische
  REM Probenhalter
  REM Präparationshalter
  EM Kathoden
  Silizium-Such-Substrate
  Gatan 3View Probenteller
  FEI Volumescope Probenteller
  Boxen für Probenteller
  Phenom Zubehör
  JEOL NeoScope Zub.
  Hitachi TM Zubehör
  Probenhalterkits

Instrumente


  Schallschutzboxen
  Kritisch-Punkt-Trockner CPD
  Cressington REM Beschichtung
  HI-Res IR-Kamera
  TEM Sample Prep
  TEM Netzchen
  Trägerfilme
  Siliziumnitrid Trägerfilme
  Graphen Filme
  TEM Probenkontrastierung
  TEM Grid Aufbewahrung
  Kryo Grid Box
  Kathoden
  Kryo Pin für Ultramikrotome
  Kunstwimper-Manipulartorset

FIB Zubehör


  FIB Lift-out Grids
  FIB flache Probenteller
  FIB Grid Probenhalter
  FIB vorgekippte Probenhalter
  FIB Grid Aufbewahrung
  REM / FIB Vergrößerung
  REM Auflösungstandards
  EDS / WDS
  TEM
  AFM / SPM
  LM

Vakuum Zubehör


  Bullseye Vakuummessung
  D215V Vakuummessung
  D801W Vakuummessung
  Schnelltest-Druckmesser
  KF/NW Vakuumbauteile
  Vakuumöle und Fette
  Vakuumprobenaufbewahrung
  Verdampferkörbe
  Quarz Kristalle
  Sputter Targets
  Kohlenstoffstäbe & Fäden
  Quarz Kristalle
  Auflagen & Substrate
  REM Präparationshalter
  Pinzetten
  Nadeln & Sonden
  Holzspatel & Tupfer
  Kryo-Behälter
  OCT Kryo-Einbettungsmittel
  Polymer Transferpipetten
  Schneidwerkzeuge / Scheren
  Leitfähige Kleber
  Leitfähige Kleberbänder & Tabs
  Nicht-leitfähige Kleber
  Edelstahlgitter
  Probenaufbewahrung
  Werkzeuge
  Schneidunterlagen
  Reinigung / Handschuhe
  Diamantpolierpaste
  AFM/SPM Metallscheiben
  AFM/SPM Halter
  AFM/SPM Aufbewahrung
  Cantilever Pinzetten
  AFM/SPM Pinzetten
  Mica Scheiben
  HOPG Substrate


LM


  Korrelative Deckgläschen
  Glas-Objektträger
  Deckgläschen
  Quarz Objektträger
  Quarz-Deckgläschen
  Schwarze Metallobjektträger
  Objektträger Aufbewahrung
  Kalibrierung
  Polymerpipetten
  Reinigungspapier für Linsen
  Petrischalen

 

 

 

EM-Tec multiple stub holders for Hitachi cylinder SEM stubs EM-Tec Multiple pin stub holders