Controlled crystal dehydration

Crystal dehydration can considerably improve the X-ray diffraction quality for poorly diffracting macromolecular crystals and finally, lead to diffraction data with higher resolution.

The below image shows a series of diffraction patterns which were taken during a dehydration experiment on a laboratory home source and a single crystal. The sample’s relative humidity was set with Arinax’s Humidity Controller for two different crystal orientations,  = 0° and  = 90°.

For each crystal orientation the diffraction data was recorded for successively decreasing relative humidity values. This experiment resulted in a resolution improvement from 8 Å at RH = 99% to 4 Å at RH = 96%.

Automatic drop size tracking

The HC-Lab control software exploits sample images, e.g. delivered by the goniometer’s video microscope. Depending on the RH set point the drop of mother liquor surrounding the crystal will shrink (low RH), increase its diameter (high RH) or remain stable in size (equilibrium RH). The drop size is constantly monitored by the control software via image recognition and dynamically plotted in a time diagram together with the actual RH value.

The sample visualization and the monitoring over time of different experimental parameters like drop size, sample temperature and RH value gives an unprecedented degree of control over dehydration experiments. Python scripting can be used for programming experiment cycles with varying parameters and successive X-ray data collection.

Having specific questions about the HC-Lab and Crystal Dehydration?

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Automatic & remote controlled nozzle exchange

Moreover, the HC-Lab can be combined with the Rapid Nozzle Exchanger REX to automate the nozzle exchange between the HC-Lab humidity nozzle and the cryo nozzle, i.e. for flash-cooling, while maintaining the alignment with respect to the sample/crystal.

See more about the REX Rapid Nozzle Exchanger

Technical specifications

Features
Compressed air supply
– Pressure 3 bar mini / 7 bar maxi
– Flow <30 L/min
– Connection 6 mm diameter
Nozzle
– Diameter 26 mm @ fixing point
– Length 265 mm
– Tubing length 2.0 m
Performance
Humid air stream
• Flow 3L/min – 6L/min
• Relative humidity
– Range 30.0 % – 99.8 % @ 23°C room temp.
– Resolution 0.01 %
– Stability ±0.05 % RMS (0.20 % peak-to-peak)
Dry protective air stream
– Flow 9 L/min – 12 L/min (typically 10L/min)
Temperature
– Range room temperature
– Precision ±0.05 °C
Software
– User interface Windows® / Linux
– Control parameters Relative humidity/ dew point
– Monitoring parameters Temperature and drop size
– Functionalities

Drop visualization
Automatic drop size tracking
Time plot (temp., RH, drop size)
Python scripting

Mains Power
– Voltage 90 VAC – 260 VAC
– Frequency 50 Hz – 60 Hz
– Power 500 W
Dimensions
Width x Height x Depth

230x500x450 mm3

Weight
20 Kg