Journal of Applied Crystallography

Volume 32, Part 1 (February 1999)

laboratory notes

J. Appl. Cryst. (1999). 32, 134-135 [ doi:10.1107/S0021889898010681 ]

Condensation-free X-ray diffraction data collection with capillaries at 277 K

D. Lim, Q. Ye and Z. Jia

Abstract: Crystallization at 277 K is routinely practiced in most crystallography laboratories. Data collection from such crystals at this temperature has been facilitated by the widespread use of versatile cryocooling devices capable of maintaining crystals at cryogenic to near room temperatures. However, temperature gradients can potentially develop along a capillary cooled by a gas stream, which may result in condensation around the crystal. A convenient protocol has been developed and used successfully to prevent this problem. By the placement of oil plugs close to both sides of the crystal, the enclosed airspace is kept free of condensation, even while the capillary is cooled for extended periods of time by a gas stream flowing at an angle to the capillary. This technique eliminates the need to work with very short capillaries and can be implemented without modification to an existing cryostat configuration.