The minimum operating temperature of the EF600 is -100C is this a problem?
It is essential to control the rate of cooling of the samples from the temperature of ice nucleation to some sub-zero temperature before the sample is transferred to the storage temperature - by direct transfer to liquid nitrogen or a "dry shipper". The conventional temperature of transfer varies with cell type (and fashion) but for many mammalian tissue culture cells, the samples are cooled at 1C min to -60°C or -80°C before being transferred to liquid nitrogen. In much veterinary IVF, embryos are cooled, at a very slow rate, to a temperature around -35°C and then transferred to liquid nitrogen. In human IVF samples are often cooled to a lower temperature and then transferred. However, -100°C is perfectly adequate and cannot compromise cell viability, there is no physical reason why it is necessary to cool to a lower temperature before transfer to liquid nitrogen.
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