The Horrors of Method Transfer
Written by: Steve Ward-Smith
Seeing apparitions of method transfer challenges?
Poltergeist activity causing you to move laboratory?
Thoughts of writing size measurements of materials methods spooking you?
The truth is we naturally fear the unknown and if we considered all the unknowns we can sleep easy, without being woken up by bumps in the night.
When designing a method for transfer many things need to be considered.
Is the laboratory built on ancient Indian burial ground? Is the temperature likely to vary? Will it take longer to get a good background in a different country if you are using a volatile organic solvent? Are the optical properties you are using appropriate for the material and give an excellent result on all the results you have done so far? Is the dispersion method as sufficiently detailed as you can make it, whilst still being simple and in a small number of steps.
There are too many methods which just say things like “sonicate” (in what, if an external bath what is the make, the model, the amount of water you’ve added and where in the bath have you placed the beaker that will contain the sample you wish to disperse.
Other methods specifiy a weight of sample to add and a concentration range, yet when followed exactly, the specified concentration range cannot be achieved from the weight, so it looks like the method was not tested on enough batches (or the size now is different to the original size at the time of method development).
The quality of acceptable data, specifically the level of background and background stability before a measurement and the measured data specifically in relation to the re-establishment of thermal equilibrium after sonication are also key.
For dry measurements an acceptable flow of powder and an appropriate pressure (to maximize dispersion and minimize breakage) are required, but care must also be taken to only have the instrument take data when there is enough powder going through the system.
A small amount of thought and care in the preparation of method transfer can save a vast amount of time later. Getting things right first time is not that difficult if some of the above tips are followed, and getting things wrong can be very costly. So if there is something strange …In your method transfer… Who are you going to call..? Our specialists are here to help.