Sample handling between despatch and injection

Taking the opening post at face value and following it one step further.

The arithmetic on sample handling between despatch is the easy part and it is where the errors are, which is an uncomfortable combination. Show your working and someone will catch it.

Building on post #5 rather than restating it.

Sample handling between despatch came up in a thread eighteen months ago and was answered well. I cannot find it, which is itself the problem, so here is the reconstruction.

Coming back to post #12, because the follow-up matters more than the original answer.

My experience of sample handling between despatch contradicts the reply above. I am posting it as a data point rather than as a refutation, because one person's experience is exactly that.

The question underneath sample handling between despatch is usually "how would I tell?" rather than "what is true?", and that one has a method attached to it.

Write down what you would expect to see under each hypothesis before you collect anything. If they predict the same observation, collecting it will not help.

The confident answers on sample handling between despatch and the well-sourced answers are not the same answers, which is the most useful thing I have learned reading this category.

A note on how sample handling between despatch gets discussed rather than on sample handling between despatch itself: the confident posts get the replies and the careful ones get ignored, and the careful ones have been right more often.

Transfer between laboratories: a method can be transferred from one lab to another, but the receiving lab needs to demonstrate that they can achieve the same performance. This requires comparative testing and sometimes small method refinements.

Accuracy: the method measures what you intend to measure. For purity methods, this is tested by spike-and-recover experiments: add a known amount of impurity to a sample and measure whether you recover the added amount.

The short version is the first sentence; the rest is why.

Picking up post #65: that is the part I would want checked first.

Adding what did not work for me on sample handling between despatch, since the failures never get written up and they are half the useful information.