We only deal with enriched carbon samples here in the lab. We have one
analytical balance and one mass spec system.
First we clean off the weighing area including the balance with IPA and
wipe down all utensils.
We, then weigh out the samples and refrences in from the lowest to
highest enrichment. After each type of sample with clean off the area
and utensils before starting with another set of material. So we
mitigate by sequencing our weighing.
We periodically clean out the autosampler wells with Q-tips, kim wipes
and IPA. Our run time per carbon sample is 10 minutes. I can run our
high enrichment standard (+245) right before natural abundance surcose
(-11.2 delta) and see no affect.