Error analysis was done by estimating uncertainty in a given measurement. Running those uncertainties through the calculation and seeing the impact. It was an estimate not a true measure.
MSA principles, IMHO, would be applicable to titration. Buy a standard (an off the shelf solution of known assay-- you will probably have to pay extra for this to get the supplier to provide a cert of analysis that the sulphuric acid is X.XX % / molarity / molality / whatever. Have your analysts test that standard and see how close they get. Google is your friend. Read about titration Wet chem labs have many opportunities for error. Your MSA participants will have their own error rates / tendencies that will show up in the final results. You should be able to get a GRR as well as an accuracy to standard element. Which analyst had the most accurate results? Which had the least variation? Titration is adding one solution to another, at the end, in a drop by drop fashion, to get a color change when an indicator is triggered at a certain concentration. Some will overshoot; some may undershoot. Plan your statistics BEFORE sending your team to the lab. Have a pre determined analysis plan and, if possible, acceptance criteria for accuracy to the standard. Will you introduce equipment variation? Different pipettes? Scales? Glassware? Etc. Or, will you keep the equpment the same and focus on the operator / tester differences.
Hope this helps