is used to quantify the uncertainty of the data. After analyzing a sequence of 5 data points from one reference (15 extractions), the average MAPE in the [acid] ini (M ) was approximated as < M AP E >x= 0.80% and [acid]org(M ) as < M AP E >y= 15%, which characterizes the human error. The same procedure was used to characterize the software error. Here, the software error yielded values for [acid] ini (M ) of < M AP E >x= 0.27%