FIG 2.

Intensity ratio for consecutive samples in accuracy assessment and both specificity assessments. (A) Accuracy assessment; (B) Specificity assessment 1; (C) Specificity assessment 2. Samples 24 and 74 were removed from the accuracy assessment due to instrument programming error. The plot of the secondary assessment includes rerunning of samples 9 and 25 due to carryover of the preceding sample. The horizontal dashed line at 0.5 represents the threshold R value for which samples were automatically called positive (R, intensity ratio, sample/internal standard).