Figure 4.

(A) Quadrupole isolation transmission efficiency. Transmission relative to rf-only (q = 0.706) operation is plotted for four stable FC-43 ions as a function of measured isolation width using an AGC target of 1 × 10⁵, 17 500 resolution, and <100 ms injection times. (B) Chromatographic and spectral performance of 1 pg octafluoronaphthalene (OFN) in 0–5% v/v diesel. Chromatographic peak areas (denoted “A”) and spectral signal-to-noise (S/N) are noted. (C) Response curves (peak area versus amount on column) for 5 of 94 EPA 8270 compounds targeted by scheduled SIM (3 Th) over 6 orders-of-magnitude. Linearity and detection limit data are given Table 1 and Supplemental Figure S4 in the Supporting Information. (D) Quantification of 2,3,7,8-TCDD at 10–15 fg on column in human pooled blood extract. At left, extracted ion chromatograms (±10 ppm, 5 pt Gaussian smoothing) of native congener quantification isotopomers, m/z 320 and m/z 322, analyzed in separate SIM (4 Th) scans, and of ¹³C-labeled internal standard (IS) congeners analyzed in full scan are plotted. The single-scan SIM mass spectra at the elution apex for the targeted native congener isotopomers are plotted at right.