At this point, it doesn't look like we're going to try and submit our results to any scientific journals (maybe Car Craft would be interested?), so here are the exact numbers (ZDDP concentrations in ppm):

Red Line 10W30: 1113.00 +/- 12.75 detection limit: 0.68
Super Tech 10W30: 675.44 +/- 7.98 detection limit: 0.82
Valvoline Conventional 10W30: 756.24 +/- 8.86 detection limit: 0.78
Valvoline VR1 10W30: 1296.78 +/- 14.83 detection limit: 0.86
Comp Cams Engine Break-In Oil Additive: 9548.28 +/- 106.97 detection limit: 2.95
Brad Penn Penn-Grade 1 10W30: 1630.61 +/- 18.60 detection limit: 1.09
Royal Purple 10W30: 842.03 +/- 9.75 detection limit: 0.67
Shell Rotella T5 10W30: 1242.12 +/- 14.41 detection limit: 1.13
Lucas 10W30: 824.45 +/- 9.58 detection limit: 0.87
IV Zn 100 ppm Lot: E2-ZN02069: 99.15 +/- 1.49 detection limit: 0.35

The last one is a NIST-calibrated sample that was used to check accuracy. To be blunt, the "industry standard" ICP-MS method people don't typically publish uncertainties for a very good reason.

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