单语范例（未经PONS编辑处理）
Tainted samples were found among 21 other suppliers, where concentrations ranged from 0.09 to 619.00 ppm.
en.wikipedia.org Concentration of nitric acid is reduced from 30% in the feed to 15 ppm in the cake produced.
en.wikipedia.org Un acclimatized humans experience extreme eye and nasal irritation at concentrations in excess of 25 ppm, and conjunctivitis from concentrations below 10 ppm has been reported.
en.wikipedia.org One vein with visible molybdenite assayed at 1,240 ppm across the vein.
en.wikipedia.org Aromatic methoxy group give responses in 4.0-4.2 ppm region but 4-methoxy group give responses in 4.40 ppm region.
en.wikipedia.org