Sentences in paper[1]
Units are “parts per million (PPM)” derived from sum-normalizing metabolomic features intensities within each LC-MS method.
Values plotted are raw measurements (not residuals) normalized to ppm units and then log10-transformed[1]
1) Gut microbiome structure and metabolic activity in inflammatory bowel disease
What’s the meaning?
This is a way of expressing very dilute concentrations of substances. Just as per cent means out of a hundred, so parts per million or ppm means out of a million. Usually describes the concentration of something in water or soil. One ppm is equivalent to 1 milligram of something per liter of water (mg/l) or 1 milligram of something per kilogram soil (mg/kg).
Parts per million (ppm) definition
PPM 是英文parts per million的缩写，译意是每百万份中的一部分，即表示百万分之（几），或称百万分率。 如1ppm即一百万千克的溶液中含有1千克溶质。 ppm与百分率（%）所表示的内容一样，只是它的比例数比百分率大而已。
