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What Is the Chemical Composition of Urine?


This is a specimen of human urine.

This is a specimen of human urine. Human urine ranges in color from nearly clear to dark amber, depending largely on the amount of water that is present.

Markhamilton, public domain

Question: What Is the Chemical Composition of Urine?

Urine is a liquid produced by the kidneys to remove waste products from the bloodstream. Human urine is yellowish in color and variable in chemical composition, but here is a list of its primary components.

Answer: Human urine consists primarily of water, with organic solutes including urea, creatinine, uric acid, and trace amounts of enzymes, carbohydrates, hormones, fatty acids, pigments, and mucins, and inorganic ions such as sodium (Na+), potassium (K+), chloride (Cl-), magnesium (Mg2+), calcium (Ca2+), ammonium (NH4+), sulfates (SO42-), and phosphates (e.g., PO43-). A representative chemical composition would be:

water 95%

urea 9.3 g/l

chloride 1.87 g/l

sodium 1.17 g/l

potassium 0.750 g/l

creatinine 0.670 g/l

with lesser amounts of other ions and compounds

Reference: NASA Contractor Report No. NASA CR-1802, D. F. Putnam, July 1971.


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