Urine is a liquid produced by the kidneys to remove waste products from the bloodstream. Human urine is transparent, yellowish in colour and variable in chemical composition. It consists primarily of water $(95 \%)$, with organic solutes including urea $(2.6 \%)$, creatinine, uric acid, and trace amounts of enzymes, carbohydrates, hormones, fatty acids, pigments, and mucins, and inorganic ions such as sodium (Na $^{+}$), potassium ( $\left.K ^{+}\right)$, chloride ( $Cl ^{-}$), magnesium ( $Mg ^{2+}$ ), calcium (Ca $^{2+}$ ), ammonium ( $NH _{4}^{+}$), sulfates ( $SO _{4}^{2-}$ ), and phosphates ( $PO _{4}^{3-}$ ).