A colorimetric urea determination method, reagent, and reagent kit useful in end point and kinetic urea determination is disclosed. Urea in a liquid sample reacts with o-phthalaldehyde and a chromogenic compound in the presence of a linear long hydrocarbon chain amidobetaine to produce an intensely colored reaction product, the concentration of which is linearly related to the urea concentration in the sample.
CROSS-REFERENCE TO RELATED APPLICATION
This is a continuation-in-part of commonly assigned application Ser. No. 292,959 filed Aug. 14, 1981 entitled "Colorimetric Urea Determination In Presence of Long Hydrocarbon Chain Amidobetaine" now U.S. Pat. No. 4,357,144 issued Nov. 2,1982.
The present invention exploits the discovery that amounts of uracil and thymine metabolites, especially .beta.-aminoisobutyric acid, in various bodily fluids, especially urine, are correlated with the occurrence of epilepsy when compared to matched control subjects. Analytical and diagnostic protocols, including a novel high performance liquid chromatography system, for use in the invention are disclosed.
A method for the colorimetric determination of nitrate ions comprises mixing the sample which is to be investigated with concentrated sulfuric acid and a color-generating compound of the formula ##STR1## wherein R is H, one equivalent of a cation, or C.sub.1-6 alkyl. A reagent and kit for colorimetric nitrate determination are also described.
