Ueber eine neue Reaction auf Kreatinin und Kreatin

Creatinine determination according to Jaffe--what does it stand for?

“…In 1886, Jaffe observed that a red colour formed when creatinine reacted with picric acid in an alkaline medium [ 5 ] and observed the needle-formed crystals under the microscope. Furthermore, he could demonstrate the nature of the precipitated compound as being a double salt of potassium and creatinine with picric acid by the typical precipitation of creatinine with zinc chloride (Neubauer reaction) [ 6 ] and by carrying out the Weyl's test [ 7 ] (adding a dilute solution of sodium nitroprusside and then putting in a few drops of sodium hydroxide that induces a ruby red colour, changing to blue on warming with acetic acid). In his landmark paper, Jaffe discussed that the alkaline picrate reaction could also be observed to a much lesser extent with a number of organic compounds (e.g.…”

Rapid Electrochemical Flow Analysis of Urinary Creatinine on Paper: Unleashing the Potential of Two-Electrode Detection

“…Despite a long history, the reaction of creatinine with ferricyanide remains relatively unexplored, and mechanistic studies and parametric optimization are lacking. − This knowledge gap exists because the reaction is difficult to incorporate into colorimetric analysis since ferrocyanide requires further reaction steps to generate a measurable color change, e.g., with Fe 3+ to form Prussian blue (Figure ). By removing this second step, the two-electrode detector format presented here offers an attractive platform for studying the kinetics and mechanisms of this reaction.…”

“…When searching for a more suitable detection system, we discovered that reactions between ferricyanide complexes and creatinine, which were discovered in the 19th century (Figure a), − remained relatively unexplored within electrochemical systems despite the attractive features of ferricyanide (fast, reversible, and wide electrode compatibility) for low-cost systems (Figure b) . Accordingly, we investigated the ferricyanide-mediated electrochemical detection of urinary creatinine and its implementation in a paper-based FIA with two-electrode detectors.…”

The Chemistry Of The Glycocyamidines

“…The former is apparently a product of hydrolysis or deamination of the latter. 3-Methylcreatinine reacts similarly, as does the diphenyl ester (CVIII) of 3-methylcreatinine- Isonitrosocreatinine is likewise formed by treating creatinine in alkaline solution with sodium nitroprusside (Weyl color reaction for creatinine (316)) and subsequently acidifying with acetic acid (192,258,268,316). Originally this substance was thought to be nitrosocreatinine (192).…”

“…Aqueous alkaline solutions of creatinine produce on treatment with sodium nitroprusside a transient red color, later turning yellow (235,316), which, on acidifying with acetic acid and subsequent heating turns green and then blue 254). It was suggested that the red coloration depends on the formation of an unstable iron complex, the structure of which is represented by either CLXXYV or CLXXXVI, and which is decomposed with formation of isonitrosocreatinine (258).…”