Patent ID: 9250190
Filing Date: 2016-02-02
CPC Classification: G01N,Y10T

Claim Text:
1. A ninhydrin reagent for use in a method for analysing nitrogen-containing compounds, the ninhydrin reagent comprising: ninhydrin; an aqueous buffer, wherein the ninhydrin reagent has a pH, and wherein the buffer maintains the pH at a value between 4.5 to 5.5; and a temperature-dependent reducing agent, which agent is inactive in the reduction of ninhydrin at a first temperature, wherein the first temperature is no greater than 30° C., and active in reducing ninhydrin to hydrindantin at a second temperature, wherein the second temperature is higher than the first temperature, further wherein the second temperature is at least 100° C.; and wherein the ninhydrin reagent is essentially free from hydrindantin.