An o-Toluidine Method for Body-Fluid Glucose Determination

o-Toluidine, 6% (v/v) in glacial acetic acid, is used to determine glucose in biologic material after deproteinization with 3% (w/v) trichloracetic acid. A stable green color develops after heating at 1000 for 10 mm., and the absorbance is determined at 630 or 635 mp. The reagent is stable for many months at room temperature, and the reaction follows Beer's Law over a very wide range of concentrations. The develop- ment of the procedure is discussed, as is the specificity of the method for glucose. \MTH THE CURRENT EMPHASIS 0fl more frequent and more intensive around-the- clock performance of clinical chemical determinations, there is need for a simple, rapid, reliable, and economical method for glucose determination that is equally adaptable to routine multiple or single analyses of any body fluid and is capable of serving as a com- patible manual stand-by and emergency test method in laboratories using automatic glucose analysis. Preferably, such a method should require only a single stable reagent, be adaptable to several of the common methods of preparing protein-free filtrates which may al- ready be employed in a given laboratory for other determinations, and should possess considerable flexibility in its other operating charac- teristics.