“…An extensive collaborative study was conducted to evaluate a comprehensive nitrogen method developed by Gehrke et al (13) and a Raney powder method (2) for acceptance as official methods of the AOAC by Rexroad and Krause (63). Twenty-nine laboratories participated, 10 samples were used, and the new methods were compared to the official method 2.045 (sulfuric-salicylic acid) (46).…”