Diacetyl Measurement in Orange Juice Using Differential Pulse Polarography

Reconstituted single strength orange juice was distilled to recover diacetyl. 0.5 mL of 1N LiOH was added to 4.5 mL of distillate. Using a static mercury drop electrode, a current vs potential scan was performed between −0.7 and −1.10 vs an Ag/AgCl reference electrode. The reduction potential for diacetyl was −0.83 V. Peak heights were proportional to concentration throughout the test range (8.3 ppb to 1 ppm). Diacetyl recoveries were approximately 85%.