Limonin Content in Citrus Juices

We used the Bidentate C18 2.o™ column to separate limonin from matrix components in citrus juice extracts. The column produces high-efficiency, sharp peaks which is important in order to obtain good limits of quantitation. The quantitaitve studies first used limonin standard solutions covering a range of 2.0–200ppm in order to establish a calibration curve. The detector response was shown to be linear in this range. Next, a non-citrus juice was chosen to serve as a matrix blank (apple juice). This juice extract had no peaks in the region where limonin elutes and therefore would be a good candidate for percent recovery studies. The extract was spiked at both 5 and 10ppm levels. Recovery was observed to be within 97.8–100.2% at these levels. Finally, two orange juice samples were analyzed and the limonin peak was correlated with the calibration cruve. The amounts of limonin were found to be 1.20 and 3.70ppm in two different juices. The approach can be used towards development of a fully validated method for limonin quantitation.