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.
