Determination of Amygdalin in Apricot Kernels and Almonds Using LC-MS/MS.

BACKGROUND
Cyanogenic glycosides are secondary metabolites in plants. In almonds and apricot kernels, amygdalin is an abundant cyanogenic glycoside. Upon consumption, amygdalin is enzymatically metabolized into hydrogen cyanide. Depending on the number of kernels consumed and the amygdalin concentration, ingestion of amygdalin-containing kernels may result in adverse effects. To better understand the U.S. marketplace, the development and validation of analytical methods to reliably measure amygdalin in apricot kernels and almonds is needed to support the collection of occurrence and consumption data in retail products.


OBJECTIVE
The aim of this study was to develop and validate a liquid chromatography-tandem mass spectrometry (LC-MS/MS) method for the quantitation of amygdalin in apricot kernels and almonds following the FDA Foods Program Guidelines for the Validation of Chemical Methods, 3rd Edition.


METHODS
Apricot kernels and almonds were cryogenically homogenized and extracted using methanol containing an internal standard (IS), geniposide, followed by filtration, dilution, and LC-MS/MS analysis. Matrix effects were minimized using dilution. Quantitation was achieved using an external, solvent-based calibration.


RESULTS
The amygdalin response was linear (r2> 0.99) over a range of 0.05-50 µg/mL. The recovery of amygdalin spiked at 10 - 10,000 µg/g in sweet apricot kernels, raw almond, and dry roasted almond ranged from 90-107% with RSDs ≤ 6%. The method limit of detection (LOD) and limit of quantitation (LOQ) was 0.8 and 2.5 ng/g, respectively. Amygdalin concentrations in 18 market samples ranged from 2- 24,000 µg/g. Corresponding estimates of cyanide concentration ranged from 0.2-1420 µg/g.


CONCLUSIONS
Method performance meets the acceptance criteria defined by FDA guidelines and is fit for purpose for the analysis of amygdalin in apricot kernels and almonds.


HIGHLIGHTS
An LC-MS/MS method is developed for the quantification of amygdalin in apricot kernels and almonds.