A Simple and Selective Method for the Measurement of Azadirachtin and Related Azadirachtoid Levels in Fruits and Vegetables Using Liquid Chromatography Electrospray Ionization Tandem Mass Spectrometry

Neem-based insecticides containing azadirachtin and related azadirachtoids are widely used inagriculture. Here, we report an analytical method for the rapid and accurate quantification of theinsecticide azadirachtin A and B and other azadirachtoids such as salannin, nimbin, and theirdeacetylated analogues on tomatoes and peaches. Azadirachtoids were extracted from fruits andvegetables with acetonitrile. Using high-performance liquid chromatography/electrospray ionizationtandem mass spectrometer, azadirachtoids were selectively detected monitoring the multiple reactiontransitions of sodium adduct precursor ions. For azadirachtin A, calibration was linear over a workingrange of 1-1000 µg/L with r > 0.996. The limit of detection and limit of quantification for azadirachtinA were 0.4 and 0.8 µg/kg, respectively. The presence of interfering compounds in the peach andtomato extracts was evaluated and found to be minimal. Because of the linear behavior, it wasconcluded that the multiple reaction transitions of sodium adduct ions can be used for analyticalpurposes, that is, for the identification and quantification of azadirachtin A and B and relatedazadirachtoids in fruit and vegetable extracts at trace levels.