A modified QuEChERS method coupled with liquid chromatography-tandem mass spectrometry for the simultaneous detection and quantification of scopolamine, L-hyoscyamine, and sparteine residues in animal-derived food products

Abstract

We developed a modified Quick, Easy, Cheap, Effective, Rugged, and Safe (CEN QuEChERS) extraction method coupled with liquid chromatography-electrospray ionization tandem mass spectrometry (LC-ESI⁺/MS-MS) to identify and quantify residues of three botanical alkaloids, namely, scopolamine, L-hyoscyamine, and sparteine, in animal-derived foods, including porcine muscle, egg, and milk. A combination of ethylenediaminetetraacetic acid disodium buffer and acetonitrile acidified with 0.5% trifluoroacetic acid was used as an extraction solvent, whereas QuEChERS (CEN, 15662) kits and sorbents were applied for cleanup procedures. The proposed method was validated by determining the limits of quantification (LOQs), with values of 1-5 µg/kg achieved for the target analytes in various matrices. Linearity was estimated from matrix-matched calibration curves constructed using six concentration levels ranging from 1- to 6-fold increases in the LOQs of each analyte, and the correlation coefficients (R² ) were ≥0.9869. Recoveries (at three concentration levels of 1-, 2-, and 3-fold increases in the LOQ) of 73-104% were achieved with relative standard deviations (RSDs) ≤7.7% (intra-day and inter-day precision). Ten types of each matrix procured from large markets were evaluated, and all tested samples showed negative results. The current protocol is simple and versatile and can be used for routine detection of plant alkaloids in animal food products.

Keywords: Egg; L-hyoscyamine; LC-MS/MS; Milk; Porcine muscle; QuEChERS; Residues; Scopolamine; Sparteine.

Graphical abstract

Fig. 1

Chemical structures of scopolamine, L-hyoscyamine, (+)-sparteine, and (−)-sparteine.

Scheme 1

Different protocols used for purification of the tested analytes in various matrices.

Fig. 2

Effects of various cleanup procedures (according to Scheme 1) on the extraction efficiency of scopolamine, L-hyoscyamine, (+)-sparteine, and (−)-sparteine in porcine muscle, egg, and milk (spiking level: 50 µg/kg).

Fig. 3

LC-MS/MS chromatograms of standard solutions of scopolamine, L-hyoscyamine, (+)-sparteine, and (−)-sparteine (spiking level: 50 µg/kg).

Fig. 4

LC-MS/MS chromatograms of standard solutions of scopolamine, L-hyoscyamine, (+)-sparteine, and (−)-sparteine in spiked blank samples (left) and market samples (right) of porcine muscle, egg, and milk (spiking level: 50 µg/kg).