A rapid and highly specific method to evaluate the presence of 2-(2-phenylethyl) chromones in agarwood by supercritical fluid chromatography-mass spectrometry.

The detection and structural characterization of the major constituents of agarwood, 2-(2-phenylethyl)chromones, are important to quality control and the establishment of the authenticity of agarwood samples. However, a highly specific and rapid method for the evaluation of 2-(2-phenylethy)chromones in agarwood has not been reported to date. In this study, we developed a method using super- critical fluid chromatography in combination with mass spectrometry (SFC-MS). Tropylium ions, the characteristic product ions of 2-(2-phenylethyl)chromones in tandem mass spectrometric experiments, were selected for the targeted detection of 2-(2-phenylethyl) chromones. This method used precursor ion scans for tropylium ions with different possible substitutions on a triple-quadrupole mass spectrometer. To evaluate the usefulness of the developed method, a diethyl ether extract from a Chinese agarwood "Qi-Nan" sample was first separated using SFC, and the elutes were later subjected to precursor ion scans, which searched for 15 common substituted tropylium ions to evaluate the 2-(2-phenylethyl)chromones. In the precursor ion scans, a total of 29 2-(2-phenylethyl)chromones were detected and investigated further using tandem mass spectrometry (MS/MS) to obtain more detailed structural information. By comparing the retention times and m/z values of the precursor ions with reference standards, nine of the detected compounds were unequivocally identified. The remaining compounds were tentatively identified by analyzing the MS/MS spectra. This method provides a rapid and efficient method for evaluating the 2-(2-phenylethyl)chromones present in a sample, which aids in quality control and the establishment of the authenticity of the agarwood sample.