The next addiction-causing drug class 4-quinazolinone derivatives: analyses of methaqualone analogs including recently discovered 2-methoxyqualone by different modes of mass spectrometry

Purpose The information on analytical methods for 4-quinazolinone recreational drugs, such as methaqualone, etaqualone and 2-methoxyqualone, is almost scant. In this study, product ion spectra of gas chromatography−tandem mass spectrometry (GC−MS/MS) with different collision energies were presented for these drugs. Because 2-methoxyqualone is a new recreational drug discovered in dubious tablets very recently, much more detailed data obtained by different types of mass spectrometry instruments, and quantification data of 2-methoxyqualone in the tablet together with its validation were demonstrated. Methods The methods for analyses were GC−MS/MS, high-resolution ultra-high-performance liquid chromatography–quadrupole time-of-flight mass spectrometry and liquid chromatography−tandem mass spectrometry. Results The GC−MS/MS product ion spectra of the three compounds with different collision energies have not been reported before. They were very useful to tentatively identify unknown compounds. If a reference standard is available, the final identification and quantification can be achieved by measurements of product ion spectra and in selected reaction monitoring mode very easily by GC−MS/MS. The final identification and quantification for the new 2-methoxyqualone were performed in this way. The content of the compound was 69.8 ± 0.5% (w/w) in the tablet. Acetaminophen and caffeine coexisted in the tablet with approximate concentrations at 10 and 5%, respectively. Conclusions In this article, we have presented product ion spectra of methaqualone, etaqualone and 2-methoxyqualone at different collision energies by GC−MS/MS for the first time. In addition, this is the first paper to describe the details of quantification of 2-methoxyqualone in the authentic seized product.