Liquid chromatography–quadrupole orbitrap and liquid chromatography–tandem mass spectrometry system for rapid identification and quantitation of thirty nonsteroidal anti‐inflammatory drugs and acetaminophen in illegal products

Rationale As the public interest in healthcare increases, illegal dietary supplements, foods, and drugs containing unauthorized pharmaceutical ingredients, including nonsteroidal anti‐inflammatory drugs (NSAIDs) and acetaminophen, have been identified. Excessive and unintentional consumption is toxic to the gastrointestinal tract, kidneys, and liver; therefore, these pharmaceuticals must be monitored using analytical methods. Methods A rapid and reliable analysis system involving liquid chromatography–quadrupole orbitrap mass spectrometry (LC‐Q‐Orbitrap/MS) and liquid chromatography–tandem mass spectrometry (LC/MS/MS) was established and validated to identify and quantify 30 NSAIDs and acetaminophen. In addition, we obtained the MS2 spectrum for each component with the proposed structure of the fragment ions. Results The analytical method was applied to 505 samples of illicitly distributed dietary supplements, foods, and pharmaceuticals. Non‐steroidal analgesics were detected in 126 samples. Carbamazepine (42.9%) and diclofenac (30.2%) were the most detected components in the samples; other pharmaceutical adulterants were also detected in some cases. Additionally, we present the identification of an unknown component, dexamethasone (799 μg/g), using LC‐Q‐Orbitrap/MS in a sample containing the unknown component with meloxicam (15.4 mg/g). Conclusions The developed analysis system, consisting of qualitative analysis using LC‐Q‐Orbitrap/MS and quantitative analysis using LC/MS/MS, can rapidly and accurately identify and quantify NSAIDs and acetaminophen while also identifying non‐analytical components.