Development of CE-MS/MS method for unravelling nonsteroidal anti-inflammatory drugs as potential adulterants of Boswellia serrata extract.

The CE-MS/MS method for the analysis of boswellic acids, natural compounds with anti-inflammatory activity, and nonsteroidal anti-inflammatory drugs (NSAIDs) as potential adulterants of dietary supplements with Boswellia serrata extract is presented for the first time. An aqueous-organic background electrolyte comprising 40 mmol/L ammonium acetate (pH 8.5), methanol, and acetonitrile (5:1:4, v/v/v) was used for the separation of boswellic acids and thirteen NSAIDs in negative electrospray ionization mode. Design-of-experiments-guided optimization of Agilent Jet Stream ion source parameters and adjustments to the sheath liquid composition were conducted to improve sensitivity and prevent capillary breakage inside the nebulizer. The CE-MS/MS method was validated for diclofenac, flurbiprofen, ibuprofen, ketoprofen, phenylbutazone, salicylic acid, and carprofen, meeting the ICH M10 guideline requirements for accuracy, precision, matrix effects, and recovery. The lower limits of quantification ranged from 0.04 to 4 μg/mL for all NSAIDs, providing sufficient sensitivity to detect adulteration. The application of the method to dietary supplements revealed no evidence of NSAID adulteration while highlighting quantitative variations in boswellic acid profiles. Further analysis using CE-HRMS with data-dependent acquisition workflow enabled the identification of additional natural triterpenoids and undeclared compounds, such as citric acid and ascorbic acid.