Pipette-tip microextraction using carboxymethylated wooden-based sawdust sorbent for the determination of antidepressants in oral fluid by direct infusion mass spectrometry

• Published in: Microchemical journal 2024-12, Vol.207, p.112002, Article 112002
• Main Authors: González-Galán, Carmen, Millán-Santiago, Jaime, Martínez-Pérez-Cejuela, Héctor, Armenta, Sergio, Herrero-Martínez, José Manuel, Lucena, Rafael, Cárdenas, Soledad
• Format: Article
• Language: English
• Subjects: Antidepressants; Carboxymethylated sawdust; Mass spectrometry; Microextraction; Oral fluid
• ISSN: 0026-265X
• DOI: 10.1016/j.microc.2024.112002

[Display omitted] •The use of carboxymethylated wooden-based sawdust is proposed for sample preparation.•The sorbent material is hosted into pipette tips to carry out the extraction process.•Four different antidepressants are determined in human oral fluid samples.•Direct infusion tandem mass spectrometry allows a high sample throughput analysis. Matrix complexity is a challenging scenario in sample preparation and the scientific community is in the search of novel materials capable of replacing the classical sorbents to overcome the sensitivity and selectivity issues it presents. In this article, the use of a carboxymethylated wooden-based sawdust sorbent pipette-tip microextraction is introduced for the determination of four antidepressants (imipramine, amitriptyline, fluoxetine, and clomipramine) in human oral fluids. The different variables affecting the extraction and elution procedures, including sample pH, ionic strength, number of pushing cycles, dilution of the sample, eluent, and volume of the eluent have been evaluated by liquid chromatography – ultraviolet detection. Moreover, the proposed method was validated by direct infusion coupled to tandem mass spectrometry with limits of detection of 0.2 μg/L, limits of quantification of 0.6 μg/L, linear range spanning from 0.6 to 320 μg/L and intra-day precision (expressed as relative standard deviation) better than 14.2 %. Intra-day accuracy (expressed as relative recovery) ranged from 85.4 to 102.9 %, while inter-day accuracy was between 97.0 and 103.9 %. Finally, the analysis of two oral fluids from a patient under amitriptyline treatment were analyzed, providing values within the linear range of the proposed method.