C18-attached membrane funnel-based spray ionization mass spectrometry for quantification of anti-diabetic drug from human plasma

•Sorbent attached membrane funnel based spray platform was used for drug determination in human plasma.•The matrix suppression effect of human plasma was largely eliminated.•The method was applied to determine repaglinide in plasma volunteers.•Membrane funnel-based spray is promising for analysis of biological samples.

In this work, sorbent-attached membrane funnel-based spray ionization mass spectrometry was explored for quantitative analysis of anti-diabetic drugs spiked in human plasma. C18-attached membrane funnel was fabricated for in situ extraction and clean-up to alleviate matrix suppression effect in the ionization process. Repaglinide was used as a target analyte of anti-diabetic drugs. Under optimal working conditions, good linearity (R2 > 0.99) was obtained in the concentration range of 1–100 ng mL−1. The method detection limit of target drugs spiked in the human plasma was around 0.30 ng mL−1. Through the application of an isotope-labeled internal standard, the signal fluctuation caused by residual background matrices was largely alleviated and the precision of measurement (RSD) was below 15%. The recovery of repaglinide for 5, 25, and 100 ng mL−1 of spiked human plasma matrixes ranged from 87% to 112%. The developed method was successfully applied to determine repaglinide in plasma volunteers who orally received a dose of drug association. Our results demonstrated that membrane funnel-based spray is a simple and sensitive method for rapid screening analysis of complex biological samples.

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