Monitoring of Vancomycin in Human Plasma via Portable Microchip Electrophoresis With Contactless Conductivity Detector and Multi-Stacking Strategy

• Main Authors: Chong, Kah Chun, Thang, Lee Yien, Quirino, Joselito P, See, Hong Heng
• Format: text
• Published: Archīum Ateneo 2017
• Subjects: Micelle-to-solvent stacking; Field-enhance sample injection; Microchip electrophoresis; Vancomycin; Contactless conductivity detection; Analytical, Diagnostic and Therapeutic Techniques and Equipment; Chemistry
• Online Access: https://archium.ateneo.edu/chemistry-faculty-pubs/176; https://www.sciencedirect.com/science/article/pii/S002196731730047X
• Institution: Ateneo De Manila University

A portable microchip electrophoresis (MCE) coupled with on-chip contactless conductivity detection (C4D) system was evaluated for the determination of vancomycin in human plasma. In order to enhance the detection sensitivity, a new online multi-stacking preconcentration technique based on field-enhanced sample injection (FESI) and micelle-to-solvent stacking (MSS) was developed and implemented in MCE-C4D system equipped with a commercially available double T-junction glass chip. The cationic analytes from the two sample reservoirs were injected under FESI conditions and subsequently focused by MSS within the sample-loading channel. The proposed multi-stacking strategy was verified under a fluorescence microscope using Rhodamine 6G as the model analyte and a sensitivity enhancement factor (SEF) of up to 217 was achieved. The developed approach was subsequently implemented in the aqueous-based MCE, coupled to C4D in order to monitor the targeted antibiotic (in this case, vancomycin) present in human plasma samples. The multi-stacking and analysis time for vancomycin were 50 s and 250 s respectively, with SEF of approximately 83 when compared to typical gated injection. The detection limit of the method for vancomycin was 1.2 μg/mL, with intraday and interday repeatability RSDs of 2.6% and 4.3%, respectively. Recoveries in spiked human plasma were 99.0%–99.2%.