Jump to main content
Jump to site search

Issue 10, 2013

A multifunctional microfluidic droplet-array chip for analysis by electrospray ionization mass spectrometry

Author affiliations

Abstract

This paper describes a multifunctional semi-closed droplet-array chip coupled with electrospray ionization mass spectrometry (ESI-MS) detection for multiple sample pretreatment and analysis. A novel interfacing method for coupling droplet system with ESI-MS was proposed using a sampling probe–two-dimensional (2D) droplet-array strategy. The 2D droplet-array system was composed of an 8 × 8 microwell array chip for droplet storage and a layer of oil covering the droplets served as a “virtual wall” to avoid droplet evaporation or cross-contamination. An L-shaped capillary was adopted as the interface of the droplet array and ESI-MS, using its inlet end as a sampling probe for droplets and its outlet with a tip size of ∼20 μm as an electrospray emitter, without the need for any droplet extraction device. The droplet analysis was performed by moving the droplet-array chip to allow the capillary sampling probe to sequentially enter into the droplets through the oil and introduce the sample solution into the capillary emitter for MS detection. The MS analysis time for each droplet sample was 40 s with a sample consumption of ca. 13 nL. A good repeatability of 5.7% (RSD, n = 9) was obtained for 10−6 M reserpine droplet analysis. The uses of the semi-closed 2D droplet array and off-line interfacing mode provide the system with the substantial flexibility and controllability in droplet indexing, multi-step manipulating, and on-demand sampling for MS analysis. We applied the present system in multi-step pretreatment and identification of small amounts of proteomic samples of myoglobin and cytochrome C, including in-droplet protein reduction, alkylation, digestion, and purification based on solid-phase extraction, matrix modification, sample droplet introduction under flow injection mode, and ESI-MS detection.

Graphical abstract: A multifunctional microfluidic droplet-array chip for analysis by electrospray ionization mass spectrometry

Supplementary files

Article information


Submitted
14 Jan 2013
Accepted
02 Mar 2013
First published
04 Mar 2013

Lab Chip, 2013,13, 1876-1882
Article type
Paper

A multifunctional microfluidic droplet-array chip for analysis by electrospray ionization mass spectrometry

Y. Su, Y. Zhu and Q. Fang, Lab Chip, 2013, 13, 1876 DOI: 10.1039/C3LC00063J

To request permission to reproduce material from this article, please go to the Copyright Clearance Center request page.

If you are an author contributing to an RSC publication, you do not need to request permission provided correct acknowledgement is given.

If you are the author of this article, you do not need to request permission to reproduce figures and diagrams provided correct acknowledgement is given. If you want to reproduce the whole article in a third-party publication (excluding your thesis/dissertation for which permission is not required) please go to the Copyright Clearance Center request page.

Read more about how to correctly acknowledge RSC content.


Social activity

Search articles by author

Spotlight

Advertisements