A Dual-Column Solid Phase Extraction Strategy for Online Collection and Preparation of Continuously Flowing Effluent Streams for Mass Spectrometry

• Published in: Analytical chemistry (Washington) Vol. 84; no. 20; pp. 8467 - 8474
• Main Authors: Enders, Jeffrey R, Marasco, Christina C, Wikswo, John P, McLean, John A
• Format: Journal Article
• Language: English
• Published: Washington, DC American Chemical Society 16.10.2012
• Subjects: Analysis methods; Analytical chemistry; Applied sciences; Bioreactors; Chemistry; Desalination; Effluents; Equipment Design; Exact sciences and technology; Extraction processes; Mass spectrometry; Mass Spectrometry - instrumentation; Membrane reactors; Metabolites; Microfluidic Analytical Techniques - instrumentation; Pollution; Salts - isolation & purification; Solid Phase Extraction - instrumentation; Spectrometric and optical methods; Wastes; Solid phase extraction; Resolving power; On line; Metabolite; Time; Chemical enrichment; Sample preparation; Loading; Dynamics; Sampling; Fluid mechanics; Sample; Use; Concentration; Biological compound; Bioreactor; Desalination; Temporal study; Frequency; Strategy; Small sample; Wastes; Technique; Mass spectrometry; Effluent; Microfluidics
• ISSN: 0003-2700; 1520-6882
• DOI: 10.1021/ac3021032

Current desalination techniques for mass spectrometry-based protocols are problematic for performing temporal response studies where increased temporal resolution requires small samples and faster sampling frequencies, which greatly increases the number of samples and sample preparation time. These challenges are pertinent to cellular dynamics experiments, where it is important to sample the biological system frequently and with as little sample waste as possible. To address these needs, we present a dual-column online solid phase extraction (SPE) approach capable of preconcentrating and preparing a constantly perfusing sample stream, with minimal to no sample loss. This strategy is evaluated for use in microfluidic bioreactor studies specifically aimed at characterizing suitable sample flow rates, temporal resolving power, and analyte concentrations. In this work, we demonstrate that this strategy may be used for flow rates as low as 500 nL/min, with temporal resolving power on the order of 3 min, with analyte loadings ranging from femtomoles to picomoles for metabolites. Under these conditions, recoveries of ca. 80% are obtained even at femtomole loadings.