For the first time, a multi-lumen capillary (MLC) (126 parallel channels of 4.2 µm i.d) has been modified to produce a C18-functionalised silica porous layer open tubular (PLOT) capillary column for both on-capillary preconcentration and separation. The modified multi-lumen capillary used in this dual mode provided significant advantages over typical nano/capillary-LC–MS systems, in that it facilitated both higher sample loading capacity, the use of elevated flow rates, and simplified equipment requirements. Following modification, 100% of the channels displayed a homogenous porous silica layer, 257 ± 36 nm thick. The PLOT-MLC was first evaluated for on-capillary solid-phase extraction. Extraction of caffeine, ofloxacin, atrazine, and diuron was carried out offline using an 8-cm-long PLOT-MLC, with quantification achieved using HPLC coupled to a quadrupole-time of flight (QTOF) mass spectrometer. The results confirmed reversed-phase selectivity and average recoveries obtained were around 70%. Subsequently, a 65-cm-long PLOT-MLC was evaluated as a separator column using a capillary liquid chromatography (Cap-LC) system equipped with a nano-injector and coupled to the mass spectrometer. The short PLOT-MLC provided a baseline separation in isocratic mode [water:acetonitrile (each with 0.1% formic acid) = 70:30, v/v] of ofloxacin, atrazine, and diuron. Finally, direct coupling of the PLOT-MLC with the QTOF via a capillary electrosprayer facilitated the simultaneous use of the modified capillary as a solid-phase concentrator, separator column (carrying out concentration-focusing-separation on the PLOT-MLC) and electrospray emitter. This configuration greatly simplifies the traditional capillary-LC–MS equipment requirements, via the removal of all connectors and additional capillary between injector and MS inlet, and is demonstrated herein with large volume sample loading and step-gradient elution/separation with sensitive MS detection.

Item Type:	Refereed Article
Keywords:	liquid chromatography, mass spectrometry, multi-lumen capillary, C18-funtionalised fused silica, porous layer open tubular columns
Research Division:	Chemical Sciences
Research Group:	Analytical Chemistry
Research Field:	Separation Science
Objective Division:	Expanding Knowledge
Objective Group:	Expanding Knowledge
Objective Field:	Expanding Knowledge in the Chemical Sciences
UTAS Author:	Sanz Rodriguez, E (Dr Estrella Sanz Rodriguez)
UTAS Author:	Lam, SC (Mr Shing Lam)
UTAS Author:	Haddad, PR (Professor Paul Haddad)
UTAS Author:	Paull, B (Professor Brett Paull)
ID Code:	129223
Year Published:	2019 (online first 2018)
Funding Support:	Australian Research Council (IC140100022)
Web of Science® Times Cited:	1
Deposited By:	Chemistry
Deposited On:	2018-11-16
Last Modified:	2019-03-12
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