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Marriott P.J.,Monash University | Marriott P.J.,Australian Center for Research on Separation Science | Marriott P.J.,National University of Singapore | Marriott P.J.,RMIT University
LC-GC Europe | Year: 2015

Ionic liquids (ILs) have become recognized in gas chromatography (GC) as stable and highly polar stationary phases with a wide application range. Having customizable molecular structures, ILs also offer a particular tunability that provides additional selectivity, and therefore may improve separation for neighbouring analytes. This article presents specific properties of IL phase capillary GC columns, including polarity scale and inner surface morphologies of IL columns. Application of IL phases in achiral and chiral GC, and multidimensional GC, are highlighted. © 2015 Advanstar Communications Inc. All rights reserved. Source

Pravadali-Cekic S.,Australian Center for Research on Separation Science | Pravadali-Cekic S.,University of Western Sydney | Jones A.,Australian Center for Research on Separation Science | Jones A.,University of Western Sydney | And 11 more authors.
Microchemical Journal | Year: 2015

Reaction flow (RF) chromatography with fluorescamine reagent and UV-vis detection was used for the analysis of amino acids. The performance advantage of RF chromatography was tested against the conventional post-column derivatisation (PCD) methods. The results of the study verified that greater sensitivity could be obtained using RF columns compared to conventional PCD methods. The reaction loops employed in the conventional PCD methods did not need to be used, which resulted in more efficient separations using RF columns. The selective detection of amino acids in this RF study reduced limits of detection (LOD) and limits of quantification (LOQ) by about 50% compared to conventional methods of PCD. The calibration data of the RF-PCD technique also yielded R2≥0.99 and %RSD in peak areas ranging from 3.0-8.5%. The RF method also enabled multiplexed detection since both the derivatised and non-derivatised flow streams could be analysed simultaneously. © 2015. Source

Candish E.,Australian Center for Research on Separation Science | Gooley A.,Australian Center for Research on Separation Science | Wirth H.-J.,SGE Analytical Science | Dawes P.A.,SGE Analytical Science | And 2 more authors.
Journal of Separation Science | Year: 2012

Microextraction by packed sorbent (MEPS) has been directly hyphenated with ESI-MS for the rapid screening of opiates and codeine metabolites in urine. This study introduces a novel format of MEPS that incorporates a two-way valve in the barrel of the syringe enabling the direction of liquid flow to be manipulated. Controlled directional flow (CDF) MEPS allows sharp, concentrated sample bands to be delivered directly to the MS in small volumes and effectively eliminates the need to optimize elution. The method optimization assessed the recovery, matrix effects, and the speed of infusion, all critical variables for optimum ESI performance. Matching extraction workflows demonstrated a reduction in carryover from 65% for conventional MEPS to only 1% for CDF MEPS. The recovery (<89% for 50 μL sample), matrix effects (<42%), linearity (r2 > 0.99), and LODs (<5 ng/mL) were determined to demonstrate method performance. The optimized approach was employed for the screening of codeine metabolites in urine. The ion trace revealed sharp sample bands corresponding to the codeine metabolites. At-line MEPS-ESI-MS allowed both sample preparation and analysis to be completed in only 5 min facilitating high throughput and alleviating the burden of method development. © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim. Source

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