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Periat A.,University of Geneva | Kohler I.,University of Geneva | Bugey A.,Official Food Control Authority and Veterinary Affairs of Geneva | Bieri S.,Official Food Control Authority and Veterinary Affairs of Geneva | And 3 more authors.
Journal of Chromatography A | Year: 2014

In this study, the influence of electrospray ionization (ESI) source design on the overall sensitivity achieved in hydrophilic interaction chromatography (HILIC) and reversed phase liquid chromatography (RPLC), was investigated. State-of-the-art triple quadrupole mass analyzers from AB Sciex, Agilent Technologies and Waters equipped with brand specific source geometries were tested with various mobile phase pH on 53 pharmaceutical compounds. The design of the ESI source showed to strongly influence the gain in sensitivity that can be achieved in HILIC compared to RPLC mode. The 6460 Triple Quadrupole LC/MS system from Agilent Technologies was particularly affected by mobile phase settings. Indeed, compared to RPLC conditions, 92% of the compounds had an increased signal-to-noise ratio at a flow rate of 300. μL/min in HILIC mode at pH 6, while this percentage dropped to only 7% at 1000. μL/min and pH 3. In contrast, the influence of flow rate and mobile phase pH on the gain in sensitivity between RPLC and HILIC was found very limited with the API 5000™ LC/MS/MS system from AB Sciex, as only 15 to 36% of the tested compounds showed an enhanced sensitivity in HILIC mode. With the Xevo TQ-S instrument from Waters, superior sensitivity in HILIC was noticed for 85% of the compounds with optimal conditions (i.e., pH 3 and 1000. μL/min), whereas at sub-optimal conditions (i.e. pH 6 and 300. μL/min), it represented less than 50%. The gain in sensitivity observed in HILIC was found less significant with the recent LC-MS platforms used in this study than for old-generation instruments. Indeed, the improved ESI sources equipping the recent mass analyzers allow for enhanced evaporation efficiency, mainly for RPLC mobile phases containing high proportion of water and this even at high flow rates. © 2014 Elsevier B.V. Source


Staub Sporri A.,Official Food Control Authority and Veterinary Affairs of Geneva | Jan P.,Official Food Control Authority and Veterinary Affairs of Geneva | Cognard E.,Official Food Control Authority and Veterinary Affairs of Geneva | Ortelli D.,Official Food Control Authority and Veterinary Affairs of Geneva | Edder P.,Official Food Control Authority and Veterinary Affairs of Geneva
Food Additives and Contaminants - Part A Chemistry, Analysis, Control, Exposure and Risk Assessment | Year: 2014

In the context of multi-residue screening in honey, a complete methodology was developed for 200 veterinary drugs comprising a sample preparation step and an ultra-high-performance liquid chromatography (UHPLC) coupled to time-of-flight (TOF) mass spectrometry analysis. In addition, specific analytical strategies were developed for two compounds, streptomycin and chloramphenicol, using UHPLC and tandem mass spectrometry (MS/MS). Methodologies were then applied to real honey samples obtained from the Swiss market. © 2014 Taylor & Francis. Source

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