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Zou W.,LCGC North America | Yasuor H.,University of California at Davis | Fischer A.J.,University of California at Davis | Tolstikov V.V.,University of California at Davis
LCGC North America | Year: 2011

Detection, analysis, and characterization of low-abundant metabolites remain an unresolved problem in metabolic studies. In this study, we report a novel approach to address this challenge. The current methodology is derived from the predictive multiple reaction monitoring (pMRM) mode available on triple-quadrupole linear ion trap mass spectrometry (MS) systems. The pMRM mode offers the highest sensitivity among various acquisition modes for studying trace levels of metabolites of the herbicide clomazone in plants. Additionally, this method allows for the identification of positional isomers of metabolites. Unknown metabolites were further identified and validated by obtaining accurate masses and isotopic ratios using selected ion monitoring (SIM) and data-dependent MS-MS scans on high-resolution liquid chromatography (LC)-MS. During structural assignment of its metabolites, the unique chlorine isotopic signature of clomazone was used as a naturally occurring label to study MS-MS fragmentations. © 2011 Advanstar Communications, Inc. Source

Dolan J.W.,LCGC North America
LCGC North America | Year: 2011

For method development or routine analysis, the minimum gradient time may be a limit of throughput. © 2011 Advanstar Communications, Inc. Source

Sadikin S.,SuperGen | Zhang D.D.,SuperGen | Inloes R.,SuperGen | Redkar S.,SuperGen | Dolan J.W.,LCGC North America
LCGC North America | Year: 2011

Ghost peaks can be difficult to eliminate when minor peaks are important in an LC separation. This case study shows how to isolate the source of such peaks. © 2011 Advanstar Communications, Inc. Source

Matheson A.,LCGC North America
LCGC North America | Year: 2011

Mercks Christopher Welch spoke to Alasdair Matheson, editor of LCGC Europe, about high-throughput analysis using MISER chromatography and how it can boost your laboratory's productivity. © 2011 Advanstar Communications, Inc. Source

Gjelstad A.,LCGC North America | Taherkhani H.,LCGC North America | Rasmussen K.E.,LCGC North America | Pederson-Bjergaard S.,LCGC North America
LCGC North America | Year: 2011

In this installment of Sample Prep Perspectives, Norwegian authors from the University of Oslo describe the practical aspects of hollow fiber liquid-phase microextraction in the three-phase mode (HF3 LPME). The guest authors highlight important practical issues related to the supported liquid membrane, the hollow fiber, and the extraction itself. They also discuss practical work with electromembrane extraction (EME), which is related to HF3 LPME but uses an electrical potential as the driving force for the extraction © 2012 Advanstar Communications, Inc. Source

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