CAN108: Ion Chromatography Coupled with Mass Spectrometry for Metabolomics

Instrument Type: ICMS

Here, the author describes an ion-exchange system that provides good separation of the polar metabolities with on-line desalting to allow MS detection. This technique will allow studies of key metabolites that do not separate well on traditional reversed-phase columns. Some ionic metabolites may be positional isomers adjacent to each other in a synthetic pathway and as such, are isobaric. In such cases, MS is not sufficient to differentiate the two compounds. There is clearly a need for adequate separation techniques for isomeric metabolites.

TN137: Determination of Carbohydrates in Urine by Capillary HPAE-PAD

Instrument Type: IC

Certain carbohydrates such as mannitol, rhamnose, xylose, 3-O-methylglucose, and lactulose can be determined in urine and serum samples to evaluate disease states in animals and humans. These carbohydrates can be determined directly by HPAE-PAD, a well-established technique that eliminates the need for derivitization, in turn saving time and money. In this work, the separation and detection of the same carbohydrates of interest discussed in AN 1006 are demonstrated using a capillary Dionex CarboPac PA20 anion-exchange column on the ICS-4000 Dedicated Capillary HPIC system.

AN280: Carbohydrate in Coffee: A New Fast HPAE-PAD Method

Instrument Type: IC

A fast method using the Dionex CarboPac SA10 column was tested for determining the common coffee carbohydrates. This column achieves fast, high resolution separation of mono- and disaccharides commonly found in food samples. The Dionex CarboPac SA10 column is composed of a wide-pore macroporous substrate coated with a strong anion-exchange latex of nano-beads. The combination of the high capacity provided by the substrate and the new internal chemistry of the nano-bead functionality delivers high resolution and short analysis time for the common sugars of interest in food and beverages.

AN280: Carbohydrate in Coffee: AOAC Method 995.13

Instrument Type: IC

This study shows the AOAC official method 995.13 on a Thermo Scientific Dionex ICS-3000 system. Carbohydrates in extracts from instant coffee and green coffee beans were separated on a Dionex CarboPac PA1 column, and measured by electrochemical detection with disposable Au on polytetrafluoroethylene (PTFE) working electrodes. A few proposed modifications of the official method achieved separation of two pairs of sugars, which are otherwise difficult to resolve.