SummaryA highly stable pseudostationary phase has been synthesized and evaluated for use in micellar electrokinetic capillary chromatography (MECC). Sodium 10-undecylenate has been oligomerized to form a micelle-like structure following the procedure of Durairaj et a/.[l].The stability of this structure renders it suitable for use with mobile phases containing relatively high percentages of organic modifiers, enabling the separation and detection of hydrophobic analytes such as alkyl phthalates and polynuclear aromatic hydrocarbons (PAHs) which are difficult to analyze by conventional micellar electrokinetic chromatography. In addition to demonstrating the utility of this structure for the analysis of hydrophobic analytes, the electrophoretic and chromatographic properties of the new phase have been investigated.

Polydextrose (Litesse®) provides physiological effects consistent with dietary fiber. However, AOAC methods for measuring total dietary fiber (TDF) in foods include an ethanol precipitation step in which polydextrose and similar carbohydrates are discarded and therefore not quantitated. This study describes a method developed to quantitate polydextrose in foods. The new method includes water extraction, centrifugal ultrafiltration, multienzyme hydrolysis, and anion exchange chromatography with electrochemical detection. Six foods were prepared with 4 levels of polydextrose to test the ruggedness of the method. Internal validation demonstrated the ruggedness of the method with recoveries ranging from 83 to 104% with an average of 95% (n = 24) and relative standard deviation of recoveries ranging from 0.7 to 13% with an average of 3.3% (n = 24). The value is added to that obtained for dietary fiber content of foods using the AOAC methods, to determine the TDF content of the food.

Veltol@ @-methyl 3-hydroxy 4-pyrone) and Veltol-Plus@ (2-ethyl 3-hydroxy 4-pyrone) are patented flavor ingredients in food products. Only Veltol@ can occur naturally, but both Veltol@ and Veltol-Plus@ are often added to food products. In order to monitor the use of these compounds in food products, lower detection limits were needed. The Solid Phase Microextraction (SPME) technique for beverages and SPME coupled with Microwave Assisted Extraction (MAE) for solid food samples were studied. The influence of the pH, salt content, SPME adsorption time, GC inlet conditions, and the conditioning of the SPME fiber were investigated. Different food products were tested including coffee, beverages, chewing gums and potato chips. The coupled MAE and SPME shows good results for solid food samples. The reproducibility of the technique was less than 13%RSD and the detection limit was 10 ppb for Veltol@ and 2 ppb for Veltol-Plus@ using the SIM mode in GCNS. The technique also shows good selectivity for the target compounds investigated in different food samples.

SummaryA method using capillary zone electrophoresis has been developed for separation of a series of isomeric benzene polycarboxylic acids. The separation was found to depend largely on the geometry of the acids and their degree of ionization as well as on the buffer pH and composition. The presence of additives to the buffer such as cyclodextrin and cationic surfactants was found necessary for complete resolution of all the isomers.

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