Post Archive

August 2016

Chromatography

HPLC columns for the enantiomer separation Molecules, which are like mirror images, are called “chiral” (from the Greek word for “hand”), because they are mirror-symmetrical – like hands. They cannot be separated with conventional HPLC columns, because the physical and chemical properties of enantiomers are identical except for geometric orientation.

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Chromatography

Separation with diverse HILIC phases Zimmermann et al. tested diverse HILIC phases (Hydrophilic Interaction Chromatography) [6] optimizing the separation of stevioside and rebaudioside A under RP conditions. Thereby, the invers retention behavior of HILIC chromatography to RP chromatogaphy was advantageous. Amongst others the phases Luna® HILIC (Phenomenex), NUCLEODUR® HILIC (MACHEREY-NAGEL),

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Chromatography

HPLC separations of stevia ingredients The herbal sweetener stevia was allowed as food additive in the EU in December 2011. Thus, the analysis of stevia, a mixture of various steviol glycosides, has become more important. HPLC separations of steviol glycosides with a classical RP 18 phase based on porous silica,

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Chromatography

Screw neck vials and screw closures Screw neck vials N8 – besides crimp neck vials N11 – are among the oldest vials for HPLC and GC. More and more they are replaced by screw neck vials N9, because those are easier to fill due to the wide opening compared to

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