Application Notes

Urea and allantoin are added to cosmetic products for skin protection and regeneration, especially for the treatment of dry skin, and analyzed for QC purposes. As polar compounds, they are not ideal for reversed-phase HPLC separations. Neutral hydrophilic compounds like urea and allantoin are best analyzed by hydrophilic interaction chromatography (HILIC). Traditional HILIC columns use silica modified with a hydrophilic group such as diol or cyano. Analytes are adsorbed and subsequently eluted with mobile phases containing high percentages of organic solvent (>75%).

Gel permeation chromatography (GPC) has been used as an effective cleanup procedure for removing high molecular weight interfering molecules such as lipids, pigments, proteins, and polymers before GC or HPLC analysis. The GPC cleanup method has been extensively documented (1–3) and is also recommended in US EPA SW-846 Method 3640A. To demonstrate the efficacy of this method to extract polar and nonpolar substances by using the KNAUER Smartline GPC Cleanup Unit 6500, olive oil samples were investigated by spiking these with different types of organic pollutants, including PAHs, phthalates, phenols, and triazine.

Use imaging mass spectrometry to determine the biodistribution of erlotinib (Tarceva®) in pancreatic tumors from treated and untreated mice.

The QC for the pharmaceutical industry is based on methods developed on a variety of columns. At Orochem, we have attempted to address method development utilizing unique chemistries such as the OROSIL C18 to analyze a wide range of acidic, basic, and neutral compounds. Data is presented on a few representative compounds and unique separation criteria with their associated chromatograms.

The continuing and growing trend toward high-speed analysis in all fields of chromatography is also reflected in enantiomer separations. A variety of new 3-μm columns has been designed to meet this need. Applications of CHIRALCEL® OD-3 and CHIRALPAK® AD-3 in some enantiomer separations demonstrate the benefits of transitioning to such media.

The natural colors of the food we eat add greatly to the enjoyment of life. Consequently, the art and science of recreating food's natural colors through the use of synthetic colorants is an important success factor in the food industry.

Supercritical Fluid Chromatography (SFC) is quickly becoming a popular choice by chromatographers for analytical and preparative separations.

The tandem use of liquid chromatography and mass spectrometry has become the principal mode of pharmaceutical analysis, especially for high throughput analysis employed in DMPK studies. Rapid analytical data generation is pivotal during these early stages of drug discovery.

Polymer Laboratories, now a part of Varian, Inc. has published an application note on Overcoming Compound Volatility with Sub-ambient ELSD. Sub-ambient evaporative light scattering detection is valuable in the analysis of semi-volatile compounds. The Varian 385-LC has been specifically developed to operate at sub-ambient evaporation temperatures, using a Peltier cooled evaporation tube. This application note shows that sub-ambient ELSD at 20 ?C, as delivered by the new Varian 385-LC, increases the accuracy of measurement by minimizing compound volatility effects.

Phthalates are added to plastics to increase flexibility. Recently, concerns have been raised over the effect of phthalate exposure from plastic materials on human health.