摘要:
Embodiments of the present invention are directed to methods and kits for determining the presence or absence, and the amount if present, of vitamin D analogs in samples. One embodiment of the present method for detecting the presence or absence of vitamin D analogs in a sample comprises the steps of adding an effective amount of a multiple charge cationic agent to the sample to form a cationic treated sample. The effective amount of a multiple charge cationic agent enhances the signal from vitamin D analogs upon analysis by mass spectroscopy.
摘要:
A device and process for separating liquid and gas phases in a flowstream containing a liquefied gas or supercritical fluid under pressure mixed with a liquid. A splitter vessel separates the liquid from gas phases and transfers liquid to a collection container while conducting the gas phase out of the splitter. Separation of liquid phase out of the flowstream is provided without additional pressure schemes or solvent extractions imposed on the stream.
摘要:
The invention provides improved methods and apparatus for multidimensional analysis, especially for multidimensional liquid chromatography. Methods and apparatus for the quantitative determination of one or more components comprised in a sample mixture are described. Methods and apparatus of the invention typically allow accurate quantitative determination of more components of the mixture than prior multidimensional methods. The invention is particularly useful for, but is not limited to the analysis of complex mixtures of peptides and proteins.