Disclosed is a device for a solid phase extraction comprising two or more of the sorbents to remove phospholipids and salts from a sample, to thereby eliminate matrix effects during mass spectrometry analysis. In particular, the sorbents includes at least one sorbent which is water-wettable and contains at least one hydrophobic component and at least one hydrophilic component and at least one of sorbent having a specific affinity for a matrix interference like phospholipids. Further disclosed is a method using the device of the present invention.

The measurement of glutaraldehyde-based biocides in seawater without the use of a derivatization agent. The measurement of glutaraldehyde-based biocides in seawater may be performed without additional components to reduce background interferences. The concentration of a glutaraldehyde-based biocides in a seawater sample is determined using reversed phase liquid chromatography and a gradient mobile phase of acetonitrile and deionized water. Systems for determining the concentration of glutaraldehyde-based biocide in a seawater injection system are also provided.

A chromatograph is provided for identifying components of a mixture. Components are identified by different rates of adsorption and/or desorption with a material phase. In one embodiment, an electrical lead is connected to the material phase for supplying an electrical charge to the material phase. The electrical charge alters the rate of adsorption/desorption of the components with the material phase. In another embodiment, the material phase is disposed between two conductors with electrical leads connected to each of the conductors. A charge differential between the two conductors alters the rate of adsorption and/or desorption of components with the material phase.

Aspects of the present disclosure relate to a method of regenerating a hydrophobic interaction chromatography column to which a load mass has been applied, the method comprising passing one or more column volumes of an alkaline solution through hydrophobic interaction media within the column, wherein the alkaline solution exhibits a pH of between about 10 and about 14, and a conductivity of between 0.5 mS/cm and about 10 mS/cm, wherein material bound to the hydrophobic interaction media is removed. In some cases, the alkaline solution may include sodium hydroxide at a concentration of between, e.g., about 0.1 mM and 10 mM.

This invention employs columns and methods to apply external and internal standards and compounds. Analytical standard or compounds are adsorbed to a solid phase extraction media and are stored indefinitely. The standards or compounds remain stable on the solid phase extraction media without decomposing. The standards or compounds may be removed from the solid phase extraction media with a solvent.

A liquid chromatography column, utilizing horizontal or radial flow of sample material passing there through, includes a housing defining a chamber therein, at least one removable screw lid, and first and second longitudinally extending porous frits positioned within the chamber. A bed or packing of particulate, chromatographic separation material is positioned within the chamber and intermediate the porous frits, the first of the porous frits being adjacent the housing and an inlet channel, the second of the porous frits being positioned adjacent a core member and an outlet channel. A distributor is operatively connected to the inlet channel, and a collector is connected to the outlet channel. The distributor and the inlet channel are constructed to direct associated material to be separated in the bed evenly across a longitudinal length of the bed in a horizontal direction.

A liquid chromatography column, utilizing horizontal or radial flow of sample material passing there through, includes a housing defining a chamber therein, at least one removable screw lid, and first and second longitudinally extending porous frits positioned within the chamber. A bed or packing of particulate, chromatographic separation material is positioned within the chamber and intermediate the porous frits, the first of the porous frits being adjacent the housing and an inlet channel, the second of the porous frits being positioned adjacent a core member and an outlet channel. A distributor is operatively connected to the inlet channel, and a collector is connected to the outlet channel. The distributor and the inlet channel are constructed to direct associated material to be separated in the bed evenly across a longitudinal length of the bed in a horizontal direction.

Provided herein are methods for high throughput quantitation of testosterone utilizing at least two different derivatizing agents of different masses. In another aspect, provided herein are methods for determining the amount of testosterone in each of a plurality of human samples with a single mass spectrometric assay by subjecting each of a plurality of human samples to a different derivatizing agent to generate a differently derivatized testosterone in each of the plurality of samples; combining the plurality of samples to form a multiplex sample; and quantifying the amount of testosterone in each sample by mass spectrometry.

Provided herein are methods for high throughput quantitation of testosterone utilizing at least two different derivatizing agents of different masses. In another aspect, provided herein are methods for determining the amount of testosterone in each of a plurality of human samples with a single mass spectrometric assay by subjecting each of a plurality of human samples to a different derivatizing agent to generate a differently derivatized testosterone in each of the plurality of samples; combining the plurality of samples to form a multiplex sample; and quantifying the amount of testosterone in each sample by mass spectrometry.

A solid phase for use in separation has been modified using an aqueous phase adsorption of a headgroup-modified lipid to generate analyte specific surfaces for use as a stationary phase in separations such as high performance liquid chromatography (HPLC) or solid phase extraction (SPE). The aliphatic moiety of the lipid adsorbs strongly to a hydrophobic solid surface, with the hydrophilic and active headgroups orienting themselves toward the more polar mobile phase, thus allowing for interactions with the desired solutes. The surface modification approach is generally applicable to a diversity of selective immobilization applications such as protein immobilization clinical diagnostics and preparative scale HPLC as demonstrated on capillary-channeled fibers, though the general methodology could be implemented on any hydrophobic solid support material.