The invention relates to the detection of non-metabolized vitamin D. In a particular aspect, the invention relates to methods for detecting underivatized non-metabolized vitamin D by mass spectrometry.

The invention generally relates to methods for analyzing a tissue sample. In certain aspects, the invention provides methods that involve obtaining a tissue sample including an unsaturated compound, conducting a radical reaction on the tissue sample that targets a carbon-carbon double bond within the unsaturated compound to thereby produce a plurality of compound isomers, subjecting the plurality of compound isomers to mass spectrometry analysis to identify a location of the carbon-carbon double bond within the unsaturated compound, and quantifying the plurality of compound isomers in order to distinguish normal tissue from diseased tissue.

The invention generally relates to methods for analyzing a tissue sample. In certain aspects, the invention provides methods that involve obtaining a tissue sample including an unsaturated compound, conducting a radical reaction on the tissue sample that targets a carbon-carbon double bond within the unsaturated compound to thereby produce a plurality of compound isomers, subjecting the plurality of compound isomers to mass spectrometry analysis to identify a location of the carbon-carbon double bond within the unsaturated compound, and quantifying the plurality of compound isomers in order to distinguish normal tissue from diseased tissue.

A pretreatment method for analyzing dioxin compounds and an analytical method using the same, in which a column packed with polymer beads that are capable of selectively adsorbing dioxin compounds is used in a purification step during pretreatment, thereby remarkably reducing a time required for pretreatment and improving a recovery rate of an internal standard for purification, are provided.

A volatile organic compound collector can include a collector material configured to collect volatile organic compounds given off from a patient's skin; a wrapping configured to isolate the collector material from an external environment; a heater comprising a heating element, the heating element configured to emit a thermal pulse to desorb the volatile organic compounds from the collector material; and a mesh layer configured to prevent the collector material from contacting the patient's skin, wherein the collector material is received between the wrapping and the mesh layer.

A volatile organic compound collector can include a collector material configured to collect volatile organic compounds given off from a patient's skin; a wrapping configured to isolate the collector material from an external environment; a heater comprising a heating element, the heating element configured to emit a thermal pulse to desorb the volatile organic compounds from the collector material; and a mesh layer configured to prevent the collector material from contacting the patient's skin, wherein the collector material is received between the wrapping and the mesh layer.

Automated apparatuses for use in examining gas sorption materials are described. Devices utilize a noncontact magnetic induction heating approach for controlling the temperature of tested materials. The apparatuses can be used to generate single or multiple isotherms simultaneously. The apparatuses can examine nanogram or microgram-scale quantities of materials of interest and can do so automatically and unattended. Pressure-composition isotherms can be provided through use of disclosed apparatuses in a period of a few hours.

The present disclosure describes an apparatus of regulating a channel temperature of a field flow fractionator. In an embodiment, the apparatus includes a thermal conducting block including a top surface, and a bottom surface, where the top surface of the block is configured to be in contact with a bottom surface of a bottom plate assembly of a field flow fractionator, where the bottom plate assembly includes a material with high thermal conductivity, a heater attached to the block where the heater is configured to heat the block, a temperature sensor attached to the block, where the sensor is configured to measure a block temperature of the block, a temperature controller configured to measure a channel temperature of a channel of the field flow fractionator and configured to be connected to the heater and to the temperature sensor, and where the block is configured to heat the bottom plate assembly.

Components resolved in time by a thermal desorption separator accumulate in a sample cell and are analyzed by electromagnetic radiation-based spectroscopic techniques.

Components resolved in time by a thermal desorption separator accumulate in a sample cell and are analyzed by electromagnetic radiation-based spectroscopic techniques.